organism/neuron/postsynapse.md

postsynapse.md

Qui comprendiamo:

• POSTSYNAPSE: Postsynapse
• POST-AMPA: AMPA receptors (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors)

POSTSYNAPSE: Container

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

---

G expression:

POSTSYNAPSE
  bAP_ctx
    ms
      -- Ca Influx
      CaNDMAEnterMax: ( active: 2x )
      CaNDMAEnterMed: ( active: 4x )

  NOT bAP_ctx:
    ms
      -- Ca Influx
      CaNDMAEnterMedNotBap: ( active: 4x )
      CaNDMAEnterLow: ( active: 12x )
      -- Ca Clearence
      CaClearance: ( active: 24x ) # Low
      -- V Influx
      VPostMax: accumulator
      VPostMed: accumulator
      VPostLow: accumulator
      -- V Clearence
      VPostClearance: accumulator

  POST-AMPA
    NOT bAP_ctx
      ms
        -- Na Influx
        NaAMPAEnterMax: ( active: 2x )
        NaAMPAEnterMed: ( active: 4x )

  POST-NA-CLEAR
    NOT bAP_ctx
      ms
        -- Na Clearence
        NaClearanceHigh: accumulator
        NaClearanceLow: accumulator

TUN-POST-AMPA
  TunPossible_ctx
    sec
      CheckTunPostAmpa: ( active: 60x )

  TryTunUpPostAmpa_ctx
    sec
      PossibleUpPostAmpaTun: ( active: 10x )

  TryTunDownPostAmpa_ctx
    sec
      PossibleDownPostAmpaTun: ( active: 10x )

Tubs:

• Na: Ioni entranti tramite AMPA receptors
• NT:
• Ca2+: Ioni entranti tramite NMDA
• VPost: il voltage che viene sentito in DB
• eCB:
• Nox:?

---

POSTSYNAPSE
 type: container

 expansion: 
  - POST-AMPA ( full: 10x, active: 5x, empty: 2x )
   # modulated_by: TUN-POST-IC # possible/actual
  - POST-NA-CLEAR ( full: 1x, active: 1x, empty: 0x )
   # modulated_by: ??

 tub_local:
  - Ca2+ ( full: 60x, active: 30x, empty: 0x )
  - Na ( full: 60x, active: 30x, empty: 0x )
  - Nox ( full: 100x, active: 20x, empty: 0x ) # Nitric Oxide (NO):  A gas that diffuses freely.
  - eCB ( full: 100x, active: 20x, empty: 0x ) # Endocannabinoids (e.g., 2-AG)

 tub_intricated:
  - NT ( contained_by: SYNAPSE )
  - VPost ( contained_by: BD )

 context_intricated:
  - bAp_ctx ( contained_by: SOMA )

ms: behaviors POST

CaNDMAEnterMax: accumulator

CaNDMAEnterMax: ( active: 2x )
  type: accumulator
  contained_by: POSTSYNAPSE

  in_context: bAp_ctx
    hypothesis: NOT (Ca2+ full) AND
               (Na fullness OR Na mediumness)
      action: [Ca2+ increase]
      trace: 

CaNDMAEnterMed: accumulator

CaNDMAEnterMed: ( active: 4x )
  type: accumulator
  contained_by: POSTSYNAPSE

  in_context: bAp_ctx
    hypothesis: NOT (Ca2+ full) AND (Na emptiness)
      action: [Ca2+ increase]
      trace: 

CaNDMAEnterMedNotBap: accumulator

CaNDMAEnterMedNotBap: ( active: 4x )
  type: accumulator
  contained_by: POSTSYNAPSE

  in_context: NOT bAP_ctx
    hypothesis: NOT (Ca2+ full) AND (Na fullness)
      action: [Ca2+ increase]
      trace: 

CaNDMAEnterLow: accumulator

CaNDMAEnterLow: ( active: 12x )
  type: accumulator
  contained_by: POSTSYNAPSE

  in_context: NOT bAP_ctx
    hypothesis: NOT (Ca2+ full) AND (Na mediumness)
      action: [Ca2+ increase]
      trace: 

CaClearance: accumulator

CaClearance: ( active: 24x ) # Low
  type: accumulator
  contained_by: POSTSYNAPSE

  in_context: NOT bAP_ctx
    hypothesis: NOT (Ca2+ empty)
      action: [Ca2+ decrease]
      trace: None

VPostMax: accumulator

VPostMed: accumulator

VPostMin: accumulator

VPostClearance: accumulator

Il clearance lo facciamo qui nel container dove creaiamo anche i VPost, perche' altrimenti, se lo facessimo in DB, perderemmo l'aspetto temporale della contribuzione dei singoli POST.

POST-AMPA: Container

POST-AMPA
  type: container

  tub_intricated:
    - NT ( contained_by: ASTROCYTE/SYNAPSE )

  context_intricated:
    - Na ( contained_by: POSTSYNAPSE )

ms: behaviors AMPA

NaAMPAEnterMax: accumulator

NaAMPAEnterMax: ( active: 2x )
  type: accumulator
  contained_by: POST-AMPA

  in_context: NOT bAP_ctx
    hypothesis: (NT fullness)
      action: [Na increase]
      trace: 

NaAMPAEnterMed: accumulator

NaAMPAEnterMed: ( active: 4x )
  type: accumulator
  contained_by: POST-AMPA

  in_context: NOT bAP_ctx
    hypothesis: (NT mediumness)
      action: [Na increase]
      trace: 

POST-NA-CLEAR: Container

Il clearance lo mettiamo qui come container, perche' gli AMPA creano, e questo container pompa fuori. Qui non e' un problema di perdere l'integrazione temporale, perche' gli AMPA sono tutti uguali nel loro behavior. Abbiamo messo gli AMPA come container perche' cosi' possiamo modularne la numerosita'.

POST-NA-CLEAR
  type: container

  context_intricated:
    - Na ( contained_by: POSTSYNAPSE )

ms: behaviors NA-CLEAR

NaClearanceHigh: Interacting

NaClearanceLow: Interacting

TUN-POST-AMPA: Tuner

TUN-POST-AMPA
  type: tuner
  contained_by: BEH-POST

  tunes: BEH-POST/expansion/BEH-POST-IC

  tub_modulation: # in TUN agiamo su POS/ACT
   - posMod ( fullness: None, active: BEH-POST-IC/fullness, empty: 0x)  # riferimento a possible di BEH-PRE
   - actMod ( fullness: None, active: BEH-POST-IC/active, empty: BEH-POST-IC/emptiness)  # riferimento a active di BEH-PRE

  context_intricated:
  - TunPossible ( contained_by: DAY-N )

  tub_local:

  tub_intricated:

CheckTunPostAmpa: contextor

  CheckTunPostAmpa: ( active: 60x )
  type: contextor
  contained_by: TUN-POST-AMPA

  in_context: TunPossible_ctx
    condition:   tbd1
    out_context: TryTunUpPostAmpa_ctx

    condition:   tbd2
    out_context: TryTunDownPostAmpa_ctx

PossibleUpPostAmpaTun: accumulator

PossibleUpPostAmpaTun: ( active: 10x )
  type: accumulator
  contained_by: TUN-POST-AMPA

  in_context: TryTunUpPostAmpa_ctx
    hypothesis:  
      action: 
      trace: 

PossibleDownPostAmpaTun: accumulator

PossibleDownPostAmpaTun: ( active: 10x )
  type: accumulator
  contained_by: TUN-POST-AMPA

  in_context: TryTunDownPostAmpa_ctx
    hypothesis:  
      action: 
      trace: