# soma.md Qui comprendiamo: - SOMA: il soma - VGSC-SOMA-H: Na ion channels. Open only when VDB high - VGSC-SOMA-M: Na ion channels. Open only when VDB medium - VGSC-SOMA-L: Na ion channels. Open only when VDB low ## SOMA: Container --- **Simplified verifiable behaviors**: — ms: - Resting at -70 mV: Leak channels + pumps (keep at resting) - VDB Depolarization : ~1-2 ms: Na⁺ enters (some VGSCs open) - Opened VGSC and then remain closed for a refractory period - Spike if depolarized above threshold: to -50 mV - Ca2+ enter - Repolarization to -70 mV: ~1-2 ms: K⁺ exits (VG K⁺ channels open) ← NOT pumps! - After-hyperpolarization: ~5-20 ms: K⁺ channels still open — secs: - Return to exact -70 mV: ~100-1000 ms: Na⁺/K⁺ pumps restore gradients - Ca2+ accumulation — mins: - VGSC modulation --- **G expression**: — ms: - based on VDB, VGSC open and let Na+ in. VGSG then go into refractory - if Na fullness then ApCtx. Here the threshold is based only on the integration of Na+ - increase SpikeTrainTraces (fast at spike) - increase Ca2+ traces - decrease Na: fast pump which decreases Na+, we do not model K+ -- there is a tug of war between Na entering and exiting. Na can reach fullness only if VDB increases fast (derivative) - there are 2 context: ApCtx and RefractorySoma imlemented with timers and tunable - decrease SpikeTraintraces slow, only if away from spiketrain this is empty - Tune: -- The threshold is tuned during the spiketrain. Low threshold at rest, to increase sensitivity, threshold increase during spike to increase discrimination — secs: - SpikeTrainTraces — mins: - Tune: -- refractory lenght --- **Tubs:** - **VDB**: dendrites deliver current - **Na**: are a proxy for the Coulombs of charge building up on the somatic membrane. They are used to check threshold, but also to mimic Na+ and K+ pumping - **Ca2+**: Medium term traces to guide tuning and Night development. It is a local trace, ATP is a global (Astrocyte) - **SpikeTrainTraces**: sono le tracce che consentono al neurone di far partire il Tuning neuronale, quando e' lontano da uno spike-train, ovvero e' in riposo. --- ```Gen container: SOMA expansion: - VGSC-SOMA-H ( fullness: 50x, active: 20x, emptiness: 10x ) # modulated_by: VGSC-SOMA-H-TUN # possible/actual - VGSC-SOMA-M ( fullness: 50x, active: 20x, emptiness: 10x ) # modulated_by: VGSC-SOMA-M-TUN # possible/actual - VGSC-SOMA-L ( fullness: 50x, active: 20x, emptiness: 10x ) # modulated_by: VGSC-SOMA-L-TUN # possible/actual tub_local: - VDB - Na - Ca2+ tub_intricated: - SpikeTrainTraces ( contained_in: DAY-N ) ``` ### ms: SOMA #### CheckVDB: Episode As dendrites deliver current (VDB​), the soma acts like a capacitor. It "stores" this charge in the form of membrane potential. This contextualizes VGSC-SOMA to open ion channels that let Na+ ions in. This only applies if not ApCtx, or in other words, SOMA is not in refractory period. ```Gen episode: CheckVDB contained_by: SOMA context: Fixed rf: ( active: 60x ) condition: (VDB fullness ) AND NOT ApCtx out_context: VDBMax condition: ( VDB mediumness ) AND NOT ApCtx out_context: VDBMedium condition: ( VDB emptiness ) AND NOT ApCtx out_context: VDBLow ``` #### SomaSpike: Episode Qui siamo nella fase effettiva di spike, non refractory che viene dopo. Fa da contesto di durata fra un RF ed un altro. ```Gen episode: SomaSpike contained_by: SOMA context: Fixed rf: ( active: 60x ) condition: ( Na fullness ) AND ( NOT SomaRefractory ) out_context: ApCtx out_context: bApCtx ``` #### APInteracting: Interacting Durante la fase effettiva di spike, eliminiamo Na accumulati e riempiamo per fase di refractory ```Gen interacting: APInteracting contained_by: SOMA context: ApCtx rf: ( active: 8x ) hypothesis: NOT Na empty action: [ decrease Na ] trace: hypothesis: NOT RefractorySoma full action: [ increase RefractorySoma ] trace: ``` #### ClearRefractorySoma: Interacting ```Gen interacting: ClearRefractorySoma contained_by: SOMA context: Fixed rf: ( active: 8x ) hypothesis: NOT RefractorySoma empty action: [ decrease RefractorySoma ] trace: ``` ### sec: SOMA ### min: SOMA #### VGSC-SOMA-TUN: Tuner ```Gen tuner: VGSC-SOMA-TUN contained_by: SOMA tunes: SOMA/expansion/VGSC-SOMA context_intricated: - TunPossible ( contained_by: DAY-N ) tub_local: tub_intricated: ``` ##### Check: Episode ```Gen context: episode contained_by: VGSC-SOMA-TUN context: TunPossible rf: ( active: 60x ) condition: out_context: TunSomaVcgg ``` ##### ?: Interacting ```Gen interacting: ? contained_by: TUN-PRE-VGCC context: TunSomaVcgg rf: ( active: x ) hypothesis: action: trace: ``` ## VGSC-SOMA-H: Container Voltage Gated Sodium Channel: difficult to open (High) ```Gen container: VGSC-SOMA-H tub_local: Ready ( ) tub_intricated: Na ( contained_in: SOMA) ``` ### sec: VGSC-SOMA-H #### NaEnterH: Interacting Se metto il controllo sulla (NOT Ready fullness) il VGSC puo' far entrare un numero di Na non superiore ad un massimo. ```Gen interacting: NaEnterH contained_by: VGSC-H-SOMA context: VDBMax AND ( NOT RefractoryH ) rf: ( active: 1x ) hypothesis: ( NOT Na fullness ) AND ( NOT ReadyH fullness ) action: [ Na increase, ReadyH increase ] trace: None ``` ##### CheckRefractoryH: Episode Il check su refractory deve essere fatto ad un RF maggiore della eliminazione di Refractory. Questo perche' e' un era nella qualle avviene l'episodio. ```Gen episode: CheckRefractoryH contained_by: VGSC-H-SOMA context: NOT RefractoryH rf: ( active: 60x ) condition: ( ReadyH fullness ) out_context: RefractoryH ``` ##### RefractoryH: Interacting Questo episodio deve girare varie volte nell'ambito del contesto di refractory che viene controllato ad un RF maggiore. ```Gen interacting: RefractoryH contained_by: VGSC-H-SOMA context: RefractoryH rf: ( active: 1x ) hypothesis: NOT ( Ready emptyness ) action: [ Ready decrease ] trace: None ``` ## VGSC-SOMA-M: Container Voltage Gated Sodium Channel ```Gen container: VGSC-SOMA-M ``` ### sec: VGSC-SOMA-M #### Interacting2 ```Gen interacting: ?? contained_by: VGSC-M-SOMA context: xxx rf: ( active: 1x ) hypothesis: action: trace: None ``` ## VGSC-SOMA-L: Container Voltage Gated Sodium Channel ```Gen container: VGSC-SOMA-M ``` ### sec: VGSC-SOMA-L #### Interacting3 ```Gen interacting: ?? contained_by: VGSC-L-SOMA context: xxx rf: ( active: 1x ) hypothesis: action: trace: None ```