Update 2026-06-22-tripartite-synapse_v13.md

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)