THE NEUROLOGY OF BIOFEEDBACK
A Neuro-anatomical and Physiological Review
Mariella Fischer-Williams, MD, FRCP |
I. Introduction.
2. The brain functions as a communication system.
3. The brain functions as a gland, with neurotransmitters
and neuropeptides.
4. The brain functions as a system of adaptation.
5. The brain controls emotions. Mood related to
patho-physiology.
6. The brain controls activity and behavior. Hypo-activity
and hyper-activity.
7. The nervous system is built on stimulus-response
mechanisms.
8. Biofeedback as a treatment modality in neuropsychiatry.
9. Biofeedback as a treatment modality in restorative
neurology.
1. INTRODUCTION
People commonly ask the questions : "Why?",
"How does a thing work?" and "How can I fix it?". I do not attempt to
answer "Why?" because it is a metaphysical question. Much of this book answers
the question of "How can I fix it?".
I shall mainly describe "How does the brain
work?" which I freely acknowledge is an immodest goal.
The nervous system is built upon a living network of
feedback, constantly adapting to the environment, both the internal and the external. The
prefix"bio" in biofeedback is semantically unnecessary since we are dealing with
systems during life. However, because of the historical use of "biofeedback" as
a treatment modality the term can be accepted.
Biofeedback is an important technique in the wide spectrum
of behavioral medicine. Behavior is the motor output of the nervous system which depends
upon the conscious and unconscious reception and acceptance of stimuli by an individual.
It is the response to a continuous stream of stimuli in the waking and the sleeping state.
Biofeedback professionals learn the art of encouraging self-awareness both of themselves
and of their patients, in order for perception of stimuli to be changed if desired.
Therefore we need to become more self-aware of the
physiology that generates our behavior. We need to harness our feedback forces, and to use
the inherent physiological mechanisms of feedback to the best advantage of ourselves and
of those whom we contact.
Behavioral responses can be modified by the way the
individual perceives these incoming stimuli. Similar stimuli are experienced differently
by different people, and they also vary according to the actual psycho-physiological state
of the individual, including their age and experiences.
A.R. Luria in his classic book "Higher Cortical
Function in Man" analysed "the reflex mechanisms by means of which the organism
maintains its equilibrium with the environment" and "the problem of the cerebral
mechanisms of mental activity". Replace the word "reflex" by
"biofeedback" and we see how we are perpetually studying these mechanisms.
For an excellent review of the central autonomic network
(CAN), with its functional organization and dysfunction, the reader is referred to the
article by Eduardo Benarroch (1993), (see Fig 1).
2. THE BRAIN AS A COMMUNICATION SYSTEM
The brain functions as a system for communication over the
entire body. The nervous system consists of a CENTRAL part (the brain and the spinal cord)
and a PERIPHERAL part which comprises the nerves that arises from the brain and spinal
cord. These nerves supply the special senses, the musculature and the sensation of the
trunk and the four limbs.
This chapter deals with the central nervous system (CNS).
It is a bilateral and in many ways symmetrical group of structures consisting of 6 parts:
(1) the Spinal cord; (2) the Brain stem subdivided into 3 regions, the midbrain, the pons
and the medulla; (3) the Cerebellum, important for modulating and co-ordinating motor
movement together with (4) the Basal ganglia, (the caudate nucleus, putamen and globus
pallidus); (5) the Diencephalon (the thalamus, hypothalamus, subthalamus, and epithalamus)
and (6) the Cerebral Hemispheres capped by the cerebral cortex or rind with higher
perceptual cognitive and motor functions, (Kandel). (see fig 2). The brain weighs 3 lbs.
The spinal cord is like a tail arising from the base of the brain and its thickness
averages that of a human finger.
Broadly speaking the tasks of the brain can be divided into
three categories:
(1) the RECEPTION OF STIMULI (this is the sensory system);
(2) the association of stimuli and the analysis or
PERCEPTION OF INCOMING STIMULI; and (
3) the MOTOR RESPONSE to those stimuli. These motor
responses summate so as to constitute the behavior of the individual. At the cellular
level, sensory signals are transformed into motor acts.
(1) The RECEPTION OF STIMULI by the brain occurs via the
AFFERENT PATHWAYS FOR SENSATION. (The term"afferent" indicates travelling
towards the brain, and "efferent" travelling away from the brain.) The pathways
for light touch, (tickle), pain, pressure, heat, cold and vibration from the periphery to
the cerebral cortex are well-known and they do not vary significantly. It is the conscious
PERCEPTION by the individual of these stimuli (when they reach the appropriate area of the
cerebral cortex) which varies constantly throughout life.
