THE CONNECTION OF BODY WITH MIND--PHYSIOLOGICAL PSYCHOLOGY--MENTAL
DISEASES.
In the foregoing pages we have had intimations of some of the
important questions which arise about the connection of mind with
body. The avenues of the senses are the normal approaches to the mind
through the body; and, taking advantage of this, experiments are made
upon the senses. This gives rise to Experimental Psychology, to which
the chapter after this is devoted. Besides this, however, we find the
general fact that a normal body must in all cases be present with a
normal mind, and this makes it possible to arrange so to manipulate
the body that changes may be produced in the mind in other ways than
through the regular channels of sense. For example, we influence the
mind when we drink too much tea or coffee, not to mention the greater
changes of the same kind which are produced in the mind of the drinker
of too much alcohol or other poisonous substances. All the methodical
means of procedure by which the psychologist produces effects of this
kind by changing the condition or functions of the body within itself
belong to Physiological Psychology. So he modifies the respiration,
changes the heart beat, stimulates or slows the circulation of the
blood, paralyzes the muscles, etc. The ways of procedure may be
classified under a few heads, each called a method.
1. _Method of Extirpation._--This means simply the cutting away of a
part of the body, so that any effect which the loss of the part makes
upon the mind may be noted. It is used especially upon the brain.
Pieces of the brain, great or small--indeed, practically the whole
brain mass--may be removed in many animals without destroying life.
Either of the cerebral hemispheres entire, together with large
portions of the other, may be taken from the human brain without much
effect upon the vital processes, considered as a whole; the actual
results being the loss of certain mental functions, such as sight,
hearing, power of movement of particular limbs, etc., according to the
location of the part which is removed. Many of the facts given below
under the heading of Localization were discovered in this way, the
guiding principle being that if the loss of a function follows the
removal of a certain piece of the brain, then that portion of the
brain is directly concerned in the healthy performance of that
function.
2. _Method of Artificial Stimulation._--As the term indicates, this
method proceeds by finding some sort of agent by which the
physiological processes may be started artificially; that is, without
the usual normal starting of these processes. For example, the
physician who stimulates the heart by giving digitalis pursues this
method. For psychological purposes this method has also been fruitful
in studying the brain, and electricity is the agent customarily used.
The brain is laid bare by removing part of the skull of the animal,
and the two electrodes of a battery are placed upon a particular point
of the brain whose function it is wished to determine. The current
passes out along the nerves which are normally set in action from this
particular region, and movements of the muscles follow in certain
definite parts and directions. This is an indication of the normal
function of the part of the brain which is stimulated.
Besides this method of procedure a new one, also by brain stimulation,
has recently been employed. It consists in stimulating a spot of the
brain as before, but instead of observing the character of the
movement which follows, the observer places galvanometers in
connection with various members of the body and observes in which of
the galvanometers the current comes out of the animal's body (the
galvanometer being a very delicate instrument for indicating the
presence of an electric current). In this way it is determined along
what pathways and to what organs the ordinary vital stimulation passes
from the brain, provided it be granted that the electric current takes
the same course.
3. _Method of Intoxication, called the "Toxic Method._"--The remarks
above may suffice for a description of this method. The results of the
administration of toxic or poisonous agents upon the mind are so
general and serious in their character, as readers of De Quincy know,
that very little precise knowledge has been acquired by their use.
4. _Method of Degeneration._--This consists in observing the progress
of natural or artificially produced disease or damage to the tissues,
mainly the nervous tissues, with a view to discovering the directions
of pathways and the locations of connected functions. The degeneration
or decay following disease or injury follows the path of normal
physiological action, and so discloses it to the observer. This method
is of importance to psychology as affording a means of locating and
following up the course of a brain injury which accompanies this or
that mental disease or defect.
_Results_--_Localization of Brain Functions._--The more detailed
results of this sort of study, when considered on the side of the
nervous organism, may be thrown together under the general head of
Localization. The greatest result of all is just the discovery that
there is such a thing as localization in the nervous system of the
different mental functions of sensation and movement. We find
particular parts of the nervous organism contributing each its share,
in a more or less independent way, to the whole flow of the mental
life; and in cases of injury or removal of this part or that, there
is a corresponding impairment of the mind.
