Cortex

“ But when perceptions become complex, and one primary evokes a number of secondary perceptions—in other words, when the cells of the corresponding portions of grey matter in the cortex of the brain are set vibrating by a variety of complex and conflicting molecular motions, the feeling of free-will inevitably arises. ”

“ This seems to indicate that in some way or another the movements that pass to the nerve cells of the cerebral cortex are there transformed into sensations, thoughts and ideas, into what we group together and think of as a different and separate kind of thing and call the mind. ”

“ In short, a consistent spiritualistic theory of the relations of mind and body is simply impossible, and we therefore turn to the only hypothesis which remains — the hypothesis according to which the physical series is the condition of the mental. This means that physical events take place independently, according to laws of their own, and that a few of them — namely, certain events in the cortex — are the indispensable condition for the occurrence of mental events. ”

“ The soul consists of the totality of cerebral functions. This soul or thought organ in man, a certain area of the cerebral cortex, acts in accordance with the same laws of psychophysics as in the other mammals. ”

“ It may be, however, that the phenomena were due to the fact that in these animals the cortical 'centres' for vision reach outside of the occipital zone, and that destruction of the latter fails to remove them as completely as in man. This, as we know, is the opinion of the experimenters themselves. For practical purposes, nevertheless, and limiting the meaning of the word consciousness to the personal self of the individual, we can pretty confidently answer the question prefixed to this paragraph by saying that the cortex is the sole organ of consciousness in man. ”

“ Yet when we consider that the brain, the physical brain, is the exceedingly delicate organ by means of which we think and feel and desire, love and hate and worship, it is not surprising that that organ should be modified by the work it has to do; to put the matter picturesquely, it is as if every familiar train of thought made a rut in the nervous substance of the brain into which the thoughts run lightly of their own accord, and out of which they can only be got by an effort of will. ”

“ But reasoning upon the phenomenon which I have now described, according to all that we can learn from our own experience or from observation of others, I reach the conclusion that the mind, the thinking and reasoning entity, can and does, in profound sleep of the body and the brain, employ itself upon a subject that has occupied us when awake, and can perceive new relations of that subject, which had not before occurred to us, without the activity of any portion of the nerve-center which is called the brain. ”

“ WHATEVER that thing, fact, function, or idea which we call mind may be, or whether the brain, as is generally believed, is or is not its sole organ of manifestation, it is universally admitted that varying bodily conditions are accompanied by related variations of mental states. ”

“ Contemplate, then, if you can, a duplex intelligent brain, in a state of activity, but cut off from all communication with the external world through the media of the senses and from all control over the body;—in fact, an isolated, self-acting, self-contained mechanism, the organ of intelligence and emotion. ”

“ All these mental acts, and many others, are developed through the action of the brain; not that the brain and the mind are the same, or that the brain secretes memory, imagination, or the ideas of truth and justice, as the stomach secretes the gastric juice. But rather, as the nerve of the eye, stimulated by the subtile waves of light, occasions the notion of color, so the brain, called into action by the mysterious influences of the immaterial soul, gives rise to all the intellectual, emotional, and voluntary activities of mankind. ”

“ Here we have, then, a purely subjective mental activity acting through a mechanism of which the boy is quite ignorant, and which he is unable to control, and producing that action on the vessels of dilation or contraction which, as we have seen, is the essential condition of brain activity and the evolution of thought, and is related to the quickening or the abolition of consciousness, and to the activity or abeyance of function in the will centers and upper convolutions of the brain, as in its other centers of localization. ”

“ Go on!” implored the artists, writers, lawyers, and physicians.
“I suppose,” my friend continued, “that every one of us will concede that the human brain has always been made of the same material, that ages ago it was composed of the same parts, that its actions were governed by the same laws, that its surface was composed of the same convolutions, and that ages ago even there was deposited in these convolutions that wonderful gray matter, surrounded with white matter and composed of nerve-cells, which modern physiologists designate as the seat of thought, reason, judgment, and talent. ”

“ And this philosopher's well-known formula assumed: there exists a spiritual, non-extended, indivisible substance, an objective, immortal entity, superadded to and independent of brain, which thinks, feels, and wills—a substance cognizable by self-consciousness alone, and which is in fact the "thinking principle" or proper "soul." Mind thus becomes absolutely and wholly an extra-cerebral product, and the possible offspring of activity on the part of the "soul" alone. ”

“ We may easily dispense with the phrase "substance of the mind," if we wish to avoid a term of matter; but if mind is constituted by the perception of feelings excited in the nervous system, what is it that perceives? Is there a something that is reached by the feelings which constitute sensations in the great nerve-center, which takes cognizance of them, which combines them into portions of consciousness, or is consciousness nothing but a succession of sensations, and if so, what is "thought"? ”

“ But evidence has yet to be sought that the consciousness of ideas, whether they be intellectual or emotional, has its seat elsewhere than in that part of the brain where these ideas are formed, namely, in the cortical layer of the cerebral convolutions. ”

“ But, as a matter of fact, like other fundamental questions, this is exactly as it has ever been, and so far as Science is concerned, we are just as much in the dark respecting it as men ever were. Though the philosophers of former days were unaware of all the departmental details of brain activity, they understood as well as we do the essential point, that in our composite nature soul and body form one being, whose every operation is of mixed character like itself. ”

“ The Brain is a center of consciousness with avenues of perception and impulse and departments that by aggregation, separation or association, enable the Individual Intelligence to determine the relation in time, or duration, force and orderly relation of perceptions, desires, motives, actions (or thoughts and feelings) as to sequence or results.
This whole conscious realm is the Mind. It is the inner chamber of the Soul. It is in no sense an entity. The actor, the real entity, is the Individual Intelligence. ”

