PSYC-375 Lecture Notes - Lecture 1: Tryptophan Hydroxylase, Resting Potential, Apomorphine
11 Mar 2019
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Electrical messages in neurons the action potential: action potentials are generated at the segment of axon that touches the cell body, called the axon initial segment. It is here that the neuron determines whether to fire an action potential. If the neuron receives sufficient stimulation (from other neurons) that moves down the dendrites and reaches threshold at the axon initial segment, an action potential will be initiated. In this process, voltage-dependent sodium (na+) channels will open, resulting in. Interestingly, the membrane potential actually dips below -70 mv briefly before all the voltage-dependent k+ channels close. Na+ k+ pumps actively move na+ ions out of the neuron and bring k+ back in to reset the concentrations of these ions: now the neuron is ready to fire another action potential. Since the concentration of ca2+ ions is higher outside of the neuron and the ions are positive, they are drawn into the presynaptic terminal.
