NESC 2470 Chapter Notes - Chapter 19: Brainstem, Reticular Formation, Cholinergic
21 Jun 2015
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Document Summary
Measurement that enables us to glimpse the generalized activity of the cerebral cortex. Used to help diagnose neurological conditions and research purposes (sleep) 2 dozen electrodes are fixed to standard positions on the head and connected to amplifiers and recording devices. Small voltage fluctuations are measured between selected pairs of electrodes. Eeg measures voltage generated by the currents that flow during synaptic excitation of the dendrites of pyramidal neurons in the cerebral cortex. Take thousands + of underlying neurons, activated together to generate and eeg signal big enough to see. Amplitude of eeg signal depends on how synchronous the activity of the underlying neuron is. When group of cells is excited simultaneously, they sum to generate 1 large surface signal. When each cell receives excitation at different times, the summed signals are meagre and irregular. Magnetoencephalography (meg) = another way to record the rhythms of the cerebral cortex. Better than eeg at localizing sources of neural activity.
