diff --git a/elements/neuron/appunti/2026-06-29-biological-reference_v16.md b/elements/neuron/appunti/2026-06-29-biological-reference_v16.md index 0d4583a..c63d856 100644 --- a/elements/neuron/appunti/2026-06-29-biological-reference_v16.md +++ b/elements/neuron/appunti/2026-06-29-biological-reference_v16.md @@ -1,974 +1,454 @@ -# Tripartite Synapse — Pseudocode v16 +# Tripartite Synapse — Biological Reference (companion to v16 pseudocode) -> Companion: `tripartite_synapse_v16_biology.md` · principle: `logic_principles_v3`. -> Changes from v15 — NIGHT gains HIGHER-SCALE ACTORS and a PHASED structure: -> (1) NIGHT is enacted by a hierarchy of homeostatic actors, NOT the DAY components alone: -> COMPONENT (commits own ceilings) → ASTROCYTE territory (reallocates across its synapses) -> → NEURON (renormalizes total weight) → [assembly/network replay: external arrived signal] -> (2) the NEURON and ASTROCYTE-territory actors ACCUMULATE aggregate traces by DAY -> (total weight/activity; territory demand) and ACT by NIGHT (renormalize; reallocate) -> (3) OCCUPANCY is reset each NIGHT: multiplicative-global downscaling drives VGCC_active, -> AMPA_surface, possible_tag back toward baseline — only CEILINGS persist across a night -> (4) NIGHT is PHASED: early cycles DOWNSCALE (subtractive, reset occupancy, make room), -> late cycles COMMIT (additive, build ceilings for the survivors) -> (5) governing rule: what persists across a night must have EARNED persistence — -> occupancy that earned no tag returns to baseline; the system acts locally, consolidates -> hierarchically -> Carried: cyclic NIGHT, tag-as-fuel, emergent termination, DAY-up/NIGHT-down, seven-group grammar. +> Companion to `tripartite_synapse_v16_pseudocode.md` · principle: `logic_principles_v3`. +> v16 gives NIGHT a hierarchy of homeostatic actors at scales above the single synapse, and a +> phased structure. The actors of consolidation are not the actors of transmission: by day the +> six local components transmit; by night a hierarchy — astrocyte territory, the whole neuron, +> and (as an external signal) the assembly/network — renormalizes and reallocates. Early-night +> cycles downscale the day's transient changes (synaptic homeostasis); later cycles consolidate +> the survivors. Occupancy filled by day (receptor surface, channel coupling) is returned to +> baseline each night, so only what was written into a structural ceiling persists. --- -## Functional groups (seven-group grammar) +## The three synaptic components and their support structures -``` -RECEIVE take in resources + signals that arrived from outside (boundary: in) -TRACE maintain the trace hierarchy — deposit fast trace; accumulate - possible_tag + endurance_need; stabilize tag on coincidence -ADJUST compute local operating parameters from structure + traces + modulators -BEHAVE the component's defining action, within both ceilings -EMIT send out — signals (messages) + resources (shipments) (boundary: out) -RECOVER refill own private pools consumed by behaving -DECAY let traces recede, closing their windows -``` +A SYNAPSE is composed of three first-class components: +- **PRE** — presynaptic bouton (the axon's terminal at this synapse) +- **POST** — postsynaptic spine (the dendrite's terminal at this synapse) +- **ASTRO** — astrosynapse, the perisynaptic astrocytic process (the astrocyte's terminal) -EVALUATE merged into TRACE: judging a behavior is always maintaining a trace, whether or not -a trace is written. BEHAVE and EMIT stay separate — EMIT is the output half of the locality -interface (RECEIVE/EMIT are the only boundary crossings). TRACE spans all timescales: the -soma's inactivation, adaptation, and nuclear-Ca deposits are all TRACE. Order within a context -follows data dependencies; TRACE reads/writes whatever trace state is current. +Each has an upstream support structure that supplies it: +- **AXON** supplies PRE (transmission + transport from soma) +- **DEND** supplies POST (integration + transport from soma) +- the **astrocyte cell body** supplies ASTRO (energy + ECM material) +- **SOMA** is the integrating center and the root of neuronal material -EVERY FLOW HAS A TIMESCALE. Decay relaxes toward 0 over τ; creation/arrival relaxes toward a -target over τ — the same first-order operator. Within-step writes are the special case τ ≪ Δt. -Rate-limited inflows (fill/refill/flux·Δt) carry their τ implicitly; shipment carries an -explicit transit delay (see `transit`). - -THE GROUPS MOVE BETWEEN TIERS (the ladder; see logic_principles "The Timescale Ladder"). -Four tiers: FAST (ms–s) · MEDIUM (s–min) · SLOW (hr) · PERSISTENT (NIGHT-written). The groups -move evidence UP the ladder and read capacity DOWN it: - -``` - ADJUST reads PERSISTENT ceiling + FAST trace → sets this step's operating point (down) - BEHAVE acts at FAST, bounded by the PERSISTENT ceiling (down) - TRACE deposits FAST, accumulates FAST→MEDIUM evidence, stabilizes MEDIUM→SLOW tag (up) - RECOVER refills toward the PERSISTENT ceiling (down) - DECAY relaxes FAST · MEDIUM · SLOW (PERSISTENT never decays in DAY) - NIGHT commits SLOW tag + MEDIUM endurance_need → PERSISTENT ceilings (up) -``` - -Capacity flows downward (slow sets the ceiling for fast); evidence flows upward (fast -accumulates toward slow). Each component's DECAY group below is banded by tier to show this. - -NIGHT IS THE SAME GRAMMAR, ITERATED, WITH THE FLOW REVERSED. NIGHT is not a separate section — -each component carries a `NIGHT |` block, and a driver loops all blocks for cycle = 1,2,3… -until the night ends. DAY runs bottom-up (consumers act first, evidence ascends leaves→roots); -NIGHT runs top-down (producers act first, capacity descends roots→leaves). Per cycle, each -component: - -``` - RECEIVE take in the material + energy batch that arrived from my producer this cycle - TRACE read my own tag / endurance_need (the standing demand) - ADJUST size this cycle's commit from material + energy actually on hand - BEHAVE commit a BATCH: structure += Δ (from tag) ; budget_ceiling += Δ' (from need) - spend material + energy ; SPEND the tag/need by the committed amount (tag-as-fuel) - EMIT ship a batch of material + energy one hop down to my consumers (demand-weighted) - RECOVER reclaim material from any ceiling that decayed this cycle (energy is NOT recovered) - DECAY unmaintained ceilings drift down a little; tags decay a little -``` - -Roots (SOMA, ASTRO cell body) PRODUCE the batch each cycle (RECEIVE = production, capped by -glucose / CREB). The night ends when DEMAND is exhausted (no tag stands above tag_expiry, -system-wide) OR SUPPLY is spent (the night's energy throughput is used up) — whichever first. -Unspent tags are NOT cleared; they carry to the next DAY and compete again next NIGHT. The -top-down order needs no schedule: iterating the local cycle delivers capacity to distal sites -over successive cycles, as transport physically does. - -NIGHT'S ACTORS ARE NOT DAY'S ACTORS — THE SYSTEM ACTS LOCALLY, CONSOLIDATES HIERARCHICALLY. -DAY is enacted by the six local components. NIGHT is enacted by a HIERARCHY of homeostatic -actors, each conserving a quantity at its own scale and constraining the scale below: - -``` - [ ASSEMBLY / NETWORK ] replay re-presents the day across neurons (EXTERNAL signal) - ↓ constrains → arrives as replay_reweight[·] (like dopamine/glucose: external) - NEURON (the whole cell) conserves TOTAL synaptic weight; renormalizes so no synapse - ↓ constrains grows beyond the cell's global budget; drives occupancy downscaling - ASTROCYTE territory conserves total metabolic output; reallocates energy/material - ↓ constrains across ALL synapses it wraps, by accumulated territory demand - COMPONENT commits its own ceilings within the allocation handed down -``` - -These higher actors are DORMANT-BUT-ACCUMULATING by DAY and ACTIVE-AND-CONSTRAINING by NIGHT. -By DAY they only integrate an aggregate trace of the components' emitted activity (they sum -what was emitted, never read a component's interior — locality holds): the NEURON accumulates -`neuron_total_weight` and `neuron_activity`; the ASTROCYTE territory accumulates -`astro_territory_demand[·]`. By NIGHT they act on those aggregates: the astrocyte reallocates, -the neuron renormalizes. The assembly/network tier is not modelled here; its effect enters as -an external arrived signal `replay_reweight`, exactly as dopamine and glucose do. - -NIGHT IS PHASED. Early cycles DOWNSCALE (subtractive): occupancy filled during the day — -VGCC_active, AMPA_surface, possible_tag — is driven back toward baseline by multiplicative-global -scaling, and total weight is renormalized. Late cycles COMMIT (additive): the survivors' tags -build ceilings. The rule the phasing enforces: WHAT PERSISTS ACROSS A NIGHT MUST HAVE EARNED -PERSISTENCE. Occupancy that earned no tag returns to baseline; only ceilings carry forward. The -relative potentiation of a tagged synapse survives because it was written into its ceiling, not -because its transient occupancy was spared. +The compartment analogy: AXON:PRE = DEND:POST = astrocyte-body:ASTRO = supply line : terminal. --- -## Conventions +## Resource variables -``` -SCOPE = {DAY, NIGHT} CONTEXT = {AP, NOT_AP, bAP, NOT_bAP, CONTINUOUS} +### DAY budget (one per component) +Aggregates fast energy AND fast consumables — everything needed to run moment-to-moment. -VARIABLE TIERS (timescale = meaning; see logic_principles "The Timescale Ladder") - FAST (ms–s) immediate response fast_trace - MEDIUM (s–min) occupancy + evidence possible_tag · endurance_need · VGCC_active · AMPA_surface · RRP - SLOW (hr) consolidation bridge tag - ───────────────────────────────────────────────────────────────────────────── - PERSISTENT (NIGHT) capacity (the ceilings) structure · budget_ceiling - energy (not recoverable) · material (recoverable) +- **pre_budget** — ATP for VGCC gating, vesicle fusion (SNARE), VATPase vesicle refill, + plus fast consumables: vesicle membrane lipids, synaptotagmin recycling. +- **post_budget** — ATP for the NaK pump (membrane reset after current), NMDA current + handling, plus fast actin monomers for transient spine changes and receptor-recycling