PGY 300 Lecture 6: Neurophysiology - Memory Mechanisms
11 Feb 2017
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Information stored by a collection of neurons (like a hologram) Information stored by a single neuron (the (cid:1445)grandmother cell(cid:1446); (cid:1445)jennifer aniston neuron(cid:1446) in hippocampus involved with short term memory) One presynaptic neuron sends signal to multiple postsynaptic neurons. Modulation of network more/less sensitive to stimuli. Many presynaptic cells send signal to one postsynaptic cell. Rod system trying to see in dim light. Important: if one or two neurons give weak signal, it won"t reach threshold level at trigger zone signal ignored. Many neurons giving that one postsynaptic neuron same information large signal summated reaches threshold action potential. Postsynaptic neuron receives signal from multiple presynaptic neurons at the same time. When responses are close enough to each other within a short period of time, they can summate. With summation, an inhibition signal can take away (hyperpolarize) from the summation of depolarizing signals may not reach threshold. Hyperpolarize presynaptic terminal (gaba, glycine, cl channels) not depolarized enough to activate ca channels (indirect)
