12) Assume a neuron has four inputs, A, B, C, and D. A, C, and D are glutamaterg
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Question
12) Assume a neuron has four inputs, A, B, C, and D. A, C, and D are glutamatergic while B is GABAergic. The membrane's resting potential is-70 mV, and the threshold potential is-55 mV. These inputs can change the postsynaptic potential by the following amounts: 18 B 11 A: 10 mV B:8 mV C: 15 mV D: 4 mV 25 For all of the following, note if an action potential would fire or not. Please include in your answer the membrane potential after all inputs are summed, Note that I did not define if the potential changes are each, 10 points total) ?? a. Calone - S 15 ?? b. B+C- c. B+C+ D- d. A+C+B ??Explanation / Answer
GABAergic synapses cause hyperpolarization and thus are inhibitory in function I.e. they produce IPSP or inhibitory post synaptic potential in post synaptic neuron whereas glutamate produces depolarization and EPSP or excitatory post synaptic potential. A depolarization is induced by a positive potential whereas a hyperpolarization is induced by a negative potential.
a) C is glutamatergic and would induce EPSP of +15mV
Resting membrane potential -70mV
= -70+15= -55mV
b) B+C
B is GABAergic and would induce IPSP of -8mV
= -70+15-8= -63mV
C) B+C+D
D is glutamatergic and would induce a EPSP of +4mV
= -70mV-8+15+4 = -59 mV
D)A+B+C
A is glutamatergic and would induce a EPSP of +10mV.
=-70+15-8+10=-53 mV
E)A+B+C+D
= B is GABAergic whereas A,C and D are glutamatergic
-70mV+10-8+15+4= -49mV
All the cummulative potentials about -55mV or more positive than -55mV which is the threshold will fire up an action potential.
a, d and e combinations of neurons will fire up an action potential.
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