First of all, it is found that the nervous system has a certain
up-and-down arrangement from the segments of the spinal cord up to the
gray matter of the rind or "cortex" of the large masses or hemispheres
in the skull, to which the word brain is popularly applied. This
up-and-down arrangement shows three so-called "levels" of function.
Beginning with the spinal cord, we find the simplest processes, and
they grow more complex as we go up toward the brain.
The lowest, or "third level," includes all the functions which the
spinal cord, and its upper termination, called the "medulla," are able
to perform alone--that is, without involving necessarily the activity
of the nervous centres and brain areas which lie above them. Such
"third-level" functions are those of the life-sustaining processes
generally: breathing, heart-beat, vasomotor action (securing the
circulation of the blood), etc. These are all called Automatic
processes. They go regularly on from day to day, being constantly
stimulated by the normal changes in the physiological system itself,
and having no need of interference from the mind of the individual.
In addition to the automatic functions, there is a second great class
of processes which are also managed from the third level; that is, by
the discharge of nervous energy from particular parts of the spinal
cord. These are the so-called Reflex functions. They include all those
responses which the nervous system makes to stimulations from the
outside, in which the mind has no alternative or control. They happen
whether or no. For example, when an object comes near the eye the lid
flies to reflexly. If a tap be made upon the knee while one sits with
the legs crossed the foot flies up reflexly. Various reflexes may be
brought out in a sleeper by slight stimulations to this or that region
of his body. Furthermore, each of the senses has its own set of reflex
adjustments to the stimulations which come to it. The eye accommodates
itself in the most delicate way to the intensity of the light, the
distance of the object, the degree of elevation, and the angular
displacement of what one looks at. The taking of food into the mouth
sets up all sorts of reflex movements which do not cease until the
food is safely lodged in the stomach, and so on through a series of
physiological adaptations which are simply marvellous in their variety
and extent. These processes belong to the third level; and it may
surprise the uninitiated to know that not only is the mind quite "out
of it" so far as these functions are concerned, but that the brain
proper is "out of it" also. Most of these reflexes not only go on when
the brain is removed from the skull, but it is an interesting detail
that they are generally exaggerated under these conditions. This shows
that while the third or lowest level does its own work, it is yet in a
sense under the weight--what physiologists call the inhibiting
action--of the higher brain masses. It is not allowed to magnify its
part too much, nor to work out of its proper time and measure. The
nervous apparatus involved in these "third-level" functions may be
called the "reflex circuit" (see Fig. 2), the path being from the
sense organ up to the centre by a "sensory" nerve, and then out by a
"motor" nerve to the muscle.
[Illustration: FIG. 2.--_s c mt_ = reflex circuit; _s c sp mp c mt_ =
voluntary circuit.]
Going upward in the nervous system, we next find a certain group of
bodies within the gross mass of the brain, certain centres lying
between the hemispheres above and the medulla and spinal cord below,
and in direct connection by nervous tracts with both of these. The
technical names of the more important of these organs are these: the
"corpora striata," or striped bodies, of which there are two, the
"optic thalami," also two in number, and the "cerebellum" or little
brain, situated behind. These make up what is called the "second
level" in the system. They seem to be especially concerned with the
life of sensation. When the centres lying above them, the hemispheres,
are removed, the animal is still able to see, hear, etc., and still
able to carry out his well-knit habits of action in response to what
he sees and hears. But that is about all. A bird treated thus, for
example, these second-level centres being still intact while the
hemispheres are removed, retains his normal appearance, being quite
able to stand upon his feet, to fly, walk, etc. His reflexes are also
unimpaired and his inner physiological processes; but it soon becomes
noticeable that his mental operations are limited very largely to
sensations. He sees his food as usual, but does not remember its use,
and makes no attempt to eat it. He sees other birds, but does not
respond to their advances. He seems to have forgotten all his
education, to have lost all the meanings of things, to have
practically no intelligence. A dog in this condition no longer fears
the whip, no longer responds to his name, no longer steals food. On
the side of his conduct we find that all the actions which he had
learned by training now disappear; the trick dog loses all his tricks.
