Studies in the Osteopathic
The Physiology of Consciousness:
Louisa Burns, M.S., D.O., D.Sc.O.
CERTAIN OLDER VIEWS.
The older philosophers recognized the existence
of mind, or soul, as altogether distinct from material or physical things.
The distinction between mind and life appears, then, to be as vague as
now it is in the writings of certain modern authors. The very words we
use are indicative of this old vagueness. Psyche, anima, spiritus, atman,
rush, in Greek, Latin, Sanskrit and Hebrew, all mean, originally, wind,
thus breath, and then life, and the chief phenomena of life, so far as
individual experience goes, the consciousness. The word mind, or mynd,
is of Anglo-Saxon origin, and has the significance of love, memory, or
the vote. Except for the dubious uses to which the word has been put, it
is of philologically excellent worth. Consciousness means the “knowing
together,” literally, and is fairly exact in its meaning at present.
Materialistic expressions have been used in a figurative
sense in the expression of mental phenomena. Feeling, the sense of touch,
has come to indicate the consciousness of emotional states. Emotion, literally
a moving out or forward, is applied to the consciousness associated with
the more or less involuntary reactions coordinated by the ganglionar centers
of the cerebrum. Apprehension and understanding, impression and faculty,
all are terms of materialistic origin, and used in the expression of conscious
Difficulty of the Vocabulary
The rational study of the phenomena of consciousness
has been hindered greatly by the misuse of the terms employed in discussions.
Almost every writer of ancient times, and modern, too, for that matter,
has employed old terms in distorted and grotesque meanings. Almost all
of these writers have added phrases of material origin in the descriptions
of the immaterial or mental life, or they have attributed the phenomena
associated with the immaterial life to material objects. It thus becomes
almost impossible to determine, in many cases, the exact interpretation
which should be put upon the writer’s views. Thus we have the spectacle,
not always edifying, of pupils of the greater authors wrangling among themselves
concerning the meanings of the writings of their master, and not seeking
to ascertain the actual facts of the conditions.
From the beginning there has been recognized an
existence of mind as being divided into different parts. The Eleatics had
a division of the mind into Sensation, Opinion and Reason. Aristotle gave
a division into the Cognitive and the Motive. Much later Kant gave the
division into Cognitive Faculties, Feelings (emotions) and Will.
In the physiological view, there is no need for classification
of processes of mentality. Sensation is the consciousness associated with
the activity of the sensory areas. Reason is the consciousness associated
with the activity of the intermediate areas. Cognition is the consciousness
associated with the activity of the sensory, overflow areas, perhaps with
a certain amount of activity of the intermediate areas. Any feeling (emotion)
is the consciousness associated with the occurrence of certain somatic
and visceral reactions, usually together with the sensations initiated
by the exciting cause of these reactions. Will is the consciousness associated
with the activity of the primary motor areas, or the motor overflow.
The fact that the material world could act upon
the immaterial mind, and that the immaterial mind could act upon the material
world, was found in very early days to present great difficulty. Empedocles
laid down the maxim that like could act only upon like. Democritus supposed
the mind to be composed of matter in an infinitely fine state of division.
Locke refers always to the mind as perceiving the idea, and upon this he
builds a fantastic philosophy, which begins with unsubstantial ideas and
terminates—nowhere. The necessity for supposing a sort of “tertium quid”
which could be fine enough to affect and be affected by the mind, and at
the same time substantial enough to act upon and be acted upon by the material
world, was considered by philosophers everywhere. This idea is constantly
arising, and always in some new guise.
Kant supposed that the mind received “impressions”
from the external world, and that it coordinated these impressions into
This coordination of “impressions by the mind,” as
Kant and others have given it, may be supposed to be verified in the coordination
of the nerve impulses by the activity of the cortical neurons. The “tertium
quid” of the older philosophers may be associated with the neuronic activity,
which is certainly an extremely delicate form of matter in action. Locke’s
mind as perceiving the idea may be referred to the fact of the isolation
of the cortex, and the other fact that consciousness is associated with
the activity of the cortical neurons.
