Cortical unit responses to visual stimuli in nonanesthetized cats.

This paper represents the beginning of an attempt to improve our understanding of the nervous system by studying normal activity in single cells. The approach we have em­ ployed involves recording from single units in the unanesthetized unrestrained animal. We have done this in order to examine dis­ charge patterns in various states such as wakefulness and natural sleep, and to influ­ ence these patterns, if possible, by physi­ ologic stimuli. We have thus hoped to com­ bine the advantages of two important recent advances in electrophysiology, the develop­ ment of methods for the chronic implanta­ tion of electrodes on the one hand, and the use of microelectrodes on the other. We have felt that such a combination might be espe­ cially promising in studies of the higher cen­ tral nervous system, where such things as anesthetics, brain stem sections, and paralyz­ ing drugs are most likely to distort normal neuronal discharges.