What was called Apperception in the earlier chapter seems to have been
taken away with the hemispheres.
Coming to the "first level," the highest of all, both in anatomical
position and in the character of the functions over which it presides,
we see at once what extraordinary importance it has. It comprises the
cortex of the hemispheres, which taken together are called the
cerebrum. It consists of the parts which we supposed cut out of the
pigeon and dog just mentioned; and when we remember what these animals
lose by its removal, we see what the normal animal or man owes to the
integrity of this organ. It is above all the organ of mind. If we had
to say that the mind as such is located anywhere, we should say in the
gray matter of the cortex of the hemispheres of the brain. For
although, as we saw, animals without this organ can still see and hear
and feel, yet we also saw that they could do little else and could
learn to do nothing more. All the higher operations of mind come back
only when we think of the animal as having normal brain hemispheres.
Further, we find this organ in some degree duplicating the function of
the second-level centres, for fibres go out from these intermediate
masses to certain areas of the hemispheres, which reproduce locally
the senses of hearing, sight, etc. By these fibres the functions of
the senses are "projected" out to the surface of the brain, and the
term "projection fibres" is applied to the nerves which make these
connections. The hemispheres are not content even with the most
important of all functions--the strictly intelligent--but they are
jealous, so to speak, of the simple sensations which the central brain
masses are capable of awaking. And in the very highest animals,
probably only monkeys and man, we find that the hemispheres have gone
so far with their jealousy as to usurp the function of sensation. This
is seen in the singular fact that with a monkey or man the removal of
the cortical centres makes the animal permanently blind or deaf, as
the case may be, while in the lower animals such removal does not have
this result, so long as the "second-level" organs are unimpaired. The
brain paths of the functions of the second and first levels taken
together constitute the so-called "voluntary circuit" (see Fig. 2).
In addition to this general demarcation of functions as higher and
lower--first, second, and third level--in their anatomical seat, many
interesting discoveries have been made in the localization of the
simpler functions in the cortex itself. The accompanying figures
(Figs. 3 and 4) will show the principle centres which have been
determined; and it is not necessary to dwell upon additional details
which are still under discussion. The areas marked out are in general
the same on both hemispheres, and that is to say that most of the
centres are duplicated. The speech centres, however, are on one side
only. And in certain cases the nervous fibres which connect the cortex
with the body-organs cross below the brain to the opposite side of the
body. This is always true in cases of muscular movement; the movements
of the right side of the body are controlled by the left hemisphere,
and _vice versa_. The stimulations coming in from the body to the
brain generally travel on the same side, although in certain cases
parallel impulses are also sent over to the other hemisphere as well.
For example, the very important optic nerve, which is necessary to
vision, comes from each eye separately in a large bunch of fibres, and
divides at the base of the brain, so that each eye sends impulses
directly to the visual centres of both hemispheres.
[Illustration: FIG. 3.--Outer surface of left hemisphere of the brain
(modified from Exner): _a_, fissure of Rolando; _b_, fissure of
Sylvius.]
[Illustration: FIG. 4.--Inner (mesial) surface of the right hemisphere
of the brain (modified from Schäfer and Horsley). In both figures the
shaded area is the motor zone.]
Of all the special questions which have arisen about the localization
of functions in the nervous system, that of the function of certain
areas known as "motor centres" has been eagerly discussed. The region
on both sides of the fissure of Rolando in Fig. 3 contains a number of
areas which give, when stimulated with electricity, very definite and
regular movements of certain muscles on the opposite side of the body.
By careful exploration of these areas the principal muscular
combinations--those for facial movements, neck movements, movements of
the arm, trunk, legs, tail, etc.--have been very precisely
ascertained. It was concluded from these facts that these areas were
respectively the centres for the discharge of the nervous impulses
running in each case to the muscles which were moved. The evidence
recently forthcoming, however, is leading investigators to think that
there is no cortical centre for the "motor" or outgoing processes
properly so called, and that these Rolandic areas, although called
"motor," are really centres for the incoming reports of the movements
of the respective muscles after the movements take place, and also for
the preservation of the memories of movement which the mind must have
before a particular movement can be brought about (the mental images
of movement which we called on an earlier page Kinæsthetic
Equivalents). These centres being aroused in the thought of the
movement desired, which is the necessary mental preparation for the
movement, they in turn stimulate the real motor centres which lie
below the cortex at the second level. This is in the present writer's
judgment the preferable interpretation of the evidence which we now
have.