Plato, Socrates, Aristotle and other Greek philosophers
assume the existence of a soul, or mind, capable of being cultivated and
trained. But the methods given for the cultivation of the soul, in so far
as they are efficient, act through the effects of sensory impulses and
the coordination of these. Music, the gymnasium, sculpture, letters, all
are advised, and the cultivation of the sound body as a dwelling place
for the sound mind is everywhere considered as the summum bonum of human
Comensius, in the middle of the seventeenth century,
said, “There is nothing in the understanding that was not first in the
senses,” and thus one of the first beginnings of a scientific study of
the associative processes was made. The monumental work of Herbert Spencer
laid many foundation stones for a rational study of these processes.
Spencer assumes the existence of mind as if it were
apart from physiological activities, or at least as if it were able to
act upon the bodily activities. He says: “The child, in learning to walk,
wills the action before he walks it.” This and other similar statements
seem to indicate the existence of something which wills, apart from that
which is controlled thereby.
According to the physiological view, the activity
of the motor cortex is associated with certain phases of consciousness,
which occur before the movements of the muscles affected by that activity.
So the child, in learning to walk, is conscious of the initiation of the
motor impulse before these impulses reach the lower centers. So he soon
learns that the consciousness associated with the activity of the motor
cortex is associated with impending movements. Ultimately, the consciousness
of volition is associated with the activity of the primary motor cortex
and the motor overflow.
Wundt, who has inspired many of the modern psychiatrists,
considers the impressions from environmental changes as signs, which must
be interpreted by unconscious reasoning. It is evident that the supposition
that reasoning is properly placed before sensation is out of harmony with
the views of most psychologists, by whom sensations are supposed to make
a basis for reason. But the views of Wundt are true, in a way. For what
he terms “unconscious reasoning” can be referred to the activities of the
cortex, and especially to the sensory overflow areas. It is probable that
a certain amount of the coordination of the sensory impulses, and the associated
activity of the sensory overflow areas, is essential to the consciousness
of sensations. This activity of the overflow areas is the physiological
expression of the condition of “unconscious reasoning.”
Stated in physiological terms, this view of Wundt
is, that the activity of the overflow areas is associated with vivid consciousness,
and that the activity of the primary sensory areas, if associated with
consciousness at all, is concerned with only feeble states of consciousness.
Mind and Life
Many recent authors define the term mind in such
a manner as to include all of the phenomena of life. This definition scarcely
eliminates the characteristics of crystallization from the mental state.
This definition is good enough, provided it can be understood in using
the term that the phenomena of life are indicated. It is rather difficult
to see why any term other than life should be needed to express the significance
of the word life. If by the use of this term it is intended to state that
the unity of physiological processes is absolute, it has a certain value.
For it seems fairly evident that what are commonly termed mental phenomena
are the result of the physiological activities of the cortical neurons.
The cortical neurons are simply cells, highly differentiated cells, it
is true, but still simply physiological units, engaged in about the same
processes of nutrition, elimination and varying activities which occupy
the time of other cells.
Two tendencies have appeared among psychologists
and educators in late years. The first of these tendencies is the endeavor
to compare sensations in consciousness with the nature of the variations
in the external world which produce the conscious phenomena. Exact determinations
have been made of the threshold limits of the different senses, the variations
of the threshold limits under various normal and abnormal conditions, and
the manner in which physiological phenomena have been modified by sensory
impulses. Many of the laws controlling the initiation and the modification
of the nerve impulses have been determined in the laboratories for the
study of psychology. This work has been dignified by the name “new psychology.”
The names of Scripture and Titchener are associated in this movement.
The other and more recent trend was perhaps a reaction
from the one just mentioned. The use of the term “subconscious” and the
building of many varying and complex philosophies upon the word have occupied
many pages and much nervous energy. Whatever value the use of the word
may have had has been destroyed by the fact that it has been employed in
a different sense by every author whose works have been consulted in preparing
this volume. Yet, because the idea has been given so wide attention by
physicians and educators everywhere, it seemed advisable to give a very
short resume of the use made of the expression by different authors.
Carpenter first used the term “unconscious cerebration”
to express the activity of the cortical neurons which are not associated
with conscious changes. The term is unwieldy, but it conveys no false idea,
and it has its own significance, and none other. It is certainly true that
only a part of the activities of the cortical neurons is associated with
variations in consciousness. Probably the activities of the cells of the
external layer of the cortex are concerned in consciousness, but it is
not possible to say for sure whether all of them, or whether any of them,
are associated with the conscious effects produced at any given time. There
is some reason to believe that the activities of the deeper layers of the
cortex act without producing any noticeable effect in consciousness, except
as the activities of these cells may affect the activities of the cells
of the external layer. That unconscious cerebration does occur there is
According to Bernard Hart the term “sub-consciousness”
or “sub-conscious mind” is purely conceptual, and has no place in any experience.
