PSYC 3800 Lecture Notes - Lecture 2: Voltage Clamp, Current Clamp, Squid Giant Axon
Document Summary
Relative ability for the charge to migrate. Difference in charge between anode and cathode. Several stimuli control the opening/closing of ion channels. Threshold, rising phase, overshoot, falling phase, and undershoot (hyperpolarization) The action potential has for important qualities that relating to neuronal communication: there is a threshold for initiation. The vm changes as a function of ohm"s law (v=i/g or v=ir: the action potential is all-or-none, the action potential conducts without decrement, the action potential is followed by a brief refractory period. All-or-none : cross threshold value for action potential to occur. Chain of events that initiates the action potential. Artificially - inject current into a neuron using a microelectrode (two electrodes- 1 stimulating, 1 recording) Firing frequency reflects the magnitude of the depolarizing current. Small amount of current- cell may fire 1 hz (1/sec) Progressive steps lead to increases in firing rate. Depends on the absolute and relative refractory periods.