BIO 588 lecture 5 I/EPSPS

excitation

postsynaptic are more likely to fire APs +

inhibition

postsynaptic neuron are less likely to fire APs -

threshold potential

the critical level to which the membrane potential must be depolarized in order to initiate an action potential

excitation makes the postynaptic neuron

more likely to reach threshold

inhibition makes the postynaptic neuron

less likely to reach threshold

EPSPs

the input must make the postsynaptic neuron more likely to reach threshold

IPSPs

the input must make the postsynaptic neuron less likely to reach threshold

postsynaptic currents

change in the membrane current in the postsynaptic current

change in membrane potential is measured in

current clamp

change in membrane current is measured in

voltage clamp

reversal potential

the MP of a receiving neuron at which the action of a given neurotransmitter causes NO NET CURRENT FLOW

What determines postsynaptic excitation and inhibition?

reversal potentials and threshold potentials

if the reversal potential is more positive than the threshold

excitation results

inhibition occurs if the

reversal potential is more negative than threshold

synaptic integration

one neuron receives thousands of signals and integrates all info to “decide to fire”

Where do APs typically “decide to fire” from

the axon hillock

lambda is

the dendritic length constant

the amplitude of passive current flow along a dendrite

decreases with distance depending on resistance

the dendritic length constant is the distance

where depolarization is 37% of its origin

temporal summation

inputs combined because of time proximity

spatial summation

inputs combined because of physical proximity