The term is supposed by him to be of the same nature as the terms “line”
and “point” in mathematics. These expressions represent nothing existent,
nothing which can possibly be subjected to experience or even imagined
as existing; but the terms are used for the sake of meeting the necessities
of the mathematical sciences. So he considers the expressions, atoms or
molecules in chemistry, and the imponderable, frictionless ether of physicists.
The term “sub-consciousness” he considers the equivalent of these expressions
in the other sciences, and he considers it to be essential to the requirements
of psychology as a science in order that no discontinuity of logical sequence
be observed, and still no reference to physiological reactions become necessary.
The crux of the whole question, from this point of view, lies in the decision
as to the need for the hypothetical terminology in this case, the value
of the specific term proposed, and the more crucial question as to whether
the matter under consideration properly belongs in the domain of psychology
or not. To take his own illustration, it is evident that lines and angles
are terms of mathematics. Is it needful that some new term should be devised
in order that a consideration of lines and angles should be made a part
of chemistry? Or must mathematicians devise a new terminology by means
of which the movements of atoms may be considered as a science apart from
chemistry? The ultimate aim of every science is to bring all human knowledge
to a unit; physics and chemistry, and mathematics and astronomy, must ultimately
be found one and indivisible. To endeavor to dissociate by new, and abstruse,
and meaningless terms, merely for the same of the dissociation, is fruitful
of nothing but endless discussion, chaotic thinking and inextricable confusion.
Hart recognizes this idea and makes a very earnest plea for the maintenance
of the identity of psychology as psychology, and of physiology as physiology.
He deplores the endeavor of certain psychologists to explain psychical
facts by physical processes. It is as unscientific to jump from psychology
to physiology and from physiology to psychology in an attempt to explain
mental phenomena as it would be to seek to explain other physiological
phenomena by an appear to art or letters.
A lake upon a mountain top can add little of beauty to the landscape,
but no one will concede that water runs down hill in order to be able to
reflect the mountain. Nor is the running of water down hill to be explained
upon altruistic grounds; there is no reason to infer that water runs down
hill in order to irrigate the fields of the people who live in the valleys.
A brook may be never so musical, yet that is not commonly held to explain
the running of water. The appeal must be made directly to physics for an
explanation of the fact that water does run down hill under certain circumstances,
and no attempt is made by rational people to employ the terms of art, or
music, or sociology in such an explanation.
Field of Psychology
It remains yet to be seen whether psychology has
any legitimate field for study. If psychical facts exist apart from physiological
facts, if the laws governing the activities of actual psychic entities
are subject to investigation, then there is a true psychology. But no psychology
is rightly named which endeavors to account for conscious phenomena in
terms of the physiology of the cerebral cortex. If the physiology of the
cerebral cortex can explain the phenomena of consciousness, then the study
of consciousness is a legitimate part of physiology, and psychology becomes
one branch of physiology—that is, the physiology of the cerebral cortex.
In order to make the matter more easily explicable,
the terms employed must be as simple as is consistent with exact significances,
and the same terms must be used as far as possible for the same occurrences
and things in every department of science.
If this test be employed, it will at once become
apparent whether there is, or is not, a need for a specific science of
the mind as apart from the physiology of the cerebral cortex.
Hart’s contention for the separation of physiology
and psychology is a good one, but the physiologists are apt to see not
very much need for a separate science of psychology, and the psychologist
must be forced, as Hart has been, to devise, and adopt, and distort many
expressions in many ways in order to explain psychological phenomena without
the use of physiological terms.
Morton Prince, of Tuft’s College, uses the term
“co-consciousness” to apply to those phenomena which are within the realm
of consciousness to which the attention is not directed, or of which only
slight present consciousness is felt by the individual. He uses the term
“awareness” in the sense in which the term consciousness is usually employed.
He uses the term “consciousness” in the sense of the “reality” or the “inner
life” of the brain changes. “The psychical is the reality of the physical.”
“I cannot conceive of consciousness excepting as the reality or inner life
of the brain changes.”