lipids. +- **dend_budget** — ATP for bAP propagation (NaK reset along branch), local translation + (ribosome running cost), SERCA Ca²⁺ resequestration, plus fast mRNA consumed by translation. +- **soma_budget** — ATP for AP generation (Na⁺/K⁺ currents + NaK reset), CREB + phosphorylation, nuclear Ca²⁺ handling, plus shipping running costs. +- **axon_budget** — ATP for AP propagation at nodes of Ranvier, kinesin/dynein motor + running cost, fast myelin maintenance. +- **astro_central_budget** — ATP from glycolysis at the astrocyte cell body; funds EAAT + clearance, serine→D-serine synthesis, lactate export, fast process motility. -DAY budget · fast_trace · possible_tag · endurance_need -BRIDGE tag (POST: CANDIDATE→STABLE) -NIGHT energy (not recoverable) · material (recoverable) · structure · budget_ceiling +### astro_lactate[i] +Lactate exported from the astrocyte cell body to synapse i. Biologically: glucose → +(glycolysis) → lactate, released into extracellular space, absorbed by neuronal MCT2 +transporters, converted to pyruvate → TCA → ATP in the neuron's mitochondria. The astrocyte +is the primary fast-energy supplier to pre, post, and dend. -LOCALITY only local state + arrived signals; no component reads another's internal state. +### NIGHT energy (one per component) — NOT recoverable +ATP for structural assembly. Distinct from DAY budget because it is spent on building, and +the work of assembly is thermodynamically gone once done (cannot be recovered by disassembly). +- pre_energy: RIM/Munc13 incorporation, VGCC clustering. +- post_energy: CaMKII anchoring, actin polymerization, PSD scaffold remodeling. +- dend_energy: mitochondria incorporation, cytoskeletal reinforcement. +- soma_energy: ribosome biogenesis, ion-channel incorporation. +- axon_energy: myelination, microtubule stabilization. +- astro_energy: process retraction, ECM secretion, racemase upregulation. -CLEFT MESSAGE CHANNELS SHIPMENT CHANNELS (transit-delayed) - glutamate PRE → POST, ASTRO soma_ship_dend SOMA→DEND - astro_Dserine ASTRO → POST soma_ship_axon SOMA→AXON - retro_NO POST → PRE (+) dend_ship_post DEND→POST - retro_eCB POST → PRE (−) axon_ship_pre AXON→PRE -``` +### NIGHT material (one per component) — RECOVERABLE +Slow structural proteins. Recoverable because disassembly (LTD) returns the proteins to a +reusable pool (ubiquitin-proteasome → amino acids; internalized receptors → endosomal reserve). +- **soma_material** (root) — all neuronal structural proteins from CREB-driven synthesis: + AMPA subunits, PSD scaffold, AZ scaffold, mRNA transcripts (Arc, BDNF), organelles. +- **dend_material** — from soma: Arc/plasticity mRNA, mitochondria, cytoskeletal proteins, + AMPA subunits in transit to spines. +- **post_material** — from dend: AMPA receptor subunits (GluA1/2), PSD scaffold (PSD-95, + SHANK, Homer), structural actin, CaMKII. +- **axon_material** — from soma: kinesin/dynein motors, microtubule components, myelin proteins. +- **pre_material** — from axon: RIM, Munc13, VGCC subunits, structural vesicle proteins. +- **astro_material** (root: astrocyte cell body) — EAAT proteins, serine racemase, ECM + proteins (Glypicans, Thrombospondins), process cytoskeleton. + +**Why energy and material are separate in NIGHT but combined in DAY:** during DAY both are +fast consumables replenished on the same timescale, so one `budget` variable suffices. During +NIGHT they diverge — material is recoverable after LTD, energy is not — so they must be two +variables. This asymmetry (material returns to the pool, energy is gone) is what makes one +synapse's depression genuinely fund another's potentiation. --- -## Primitives (return the increment; caller applies it) +## Structural variables (strength ceilings — written in NIGHT) -``` -sat(x, K) = x / (K + x) +Each aggregates several correlated structural properties into one capacity. -fill(pool, ceiling, rate, cost, budget) -> amount: // PRIVATE reserve, rate-limited (implicit τ) - amount = min(rate, ceiling - pool)·Δt; budget -= amount·cost; return amount - -refill(c from supply S) -> amount: // CONTESTED supply, gap-bounded - demand = c.budget_ceiling - c.budget - factor = min(1, S / (Σ demand over components on S + ε)); S -= demand·factor - return demand·factor - -ship(from_budget, demand_sig, frac, cost) -> amount: // emit into transit (not to target directly) - amount = min(from_budget·frac, demand_sig); from_budget -= amount·(1+ship_cost); return amount - -transit(channel, τ_transport) -> arrival: // delivers in-transit cargo over τ - arrival = channel·(Δt/τ_transport); channel -= arrival; return arrival -``` +- **pre_structure** — active zone capacity: + slot_ceiling (number of vesicle docking slots) + VGCC_coupling (Ca²⁺-channel proximity to + slots, sets release efficiency) + refill_ceiling (max RRP replenishment rate). +- **post_structure** — spine sensitivity capacity: + slot_ceiling (number of PSD anchoring slots for AMPA) + spine_volume (local reserve and + actin machinery) + reserve_ceiling (endosomal AMPA pool size). +- **dend_structure** — branch capacity: + bAP_fidelity(position) (mitochondrial density sets propagation strength, attenuates with + distance) + translation_ceiling (local mRNA capacity) + transport_speed (cytoskeletal integrity). +- **soma_structure** — somatic output capacity: + baseline_threshold (inverse: ion-channel density at axon initial segment) + AP_reliability + (Na⁺ channel density) + synthesis_ceiling (ribosome density + CREB machinery). +- **axon_structure** — axonal capacity: + propagation reliability (myelination density) + transport_ceiling (motor density + microtubule + integrity) + mitochondrial density. +- **astro_structure** — astrosynaptic environmental capacity: + perisynaptic_distance⁻¹ (wall proximity — closer = more glutamate contained) + EAAT_density + (clearance ceiling) + Dserine_tonic (baseline co-agonist) + ECM_integrity. + **Self-reinforcing both directions:** tighter wrap + more tonic D-serine make future + potentiation easier; looser wrap + zero tonic D-serine make future depression easier. --- -## SHARED parameters +## Budget ceilings (endurance ceilings — written in NIGHT) -``` -dopamine NE ACh // organism broadcasts (external) -replay_reweight[·] // assembly/network replay re-weighting (external, NIGHT) -glucose geometry // physical (external) -elig dop_thr tag_thr tag_expiry // strength gates (universal) -traj_thr endur_thr // endurance gates (universal) -ship_cost // transport overhead (all shipments) -{dend,axon,pre,post}_ship_frac // DAY budget-shipment fractions -τ_transport_{dend,axon,spine,bouton} // shipment transit times (distance-dependent) -ε -``` - -## NIGHT parameters (consolidation only) - -``` -slot_batch cap_batch f_cap // per-CYCLE commit sizes / endurance fraction -night_energy_ceiling // total energy a single night can spend (supply bound) -Δt_cycle // duration of one NIGHT cycle -maint_frac cap_frac // maintenance allocation -decay_rate capacity_decay_rate recycle // passive ceiling decay + material recovery -homeostatic_ceiling coherence_factor assembly_cost biogenesis_cost maint_cost -f_dend f_axon f_spine f_bouton // per-cycle material/energy ship fractions (down the chain) -downscale_factor // per-early-cycle multiplicative occupancy reset (<1) -neuron_weight_ceiling // the cell's total-weight budget (renormalization target) -early_phase_frac // fraction of night cycles that are DOWNSCALE phase -``` - ---- ---- -# DAY ---- - -## PRE - -The presynaptic bouton releases neurotransmitter and gathers evidence about whether that -release was worth strengthening and worth sustaining. Its behavior unfolds across two DAY -contexts and the NIGHT scope. - -**During DAY, during AP — the bouton releases neurotransmitter.** The amount released depends on -residual **calcium** from recent spikes (the fast trace, setting the drive), the current -**VGCC coupling occupancy** (how tightly calcium channels are coupled to docking slots right -now — filled short-term, bounded by structure), the two **retrograde messages** from the -postsynapse (`retro_eCB` brakes the drive; `retro_NO` will confirm release reached a responsive -target), and the availability of both **fuel and vesicles**. Two shortfalls are read -differently: a fuel shortfall on a succeeding release is evidence the bouton needs more -*endurance*; an empty pool with fuel to spare is ordinary short-term depression. - -**During DAY, during NOT_AP — the bouton consolidates, potentiates short-term, and recovers.** -With no spike to release, it latches the retrograde messages (RECEIVE); maintains its traces — -accumulating eligibility toward a dopamine-gated tag (TRACE); transiently tightens its VGCC -coupling from accumulated eligibility, with no dopamine, a reversible short-term potentiation -bounded by the structural ceiling (BEHAVE); refills both its budget (contested supply) and its -vesicle pool (private reserve) (RECOVER); and lets its traces decay, closing the windows (DECAY). - -**During NIGHT — the bouton's ceilings are rewritten.