[Illustration: FIG. 5.--The speech zone (after Collins).]
_The Speech Zone._--Many interesting facts of the relation of body and
mind have come to light in connection with the speech functions.
Speech is complex, both on the psychological and also on the
physiological side, and easily deranged in ways that take on such
remarkable variety that they are a source of very fruitful indications
to the inquirer. It is now proved that speech is not a faculty, a
single definite capacity which a man either has or has not. It is
rather a complex thing resulting from the combined action of many
brain centres, and, on the mental side, of many so-called faculties,
or functions. In order to speak a man normally requires what is called
a "zone" in his brain, occupying a large portion of the outside
lateral region (see Fig. 5). It extends, as in the figure, from the
Rolandic region (_K_), where the kinæsthetic lip-and-tongue memories
of words are aroused, backward into the temporal region (_A_), where
the auditory memories of words spring up; then upward to the angular
gyrus in the rear or occipital region (_V_), where in turn the visual
pictures of the written or printed words rise to perform their part in
the performance; and with all this combination there is associated the
centre for the movements of the hand and arm employed in writing, an
area higher up in the Rolandic region (above _K_). In the same general
zone we also find the music function located, the musical sounds being
received in the auditory centre very near the area for words heard
(_A_) while the centre for musical expression is also in the Rolandic
region. Furthermore, as may be surmised, the reading of musical
notation requires the visual centre, just as does the reading of
words. In addition to this, we find the curious fact that the location
of the whole speech zone is in one hemisphere only. Its location on
the left or the right, in particular cases, is also an indication as
to whether the person is right-or left-handed; this means that the
process which makes the individual either right or left-handed is
probably located in the speech zone, or near it. A large majority of
persons have the speech zone in the left hemisphere, and are
right-handed; it will be seen that the figure (5) shows the left
hemisphere of the brain, and with it the right hand holding the pen.
_Defects of Speech--Aphasia._--The sorts of injury which may befall a
large zone of the brain are so many that well-nigh endless forms of
speech defect occur. All impairment of speech is called Aphasia, and
it is called Motor Aphasia when the apparatus is damaged on the side
of movement.
If the fibres coming out from the speech zone be impaired, so that the
impulses can not go to the muscles of articulation and breathing, we
have Subcortical Motor Aphasia. Its peculiarity is that the person
knows perfectly what he wants to say, but yet can not speak the words.
He is able to read silently, can understand the speech of others, and
can remember music; but, with his inability to speak, he is generally
also unable to write or to perform on a musical instrument (yet this
last is not always the case). Then we find new variations if his
"lesion"--as all kinds of local nervous defects are called--is in the
brain centre in the Rolandic region, where arise the memories of the
movements required. In this latter case the aphasic patient can
readily imitate speech so long as he hears it, can imitate writing so
long as it lies before him, but can not do any independent speaking or
writing for himself. With this there goes another fact which
characterizes this form of aphasia, and which is called Cortical, as
opposed to the Subcortical Motor Aphasia described above, that the
person may not be able even to think of the words which are
appropriate to express his meaning. This is the case when those
persons who depend upon the memories of the movements of lip and
tongue in their normal speech are injured as described.
Besides the two forms of Motor Aphasia now spoken of, there are
certain other speech defects which are called Sensory Aphasia. When a
lesion occurs in one of the areas of the brain in the speech zone in
which the requisite memories of words seen or heard have their
seat--as when a ball player is struck over the sight centre in the
back of the head--special forms of sensory aphasia show themselves.
The ball player will, in this case, have Visual Aphasia, being unable
to speak in proportion as he is accustomed in his speaking to depend
upon the images of written or printed words. He is quite unable to
read or write from a copy which he sees; but he may be able,
nevertheless, to write from dictation, and also to repeat words which
are spoken to him. This is because in these latter performances he
uses his auditory centre, and not the visual. There are, indeed, some
persons who are so independent of vision that the loss of the visual
centre does not much impair their normal speech.
