From 6096202642c2cc57aeec7c43faabf1a293b76d24 Mon Sep 17 00:00:00 2001 From: ocrampal Date: Thu, 4 Jun 2026 09:33:03 +0200 Subject: [PATCH] Update 2026-06-02-astrocyte-behaviors.md --- .../appunti/2026-06-02-astrocyte-behaviors.md | 164 ++++++++++++++++++ 1 file changed, 164 insertions(+) diff --git a/elements/astrocyte/appunti/2026-06-02-astrocyte-behaviors.md b/elements/astrocyte/appunti/2026-06-02-astrocyte-behaviors.md index 15b6c5d..59279fd 100644 --- a/elements/astrocyte/appunti/2026-06-02-astrocyte-behaviors.md +++ b/elements/astrocyte/appunti/2026-06-02-astrocyte-behaviors.md @@ -96,6 +96,170 @@ Operating high-fidelity wave generators and vibrating resonators drains the syst --- --- +# Pseudocode, organized by variable, influence, and time + +## global state variables + +// ─── FAST (ms–s) ─── INTERMEDIATE (s–min) ─── SLOW (h–days) ─── + +// Presynaptic +vesicle_release_prob // P(0.1–1.0) — baseline 0.2 +active_zone_size // docking slots — scales launchpad +RRP_pool // readily-releasable pool (fast) +reserve_pool // chained vesicles in deep storage +presynaptic_Ca // [Ca²⁺] at active zone + +// Postsynaptic +AMPA_count // surface receptors = sensitivity +NMDA_Mg_block // bool — mechanical clamp on/off +postsynaptic_Ca // [Ca²⁺] in spine — triggers LTP/LTD +membrane_potential // Vm — depolarization state + +// Astrocyte +glutamate_clearance_rate // EAAT transporter speed +D_serine_release // gliotransmitter — NMDA co-agonist +astro_Ca // internal Ca²⁺ wave state +ECM_integrity // extracellular matrix density +lactate_output // fuel export rate to neurons + +// Neuromodulators (global broadcast) +dopamine_level // "save button" — validates LTP +norepinephrine_level // arousal / signal-to-noise gain +acetylcholine_level // attention — lowers LTP threshold + +## fast time scale — wave propagation (ms → s) + +function fire_action_potential(input_freq): + +// Presynapse: launch wavefront +presynaptic_Ca += spike_influx(input_freq) +released_vesicles = binomial(RRP_pool, vesicle_release_prob) +glutamate_cleft = released_vesicles × quantal_content +RRP_pool -= released_vesicles + +// Postsynapse: wavefront strikes resonator +AMPA_current = glutamate_cleft × AMPA_count +membrane_potential += AMPA_current + +// NMDA gate — needs coincidence (clamp check) +if membrane_potential > -40mV and D_serine_release > threshold: +NMDA_Mg_block = False // Mg²⁺ ejected — clamp unlocked +postsynaptic_Ca += NMDA_influx(glutamate_cleft) + +// Astrocyte: vacuum up trailing echoes +glutamate_cleft -= glutamate_clearance_rate × Δt +lactate_output += glycolysis_rate(glutamate_clearance_rate) + +// Fuel consumed by post + pre to reset +membrane_potential restored by NaK_ATPase(lactate_output) +RRP_pool refilled by VATPase_pump(lactate_output) + +## intermediate time scale — temporary tuning (s → min) + +function short_term_plasticity(input_freq): + +// Presynapse: facilitate or depress based on Ca²⁺ history +if input_freq > 20Hz: // facilitation +vesicle_release_prob *= 1.3 // residual Ca²⁺ primes launchpad +mobilize(reserve_pool → RRP_pool) // break storage chains +elif input_freq < 5Hz: // depression +vesicle_release_prob *= 0.7 // RRP depleted faster than refill + +// Postsynapse: NMDA gate primed if frequency sustained +if input_freq >= 50Hz and duration > 1s: +NMDA_Mg_block = False // sustained depolarization +postsynaptic_Ca accumulates // early-LTP signal rises + +// Astrocyte: sense volume → deploy co-agonist +if glutamate_cleft > threshold_mid: +D_serine_release += gliotransmitter_pulse() // acoustic stabilizer +astro_Ca += IP3_wave() + +// Neuromodulators: shift operational threshold globally +LTP_threshold *= gain(1 / (1 + acetylcholine_level)) +signal_to_noise += norepinephrine_level × β_receptor_gain + +## slow time scale — structural carving (h → weeks) + +function late_LTP_consolidation(): + +// Gate: dopamine "save button" must arrive +if postsynaptic_Ca > Ca_LTP_threshold and dopamine_level > D1_threshold: + +// Postsynapse: anchor new receptors +AMPA_count += receptor_insertion(CaMKII_signal) +spine_volume *= 1.5 // spine head enlarges + +// Presynapse: expand active zone, fill launchpad +active_zone_size *= 1.4 +vesicle_release_prob += 0.1 // VGCC clustering beneath AZ + +// Astrocyte: seal the acoustic channel +ECM_integrity += secrete(Glypicans, Thrombospondins) +retract(perisynaptic_process) // astrocyte walls in closer → insulate +glutamate_clearance_rate *= 0.85 // tighter diffusion barrier + +// Late-LTP endpoint: carved channel +return synapse_state = "potentiated" + + +function LTD_active_forgetting(): + +// Trigger: low-freq, out-of-sync — discordant leakage only +if input_freq ≈ 1Hz and timing == "uncorrelated": +// Postsynapse: small Ca²⁺ rise activates phosphatases +AMPA_count -= receptor_internalization(PP1_signal) + +// Astrocyte: deploy molecular scissors → dissolve matrix +D_serine_release = 0 // cut co-agonist supply +ECM_integrity -= secrete(MMPs) // matrix metalloproteinases + +// Presynapse: dismantle launchpad +active_zone_size -= docking_slot_removal() +vesicle_release_prob *= 0.6 +sequester(RRP_pool → reserve_pool) + +return synapse_state = "depressed" + + +function shockwave_lockdown(): // Mode 3 — >100Hz uncoordinated + +// Astrocyte: global Ca²⁺ wave triggers circuit-breaker +astro_Ca = GLOBAL_WAVE // soma-level flood +release(GABA, ATP) // gel floods postsynapse +AMPA_count -= mass_internalization() +membrane_potential = HYPERPOLARIZED + +// Presynapse: overdrive clustering to preserve signal +cluster(VGCC → beneath_active_zone) // ensures penetration + +## energy supply chain — metabolic gating (continuous) + +function metabolic_loop(Δt): +// Astrocyte: glucose → lactate pipeline +glucose_uptake = blood_capillary_supply() +lactate_output = glycolysis(glucose_uptake, glutamate_clearance_rate) + +// Both neurons absorb lactate → power pumps +RRP_pool refill rate ∝ VATPase(lactate_output) +membrane_potential reset ∝ NaK_ATPase(lactate_output) + +// Feedback: harder clearance work → faster fuel pump +lactate_output *= load_factor(glutamate_clearance_rate) + + +**State variables** at the top declare every quantity that gets modified — split by which cell "owns" it. These are the nodes that the rest of the code reads and writes. + +**Three time-scale functions** then show how those variables evolve: +- `fire_action_potential` is pure fast physics — Ca²⁺ triggers vesicle release, AMPA opens, NMDA unlocks only under coincidence, astrocyte clears the cleft, fuel is consumed. +- `short_term_plasticity` runs on top of repeated firing — the presynapse facilitates or depresses based on Ca²⁺ history, the astrocyte drops D-serine when volume is high, and neuromodulators shift the gain coefficient globally. +- `late_LTP_consolidation` and `LTD_active_forgetting` are the permanent rewrite layer — they require the dopamine "save button" as an AND-gate, and they modify structural variables (`active_zone_size`, `ECM_integrity`, `AMPA_count`) that persist independently of individual spikes. + +The `shockwave_lockdown` and `metabolic_loop` sit alongside as two special-case routines that override the normal flow — one a circuit-breaker, the other a continuous background process coupling astrocyte workload to fuel delivery. + +--- +--- + # Core business of each component ## 1. The Core Businesses of Each Component