“ But the experience leaves its 'unimaginable touch' on the matter of the convolutions, and the next impression which a sense-organ transmits produces a cerebral reaction in which the awakened vestige of the last impression plays its part. Another sort of feeling and a higher grade of cognition are the consequence. 'Ideas' about the object mingle with the awareness of its mere sensible presence, we name it, class it, compare it, utter propositions concerning it, and the complication of the possible consciousness which an incoming current may arouse, goes on increasing to the end of life. ”

“ Take them in their union and we see at once what the brain is—a great exchange office or switchboard, where the stimuli that come from the outer world are received and switched on to their responsive movements. We see also what the mind is, it is the whole scheme of our activity, and we see how it functions by bringing the field of our activity to consciousness. ”

“ If each 'idea' stand for some special nascent nerve-process, then the aggregate of these nascent processes might have for its conscious correlate a psychic 'fringe,' which should be just that universal meaning, or intention that the name or mental picture employed should mean all the possible individuals of the class. Every peculiar complication of brain-processes must have some peculiar correlate in the soul. To one set of processes will correspond the thought of an indefinite taking of the extent of a word like man ”

“ I have already said that if we suppose causation to proceed from brain to mind, we must suppose this essential requirement of equivalency between the cerebral causes and the mental effects to be satisfied somewhere. ”

“ Thus, we pass from the functions of the nervous system, by way of sensation, feeling and presentation, to consciousness in the formation of ideas and in the train of ideas, which, in turn, involves attention, apperception, and will, not forgetting phenomena such as association, imagination and emotion. ”

“ Modern psychology has rendered a service of far-reaching practical benefit in showing more definitely the intimate connection between the brain and mental action. In this connection of body and soul the two are correlated; the brain is organic to the functions of the soul. ”

“ Thus, when we speak of nerve-force and mind as having a most intimate relation, no one is found to dispute it; whereas, when we talk about Brain and Mind having this intimate relation, and Mind being the function of the brain, there are a great many who will rise up against us and charge us with materialism, and atheism, and all the other deadly sins of that kind. ”

“ And it is this discipline which gives us the power of performing, unconsciously to ourselves, these elaborate mental operations; because I hold that a very large part of our mental life thus goes on, not only automatically, but even below the sphere of our consciousness. And you may easily understand this if you refer to the diagram which I drew just now on the black-board. You saw that the Cerebrum, the part that does the work, what is called the convoluted surface of the brain, lies just immediately under the skull-cap ”

“ Some think they make the notion of it clearer by calling the mental state and the brain the inner and outer 'aspects,' respectively, of 'One and the Same Reality.' Others consider the mental state as the 'reaction' of a unitary being, the Soul, upon the multiple activities which the brain presents. ”

“ The second kind of sophistication to which the world of common sense has been subjected is derived from the psychologists and physiologists. The physiologists point out that what we see depends upon the eye, that what we hear depends upon the ear, and that all our senses are liable to be affected by anything which affects the brain, like alcohol or hasheesh. Psychologists point out how much of what we think we see is supplied by association [127] or unconscious inference, how much is mental interpretation, and how doubtful is the residuum which can be regarded as crude datum. ”

“ Were our minds and senses so expanded, strengthened and illuminated as to enable us to see and feel the very molecules of the brain, were we capable of following all their motions, all their groupings, all their electric discharges, if such there be, and were we intimately acquainted with the corresponding states of thought and feeling, we should still be as far as ever from the solution of the problem—How are these physical processes connected with the facts of consciousness? ”

“ Surely no one who is cognisant of the facts of the case, nowadays, doubts that the roots of psychology lie in the physiology of the nervous system. What we call the operations of the mind are the functions of the brain, and the materials of consciousness are products of cerebral activity. ”

“ I shall now proceed to inquire how far it is conceivable that the mind or soul, its usual channels of communication with external objects, the senses namely, being suspended and unemployed, may enter into direct relation with other minds.
There is a school of physiological materialists, who hold that the mind is but the brain in action; in other words, that it is the office of the brain to produce thought and feeling. ”

“ In my last talk, in treating of Habit, I chiefly had in mind our motor habits,—habits of external conduct. But our thinking and feeling processes are also largely subject to the law of habit, and one result of this is a phenomenon which you all know under the name of 'the association of ideas.' To that phenomenon I ask you now to turn.
You remember that consciousness is an ever-flowing stream of objects, feelings, and impulsive tendencies. ”

“ Everything seems, therefore, to happen as if consciousness sprang from the brain, and as if the detail of conscious activity were modelled on that of the cerebral activity. In reality consciousness does not spring from the brain, but brain and consciousness correspond because equally they measure ... the quantity of choice that the living being has at its disposal” (Creative Evolution, pp. 266–7) . ”

“ Such are the only means by which man receives sensations, perceptions, and ideas. These successive modifications of his brain are effects produced by objects that give impulse to his senses; they become themselves causes, producing in his soul new modifications, which are denominated thought, reflection, memory, imagination, judgment, will, action ”

“ It contends that the important happenings are the brain-changes—which are causally connected—and that our thoughts, or corresponding states of consciousness, merely accompany the brain-changes, just as the shadow of a horse may be said to accompany the horse. ”

“ It is enough to remind you that, whatever view be held, it is universally accepted that every mental process is accompanied by a physical process in the brain; that, parallel with every series of thoughts, perceptions, or feelings, there goes a series of physical changes of some kind in the brain neurons. And, conversely, whenever this same series of physical changes occurs the corresponding series of mental processes, that is, of states of consciousness, arises. ”