When, again, an injury comes to the auditory centre in the temporal
region, we find the converse of the case just described; the defect is
then called Auditory Aphasia. The patient can not now speak or write
words which he hears, and can not speak spontaneously in proportion as
he is accustomed to depend upon his memories of the word sounds. But
in most cases he can still both speak and write printed or written
words which he sees before him.
These cases may serve to give the reader an idea of the remarkable
delicacy and complexity of the function of speech. It becomes more
evident when, instead of cases of gross lesion, which destroy a whole
centre, or cut the connections between centres, we have disease of the
brain which merely destroys a few cells in the gray matter here or
there. We then find partial loss of speech, such as is seen in
patients who lack only certain classes of words; perhaps the verbs, or
the conjunctions, or proper names, etc.; or in the patients who
speak, but yet do not say what they mean; or, again, in persons who
have two verbal series going on at once, one of which they can not
control, and which they often attribute to an enemy inside them, in
control of the vocal organs, or to a persecutor outside whose abuse
they can not avoid hearing. In cases of violent sick headache we often
miscall objects without detecting it ourselves, and in delirium the
speech mechanism works from violent organic discharges altogether
without control. The senile old man talks nonsense--so-called
gibberish--thinking he is discoursing properly.
In the main cases of Aphasia of distinct sensory and motor types
psychological analysis is now so adequate and the anatomical
localization so far advanced that the physicians have sufficient basis
for their diagnosis, and make inferences looking toward treatment.
Many cases of tumour, of clot on the brain, of local pressure from the
skull, and of hæmorrhage or stopping up of the blood vessels in a
limited area, have been cured through the indications given by the
particular forms and degrees of aphasia shown by the patients. The
skull is opened at the place indicated by the defect of speech, the
lesion found where the diagnosis suggested, and the cause removed.
This account of Localization will suggest to the reader the truth that
there is no science of Phrenology. No progress has been made in
localizing the intelligence; and the view is now very general that the
whole brain, with all its interchange of impulses from part to part,
is involved in thinking. As for locating particular emotions and
qualities of temperament, it is quite absurd. Furthermore, the
irregularities of the skull do not indicate local brain differences.
It is thought that the relative weight of the brain may be an
indication of intellectual endowment, especially when the brain weight
is compared with the weight of the rest of the body, and that culture
in particular lines increases the surface of the cortex by deepening
and multiplying the convolutions. But these statements can not be
applied off-hand to individuals, as the practise of phrenology would
require.
_Defects of Memory--Amnesia._--The cases given just above, where the
failure of speech was seen to be due to the loss of certain memories
of words, illustrate also a series of mental defects, which are
classed together as Amnesias. Any failure in memory, except the normal
lapses which we call forgetfulness, is included under this term. Just
as the loss of word memories occasions inability to speak, so that of
other sorts of memories occasions other functional disturbances. A
patient may forget objects, and so not know how to use his penknife or
to put on his shoes. He may forget events, and so give false witness
as to the past.
One may forget himself also, and so have, in some degree, a different
character, as is seen, in an exaggerated way, in persons who have
so-called Dual Personality. These patients suddenly fall into a
secondary state, in which they forget all the events of their ordinary
lives, but remember all the events of the earlier periods of the
secondary personality. This state may be described as "general"
amnesia, in contrast to the "partial" amnesia of the other cases
given, in which only particular classes of memories are impaired.
The impairment of memory with advancing years also illustrates both
"general" and "partial" Amnesia. The old man loses his memory of
names, then of other words, then of events, and so gradually becomes
incapable of much retention of any sort.
_Defects of Will--Aboulia._--A few words may suffice to characterize
the great class of mental defects which arise on the side of action.
All inability to perform intentional acts is called Aboulia, or lack
of Will. Certain defects of speech mentioned above illustrate this:
cases in which the patient knows what he wishes to say and yet can not
say it. This is the type of all the "partial" Aboulias. There may be
no lack in determination and effort, yet the action may be impossible.
