Rectangular Electroanesthesia Currents and the Primary Visual Pathways
The application of rectangular electroanesthesia (EA) currents from the nasion to the inion of monkeys produces unresponsiveness sufficient for surgical intervention (1,2). A marked suppression of evoked potentials in the auditory (3), sensory (4) and visual (5) cortex was found to be coincident with the unresponsive state. Evoked potentials recorded at the thalamic level were affected to a lesser extent. The results of electronmicroscopy studies of biopsies of cortical tissue taken before, during and after the application of EA currents show that these currents produce a reversible change in the distribution of the number of synaptic vesicles per ending in the vicinity of the presynaptic membrane (6). However, the mechanisms underlying the production of unresponsiveness are not yet known. Knowledge of these mechanisms may prove to be beneficial for the efficacious clinical application of electroanesthesia.
KeywordsGanglion Cell Retinal Ganglion Cell Squirrel Monkey Occipital Cortex Firing Pattern
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