This idea lends itself well to the physiological
aspect. Consciousness may be defined as an effect produced by the activities
of the cortical neurons. Prince’s “co-consciousness” finds its physiological
expression in the fact that many of the activities of the cortical neurons,
which may not be sufficiently pronounced for the initiation of conscious
phenomena, may be sufficiently stimulated by impulses from other parts
of the cortex to cause the modification of consciousness.
The fact that “co-conscious “phenomena may afterward
be recalled consciously is, physiologically, probably due to the fact that
the neurons concerned in that particular reaction were physiologically
altered by their activity so that the liminal value was lowered, then the
subsequent stimulation of areas of related function might cause the initiation
of sufficient activity of those neurons to affect consciousness. It is
conceivable that the initial activity of the neurons concerned in the given
reaction was sufficient to produce conscious phenomena, except for the
presence of simultaneous inhibitions. The removal of the inhibitions is
sufficient to permit the stimulation of the cortical neurons of the external
layer to occur. This is probably the condition found in Prince’s co-conscious
Myers and Delboeuf, with certain other writers, assume
a rather philosophical and mystical viewpoint in dealing with the subject.
According to these, the sub-conscious mind is the real source of all that
is good, and fine, and desirable. It is a sort of reservoir of force and
wisdom. The conscious can sometimes come into relationship with this force
and wisdom, and those who are so blest are seen to possess the powers associated
with genius, and prophecy, and poetry, and power. The sub-conscious is
thus a sort of private divinity, convenient, vague, impersonal, irresponsible
The term “subjective mind” has been employed in
about the same way. The subjective mind seems to be a conglomerate of the
racial habits and instincts, together with the effects of certain disease
processes. The subjective mind is supposed to be the source of all wisdom
and blessedness, and the whole series of such discussions resembles greatly
the philosophies of certain East Indian semi-religious writings, whereby
the half-delirious imaginations associated with auto-intoxication and lack
of personal cleanliness, starvation, and the assumption of the fetal position
are held in reverence as the expressions of conditions higher than normal.
The normal Occidental mind is not capable of appreciating these oriental
abnormalities as particularly valuable. Yet the underlying principles have
attained a certain following among Occidental peoples, in connection with
the supposititious sub-conscious or subjective mind.
Among Occidental psychologists, Hartmann’s ideas
of the sub-conscious mind show the extreme development of this concept.
He considers the sub-conscious mind a universal sea of wisdom and knowledge,
whose wealth is open to those who, by means of the subjugation of the sub-conscious
mind, prepare themselves to employ it. “Let us not despair at having a
mind so practical and so lowly, so unpoetical and so little spiritual;
there is within the innermost sanctuary of each of us a marvelous something
of which we are unconscious, which dreams and prays while we labor to earn
our daily bread.” It is not easy to see how the sub-conscious mind can
be worthy of this description and at the same time be the “sum of discarded
experiences” as taught by Freud.
Hudson uses the term sub-conscious mind to indicate
the sum of total of nervous energies which are not associated with consciousness.
It is a little obscure why he should so insist upon using the term “mind”
as indicative of purely physiological nervous conditions apart from consciousness,
while still employing the term mind in the sense of consciousness. The
great mass of philosophy which Hudson builds depends largely upon the use
of the term mind in the sense in which he defines it, part of the time,
and in its commonly accepted sense at other times. That all but an extremely
small proportion of nerve impulses do not affect consciousness is generally
accepted. That these reactions unconsciously performed may so modify the
liminal value of the neurons concerned in them as to affect consciousness
at some other time appears probable. These reactions seem to be identical
with the “co-conscious” activities of Morton Prince.
Ribot speaks of “the sub-conscious,” using the term
in two senses: first, the static, which seems to be made up of the sum
of past experiences plus inherited conditions, and, second, the dynamic
in which past experiences are constantly being rearranged and recombined
with the evolution of those being rearranged and recombined with the evolution
of those ideas characteristic of genius and inventions. “The sub-conscious”
of Ribot is simply the sum of cortical activities which do not affect consciousness.
His “static” sub-conscious is the physiological conditions of the cortical
neurons. These are determined by inheritance, modified by experiences,
and they are subject to variations caused by the physiological conditions
of food supply, blood pressure, the removal or accumulation of wastes,
the presence of poisons in the pericellular lymph, and so on. His “dynamic”
sub-consciousness is another method of stating that the activities of many
of the neuron systems which transmit and coordinate nerve impulses in the
cortex do not affect consciousness. However, they may affect the cells
which do affect consciousness, at the same time or as the result of later
associated activities of the same or related cortical areas. This also
is probably identical with the “co-conscious” reactions of Prince.