** NIGHT raises the bouton's **structure** -(active-zone capacity, including the VGCC-coupling ceiling) where a validated tag accumulated, -and its **budget capacity** (mitochondrial endurance) where fuel repeatedly interrupted a -succeeding release. Both draw on the same finite material and energy shipped down the axon, so -the two kinds of growth compete — and whatever is not maintained drifts back down. - -``` -// PARAMETERS K_release · release_cost · fusion_cost · vatpase_cost · spillover · brake -// stp_thr · coupling_gain · coupling_drift · VGCC_baseline -// INTERFACE -// EMIT glutamate → POST, ASTRO -// RECEIVE retro_NO, retro_eCB ← POST (signals latched; resources refill in RECOVER) -// READ glutamate (own cleft, autobrake) ; dopamine (gates tag) -// OWN pre_structure{slot_ceiling, VGCC_coupling, refill_ceiling} ; pre_budget_ceiling -// VGCC_active (occupancy: current coupling, filled toward VGCC_coupling ceiling) -// SUPPLY astro_lactate[syn] ← ASTRO ; axon_ship_pre ← AXON ; pre_material ← AXON(NIGHT) ; pre_energy ← SOMA(NIGHT) -// EMERGENCY shockwave_lockdown ← ASTRO -// -// TRACE CREATION MODES (every trace: trace += input·Δt − trace·(Δt/τ_decay)) -// impulse input = quantum·δ(event) — a point event; no rise time, τ = decay only (FAST) -// accumulate input = rate(condition)·Δt — ramps while a condition holds; τ = rise AND decay (MEDIUM/SLOW) -// A trace's tier is set by BOTH its creation mode and its decay: the fast trace is impulse-created -// and fast-decaying; possible_tag/endurance_need are slowly accumulated and medium-decaying. - -DAY | AP: - // TRACE FAST · impulse (Ca²⁺ bolus from THIS spike — a point event; no rise time, - // decay alone sets its τ; frequency is emergent from impulse-rate vs decay) - pre_fast_trace += spike_Ca(pre_structure.VGCC_coupling)·δ(spike) - // ADJUST (release drive from residual Ca²⁺ × current coupling occupancy, + DSE brake) - drive = sat(pre_fast_trace × VGCC_active, K_release) × (1 - retro_eCB_local) - // BEHAVE (release; two distinct failure modes) - if pre_budget < release_cost: - // FUEL shortfall → endurance evidence (retro_NO-confirmed local success) - suppress(NT_flux) - // TRACE MEDIUM · accumulate (ramps while fuel keeps interrupting a succeeding release) - if pre_fast_trace > traj_thr: - pre_endurance_need += pre_fast_trace × (1 + retro_NO_local)·Δt - exit - if RRP == 0: - // OCCUPANCY shortfall → short-term depression (NOT endurance; fuel was fine) - suppress(NT_flux) - exit - NT_flux = RRP × drive; RRP -= NT_flux·Δt; pre_budget -= NT_flux·fusion_cost - // EMIT (glutamate into cleft) - glutamate += NT_flux·Δt - if glutamate > spillover: drive *= brake // own-cleft autobrake - -DAY | NOT_AP: - // RECEIVE (latch backward messages — signals only) - retro_NO_local = retro_NO; retro_eCB_local = retro_eCB - // TRACE (strength pathway — evidence climbs the ladder) - // MEDIUM · accumulate (ramps while fast_trace stays eligible; rise-rate is its τ_rise) - if pre_fast_trace > elig: pre_possible_tag += pre_fast_trace·Δt - // SLOW · accumulate (ramps only on dopamine coincidence; rise gated by validation) - if dopamine > dop_thr and pre_possible_tag > tag_thr: - pre_tag += dopamine × pre_possible_tag·Δt - // BEHAVE (short-term potentiation: eligibility tightens coupling, NO dopamine; drifts back) - if pre_possible_tag > stp_thr: - VGCC_active = min(VGCC_active + coupling_gain × pre_possible_tag, pre_structure.VGCC_coupling) - else: - VGCC_active = max(VGCC_active - coupling_drift·Δt, VGCC_baseline) // STD = consequence - // RECOVER (refill BOTH pools: contested budget + private RRP) - pre_budget += refill(pre from astro_lactate[syn] + transit(axon_ship_pre, τ_transport_bouton)) - RRP += fill(RRP, pre_structure.slot_ceiling, pre_structure.refill_ceiling, vatpase_cost, pre_budget) - // DECAY - // FAST (ms–s) - pre_fast_trace *= decay(100ms) - // MEDIUM (s–min) - pre_possible_tag *= decay(s); pre_endurance_need *= decay(min) - // SLOW (hr) - pre_tag *= decay(hr) - // (signals) arrived channels fade - dopamine *= decay(ms); retro_NO *= decay(s); retro_eCB *= decay(s) - // (PERSISTENT: pre_structure, pre_budget_ceiling — no DAY decay; NIGHT only) - -NIGHT | cycle: // leaf consumer (no downstream emit) - // RECEIVE batch arrived from AXON (material) + SOMA (energy) this cycle - pre_material += transit(pre_material_ship, τ_transport_bouton) - pre_energy += transit(pre_energy_ship, τ_transport_bouton) - // TRACE read standing demand - // (pre_tag → structure ; pre_endurance_need → budget_ceiling) - // ADJUST size commits from material + energy on hand - coh = coherence_signal // arrived: pre+post+astro tags aligned - // BEHAVE commit batches; spend tag/need as fuel - if pre_tag > tag_expiry: - Δ = min(slot_batch, pre_material, pre_energy·f_cap) - pre_structure += Δ × coh; pre_material -= Δ; pre_energy -= Δ·assembly_cost - pre_tag -= Δ // tag-as-fuel - if pre_endurance_need > endur_thr: - Δ' = min(cap_batch, pre_material·f_cap, pre_energy·f_cap) - pre_budget_ceiling += Δ'; pre_material -= Δ'; pre_energy -= Δ'·biogenesis_cost - pre_endurance_need -= Δ' - // EMIT (none — bouton is a leaf; nothing downstream) - // RECOVER reclaim material from any ceiling that decayed this cycle - pre_material += pre_ceiling_shrinkage·recycle // energy NOT recovered - // DECAY unmaintained ceilings + tags drift down a little - pre_structure -= decay_rate·Δt_cycle; pre_budget_ceiling -= capacity_decay_rate·Δt_cycle - pre_structure += min(pre_maint, maint_cost); pre_budget_ceiling += min(pre_cap_maint, cap_cost) - pre_tag *= decay(slow); pre_endurance_need *= decay(slow) -``` +- **{component}_budget_ceiling** — the maximum fuel the component can hold / the maximum + duration of sustained behavior. Biologically: mitochondrial density and local fuel-storage + capacity. Built by activity-driven mitochondrial biogenesis; lost by mitophagy when idle. + Parallel to structure: structure is strength capacity, budget_ceiling is endurance capacity. --- -## POST +## Trace variables -The postsynaptic spine is the synapse's primary memory locus: it detects coincident input, -runs the calcium dynamics that decide potentiation versus depression, and requires the most -validation (three coincidences) before committing. Its behavior unfolds across two DAY -contexts and the NIGHT scope. +### fast_trace (one per component) — DAY only, decays automatically +The local record of recent activity that biases the next behavior. +- **pre_fast_trace** — residual presynaptic Ca²⁺ after spikes (τ≈100ms). Biases NT release + (facilitation) and provides tagging eligibility. +- **post_fast_trace** — spine Ca²⁺ amplitude × rise-speed (τ≈tens ms). Encodes the LTP-vs-LTD + instruction (fast rise → CaMKII → potentiation; slow rise → phosphatase → depression). +- **dend_fast_trace** — branch Ca²⁺ from bAP + spine spillover (τ≈300ms). Integrates branch co-activity. +- **soma_fast_trace** — nuclear Ca²⁺ from each AP (τ≈seconds). Drives toward CREB activation. +- **axon_fast_trace** — propagation load (τ≈seconds). High load → Na⁺ inactivation at branch + points → propagation failure (this is axonal short-term depression). +- **astro_fast_trace** — perisynaptic Ca²⁺ from mGluR5 activation by glutamate spillover + (τ≈seconds). Drives D-serine release. -**During DAY, during NOT_bAP — the spine integrates input and decides plasticity.** Three -calcium sources feed its fast trace: AMPA current (small Ca, begins ejecting the NMDA Mg block), -NMDA (large Ca, but only on the local coincidence of depolarization + astrocyte D-serine + -glutamate), and — in the bAP context — the back-propagating spike. High calcium drives AMPA -receptors to the surface (short-term potentiation, occupancy filled toward the slot ceiling, no -dopamine); when calcium falls, they drift back (short-term depression as a consequence). The -spine also emits two retrograde messages from its own state — NO when it responded, an -endocannabinoid brake when over-driven — and accumulates a dopamine-gated tag toward -consolidation. A fuel shortfall while calcium was climbing toward a tag is endurance evidence; -a surface already at its ceiling is a structural limit, not endurance. +### soma timing traces (emergent refractory + adaptation + alignment) +- **soma_Na_inactivation** (τ≈ms) — sodium-channel inactivation after an AP. Its recovery IS + the refractory period (emergent, not a hardcoded timer). High → absolute refractory; decaying + → relative refractory; recovered → normal. +- **soma_adaptation** (τ≈100s of ms) — slow K⁺ channel (SK/M-type) activation accumulating + over a spike train, raising threshold. This is spike-frequency adaptation. +- **soma_refractory_alignment** — deposited when a suprathreshold input arrives during + refractoriness (a missed coincidence). Speeds future recovery so the soma aligns to its input + rhythm. Bottom-up: no rhythm is represented; alignment emerges from accumulated local + mismatches and decays when mismatches stop (self-limiting). -**During DAY, during bAP — the back-propagating spike confirms coincidence.** The somatic spike -arrives at the spine, adds depolarization and calcium, and supralinearly amplifies an existing -candidate — the soma's confirmation that it fired, one of the three coincidences the spine -requires. +### possible_tag (one per component) — intermediate, τ≈s–min +Graded accumulation of tagging eligibility. For POST, this is the CANDIDATE tag lifetime. -**During NIGHT — the spine's ceilings are rewritten.** NIGHT raises **structure** (the AMPA -slot ceiling, spine volume) where a validated tag accumulated — with a coherence bonus when pre, -post, and astro all tagged the same synapse — and **budget capacity** where fuel interrupted a -climbing calcium trajectory. Both draw the same finite pool, so they compete; unmaintained -ceilings drift down. +### endurance_need (one per component) — intermediate, τ≈s–min +Deposited when budget depletion interrupts a behavior that was on a LOCALLY successful +trajectory. Records that fuel — not structure, not significance — was the binding constraint +on a forming success. Requires NO dopamine (homeostatic, not associative). +**Local success proxy per component** (each uses only its own state + arrived signals): +- PRE: own fast_trace high (was releasing strongly), optionally amplified by retrograde + messenger (endocannabinoid / NO / BDNF) that has arrived. +- POST: own Ca²⁺ climbing toward tagging threshold (naturally local). +- DEND: own branch strongly active (high branch voltage/Ca²⁺) when propagation fell short. +- SOMA: own nuclear Ca²⁺ climbing toward CREB. +- AXON: own propagation load high (was carrying a strong train). +- ASTRO: own local glutamate/Ca²⁺ high (was under heavy clearance/D-serine demand). -``` -// PARAMETERS K_AMPA · AMPA_Ca · AMPA_cost · NMDA_cost · bAP_cost · pka_cost · traffic_cost -// req_cost · Mg_eject · Dserine_thr · Ca_STP · Ca_TAG · eCB_thr · drift · baseline -// NO_synth_cost · eCB_synth_cost -// INTERFACE -// EMIT retro_NO (+), retro_eCB (−) → PRE -// RECEIVE (signals) glutamate ← PRE ; astro_Dserine ← ASTRO ; bAP ← DEND/SOMA ; dopamine -// READ glutamate ; astro_Dserine ; bAP (dend_structure.bAP_fidelity) ; dopamine -// OWN post_structure{slot_ceiling, spine_volume, reserve_ceiling} ; post_budget_ceiling -// SUPPLY astro_lactate[syn] ← ASTRO ; dend_ship_post ← DEND ; post_material ← DEND(NIGHT) ; post_energy ← SOMA(NIGHT) -// EMERGENCY shockwave_lockdown ← ASTRO -// NOTE POST endurance is own-state only (own Ca climbing); no arrived feedback term. - -DAY | NOT_bAP: - // ADJUST (AMPA drive from arrived glutamate) - a = sat(glutamate, K_AMPA) - // BEHAVE (SOURCE 1 AMPA: current + small Ca + begins Mg ejection) - AMPA_current = a × AMPA_surface; Vm += AMPA_current; post_budget -= AMPA_cost - // TRACE (Ca deposited by AMPA) - post_fast_trace += AMPA_Ca·AMPA_current - // BEHAVE (SOURCE 2 NMDA: large Ca on local coincidence) - if Vm > Mg_eject and astro_Dserine > Dserine_thr and glutamate > 0: - post_fast_trace += NMDA_Ca(glutamate)·rise_speed(); post_budget -= NMDA_cost - // EMIT (+ NO/BDNF: "release reached a responsive target") - retro_NO += NO_emit(post_fast_trace); post_budget -= NO_synth_cost - // EMIT (− endocannabinoid / DSE when over-driven) - if Vm > eCB_thr: - retro_eCB += eCB_emit(Vm); post_budget -= eCB_synth_cost - post_fast_trace *= decay(ms) - // BEHAVE (STP fill slots from private reserve ; else STD drift = consequence) - if post_fast_trace > Ca_STP: - if post_budget < traffic_cost: - // FUEL shortfall → endurance (own Ca was climbing toward a tag) - if post_fast_trace > traj_thr and post_fast_trace_rising: - post_endurance_need += post_fast_trace - else if AMPA_surface < post_structure.slot_ceiling: - AMPA_surface += Ca_insert(post_fast_trace); post_budget -= traffic_cost - // else: surface already at slot_ceiling → structure-limited (not endurance) - else: - AMPA_surface = max(AMPA_surface - drift·Δt, baseline) // STD = consequence - // TRACE (strength: CANDIDATE then STABLE via dopamine) - if post_fast_trace > Ca_TAG: post_possible_tag += post_fast_trace; post_budget -= pka_cost - if dopamine > dop_thr and post_possible_tag > tag_thr: - post_tag += dopamine × post_possible_tag - // RECOVER (refill budget from contested supply) - post_budget += refill(post from astro_lactate[syn] + transit(dend_ship_post, τ_transport_spine)) - // DECAY - // FAST (ms–s) — post_fast_trace already decayed above (intra-step, pre-tagging) - // MEDIUM (s–min) - post_possible_tag *= decay(min); post_endurance_need *= decay(min) - // SLOW (hr) - post_tag *= decay(hr) - // (signals) - dopamine *= decay(ms) - // (PERSISTENT: post_structure, post_budget_ceiling — no DAY decay; NIGHT only) - -DAY | bAP: - // BEHAVE (SOURCE 3 bAP: depolarization + Ca, amplifies existing signal) - Vm += bAP_depol × dend_structure.bAP_fidelity; post_budget -= bAP_cost - // TRACE (supralinear boost only if a CANDIDATE is present) - if post_possible_tag > Ca_TAG: post_fast_trace += bAP_Ca_boost() - -NIGHT | cycle: // leaf consumer (no downstream emit) - // RECEIVE batch arrived from DEND (material) + SOMA (energy) this cycle - post_material += transit(post_material_ship, τ_transport_spine) - post_energy += transit(post_energy_ship, τ_transport_spine) - // TRACE read standing demand (post_tag → structure ; post_endurance_need → budget_ceiling) - // ADJUST coherence applies to POST (synaptic component) - coh = coherence_signal - // BEHAVE commit batches; spend tag/need as fuel - if post_tag > tag_expiry: - Δ = min(slot_batch, post_material, post_energy·f_cap) - post_structure += Δ × coh; post_material -= Δ; post_energy -= Δ·assembly_cost - post_tag -= Δ - if post_endurance_need > endur_thr: - Δ' = min(cap_batch, post_material·f_cap, post_energy·f_cap) - post_budget_ceiling += Δ'; post_material -= Δ'; post_energy -= Δ'·biogenesis_cost - post_endurance_need -= Δ' - // EMIT (none — spine is a leaf) - // RECOVER reclaim material from decayed ceilings - post_material += post_ceiling_shrinkage·recycle // energy NOT recovered - // DECAY - post_structure -= decay_rate·Δt_cycle; post_budget_ceiling -= capacity_decay_rate·Δt_cycle - post_structure += min(post_maint, maint_cost); post_budget_ceiling += min(post_cap_maint, cap_cost) - post_tag *= decay(slow); post_endurance_need *= decay(slow) -``` +### tag (one per component) — DAY→NIGHT bridge, τ≈hours +The validated record of significance that survives to NIGHT and gates strength commits. +Formed by coincidence of local eligibility + non-local validation (dopamine). +**POST is special — two-phase, three coincidences:** +- CANDIDATE: local Ca²⁺ above threshold + astrosynapse D-serine present (coincidence 1). +- amplified when bAP confirms soma fired (coincidence 2). +- STABLE: CANDIDATE + dopamine within stabilization window (coincidence 3). +Biologically: early CaMKII creates a labile tag (early-LTP); PKA driven by dopamine via D1R +stabilizes it (late-LTP). Without dopamine, the candidate degrades — early-LTP reverses. --- -## DEND +## Behaviors — biological meaning -The dendritic branch is the postsynapse's supply line and the neuron's input integrator. It -carries the back-propagating spike out to its spines, integrates their voltages toward the -soma, and ships material and budget to the spines it supports. Its behavior unfolds across two -DAY contexts and the NIGHT scope. +### PRE | AP — neurotransmitter release +`NT_flux = RRP × sat(pre_fast_trace, K_release)` models continuous NT release proportional to +the readily-releasable pool and a saturating Ca²⁺ drive (synaptotagmin's cooperative Ca²⁺ +sensitivity, simplified to a saturating curve). RRP depletes as released (short-term depression +as a consequence) and refills via VATPase (energy-throttled, so low budget deepens depression). +The mGluR2/3 brake is presynaptic autoinhibition by spillover (Gi → reduced VGCC opening). -**During DAY, during bAP — the branch propagates and integrates.** When the soma fires, the -branch propagates the back-propagating spike toward its spines, with a fidelity that attenuates -with distance (distal spines get weaker confirmation, are harder to potentiate). It deposits -branch calcium and integrates its spines' voltages into a single branch signal sent on to the -soma. A fuel shortfall that cuts propagation short while the branch was strongly active is -endurance evidence; propagation that simply attenuates with distance is a structural limit, not -endurance. +### POST | NOT_bAP — three calcium sources, two plasticity cases +- **Source 1 (AMPA):** glutamate opens AMPA → depolarizing current + small Ca²⁺; the + depolarization begins ejecting the NMDA Mg²⁺ block. +- **Source 2 (NMDA):** if depolarized enough (Mg²⁺ ejected) AND D-serine present (astrocyte + co-agonist) AND glutamate bound → large Ca²⁺ influx. This is the coincidence detector. +- **Source 3 (bAP, separate context):** back-propagating AP adds depolarization + Ca²⁺, + amplifying an existing signal supralinearly. +- **Case 1 (STP):** high Ca²⁺ drives AMPA receptors from the local reserve to the surface, + bounded by the anchoring-slot ceiling. Fast, reversible, NO dopamine. When Ca²⁺ falls, + receptors drift back — short-term depression as a passive consequence, never signaled. +- **Case 2 (LTP tag):** high Ca²⁺ + (later) dopamine sets the tag that NIGHT uses to raise the + slot ceiling. NIGHT builds slots; DAY fills them. -**During DAY, during NOT_bAP — the branch consolidates, supplies, and recovers.** It maintains -its tag toward consolidation, lowers its commit threshold under acetylcholine (attention), -ships budget down to its spines (demand-weighted by their tags), runs local translation if -tagged, refills its own budget from astrocytic lactate and somatic shipment, and lets its -traces decay. +### DEND | bAP — bidirectional signaling +Propagates the bAP from soma toward spines (fidelity attenuates with distance — distal spines +get weaker confirmation, are harder to potentiate) and integrates spine signals toward the soma. -**During NIGHT — the branch's ceilings are rewritten.** NIGHT raises **structure** (bAP -fidelity, translation capacity) where a validated tag accumulated and **budget capacity** where -fuel interrupted strong branch activity, both from the shared pool, both competing; unmaintained -ceilings drift down. +### SOMA | AP — integration, firing, emergent timing +Fires when integrated branch input exceeds a threshold that is the baseline (from structure) +raised by adaptation and modulated by neuromodulators, gated by the emergent refractory state. +Each AP deposits three traces (inactivation → refractory, adaptation → threshold rise, nuclear +Ca²⁺ → plasticity). The soma is the coincidence detector at the cellular scale (nuclear Ca²⁺ + +dopamine → CREB), and the production bottleneck: its tag gates how much material all downstream +components get in NIGHT. -``` -// PARAMETERS prop_cost · branch_Ca_cost · integrate_cost · translate_cost · ACh_gain -// INTERFACE -// EMIT bAP_local → POST ; branch_Vm → SOMA ; dend_ship_post → POST -// RECEIVE (signals) SOMA.fired ; POST.Vm + spine spillover ; dopamine ; ACh -// READ SOMA.fired ; POST.Vm + spine spillover ; dopamine ; ACh -// OWN dend_structure{bAP_fidelity(pos), translation_ceiling, transport_speed} ; dend_budget_ceiling -// SUPPLY astro_lactate[branch] ← ASTRO ; soma_ship_dend ← SOMA ; dend_material, dend_energy ← SOMA(NIGHT) -// NOTE DEND endurance fires only on FUEL-limited propagation, not structural attenuation; -// own-state proxy (strong branch activity); no arrived feedback term. +### AXON | AP — reliable propagation with frequency-dependent failure +Propagation reliability is set by myelination and degraded by high-frequency load (Na⁺ +inactivation at branch points = axonal STD). The axon also transports material to boutons and +sets the timescale of presynaptic structural commits. -DAY | bAP: - // ADJUST (propagation strength from structure — inside propagate()) - // BEHAVE (propagate bAP; distinguish fuel-limited vs structure-limited shortfall) - if dend_budget < prop_cost: - // FUEL shortfall → endurance (branch was strongly active) - if dend_fast_trace > traj_thr: - dend_endurance_need += dend_fast_trace - bAP_local, reached = propagate_partial(dend_budget) - else: - bAP_local, reached = propagate(SOMA.fired, dend_structure.bAP_fidelity, geometry) - // reached < full here is structural attenuation (distance), NOT endurance - dend_budget -= prop_cost × reached - // TRACE - dend_fast_trace += bAP_Ca(bAP_local) + spine_spillover(); dend_budget -= branch_Ca_cost - // EMIT (integrated voltage to soma ; propagated bAP already reached spines) - branch_Vm = integrate(POST.Vm, spines); dend_budget -= integrate_cost - -DAY | NOT_bAP: - // TRACE (strength) - if dend_fast_trace > elig: dend_possible_tag += dend_fast_trace - if dopamine > dop_thr and dend_possible_tag > tag_thr: - dend_tag += dopamine × dend_possible_tag - // ADJUST (commit threshold lowered by attention) - commit_threshold *= 1/(1 + ACh·ACh_gain) - // BEHAVE (local translation if tagged — fills dend capacity faster) - if dend_tag > tag_expiry and dend_budget > translate_cost: dend_budget -= translate_cost - // EMIT (ship budget to spines; demand = post tag) - dend_ship_post = ship(dend_budget, post_demand, post_ship_frac, ship_cost) - // RECOVER (refill budget from contested supply) - dend_budget += refill(dend from astro_lactate[branch] + transit(soma_ship_dend, τ_transport_dend)) - // DECAY - // FAST (ms–s) - dend_fast_trace *= decay(300ms) - // MEDIUM (s–min) - dend_possible_tag *= decay(s); dend_endurance_need *= decay(min) - // SLOW (hr) - dend_tag *= decay(hr) - // (PERSISTENT: dend_structure, dend_budget_ceiling — no DAY decay; NIGHT only) - -NIGHT | cycle: // intermediate node (relays down to POST) - // RECEIVE batch arrived from SOMA this cycle - dend_material += transit(soma_material_to_dend, τ_transport_dend) - dend_energy += transit(soma_energy_to_dend, τ_transport_dend) - // TRACE read standing demand (dend_tag → structure ; dend_endurance_need → budget_ceiling) - // ADJUST (no coherence — DEND is not a synaptic component) - // BEHAVE commit batches; spend tag/need as fuel - if dend_tag > tag_expiry: - Δ = min(slot_batch, dend_material, dend_energy·f_cap) - dend_structure += Δ; dend_material -= Δ; dend_energy -= Δ·assembly_cost; dend_tag -= Δ - if dend_endurance_need > endur_thr: - Δ' = min(cap_batch, dend_material·f_cap, dend_energy·f_cap) - dend_budget_ceiling += Δ'; dend_material -= Δ'; dend_energy -= Δ'·biogenesis_cost - dend_endurance_need -= Δ' - // EMIT ship remaining batch one hop down to POST (demand = post tag) - post_material_ship += ship(dend_material, post_demand, f_spine, ship_cost) - post_energy_ship += ship(dend_energy, post_demand, f_spine, ship_cost) - // RECOVER reclaim material from decayed ceilings - dend_material += dend_ceiling_shrinkage·recycle // energy NOT recovered - // DECAY - dend_structure -= decay_rate·Δt_cycle; dend_budget_ceiling -= capacity_decay_rate·Δt_cycle - dend_structure += min(dend_maint, maint_cost); dend_budget_ceiling += min(dend_cap_maint, cap_cost) - dend_tag *= decay(slow); dend_endurance_need *= decay(slow) -``` +### ASTRO | CONTINUOUS — gatekeeper and energy hub +Clears glutamate (EAAT), supplies D-serine (the NMDA co-agonist that gates postsynaptic LTP), +and distributes lactate to the territory by demand-weighting (active synapses generating more +clearance load pull more fuel; slow synapses get less). The same spillover that excites the +astrocyte (mGluR5 → Ca²⁺ → D-serine) also brakes the presynapse (mGluR2/3 → Gi) — one signal, +opposite effects via different receptors. The astrocyte is the energy root and the gain control +of the whole synapse. --- -## SOMA +## NIGHT operations — biological meaning -The soma is the neuron's integrating center and the root of its structural material. It sums -the branch inputs, fires when they exceed a threshold it sets from its own adaptation and the -neuromodulators, and ships material and budget out to the dendrites and axon. Its timing — -refractoriness, adaptation, rhythm alignment — emerges bottom-up from local traces, never from -a represented clock. Its behavior unfolds across two DAY contexts and the NIGHT scope. +- **Step 1 (replenish/distribute):** overnight protein synthesis peaks (CREB-driven, gated by + soma_tag — corresponds to slow-wave-sleep replay). Soma material flows to branches/axon then + spines/boutons; astrocyte material flows to astrosynapses, tag-weighted. +- **Step 2 (strength commits):** tagged components build structure — more slots, tighter + coupling, tighter astrosynaptic wrap. Coherence bonus when pre+post+astro all tagged (the + whole synapse agrees). astro_structure self-reinforces. +- **Step 2b (endurance commits):** components with high endurance_need build budget_ceiling — + mitochondrial biogenesis. Competes with step 2 for the same material/energy. +- **Step 3 (passive decay):** both ceilings decay; maintenance from the remaining pool resists + decay only where sufficient. Depotentiation and endurance-loss are both by neglect — no + signal weakens anything; unmaintained capacity simply drifts down. Recovered material (not + energy) returns to pools. +- **Step 4 (homeostatic scaling):** if the soma fired too much overall, all synapses scale down + proportionally (sleep-associated global downscaling), preserving relative differences. +- **Step 5 (clear traces):** fast traces, possible tags, endurance needs, and soma timing traces + reset; tags below expiry clear, above-expiry tags carry forward (multi-night consolidation); + structure and budget_ceiling persist. -**During DAY, during AP — the soma integrates and fires.** It computes its firing threshold -from its baseline (structure), its accumulated adaptation, and the neuromodulators, and checks -its refractory state; if the integrated branch input clears the threshold and fuel allows, it -fires. One spike deposits three traces at three timescales — sodium inactivation (refractory), -slow-potassium adaptation (threshold rise), and nuclear calcium (toward CREB and the tag). A -fuel shortfall while nuclear calcium was climbing is endurance evidence; being refractory or -sub-threshold is a timing limit, not endurance. - -**During DAY, during NOT_AP — the soma recovers, aligns, and supplies.** It self-replenishes -from its own mitochondria (its private root), integrates the latest branch inputs, deposits a -refractory-alignment trace when suprathreshold input arrived during its refractory period (so it -aligns to its input rhythm bottom-up), ships budget to dendrites and axon (demand-weighted by -their tags), recovers from refractoriness at a rate its alignment trace speeds up, and lets its -traces decay. - -**During NIGHT — the soma's ceilings are rewritten, and it gates the whole neuron's material.** -NIGHT raises **structure** (excitability, synthesis capacity) and **budget capacity** from the -shared pool; crucially the soma's own tag gates CREB-driven synthesis, so how much material all -downstream components receive depends on the soma having been tagged. - -``` -// PARAMETERS ap_cost · nuclear_cost · creb_cost · mito_output · inactivation · ap_amp · ap_contrib -// base_recovery · τ_Na · τ_adapt · τ_nuclear · τ_align -// INTERFACE -// EMIT fired → AXON (propagate) + DEND (bAP) ; soma_ship_dend → DEND ; soma_ship_axon → AXON -// RECEIVE (signals) branch_Vm ← DEND ; dopamine ; NE ; ACh -// READ dopamine ; NE ; ACh -// OWN soma_structure{baseline_threshold, AP_reliability, synthesis_ceiling} ; soma_budget_ceiling -// SUPPLY self (mitochondria, ROOT — private) -// NOTE SOMA endurance fires only on FUEL shortfall (budget < ap_cost); -// refractory / sub-threshold are timing limits, not endurance. Own-state proxy. - -DAY | AP: - // ADJUST (threshold from structure + adaptation + neuromodulators ; refractory gate) - threshold = soma_structure.baseline_threshold × (1 + soma_adaptation) × neuromod(NE, ACh) - can_fire = soma_Na_inactivation < inactivation - // BEHAVE (fire if able) - if branch_Vm > threshold and can_fire: - if soma_budget < ap_cost: - // FUEL shortfall → endurance (firing was approaching CREB) - if soma_fast_trace > traj_thr and soma_fast_trace_rising: - soma_endurance_need += soma_fast_trace - exit - // EMIT (fired → AXON, DEND) - fired = True; soma_budget -= ap_cost - // TRACE (three traces from one AP — FAST nuclear-Ca, MEDIUM adaptation, refractory) - soma_Na_inactivation += ap_amp // → refractory (emergent) - soma_adaptation += ap_contrib // → threshold rise - soma_fast_trace += nuclear_Ca(); soma_budget -= nuclear_cost - // TRACE (strength) - if soma_fast_trace > elig: soma_possible_tag += soma_fast_trace - if dopamine > dop_thr and soma_possible_tag > tag_thr: - soma_tag += dopamine × soma_possible_tag - soma_budget -= creb_cost - // TRACE (NEURON-level aggregator — the cell sums what its components emit, by DAY) - neuron_activity += 1 // total firing this day - neuron_total_weight += Σ all component structure across the cell // running weight tally - -DAY | NOT_AP: - // RECEIVE (integrate latest branch input — signal) - branch_Vm = integrate(DEND.branch_Vm, branches) - // TRACE (bottom-up refractory alignment: suprathreshold input during refractory) - if branch_Vm > threshold and soma_Na_inactivation > inactivation: - soma_refractory_alignment += (branch_Vm - threshold) × soma_Na_inactivation - // EMIT (ship downstream into transit; demand = propagated tags) - soma_ship_dend = ship(soma_budget, dend_demand, dend_ship_frac, ship_cost) - soma_ship_axon = ship(soma_budget, axon_demand, axon_ship_frac, ship_cost) - // RECOVER (self-replenish from private root ; inactivation recovery sped by alignment) - soma_budget += fill(soma_budget, soma_budget_ceiling, mito_output, 0, soma_budget) - recovery = base_recovery × (1 + soma_refractory_alignment) - soma_Na_inactivation *= decay(τ_Na / recovery) - // DECAY - // FAST (ms–s) — refractory + nuclear-Ca + alignment (sub-second to seconds) - soma_fast_trace *= decay(τ_nuclear); soma_refractory_alignment *= decay(τ_align) // self-limiting - // MEDIUM (s–min) — adaptation + tagging evidence - soma_adaptation *= decay(τ_adapt) - soma_possible_tag *= decay(s); soma_endurance_need *= decay(min) - // SLOW (hr) - soma_tag *= decay(hr) - // (signals) - dopamine *= decay(ms) - // (PERSISTENT: soma_structure, soma_budget_ceiling — no DAY decay; NIGHT only) - -NIGHT | cycle: // ROOT (neuronal material) — produces each cycle - // RECEIVE = PRODUCTION: synthesize this cycle's batch, gated by own tag, capped externally - soma_material += CREB_synth(soma_tag)·Δt_cycle // material — recoverable - soma_energy += mito_synth()·Δt_cycle // energy — NOT recoverable, bounded by night budget - night_energy_spent += mito_synth()·Δt_cycle // track against night supply ceiling - // TRACE read standing demand (soma_tag → structure ; soma_endurance_need → budget_ceiling) - // ADJUST (no coherence — SOMA is not a synaptic component) - // BEHAVE commit own batches - if soma_tag > tag_expiry: - Δ = min(slot_batch, soma_material, soma_energy·f_cap) - soma_structure += Δ; soma_material -= Δ; soma_energy -= Δ·assembly_cost; soma_tag -= Δ - if soma_endurance_need > endur_thr: - Δ' = min(cap_batch, soma_material·f_cap, soma_energy·f_cap) - soma_budget_ceiling += Δ'; soma_material -= Δ'; soma_energy -= Δ'·biogenesis_cost - soma_endurance_need -= Δ' - // EMIT ship batches one hop down to DEND and AXON (demand = propagated tags) - soma_material_to_dend += ship(soma_material, dend_demand, f_dend, ship_cost) - soma_material_to_axon += ship(soma_material, axon_demand, f_axon, ship_cost) - soma_energy_to_dend += ship(soma_energy, dend_demand, f_dend, ship_cost) - soma_energy_to_axon += ship(soma_energy, axon_demand, f_axon, ship_cost) - // RECOVER reclaim material from decayed ceilings (own + returned from downstream) - soma_material += soma_ceiling_shrinkage·recycle - // DECAY - soma_structure -= decay_rate·Δt_cycle; soma_budget_ceiling -= capacity_decay_rate·Δt_cycle - soma_structure += min(soma_maint, maint_cost); soma_budget_ceiling += min(soma_cap_maint, cap_cost) - soma_tag *= decay(slow); soma_endurance_need *= decay(slow) -``` +### Shockwave lockdown +Emergency global astrocytic Ca²⁺ wave → GABA + ATP release → mass AMPA internalization and +hyperpolarization. Bypasses budget gates. A circuit breaker against runaway excitation. --- -## AXON +## Pool-filling: private reserve vs contested supply -The axon carries the soma's spike out to its boutons and is the presynapse's supply line. It -propagates reliably or not depending on its myelination and its recent load, and ships material -and budget to the boutons. Its behavior unfolds across two DAY contexts and the NIGHT scope. +The pseudocode uses two filling primitives, distinguished by where the resource comes from. -**During DAY, during AP — the axon propagates the spike.** Reliability is set by structure -(myelination) and degraded by recent high-frequency load (sodium inactivation at branch points — -axonal short-term depression). A fuel shortfall while carrying a strong train is endurance -evidence; load-driven failure is short-term depression, a consequence, not endurance. +**`fill` (private reserve).** The pool is replenished from a source the component owns +outright, uncontested by siblings, bounded by the component's own ceiling and a rate cap. +- RRP refill — vesicles mobilized from the bouton's own reserve pool toward the docking-slot + ceiling, rate-limited by VATPase. The reserve is private to the bouton. +- SOMA self-replenish — the soma fuels itself from its own mitochondria toward its budget + ceiling. No other component draws on it. -**During DAY, during NOT_AP — the axon supplies and recovers.** It maintains its tag, ships -budget to its boutons (demand-weighted by their tags), refills its own budget from somatic -shipment and astrocytic lactate, and lets its traces decay. +**`refill` (contested supply).** The pool is replenished from a supply that multiple +components compete for, rationed by demand (gap to ceiling). +- pre/post/dend/axon budgets — drawn from astrocytic lactate (shared across all synapses the + astrocyte wraps) plus shipment from soma/axon/dendrite (shared across downstream targets). -**During NIGHT — the axon's ceilings are rewritten.** NIGHT raises **structure** (myelination, -transport capacity) and **budget capacity** from the shared pool, both competing; unmaintained -ceilings drift down. +**Neither primitive (their own forms).** Some inflows are not fills toward a ceiling: +- AMPA surface insertion — Ca²⁺-driven rate from the spine's private endosomal reserve, with + an explicit passive drift-back (short-term depression) when Ca²⁺ is low. Not a steady fill. +- D-serine release — demand-driven (saturating in astro Ca²⁺) and budget-limited, like NT + release; a release process, not a pool top-up. +- Root productions — `glycolysis(glucose)` at the astrocyte and `CREB_synth(soma_tag)` at the + soma are the system's energy and material roots: raw inflows capped only by the external + vascular supply, not fills toward an internal ceiling. -``` -// PARAMETERS prop_cost · budget_factor -// INTERFACE -// EMIT APs_delivered → PRE (propagation) ; axon_ship_pre → PRE -// RECEIVE (signals) SOMA.fired ; dopamine -// READ SOMA.fired ; dopamine -// OWN axon_structure{propagation, transport_ceiling, mito_density} ; axon_budget_ceiling -// SUPPLY soma_ship_axon ← SOMA ; astro_lactate[shaft] ← ASTRO ; axon_material, axon_energy ← SOMA(NIGHT) -// NOTE AXON endurance fires only on FUEL shortfall; load-driven failure fail(fast_trace) -// is axonal STD (a consequence), not endurance. Own-state proxy. - -DAY | AP: - // ADJUST (reliability from structure − load-driven failure) - reliability = axon_structure.propagation × (1 - fail(axon_fast_trace)) // fail() = STD, not endurance - // BEHAVE (propagate; FUEL shortfall degrades + flags endurance) - if axon_budget < prop_cost: - reliability *= budget_factor - if axon_fast_trace > traj_thr: // FUEL-limited → endurance - axon_endurance_need += axon_fast_trace - delivered = fired × reliability; axon_budget -= prop_cost × delivered - // EMIT (delivered APs reach boutons) - // TRACE - axon_fast_trace += delivered; axon_fast_trace *= decay(s) - -DAY | NOT_AP: - // TRACE (strength) - if axon_fast_trace > elig: axon_possible_tag += axon_fast_trace - if dopamine > dop_thr and axon_possible_tag > tag_thr: - axon_tag += dopamine × axon_possible_tag - // EMIT (ship to boutons; demand = pre tag) - axon_ship_pre = ship(axon_budget, pre_demand, pre_ship_frac, ship_cost) - // RECOVER (refill budget from contested supply) - axon_budget += refill(axon from soma_ship_axon + astro_lactate[shaft]) - // DECAY - // FAST (ms–s) - axon_fast_trace *= decay(s) - // MEDIUM (s–min) - axon_possible_tag *= decay(s); axon_endurance_need *= decay(min) - // SLOW (hr) - axon_tag *= decay(hr) - // (PERSISTENT: axon_structure, axon_budget_ceiling — no DAY decay; NIGHT only) - -NIGHT | cycle: // intermediate node (relays down to PRE) - // RECEIVE batch arrived from SOMA this cycle - axon_material += transit(soma_material_to_axon, τ_transport_dend) - axon_energy += transit(soma_energy_to_axon, τ_transport_dend) - // TRACE read standing demand (axon_tag → structure ; axon_endurance_need → budget_ceiling) - // ADJUST (no coherence — AXON is not a synaptic component) - // BEHAVE commit batches; spend tag/need as fuel - if axon_tag > tag_expiry: - Δ = min(slot_batch, axon_material, axon_energy·f_cap) - axon_structure += Δ; axon_material -= Δ; axon_energy -= Δ·assembly_cost; axon_tag -= Δ - if axon_endurance_need > endur_thr: - Δ' = min(cap_batch, axon_material·f_cap, axon_energy·f_cap) - axon_budget_ceiling += Δ'; axon_material -= Δ'; axon_energy -= Δ'·biogenesis_cost - axon_endurance_need -= Δ' - // EMIT ship remaining batch one hop down to PRE (demand = pre tag) - pre_material_ship += ship(axon_material, pre_demand, f_bouton, ship_cost) - pre_energy_ship += ship(axon_energy, pre_demand, f_bouton, ship_cost) - // RECOVER reclaim material from decayed ceilings - axon_material += axon_ceiling_shrinkage·recycle // energy NOT recovered - // DECAY - axon_structure -= decay_rate·Δt_cycle; axon_budget_ceiling -= capacity_decay_rate·Δt_cycle - axon_structure += min(axon_maint, maint_cost); axon_budget_ceiling += min(axon_cap_maint, cap_cost) - axon_tag *= decay(slow); axon_endurance_need *= decay(slow) -``` +The distinction matters biologically: a private reserve guarantees a component some autonomy +(the bouton can refill its RRP from its own vesicles even when lactate is scarce), while a +contested supply couples a component's fate to its neighbours' demands (operational budget +fails first where many active synapses compete for the same lactate). --- -## ASTRO +## PRE ↔ POST interaction: local computation, message-only coupling -The astrosynapse is the synapse's gatekeeper and energy hub. It clears glutamate, supplies the -D-serine that gates postsynaptic NMDA, and distributes lactate across its territory by demand. -Unlike the others it runs in a single continuous context rather than spiking, and its structure -reshapes the synapse's operating point rather than just its range. +The presynapse and postsynapse never read each other's internal state. They interact only +by writing to and reading from shared cleft channels. Each side computes entirely locally on +what it has: its own variables plus whatever signals have arrived in the cleft. This is the +message-passing realization of the locality principle. -**During DAY, continuously — the astrosynapse clears, gates, and fuels.** It produces energy at -its cell body (glycolysis from glucose, the system's energy root), then allocates lactate across -its astrosynapses weighted by each one's clearance demand. At each astrosynapse it clears -spillover glutamate (EAAT) and supplies tonic D-serine; when spillover is high it adds a -demand-driven D-serine pulse, brakes nothing of the presynapse directly (the presynaptic brake -is PRE reading its own cleft), deposits its calcium trace, and accumulates a dopamine-gated tag. -A D-serine pulse cut short by low budget while demand was high is endurance evidence; one cut -short by precursor/material exhaustion is a material limit, not endurance. Excess overflow -triggers the protective shockwave lockdown. +**Forward channel — glutamate (PRE → POST and ASTRO).** The presynapse writes glutamate via +NT_flux. The postsynapse reads it (AMPA, NMDA) and the astrosynapse reads it (clearance, +mGluR5). The astrosynapse clears it. PRE never knows whether POST responded — it only emits. -**During NIGHT — the astrosynapse's ceilings are rewritten.** NIGHT raises **structure** -(perisynaptic wrap, EAAT density, tonic D-serine) where a validated tag accumulated and **budget -capacity** where budget-limited synthesis recurred; astro_structure is self-reinforcing in both -directions, so it amplifies whatever trajectory the synapse is already on. +**Gate channel — astro_Dserine (ASTRO → POST).