FoundationalConceptsNeuroscience

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Time (milliseconds)

Membrane^

potential

(mV)

BR

Figure 5.4. Hyperpolarization (left) may result from opening potassium chan-

nels or chloride channels (right).

Membrane^

potential

(mV)

&

8

a

?

rT

Time (milliseconds)

Figure 5.5. Depolarization (left) may result from opening sodium channels or

calcium channels (right).

What is happening when a signal moves through a neuron? As stated
above, when observing the membrane potential in a cell at rest (al-
though a neuron is never really at rest; interesting things are always
going on), there may be small deviations of hyperpolarization and
depolarization around the resting potential. But nothing really big