fill vs refill

elements/neuron/appunti/2026-06-19-biological-reference-v10.md

@@ -242,3 +242,35 @@ of the whole synapse.
 ### Shockwave lockdown
 Emergency global astrocytic Ca²⁺ wave → GABA + ATP release → mass AMPA internalization and
 hyperpolarization. Bypasses budget gates. A circuit breaker against runaway excitation.
+
+---
+
+## Pool-filling: private reserve vs contested supply
+
+The pseudocode uses two filling primitives, distinguished by where the resource comes from.
+
+**`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.
+
+**`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).
+
+**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.
+
+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).

elements/neuron/appunti/2026-06-19-tripartite-synapse_v10.md

@@ -66,9 +66,18 @@ Replenishment contexts (NOT_AP, NOT_bAP): competitive refill, ship downstream, d
 
 ---
 
-## Shared competitive replenishment (used by all NOT contexts)
+## Pool-filling primitives
+
+Two shapes share the core "rise toward a ceiling, bounded by the gap, paying budget":
 
 ```
+// PRIVATE: fill own pool from own reserve toward own ceiling, at a rate cap
+fill(pool, ceiling, rate_cap, cost, budget):
+    amount   = min(rate_cap, ceiling - pool)·Δt          // bounded by rate AND gap
+    pool    += amount
+    budget  -= amount·cost
+
+// CONTESTED: fill toward ceiling by a rationed share of a shared supply S
 refill(component c from supply S):
     demand   = c.budget_ceiling - c.budget               // claim = gap to ceiling
     total    = Σ demand over components on S
@@ -77,6 +86,11 @@ refill(component c from supply S):
     S        -= demand × factor
 ```
 
+Choose by source: a pool drawn from a **private reserve** uses `fill`; a pool drawn from a
+**contested shared supply** uses `refill`. The distinction is biologically real — RRP comes
+from the bouton's private reserve pool, while operational budget comes from astrocytic lactate
+that neighbours compete for.
+
 ---
 
 ## PRE
@@ -93,16 +107,13 @@ DAY | AP:
     if RRP > 0:
         NT_flux   = RRP × drive
         glutamate += NT_flux·Δt;  RRP -= NT_flux·Δt;  pre_budget -= NT_flux·fusion_cost
-    RRP += min(refill_rate, pre_structure.refill_ceiling)·Δt
-    RRP  = clamp(RRP, 0, pre_structure.slot_ceiling)
-    pre_budget -= RRP_refill·vatpase_cost
-    if glutamate > spillover: drive *= brake
+    fill(RRP, pre_structure.slot_ceiling, pre_structure.refill_ceiling, vatpase_cost, pre_budget)
+    if glutamate > spillover: drive *= brake             // output brake (not a fill)
 
 DAY | NOT_AP:
     pre_fast_trace *= decay(100ms);  pre_endurance_need *= decay(min)
-    refill(pre from astro_lactate[syn] + axon_ship_pre)
-    RRP += min(refill_rate, pre_structure.refill_ceiling)·Δt
-    RRP  = clamp(RRP, 0, pre_structure.slot_ceiling)
+    refill(pre from astro_lactate[syn] + axon_ship_pre)  // contested: lactate + shipment
+    fill(RRP, pre_structure.slot_ceiling, pre_structure.refill_ceiling, vatpase_cost, pre_budget)
     if pre_fast_trace > elig: pre_possible_tag += pre_fast_trace
     pre_possible_tag *= decay(s);  dopamine *= decay(ms)
     if dopamine > dop_thr and pre_possible_tag > tag_thr:
@@ -129,10 +140,11 @@ DAY | NOT_bAP:
 
     post_fast_trace *= decay(ms)
 
-    // CASE 1 — short-term potentiation: fill slots (no dopamine)
+    // CASE 1 — short-term potentiation: fill slots from private reserve (no dopamine)
+    // NOT generic fill(): rate is Ca-driven, and the else-branch is the STD consequence
     if post_fast_trace > Ca_STP:
         AMPA_surface = min(AMPA_surface + Ca_insert(post_fast_trace),
-                           post_structure.slot_ceiling)
+                           post_structure.slot_ceiling)    // private: spine endosomal reserve
         post_budget -= traffic_cost
     else:
         AMPA_surface = max(AMPA_surface - drift·Δt, baseline)     // STD = consequence
@@ -223,7 +235,7 @@ DAY | NOT_AP:
     soma_fast_trace           *= decay(τ_nuclear)
     soma_refractory_alignment *= decay(τ_align)          // self-limiting
     soma_endurance_need       *= decay(min)
-    soma_budget += mito_output·Δt                        // self-replenish (root)
+    fill(soma_budget, soma_budget_ceiling, mito_output, 0, soma_budget)  // private: own mitochondria, no external cost
     branch_Vm = integrate(DEND.branch_Vm, branches)
     ship(soma_budget → dend_budget, gap_to(dend))
     ship(soma_budget → axon_budget, gap_to(axon))