From 09e0d9d98435405a8d85a7597d4af206df1c81b7 Mon Sep 17 00:00:00 2001 From: ocrampal Date: Fri, 26 Jun 2026 16:23:35 +0200 Subject: [PATCH] Update 2026-06-22-tripartite-synapse_v13.md --- .../2026-06-22-tripartite-synapse_v13.md | 47 ++++++++++++++++--- 1 file changed, 40 insertions(+), 7 deletions(-) diff --git a/elements/neuron/appunti/2026-06-22-tripartite-synapse_v13.md b/elements/neuron/appunti/2026-06-22-tripartite-synapse_v13.md index 788d7b2..b665945 100644 --- a/elements/neuron/appunti/2026-06-22-tripartite-synapse_v13.md +++ b/elements/neuron/appunti/2026-06-22-tripartite-synapse_v13.md @@ -111,21 +111,49 @@ f_dend f_axon f_spine f_bouton // material distribution fractions ## 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 astro_lactate[syn] ← ASTRO ; axon_ship_pre ← AXON ; retro_NO, retro_eCB ← POST -// pre_material ← AXON(NIGHT) ; pre_energy ← SOMA(NIGHT) +// 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 DAY | AP: // TRACE (Ca²⁺ bolus from THIS spike — also drives release; frequency is emergent) pre_fast_trace += spike_Ca(pre_structure.VGCC_coupling) - // ADJUST (release drive from residual Ca²⁺ + received DSE brake) - drive = sat(pre_fast_trace, K_release) × (1 - retro_eCB_local) + // 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) @@ -143,14 +171,19 @@ DAY | AP: if glutamate > spillover: drive *= brake // own-cleft autobrake DAY | NOT_AP: - // RECEIVE (latch backward messages ; replenish budget from contested supply) + // RECEIVE (latch backward messages — signals only) retro_NO_local = retro_NO; retro_eCB_local = retro_eCB - pre_budget += refill(pre from astro_lactate[syn] + transit(axon_ship_pre, τ_transport_bouton)) // TRACE (strength: eligibility → tag via dopamine) if pre_fast_trace > elig: pre_possible_tag += pre_fast_trace if dopamine > dop_thr and pre_possible_tag > tag_thr: pre_tag += dopamine × pre_possible_tag - // RECOVER (RRP from private reserve toward its ceiling) + // 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 pre_fast_trace *= decay(100ms); pre_possible_tag *= decay(s)