aggiunti behavior description

2026-04-02 12:14:56 +02:00
parent 8b421ad86d
commit 1949772b13
2 changed files with 167 additions and 3 deletions
@@ -296,4 +296,90 @@ Structural-Update: Context
    — Harder to reach NMDA_Open → weakens synapse further
    — Negative feedback: LTD stabilises by reducing
      future coincidence probability
-```
+```
+
+---
+
+---
+
+---
+
+**Behaviors:**
+
+— ms:
+
+- NT arrives in cleft → AMPA receptors bind NT, gated by Desensitization_level
+- V_post rises with AMPA conductance, decays passively each ms
+- bAP arrives → V_post receives additional depolarisation boost
+- NMDA gate checks coincidence: NT_cleft AND V_post both non-zero
+- Ca²⁺ enters spine via NMDA — amount determined by NT_cleft × Mg_block_removal
+- Ca²⁺ cleared slowly from spine (single decay term, ATP detail not modelled)
+- V_post history updated every ms (rolling buffer, feeds seconds loop)
+- Desensitization_level rises with NT_cleft exposure, recovers during silence
+- ATP cost charged per V_post level (Na/K-ATPase recharge, continuous)
+- ATP cost charged per unit Ca²⁺ cleared (PMCA cost, continuous)
+
+— seconds:
+
+- Ca_post_history computed (2 s rolling mean of Ca_post)
+- eCB synthesised when Ca_post_history exceeds threshold
+- eCB_level decays when Ca_post_history falls below threshold
+- eCB_level written → read by presynapse as retrograde brake on VGCCs
+- Ca_post_history compared to LTP/LTD thresholds → plasticity tag set
+- Desensitization recovery continues passively
+
+— mins:
+
+- ATP_demand_post (accumulated from ms loop) reduces ATP_level_post
+- ATP_demand_post resets to zero
+- Glucose level (shared with presynapse) sets ATP_level_post
+- If ATP_level_post low → Ca²⁺ clearance slows → false eCB trigger risk
+- If Plasticity_LTP tagged AND ATP_level_post not empty → AMPA density increases
+- If Plasticity_LTD tagged → AMPA density decreases
+- AMPA density feeds back into receptor_conductance ceiling for next cycle
+
+---
+
+**Simplified comprehension:**
+
+In this comprehension we decide to simplify:
+
+- We do not model ATP — the postsynaptic energy loop is removed
+- We do not model Desensitization_level — receptor availability is assumed constant
+- We do not model Ca²⁺ clearance detail — Ca_post decays with a single slow term
+
+The simplification implies that:
+
+- Removing ATP removes the false eCB trigger mechanism entirely. The retrograde signal remains but it is always genuine — driven by real Ca_post elevation from NMDA coincidence, not pump failure. The synapse cannot enter the excitotoxic protection cascade.
+- Removing Desensitization_level means the postsynapse cannot fatigue under sustained NT exposure. Receptor availability is always at maximum, so the tenth burst produces the same AMPA response as the first. This preserves the short-term dynamics of V_post without the adaptation layer.
+- Removing Ca²⁺ clearance detail means Ca_post reflects the cumulative history of coincidence events with a single decay constant rather than the interplay of PMCA, NCX speed, and ATP availability. Ca_post will still accumulate under high-frequency coincident firing if the decay is slow relative to the event rate, which preserves the eCB trigger dynamic even without the full pump machinery.
+
+---
+
+**Simplified Behaviors:**
+
+— ms:
+
+- NT arrives in cleft → AMPA receptors bind NT (receptor availability constant, no desensitization)
+- V_post rises with AMPA conductance, decays passively each ms
+- bAP arrives → V_post receives additional depolarisation boost
+- NMDA gate checks coincidence: NT_cleft AND V_post both non-zero
+- Mg_block_removal = V_post / (V_post + V_NMDA_half) — sigmoid of V_post
+- Ca²⁺ enters spine via NMDA: Ca_post += k_NMDA × NT_cleft × Mg_block_removal
+- Ca_post decays slowly each ms (single exponential, no pump detail)
+- Ca_post_history updated every ms (feeds seconds loop)
+- V_post_history updated every ms (retained for reference)
+
+— seconds:
+
+- Ca_post_history mean computed over past 2 s
+- eCB synthesised when Ca_post_history mean exceeds eCB threshold
+- eCB_level decays when Ca_post_history mean falls below threshold
+- eCB_level written → read by presynapse as retrograde brake on VGCCs
+- Ca_post_history compared to LTP/LTD thresholds → plasticity tag set
+
+— mins:
+
+- If Plasticity_LTP tagged → AMPA density increases
+- If Plasticity_LTD tagged → AMPA density decreases
+- AMPA density feeds back into receptor_conductance ceiling for next cycle