In order to prevent overloading of the individual by a
continous stream of stimuli, the nervous system has developed a variety of methods of
INHIBITION. Inhibition is an important neurological concept for biofeedback professionals
since learning how to inhibit sensations, thoughts or behavior is basic in biofeedback
training. Inhibition as applied to synaptic transmission refers to an active process by
which excitatory transmission is prevented. Inhibition occurs in the CNS both before and
after the synapse ("pre-synaptic" and "post-synaptic"). A major
pre-synaptic neurotransmitter, which is inhibitory in many processes, is
gamma-amino-butyric-acid (GABA). In the thalamus (its nucleus is the main way-station for
sensation) there is both pre- and post-synaptic inhibition. At higher levels in the brain,
both in the cerebellum and in the cerebral cortex, inhibition is mainly post-synaptic.
Inhibition can be directed from the cerebral cortex.
Efferent pathways from the sensori-motor cortex excite thalamo-cortical relay cells. By
exerting inhibition the cerebral cortex is able to block the synapses and thus to protect
itself from being stimulated by cutaneous stimuli; it can neglect these stimuli. This
happens for example when one is deep in thought, preoccupied with an experience or
intensely involved in carrying out an action. Counter-irritation to relieve pain acts in
this way. Discharges from the cerebral cortex down the pyramidal tracts and other pathways
may exert an inhibitory blockage at the relays in the spino-cortical pathways. This can
inhibit unwanted motor movements.
INHIBITORY FUNCTIONS OF THE CEREBELLUM.
The cerebellum is the great "smoother" of all
motor activities. The Purkinje cells are large nerve cells in the cerebellar cortex. The
unique feature of the cerebellar cortex is that its output is expressed entirely by the
inhibitory Purkinje cells.
Nowhere else in the brain is inhibition so dominant. How
can information be conveyed effectively in this negative manner? Because this inhibitory
action is exerted on nuclear cells that have a strong background discharge.
Eccles gives the analogy of the sculpture of stone. A
sculptor has a block and achieves form by "taking away" stone through
chiselling. Similarly the Purkinje cells of the cerebellum achieve form in the nuclear
cell discharge by taking away from the background discharges through the process of
inhibition.
(2) The association of stimuli and the analysis or
PERCEPTION OF INCOMING STIMULI is carried out in the cerebral hemispheres. Here memory,
judgement, thought association, verbal and non-verbal communication, the emotional
coloring of stimuli all combine to create the personal interpretation of on-going stimuli.
This is the meeting-ground which regulates the psycho-physiology of the individual.
(3) THE MOTOR RESPONSE TO THE STIMULI. This is the output
of the brain, the efferent system, via the pyramidal, extra-pyramidal and non-pyramidal
pathways.
These responses require exquisite MOTOR COORDINATION.
The CEREBELLUM is concerned with the reliable and regulated
control of movement. The cerebellum is the part of the brain which through the process of
evolution has come to function as a special computer by handling all the complex inputs
from receptors or from other parts of the brain. The articulation of speech is subserved
by cerebellar mechanisms.
Let us visualize the neural events in the
cerebro-cerebellar circuits during a skilled action, such as running a machine at work or
playing the piano. There will be initially a motor command with a preprogramming of the
movements by circuits in the association cortex, cerebellum, basal ganglia and thalamic
nuclei. The learned skills are mobilized and the discharge leads on to the action impulses
in the pyramidal tract, with the consequent report of the discharge to the part of the
cerebellar cortex receiving and projecting both to the cerebrum and the spinal cord.
Cerebral"willing" of a muscle movement sets in train neural events that lead to
the discharge of pyramidal cells.
There is a sequence of neuronal events, a chain reaction,
such that one part is called into operation (in the temporal or time sense) and this leads
other parts to go into action which generates further activity . Since, however, all areas
of the brain are constantly (and therefore concurrently) active, many elements are
carrying out their own intrinsic activities (cross-talks between the cells) which are not
apparent to an outside observer; these do not impinge on the consciousness of the
individual concerned. It is clear, therefore, that a good deal of cerebral activity goes
unheeded by the originator and all observers.
Biofeedback treatment is based on learning. How does the
brain as the organ of communication bring about learning?
The process of learning consists of excluding from
consciousness all stimuli except the one which the individual chooses to focus upon, and
to which his attention is directed. The acquisition of new data thus involves a process of
selective listening and consists mainly of rejection or ignoring of stimuli which are
nonrelevant at that time.
