Question

Explain the difference between EPSP and IPSP.  Which of the two will facilitate/inhibit a neuron? How do these affect the firing rate of the postsynaptic neuron?  

Answer 1

Answers

EPSP (excitatory post synaptic potential) is a post synaptic potential that makes the post synaptic neurons more likely to fire an action potential. opening gated ion chanels in the post synaptic neurons allows the positive charged ions(sodium ions ) to enter inside. when multiple EPSP occures on a single post synaptic membrane , their combined effects is sum of individuals EPSP. larger EPSP results in greater membrane depolarization and thus increases the chance that post synaptic cell reaches the threshold for firing an action potential. the neurotransmitter most often assosiated with EPSP is amino acid glutamate , and is the main excitatory neurotransmitter in central nervous system of vertebrates.

IPSP(inhibitory post synaptic potential ) is synaptic potential that makes a postsynaptic neurons less likely to generate action potential. inhibitory presynaptic neurons releases neurotransmitters that then binds to the post synaptic receptors , this induces a change in permiability of post synaptic neuronal membrane to particular ions(chloride ions permiability increases). the post synaptic membrane potential became more negetive than resting membrane potential , called hyperpolarisation. this makes the post synaptic membrane less likely for depolarisation to sufficiently occur to generate an action potential in post synaptic neuron. GABA is common inhibitory neurotransmitter . IPSP allows less firing in post synaptic neurons.