ORGANIZATION OF HUMAN BRAIN — PENFIELD 439 



This must be the same sort of strip that the neurosurgeon had 

 stumbled upon when he placed his exploring electrode at random upon 

 the patient's hypersensitive cortex. A gentle electrical current, of 60 

 impulses per second for example, applied at a point on the temporal 

 cortex activated one strip of experience and only one at a time. Thus, 

 past experience was brought into the present, and the patient was 

 aware of a doubling of his consciousness. An experience on a South 

 African farm and present experience in a Montreal operating theater 

 are presented to consciousness simultaneously. The man himself 

 pointed out his awareness of the incongruity of the situation in his 

 initial exclamation. He made his own decision as to which was the 

 true present, and which must be the counterfeit. Patients often say, 

 "this is not a memory, it is more vivid than that." The mechanism 

 which the electrode has brought to light might well be considered 

 an essential element in the very basis of consciousness by use of the 

 following hypothesis : 



The pattern of each successive experience is somehow projected 

 from the centrencephalic system outward to the temporal cortex on 

 the two sides (including hippocampal regions perhaps) in a contin- 

 uous flow of patterned impulses, a flow that is interrupted only by 

 deep sleep or by coma. It would seem that the projection could only 

 come from this central integrating area, since it is there and only there 

 that all sensory and psychical elaborative circuits converge. Each 

 experience is made up of those elements of sensation of which a man 

 is, for the moment, aware, together with his interpretation of each 

 experience and the attendant emotion. 



It must be that this outflow of nerve impulses creates a ganglionic 

 pattern in the temporal cortex although perhaps not wholly there. 

 Furthermore, it may be that a reprojection of impulses back from the 

 temporal cortex to the centrencephalic system occurs invariably like 

 a reflection in a mirror, a reflection of which the individual takes 

 cognizance. That may seem an extraordinary hypothesis, and yet if 

 stimulation with a simple electrical current can recreate a total ex- 

 perience, the reflection mechanism exists. The neurone record is there 

 and the records of previous similar experiences are there also so that 

 judgments of familiarity or strangeness may be made and other elab- 

 orative processes. I suggest that reflection or reverberation back into 

 the centrencephalic or integrative circuits must occur normally. 



I would surmise then that the neurone processes involved in the 

 original creation of the record of present experience are those involved 

 in the act of attention, and that the instantaneous reprojection or re- 

 flection of the record back again together with some sort of reflection 

 of previous similar experience constitutes an essential neurone mecha- 

 nism in consciousness. 



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