Pierre Janet, College of France, has written much
concerning the phenomena of hysteria. He uses the term “sub-conscious”
in the meaning of certain facts of clinical significance. The name is applied
to the particular form which the personality takes in hysteria. Sub-consciousness
as applied to a normal person would necessarily refer to some accident
or temporary disturbance of the normal psychical processes. In other words,
in the sense in which Janet uses the term, a normal person could be subject
to sub-conscious activities only as a very temporary and passing disturbance,
itself to be considered as a slight abnormality, only set apart from hysterical,
or neurasthenic, or psychasthenic conditions by its extremely transitory
condition. Janet interprets most by its extremely transitory condition.
Janet interprets most cases of neurasthenic, psychasthenic and hysterical
types to the existence of sub-conscious conditions. He treats these cases
by what he calls “suggestion,” which is really what may be properly termed
“education.” He defines suggestion as “a motor reaction brought about by
language or perception.” The physiological interpretation is obvious.
Freud’s ideas of the sub-conscious are about as
far from the ideas of Hartmann, Meyer and others of that school as anything
very well can be. Freud supposes that the sub-conscious is a sort of lower
level of mind, in which are stored all of the discarded experiences, arranged
and rearranged into complexities of great size. This lower level he supposes
to be made up of two streams or forces; one of these is seeking, or tending,
to bring into consciousness those previous experiences, the cast-off compeces,
which are full of mistakes and unfortunate and r egrettae occurrences,
while the other stream or tendency seeks to inhibit the first, and to produce
in consciousness good and pleasant ideas The second stream is thus a safety,
or a guard, or an anti-toxin, if the term be permissible.
It is supposed that the production of these discarded
complexes in consciousness, with associated full and complete expression
of the effects initiated in consciousness, and especially in the feelings,
by those experiences, relieves the conscious mind of the burden of carrying
these discarded complexes and recovery results.
The Cathartic Method
The “carthartic method” of dealing with such conditions
is advocated by certain psychologists, following Freud.
Stripped of details, this method consists of securing
the cooperation of the patient, then causing him to describe in great detail
the incident of his life, with especial reference to the origin of his
abnormal condition. Freud’s idea is that these emotional inhibitions are
harmful, and that the free expression of the repressed feelings exerts
a sort of “cathartic” effect upon the mind, and the cause of the disorder
is removed. Freud finds in many of the borderland cases that sexual feelings,
which may or may not be associated with feelings of intense disgust, have
been active since childhood or early puberty and that the psychosis may
be speedily removed by the full and unimpeded expression of those ideas
so long repressed.
The physiological nature of the “cathartic” method
is evident. The neuron systems concerned in the inhibitory circle are subjected
to a new stimulation; the circle is broken by the discharge of the efferent
impulses, as in the expression of the ideas involved, and the harmful activities
become inefficient. The place for discussion lies in the value of Freud’s
methods form the diagnostic standpoint.
In this world, especially under present conditions
of silence, mock prudery and shame concerning sexual matters, it is scarcely
possible for a child to reach puberty without seeing or hearing things
which cause disgust or curiosity. Certainly no normal child could pass
through the puberty changes, with their intense motional storms, without
being subjected to occurrences associated with at least a certain degree
of shame or of exaltation. This is the common experience. Freud’s tests,
then, are predestined to success, under his conditions. He explains that
the ideas are to be fully expressed, that no feelings of shame or disgust
shall prevent the fullest expression of the ideas, and he provides conditions
which lead to a more or less complete hypnosis, or at any rate an increase
of suggestibility. People who need such measures are, by that very fact,
abnormal. Many of them suffer diseases which affect the sexual organs.
The slight nauseas and associated digestive disturbances also give rise
to ideas of a more or less disgusting nature. Thus it is no wonder that
in practically all of the cases tested the method resulted n the “discovery”
of the occurrences expected by Freud and those of his school. Since the
treatment of such cases, as he gives it, depends upon the explanation of
the significance of the results of the “catharsis,” it is evident that
the results may be interpreted as being due to the educational methods,
or, perhaps, to the effects of the energetic suggestions.
