Afferent discharges to the cerebral cortex from peripheral sense organs

IN a recent paper by Adrian & Moruzzi [1939] the electrical activity of the motor area of the brain was correlated with the discharge of impulses in the pyramidal tract. It was found that there was in general a close agreement between the larger potential waves of the cortex and the groups of impulses in the pyramidal discharge, and from this various conclusions could be drawn as to the activity of the cortical nerve cells. For further progress it seemed essential to have a survey of the sensory area made from the same point of view. A great deal is already known about the electrical activity of the various regions of the cortex which receive messages from the sense organs: the reactions of the visual area have been analysed in detail by Bartley & Bishop [1933], those of the auditory area in the cat by Bremer [1938] and of the sensory area in the monkey by Marshall, Woolsey & Bard [Bard, 1938], and general surveys have been made by Kornmiiller [1937], by Gerard, Marshall & Saul [1936] and Derbyshire, Rempel, Forbes & Lambert [1936]. Much of the present work has merely confirmed what has been done already, but the recording of nerve impulses as well as cortical potentials can add some details to the picture of events taking place in the brain, and in existing circumstances it seemed advisable to publish what had been done. The greater part was written before the appearance of two important papers by Marshall [1941] and Marshall, Woolsey & Bard [1941] covering the same field. This must excuse the absence of detailed reference to the many points of agreement and to the few discrepancies between the present results and theirs. It is scarcely necessary to point out how much the present work is indebted to their earlier paper which showed the precise localization of electrical reactions in the sensory area.