Practice question

Alpha rhythm at 8-13 Hz indicates synchronous idling of visual cortex during eyes-closed relaxed wakefulness maintained by thalamic pacemaker activity. When attention increases, eyes open, or emotional excitement occurs, thalamocortical circuits desynchronize due to enhanced reticular activation, cholinergic drive and increased synaptic bombardment, suppressing alpha amplitude. Faster low-amplitude beta activity spanning 13-30 Hz emerges reflecting active information processing and increased cortical excitability. Theta and delta dominate drowsiness and sleep, gamma appears during binding, but classical electrophysiological shift from relaxed alpha to alert excitement is replacement by beta.