** The astrosynapse writes D-serine; the +postsynapse reads it as the obligatory NMDA co-agonist. POST cannot open NMDA without this +arrived signal, but it does not read the astrocyte's state — only the delivered D-serine. -``` -// PARAMETERS K_Dserine · Ds_max · Ds_frac · Ds_cost · EAAT_cost · lactate_cost · spillover · overload -// INTERFACE -// EMIT astro_lactate[i] → pre/post/dend budgets ; astro_Dserine[i] → POST (gate) -// RECEIVE (signals) glutamate ← PRE (clearance + spillover) ; dopamine -// READ glutamate ; dopamine -// OWN astro_structure{perisynaptic_distance⁻¹, EAAT, Dserine_tonic, ECM} ; astro_budget_ceiling -// SUPPLY glucose (ROOT) ; astro_material, astro_energy ← cell body (NIGHT) -// NOTE ASTRO endurance fires on BUDGET-limited synthesis (got spillover: - // TRACE - astro_fast_trace[i] += mGluR_Ca(); astro_fast_trace[i] *= decay(s) - // ADJUST (D-serine demand from spillover) - want = sat(astro_fast_trace[i], K_Dserine) × Ds_max - got = min(want, astro_central_budget × Ds_frac) - // BEHAVE + EMIT (D-serine pulse to POST gate) - astro_Dserine[i] += got; astro_central_budget -= got·Ds_cost - // TRACE (endurance: BUDGET-limited synthesis under high own demand) - if got < want and astro_central_budget low and astro_fast_trace[i] > traj_thr: - astro_endurance_need[i] += (want - got) - // TRACE (strength) - if astro_fast_trace[i] > elig: astro_possible_tag[i] += astro_fast_trace[i] - if dopamine > dop_thr and astro_possible_tag[i] > tag_thr: - astro_tag[i] += dopamine × astro_possible_tag[i] - // DECAY - // FAST (ms–s) — astro_fast_trace already decayed above (intra-step) - // MEDIUM (s–min) - astro_possible_tag[i] *= decay(s); astro_endurance_need[i] *= decay(min) - // SLOW (hr) - astro_tag[i] *= decay(hr) - // (PERSISTENT: astro_structure, astro_budget_ceiling — no DAY decay; NIGHT only) - // EMERGENCY - if astro_fast_trace[i] > overload: emit(shockwave_lockdown) + `retro_NO_local` is exactly the grounding of the presynaptic endurance signal. The + presynapse's local success proxy is "I was releasing strongly" (`pre_fast_trace` high). On + its own that only says the bouton was working hard, not that the work mattered. `retro_NO` + adds the missing confirmation — that the postsynapse responded — without PRE ever reading + POST's calcium. So PRE deposits endurance need as `pre_fast_trace × (1 + retro_NO_local)`: + strong release that was confirmed effective makes the strongest claim that fuel, not + futility, was what interrupted a forming success. retro_NO is short-lived (NO degrades and + diffuses within seconds), so the channel decays fast — confirmation must be recent to count. + +**Backward channel − — retro_eCB (POST → PRE).** When the postsynapse is strongly +depolarised, it synthesises endocannabinoids (2-AG, anandamide) that diffuse retrogradely and +bind presynaptic CB1 receptors, suppressing release. This is depolarisation-induced +suppression of excitation (DSE) — a homeostatic negative feedback: an over-driven postsynapse +tells the presynapse to release less. In the model, POST emits `retro_eCB` from its own +membrane potential, and PRE reads it as `retro_eCB_local`, which reduces the release drive +`sat(...) × (1 - retro_eCB_local)`. Again POST computes from its own state; PRE adjusts from +the arrived signal; neither reads the other's interior. + +The two backward channels are opposite-signed messages the postsynapse sends about its own +condition: retro_NO says "your input was effective — worth sustaining," retro_eCB says "I am +saturated — ease off." Together with the forward glutamate and the D-serine gate, they make +the synapse a fully message-coupled system of locally-computing components. + +**Why RRP refill is in NOT_AP only.** During an AP the bouton releases — RRP depletes. Refill +(VATPase reloading vesicles from the reserve pool) is a recovery process that proceeds between +spikes. Placing `fill(RRP, ...)` only in the NOT_AP context makes the AP context pure +depletion and the NOT_AP context pure recovery. A consequence falls out for free: during +sustained high-frequency firing there are many AP steps and few NOT_AP steps, so RRP depletes +faster than it recovers — short-term depression deepens with frequency, with no explicit +depression rule. The release itself is throttled further when budget is low (VATPase refill +is energy-limited), coupling metabolic state to the depth of depression. -NIGHT | cycle: // ROOT (synaptic energy + ECM) — produces each cycle - // RECEIVE = PRODUCTION: glycolysis + ECM synthesis this cycle, capped by glucose - astro_central_energy += overnight_glycolysis(glucose)·Δt_cycle // energy — NOT recoverable - astro_central_material += astro_cellbody_synth()·Δt_cycle // material — recoverable - night_energy_spent += overnight_glycolysis(glucose)·Δt_cycle - // ADJUST tag-weighted shares across the territory - W = Σ astro_tag[i] over astro_tag[i] > tag_expiry - // EMIT distribute this cycle's batch to astrosynapses (demand = own tag) - for each i with astro_tag[i] > tag_expiry: - w = astro_tag[i]/W - astro_energy[i] += astro_central_energy·w - astro_material[i] += astro_central_material·w - // BEHAVE each astrosynapse commits; spend tag/need as fuel (coherence applies — synaptic) - for each astrosynapse i: - coh = coherence_signal[i] - if astro_tag[i] > tag_expiry: - Δ = min(slot_batch, astro_material[i], astro_energy[i]·f_cap) - astro_structure[i] += Δ × coh // self-reinforcing both directions - astro_material[i] -= Δ; astro_energy[i] -= Δ·assembly_cost; astro_tag[i] -= Δ - if astro_endurance_need[i] > endur_thr: - Δ' = min(cap_batch, astro_material[i]·f_cap, astro_energy[i]·f_cap) - astro_budget_ceiling[i] += Δ'; astro_material[i] -= Δ' - astro_energy[i] -= Δ'·biogenesis_cost; astro_endurance_need[i] -= Δ' - // RECOVER reclaim material from decayed ceilings - astro_central_material += astro_ceiling_shrinkage·recycle // energy NOT recovered - // DECAY - for each i: - astro_structure[i] -= decay_rate·Δt_cycle; astro_budget_ceiling[i] -= capacity_decay_rate·Δt_cycle - astro_structure[i] += min(astro_maint[i], maint_cost) - astro_budget_ceiling[i] += min(astro_cap_maint[i], cap_cost) - astro_tag[i] *= decay(slow); astro_endurance_need[i] *= decay(slow) -``` --- -## Special — Shockwave Lockdown +## Presynaptic short-term potentiation — VGCC coupling occupancy -``` -DAY or NIGHT | OVERLOAD: - Vm = HYPERPOLARIZED; AMPA_surface = mass_internalize() → post reserve - axon_fast_trace += overdrive(); astro_central_budget -= emergency_cost -``` +`VGCC_active` is the presynaptic parallel to the postsynaptic `AMPA_surface`. Both are MEDIUM-tier +occupancy variables: a current operating value filled toward a NIGHT-built ceiling, no dopamine, +reversible, drifting back when undriven. ---- ---- -# NIGHT — the driver (a hierarchy of actors, phased) -NIGHT runs a loop of cycles. Each cycle has FOUR actor tiers acting in order from the top of the -hierarchy down: the external replay signal arrives, the NEURON renormalizes, the ASTROCYTE -territory reallocates, then the COMPONENTS commit within what they were handed. The night is -PHASED: early cycles DOWNSCALE (reset occupancy, renormalize weight — subtractive, make room), -later cycles COMMIT (build ceilings for the survivors — additive). It ends emergently. +Biologically, `VGCC_active` represents the effective coupling between voltage-gated calcium +channels and the vesicle docking slots — how reliably each calcium influx is converted into +release. Repeated eligible activity (accumulated `pre_possible_tag`) transiently tightens this +coupling — through calcium-channel facilitation, active-zone protein phosphorylation, and +channel-to-sensor proximity changes — raising release efficiency without changing the number of +channels (which is the structural ceiling `pre_structure.VGCC_coupling`, written only at NIGHT). +When eligibility falls, the coupling relaxes back to baseline over seconds-to-minutes: presynaptic +short-term depression as the passive consequence of undriven coupling, never a signalled act. -``` -NIGHT driver: - night_energy_spent = 0 - N_cycles_early = early_phase_frac × estimated_cycles - repeat cycle = 1, 2, 3, …: - phase = (cycle ≤ N_cycles_early) ? DOWNSCALE : COMMIT +This gives the presynapse a genuine intermediate-timescale memory it previously lacked — a +"this bouton has been reliably active lately" state that outlasts individual spikes and bursts, +filling the gap between the fast trace (residual calcium, ~100 ms) and the tag (hours). It also +completes the capacity/occupancy symmetry across the synapse: both PRE and POST now fill a +MEDIUM occupancy variable toward a PERSISTENT structural ceiling, rather than PRE reading its +ceiling directly as if capacity and occupancy were the same thing. - // ── TIER 0: ASSEMBLY/NETWORK (external) ─────────────────────────────── - // replay_reweight[s] arrives this cycle: re-presents the day's patterns and - // re-weights which synapses the assembly found significant (external signal). - - // ── TIER 1: NEURON (renormalize total weight; drive occupancy downscaling) ── - if phase == DOWNSCALE: - // multiplicative-global occupancy reset — only CEILINGS will persist - for each synapse s: - VGCC_active[s] *= downscale_factor - AMPA_surface[s] *= downscale_factor - possible_tag[s] *= downscale_factor // medium evidence renormalized too - // renormalize total committed weight toward the cell's budget (Tononi-style) - if neuron_total_weight > neuron_weight_ceiling: - g = neuron_weight_ceiling / neuron_total_weight - for each component c in cell: c_structure *= g - soma_material += Σ reduction·recycle // freed material returns to pool - - // ── TIER 2: ASTROCYTE territory (reallocate metabolic support) ───────── - // reallocate this cycle's energy/material across the territory by accumulated demand, - // re-weighted by replay — the astrocyte is the metabolic arbiter of its synapses - for each astrosynapse i: - astro_alloc[i] = (astro_territory_demand[i] × replay_reweight[i]) - / Σ(astro_territory_demand × replay_reweight) - // (astro_alloc biases