The code provided models a presynaptic neuron component involved in the initiation of synaptic transmission. This model is focused on simulating the conditions under which an action potential can lead to neurotransmitter release from the presynaptic terminal.
Action Potential Initiation:
v
) of the presynaptic neuron surpasses a defined threshold (thresh
). This mimicry represents the biological process wherein a neuron’s voltage must exceed a certain level to trigger the opening of voltage-gated ion channels.Thresdholding Mechanism:
thresh
parameter symbolizes the critical membrane potential level necessary for the neuron's axon hillock to initiate an action potential. Biologically, this would relate to the voltage at which enough sodium channels open to cause a rapid depolarization.Spike Detection:
spk
and spk_internal
variables are utilized to monitor the occurrence of a “spike” or an action potential. spk
is the output, indicating to other components or processes in the model that an action potential has occurred. spk_internal
ensures that the spike is only registered once for each depolarization event.Neurotransmitter Release:
newspike()
function called when the threshold is exceeded is the release of neurotransmitters into the synaptic cleft. This simulates how a spike leads to vesicle fusion with the presynaptic membrane, a crucial step in synaptic communication.Point Process:
The code is a streamlined representation of presynaptic mechanisms pivotal for synaptic transmission, focusing particularly on the electrical conditions necessary for neurotransmitter release. By setting a voltage threshold, the model captures the essence of electrical excitability required to trigger presynaptic activity, crucial for neuron-to-neuron communication in the brain.