A and P chp 12 pt 2 - Cellular info processing summation: integrating EPSPs and IPSPs

what is postsynaptic potential?

develops in postsynaptic membrane in response to a neurotransmitter

what are the two types of postsynaptic potential?

1. Excitatory postsynaptic potential = EPSP

2. Inhibitory postsynaptic potential = IPSP

What does EPSP cause?

depolarization of the postsynaptic membrane

what does IPSP cause?

hyper polarization of postsynaptic membrane

why do postsynaptic potential combine through summation?

• individual postsynaptic potentials have minimal effect on the postsynaptic membrane

• summation= sums the postsynaptic potentials = end results is action potential generation in the postsynaptic cell

what are the two types of summation?

1. temporal

2. spatial

   • both ESPS and ISPS are able to summate spatially and temporally, the postsynaptic neuron will respond based on the number of ESPS or ISPS stimuli coming in.

describe temporal summation

• increased FREQUENCY of stimulus applied at a single synapse.

• The degree of depolarization of the postsynaptic membrane increases every action potential causes the release of a neurotransmitter from the pre-synaptic neuron

• Key concept: a series of small steps bring the hillock to the threshold

describe spatial summation

• simultaneous stimuli applied at different locations have a cumulative effect

• multiple synapses activated simultaneously