each synapse's share of the astrocyte's produced batch this cycle) - - // ── TIER 3: COMPONENTS (commit within the allocation handed down) ────── - // coherence signal (cross-component) from this cycle's standing tags - for each synapse s: - coherence_signal[s] = (pre_tag[s], post_tag[s], astro_tag[s] all > tag_expiry) - ? coherence_factor : 1 - if phase == COMMIT: - run PRE, POST, DEND, SOMA, AXON, ASTRO NIGHT | cycle // build ceilings - else: - run SOMA, ASTRO NIGHT | cycle (PRODUCE + EMIT only) // pre-stage material downstream - - // ── termination — emergent, OR of two conditions ────────────────────── - night_energy_spent updated by the roots' production this cycle - demand_left = Σ all tags > tag_expiry (system-wide) - if demand_left ≈ 0: break // DEMAND exhausted (rested) - if night_energy_spent ≥ night_energy_ceiling: break // SUPPLY spent (overloaded) - - // ── CODA (once at end of night) ──────────────────────────────────────────── - // clear DAY traces and the DAY aggregators; occupancy already reset by downscaling - all fast_trace, possible_tag, endurance_need = 0 - soma_Na_inactivation = soma_adaptation = soma_refractory_alignment = 0 - neuron_activity = 0; neuron_total_weight = recomputed from surviving structure - astro_territory_demand[·] = 0 - // tags are NOT cleared — unspent tags carry forward, decaying on their slow τ - // structure and budget_ceiling PERSIST as the next DAY's ceilings - // VGCC_active / AMPA_surface have been returned to baseline by downscaling -``` - -Notes. (1) The phasing makes cycles genuinely different: an early cycle reshapes the landscape -(reset occupancy, renormalize weight, pre-stage material), a late cycle builds on the reshaped -landscape — so what gets committed depends on the order, and could not be computed in one shot. -(2) Higher actors never read a component's interior: the neuron renormalizes a sum it accumulated -from emitted activity; the astrocyte reallocates by demand it accumulated; coherence and replay -arrive as signals. Locality holds — the system acts locally and consolidates hierarchically. -(3) Occupancy is reset every night, so each DAY starts from baseline occupancy against whatever -ceilings persisted: the only thing that carries a day forward is what earned a ceiling. --- -## One-view summary +## NIGHT as iterated NREM cycles — the biology -``` -SEVEN-GROUP GRAMMAR, TWO SCOPES, ONE LADDER - RECEIVE · TRACE · ADJUST · BEHAVE · EMIT · RECOVER · DECAY +The distributed, cyclic NIGHT models sleep-dependent consolidation more faithfully than a single +commit step. -DAY grammar on OCCUPANCY within two ceilings (structure=strength, budget_ceiling=endurance) - bottom-up: consumers act, evidence ascends leaves→roots - TRACE yields two evidence streams from local state + arrived signals: - fast_trace + dopamine → tag (strength) - FUEL shortfall + interrupted LOCAL success → endurance_need (endurance) - OCCUPANCY/structure/timing shortfalls → short-term depression (NOT endurance) -NIGHT enacted by a HIERARCHY of actors (not the DAY components alone), PHASED: - assembly/network replay (external) → NEURON renormalize total weight + downscale occupancy - → ASTROCYTE territory reallocate → COMPONENTS commit ceilings within what's handed down - early cycles DOWNSCALE (reset occupancy multiplicatively-global, make room), - late cycles COMMIT (build ceilings for survivors) - higher actors ACCUMULATE aggregate traces by DAY, ACT by NIGHT (locality holds) - ends when DEMAND exhausted (no tag stands) OR SUPPLY spent (night energy used) - what persists must EARN it: occupancy resets to baseline, only CEILINGS carry; - unspent tags carry to next night; material recycles, ENERGY does not (arrow of time) -RULE the system ACTS LOCALLY (DAY, local components) and CONSOLIDATES HIERARCHICALLY (NIGHT) -FLOWS every flow has a timescale; shipment is transit-delayed (distal fills over cycles) -LOCAL every group uses only own state + arrived signals; RECEIVE/EMIT are the only crossings -``` +**Why cycles, not one event.** NREM sleep proceeds in repeated cycles (the ultradian ~90-minute +rhythm, and within it the <1 Hz slow oscillation with its up- and down-states). Protein synthesis, +hippocampal–cortical replay, and synaptic renormalization all advance incrementally across these +cycles rather than in a single consolidation moment. Modeling NIGHT as a loop of cycles captures +this: each cycle is a small, local round of produce → transport → incorporate. + +**Production each cycle (the roots).** The soma's CREB-driven transcription/translation produces a +batch of structural material per cycle, gated by the soma's own tag (replay-driven activity). +The astrocyte cell body produces a batch of energy (glycolysis) and ECM material per cycle, capped +by glucose. These are the two roots; everything downstream lives on what they ship. + +**Transport over cycles (the descent).** Material and energy move one hop down the supply chains +per cycle — soma → dendrite/axon → spine/bouton; astrocyte body → astrosynapses — by the same +motor transport that carries cargo by day, now at the consolidation timescale. A distal bouton on +a long axon therefore receives its material only after several cycles, so its consolidation lags +a proximal one. This is the NIGHT-scale image of the transit delay. + +**Incorporation and tag consumption (the commit).** A tagged synapse incorporates arrived material +into structure (more receptor slots, tighter active zone, tighter astrocytic wrap) or into budget +capacity (mitochondrial biogenesis), spending energy on the assembly. The tag is consumed in +proportion to what was built — the molecular tag (CaMKII/PKA-maintained eligibility) is discharged +as capture completes. A strong tag is satisfied early; a marginal one waits for later cycles. + +**Two ways the night ends.** Either the standing tags are all spent (consolidation finished — the +rested case) or the night's metabolic budget is exhausted (ran out of night — the overloaded +case). Unspent tags are not discarded: they persist (decaying slowly) into the next day and +compete again the next night, so importance is re-tested across nights and a marginal memory may +consolidate over several nights or, if it decays first, never. + +**Energy is the irreversible cost.** Material released when an unmaintained structure is pruned +returns to the pool and is reused; the energy burned to build or to prune is gone. Across a +lifetime this energy throughput bounds how much the system can ever consolidate — the metabolic +arrow of time underlying the whole model. + + +--- + +## NIGHT's hierarchy of actors — the biology + +**Why the actors differ from DAY's.** Transmission is local — a bouton releases, a spine +integrates, an astrosynapse clears. Consolidation is not: it involves quantities no single +synapse can see. Whether one synapse's strengthening "fits" depends on the neuron's total +synaptic weight; reallocating metabolic support depends on an astrocyte's whole territory; +deciding which memories to replay depends on assemblies of neurons. So NIGHT is enacted by +actors at higher scales, each conserving a quantity at its scale. + +**The astrocyte territory (Tier 2).** The astrocyte cell body supports hundreds to thousands of +synapses. By day it allocates lactate by demand; by night it reallocates its produced energy and +ECM material across its whole territory, biased by the demand it accumulated and by replay. This +is a genuine territory-level actor — the astrocyte is the metabolic arbiter of its domain, and +its nightly reallocation decides which of its synapses can afford to consolidate. + +**The neuron as a whole (Tier 1).** Synaptic homeostasis (the synaptic homeostasis hypothesis of +Tononi and Cirelli) operates on the neuron's *total* synaptic weight: across sleep, the cell's +synapses are renormalized downward multiplicatively, preserving relative differences while +restoring overall excitability and freeing capacity. This is a neuron-scale operation — no synapse +can perform it, because no synapse knows the cell's total weight. In the model the neuron +accumulates that total by day and renormalizes it by night, scaling all the cell's structures by +a common factor when the total exceeds the cell's budget. + +**The assembly / network (Tier 0, external).** Systems consolidation — hippocampal–cortical replay +— reactivates the day's patterns across ensembles of neurons during NREM, and this dialogue +selects which assemblies are written into cortex. This is a network-scale process beyond a single +neuron, so the model treats it as an external arrived signal (`replay_reweight`), exactly as it +treats dopamine and glucose. Fully modeling it requires a network of these neurons. + +**Occupancy downscaling — why only ceilings persist.** During the day, synapses fill occupancy: +receptors trafficked to the surface (AMPA_surface), calcium-channel coupling tightened +(VGCC_active), eligibility accumulated (possible_tag). These are transient and reversible. If they +carried across the night undiminished, a synapse could become lastingly strong without ever +earning a tag or paying the consolidation cost — bypassing the entire validation machinery. +Multiplicative-global downscaling during early-night cycles returns occupancy to baseline. A +synapse that was tagged and had its *ceiling* raised starts the next day strong; one that merely +filled occupancy during the day starts back at baseline. The relative potentiation survives only +where it was written into structure — which is precisely synaptic homeostasis enforcing that the +slow tier carries the learning and the fast/medium tier is renewed each day. + +**Why phased.** A single sweep cannot both reset and build, because building should act on the +*post-reset* landscape. Early cycles are subtractive (downscale occupancy, renormalize weight, +make metabolic room); later cycles are additive (commit the survivors). This is the NREM arc — +slow-wave-dominated downscaling early, selective consolidation later — and it makes each cycle's +*kind* depend on where in the night it falls, so the cycles are genuinely different operations, +not installments of one.