But, in contrast with this, there is a more grave defect called
"general" Aboulia. Here we find a weakening of resolution, of
determination, associated with some lack of self-control showing
itself frequently by a certain hesitation or indecision. The patient
says: "I can not make up my mind," "I can not decide." In exaggerated
cases it becomes a form of mania called "insanity of doubt." The
patient stands before a door for an hour hesitating as to whether he
can open it or not, or carries to its extreme the experience we all
sometimes have of finding it necessary to return again and again to
make sure that we have locked the door or shut the draught of the
furnace.
With these illustrations our notice of mental defects may terminate.
The more complex troubles, the various insanities, manias, phobias,
etc., can not be briefly described. Moreover, they are still wrapped
in the profoundest obscurity. To the psychologist, however, there are
certain guiding principles through the maze of facts, and I may state
them in conclusion.
First, all mental troubles involve diseases of the brain and can be
cured only as the brain is cured. It does not follow, of course, that
in certain cases treatment by mental agencies, such as suggestion,
arousing of expectation, faith, etc., may not be more helpful here,
when wisely employed, than in troubles which do not involve the mind;
but yet the end to be attained is a physical as well as a mental cure,
and the means in the present state of knowledge, at any rate, are
mainly physical means. The psychologist knows practically nothing
about the laws which govern the influence of mind on body. The
principle of Suggestion is so obscure in its concrete working that the
most practised and best-informed operators find it impossible to
control its use or to predict its results. To give countenance, in
this state of things, to any pretended system or practice of mind
cure, Christian science, spiritual healing, etc., which leads to the
neglect of ordinary medical treatment, is to discredit the legitimate
practice of medicine and to let loose an enemy dangerous to the public
health.
Moreover, such things produce a form of hysterical subjectivism which
destroys sound judgment, and dissolves the sense of reality which it
has taken modern science many generations to build up. Science has all
along had to combat such wresting of its more obscure and unexplained
facts into alliance with the ends of practical quackery, fraud, and
superstition; and psychologists need just now to be especially alive
to their duty of combating the forms of this alliance which arise when
the newer results of psychology are so used, whether it be to
supplement the inadequate evidence of "thought-transference," to
support the claims of spiritualism, or to justify in the name of
"personal liberty" the substitution of a "healer" for the trained
physician. The parent who allows his child to die under the care of a
"Christian Science healer" is as much a criminal from neglect as the
one who, going but a step further in precisely the same direction,
brings his child to starvation on a diet of faith. In France and
Russia experimenting in hypnotism on well persons has been restricted
by law to licensed experts; what, compared with that, shall we say to
this wholly amateurish experimenting with the diseased? Let the
"healer" heal all he can, but let him not experiment to the extremity
of life and death with the credulity and superstition of the people
who think one "doctor" is as good as another.
Second, many experts agree that diseases of the mind, whatever their
brain seat may be, all involve impairment of the Attention. This, at
any rate, is a general mark of a deranged or defective mind. The idiot
lacks power of attention. The maniac lacks control of his attention.
The deluded lacks grasp and flexibility of attention. The crank can
only attend to one thing. The old man is feeble in the attention,
having lost his hold. So it goes. The attention is the instrument of
the one sort of normal mental activity called Apperception, and so
impairment of the attention shows itself at once in some particular
form of defect.
Third, it is interesting to know that in progressive mental failure
the loss of the powers of the mind takes place in an order which is
the reverse of that of their original acquisition. The most complex
functions, which are acquired last, are the first to show impairment.
In cases of general degeneration, softening of the brain, etc., the
intelligence and moral nature are first affected, then memory,
association, and acquired actions of all sorts, while there remain,
latest of all, actions of the imitative kind, most of the deep-set
habits, and the instinctive, reflex, and automatic functions, This
last condition is seen in the wretched victim of dementia and in the
congenital idiot. The latter has, in addition to his life processes
and instincts, little more than the capacity for parrot-like
imitation. By this he acquires the very few items of his education.
The recovery of the patient shows the same stages again, but in the
reversed direction; he pursues the order of the original acquisition,
a process which physicians call Re-evolution.