Struct VesiclePool 

pub struct VesiclePool {
    pub available_fraction: f64,
    pub utilization: f64,
    pub baseline_utilization: f64,
    pub tau_recovery: f64,
    pub tau_facilitation: f64,
    pub total_vesicles: usize,
    pub docked_vesicles: usize,
    pub reserve_pool: usize,
    pub recycling_pool: usize,
    pub calcium_cooperativity: f64,
    pub calcium_half_max: f64,
}

Vesicle pool dynamics implementing the Tsodyks-Markram model.

The model tracks three pools of vesicles:

1. Ready Releasable Pool (RRP) - immediately available for release
2. Reserve pool - can be recruited to RRP
3. Released/recycling pool - recovering from release

Key equations:

• dx/dt = (1 - x)/τ_rec - Uxδ(t_spike) (recovery from depression)
• du/dt = (U₀ - u)/τ_facil + U₀(1-u)δ(t_spike) (facilitation)

Fields

available_fraction: f64

Fraction of available vesicles (0 to 1).

utilization: f64

Utilization parameter (effective release probability, 0 to 1).

baseline_utilization: f64

Baseline utilization (U₀).

tau_recovery: f64

Recovery time constant from depression (ms).

tau_facilitation: f64

Facilitation time constant (ms).

total_vesicles: usize

Total number of vesicles in readily releasable pool.

docked_vesicles: usize

Number of docked vesicles ready for release.

reserve_pool: usize

Reserve pool size.

recycling_pool: usize

Recycling pool size.

calcium_cooperativity: f64

Calcium sensitivity exponent.

calcium_half_max: f64

Half-maximal calcium concentration for release (μM).

Implementations

impl VesiclePool

pub fn new() -> Self

Create a new vesicle pool with default parameters.

pub fn with_params( baseline_u: f64, tau_rec: f64, tau_facil: f64, ) -> Result<Self>

Create a vesicle pool with custom parameters.

Arguments

• baseline_u - Baseline utilization (0 to 1)
• tau_rec - Recovery time constant (ms)
• tau_facil - Facilitation time constant (ms)

pub fn depressing() -> Self

Create a depressing synapse (high U, fast recovery).

Typical for cortical excitatory synapses.

pub fn facilitating() -> Self

Create a facilitating synapse (low U, slow recovery).

Typical for some cortical and hippocampal synapses.

pub fn update(&mut self, dt: f64) -> Result<()>

Update vesicle pool dynamics over time.

Implements continuous recovery and facilitation decay.

Arguments

• dt - Time step (ms)

pub fn calcium_release_probability(&self, calcium_concentration: f64) -> f64

Calculate release probability given calcium concentration.

Uses Hill equation: P = [Ca]^n / ([Ca]^n + K^n)

Arguments

• calcium_concentration - Presynaptic calcium concentration (μM)

pub fn release(&mut self, calcium_concentration: f64) -> Result<usize>

Trigger vesicle release (spike arrives).

Updates both depression and facilitation according to Tsodyks-Markram model.

Arguments

• calcium_concentration - Presynaptic calcium concentration (μM)

Returns

Number of vesicles released

pub fn release_probability(&self) -> f64

Get current release probability (without calcium dependence).

pub fn reset(&mut self)

Reset vesicle pool to initial state.

Trait Implementations

impl Clone for VesiclePool

fn clone(&self) -> VesiclePool

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for VesiclePool

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for VesiclePool

fn default() -> Self

Returns the “default value” for a type.