The harm which may result from the use of such methods
in certain cases is apparent. For one thing, the endeavor to produce “free”
expression may be associated with increased stimulation of the centers
concerned and the psychasthenic conditions made worse. This is found to
be the case in some of the histories given.
The physiological interpretation of the facts as
Freud states them as they are present in favorable cases is fairly simple.
It will be remembered that the phenomena of inhibition are probably due
to the functional activities of the circles of neurons of the different
layers of the cortex, with the inverted pyramids carrying the impulses
toward the cortex constantly. The lowering of the liminal value of the
neuron systems concerned in producing any given inhibition causes the impulses
ordinarily initiated by the daily affairs of life to stimulate them to
increased activity. The variations in the physiological condition of the
neuron systems primarily concerned with the “discarded complex” may be
responsible for almost any kind of unbalanced neuronic activity, both conscious
Hugo Munsterburg, of Harvard disapproves the use
of the term altogether. He finds no reason for attributing a supposititious
“mind” to those activities of the cortical neurons which are not associated
with consciousness. He admits the facts of the phenomena of dissociated
experiences, etc., but deplores the use of terms signifying mentality,
or the psychic idea, or consciousness, for the expression of ideas which
are, at the root, purely physiological. He says: “No fact of abnormal experience
can of itself prove that a psychological and not a physiological explanation
is needed; it is a philosophical problem which must be settled by principle
before the explanation of special facts begins.” In other words, if dissociated
ideas have no existence in normal psychology, they are not to be lightly
evoked simply for the purpose of “explaining” disease.
Munsterburg probably goes farther in the direction
of a physiological interpretation of conscious phenomena than any other
author of note. He has shown the effects of the emotional states upon the
heart’s beat, the blood pressure, involuntary muscular activity, and many
other somatic conditions.
New methods for the detection of criminals based
upon his work may lead to the elimination of the inhuman “third degree”
and the reformation of criminals not physically incapable of reformation.
The more exact diagnosis of certain diseases, and of almost any disease
under certain conditions, is facilitated by the use of the methods based
upon this work. Munsterburg himself uses hypnotism under certain conditions
in the treatment of some peculiar mental conditions, especially associated
with the neurasthenic states.
This work is a beginning of a rational study of the
real physiology of consciousness, and must ultimately lead to the elimination
of much that is mystical, and idealistic, and fanciful in psychology.
Among psychiatrists, Wernicke has offered a new
classification of mental diseases which is suggestive. He considers psychic
disorders as classified according to the psychic involvement—that is, he
considers certain disorders to be due to the involvement of the psychic-sensory
sphere, others to the intro-psychic sphere, others to the psycho-motor
sphere. This classification is based upon the study of more than five thousand
cases. The classification is useful in a way, and it presents about the
same relationship to ordinary methods of classification of mental diseases
as the classification of physical diseases upon a basis of physical diagnosis
does to the commonly accepted classification of diseases. Wernicke’s classes
are interesting in the study of consciousness from the physiological standpoint,
since they make possible the use of the phenomena of insanity as indicative
of certain psychological tendencies.
Diseases affecting the psychic-sensory sphere, then,
would be associated with malfunction of the primary sensory areas, in which
case sensory abnormalities, without recognizable psychic deficiency, would
be found; or malfunction of the sensory overflow areas, in which case the
conditions known as mind-blindness, mind-deafness, astereognosis, and such
abnormalities, would be found, sometimes with and sometimes without apparent
disorders of mentality.
Disorders of the intra-psychic sphere would be associated
with malfunction of the intermediate areas. The disordered orientation
and the lack of the so-called higher mental qualities would be associated
with malfunction of either the pre-frontal areas or the parietal areas
according to the conditions present.
Disturbances of the psychic-motor sphere must be associated
with malfunction of the motor areas. Destructive lesions of the primary motor
area are associated with paralysis, more or less localized, and not necessarily
associated with any lack of mentality. Lesions involving the motor overflow
must be associated with disturbances of the motor memories, motor aphasia, etc.
Functional disturbances of the primary motor area may be the cause of increased
or decreased motor activity, not usually properly adapted to environmental conditions.
Either the increase or the decrease of the motor activities may be found affecting
groups of muscles which may be strictly localized, or may be quite general in