Biofeedback consists of acquiring a technique for selective
"listening" to a particular set of stimuli, which may come from the external
environment or from inside the individual's own body (internal environment) . The purpose
of the technique is for the student to have the ability to regulate psycho-physical
function himself. In order to acquire and to teach this technique, we have to know, first,
the GEOGRAPHY OF SPECIALIZED FUNCTIONING, meaning the localization within the brain of
neurons with specialized function. These neurons in different parts of the brain vary
greatly one from another. For example they vary in size as a petunia varies from an oak
tree, (Stevens). Second, we have to understand the interconnections (neural connections)
or microstructural changes in SYNAPSES, linkages or pathways of the brain, because this
gives a basis of the HOW of behavior, both of the patient and of ourselves. Third, we have
to understand the concept of EXCITATION and INHIBITION. The neurons are either excitatory
or inhibitory and/or secretory. When two parts of the brain (two neuronal populations)
interact, they may each exert an excitatory or an inhibitory effect.
A neuronal impulse may release a neurotransmitter which
excites or inhibits. If one part fails to act, there is uncontrolled or deafferented
functioning of neurones, because they are lacking their accustomed stimulation or input.
NEURONAL FUNCTION.
Neurons have four main functions: (1) they respond to
specific neurotransmitters by altering membrane permeability to common ions (sodium,
chloride, potassium, calcium); (2) they conduct electrical impulses; (3) they secrete
transmitters (see below in "Neurotransmitter"); (4) they communicate with other
post-synaptic cells by the process of synaptic transmission.
Neurons are able to respond and act as
"receptors"; this is because their intrinsic membranes (coverings) contain
proteins which can receive messages and are therefore called receptors. The membranes of
different neurons contain different receptors.. These receptors are protein-complexes
bound in the intrinsic membrane of the neuron.
3. THE BRAIN AS A GLAND
When we add together the concepts of the brain as the organ
for communication and the brain as a gland, secreting chemicals, we see that the sensory
messages that arrive at the brain from the periphery are being continuously changed,
altered, modified, censored, embellished, intensified or inhibited by NEUROTRANSMITTERS. A
transmitter is a chemical substance that is released synaptically by one neuron and that
affects another cell (neuron or effector organ) in a specific manner. However, a given
transmitter does not always open the same ionic gates or bring about the same biochemical
change in the postsynaptic neuron; the receptor determines whether the synapse will be
excitatory or inhibitory.
These transmitters act at the neuro-muscular junctions, the
interneuronal junctions and the sensory way-stations, and they are either repressed or
further attended to and analysed according to the state of the "receiving"
cortex. The incoming sensations are matched with previous experiences. The brain can
discard anything "foreign" in the same way that foreign substances like grafts,
bacteria or other non-self substances are rejected by the tissues which represent the
"self". Some nerve cell receptors have been found to be isomers of immune cell
receptors.
SYNAPTIC TRANSMISSION. There are four biochemical steps in
synaptic transmission: (1) synthesis of the neurotransmitter substance; (2) release of
transmitter into the synaptic cleft; (3) binding of transmitter to the postsynaptic
receptor, and (4) removal or destruction of the transmitter substance, (Schwartz).
There are eight substances which are the original classical
neurotransmitters: Acetylcholine, the 4 biogenic amines: Dopamine, Histamine,
Nor-epinephrine (the locus caeruleus is rich in nor-epinephrine), and Serotonin
(5-hydroxy-tryptamine) ; and 3 amino-acids: Gamma-amino-butyric acid (GABA), Glycine and
Glutamate.
NEUROPEPTIDES. Some neurotransmitters are, chemically,
neuropeptides.
Neuroactive peptides or neuropeptides have been found to be
localized in neurons. More than 50 neuropeptides have now been isolated and arranged in a
chemical sequence. They range is size from small peptides (two amino acids joined by a
single peptide bond) to a large molecule such as corticotropin-releasing-factor (CRF)
which is comprised of 41 amino acids.(Nemeroff). The amino acids arranged in chains
include Glycine, Alanine, Leucine, Aspartine and Arginine.
These neuropeptides act as hormones in some tissues, (a
hormone is a chemical messenger, a substance released at considerable distance from its
intended site of action); and in other tissues these peptides act as neurotransmitters
( a neurotransmitter is released directly onto the site of
the intended action).
Neuropeptides are important in the field of biofeedback
because their action is closely related to the psycho-physical state of the individual.
Certain neuropeptides are involved in the perception of
pain, pleasure, fear, depression and other emotions. Others are involved in the control of
blood pressure, reproduction, and the mobilizing of energy. Some can be termed
neuromodulators because they are substances that modulate the action of classical
neurotransmitters, (the first 25 or so neurotransmitters to be isolated), but the field is
increasing so rapidly that terms change their exact meaning.
The brain, functioning as a gland secreting chemicals,
regulates our psycho-physical state through many systems, including the gastro-intestinal,
the cardio-vascular and the immune systems. Many brain areas are particularly involved,
including the hypothalamus. the pituitary, and the amygdala. We shall discuss these
biochemical factors as they relate to mood and behavior.
First we review the brain areas identified as specially
important.
The HYPOTHALAMUS.
The hypothalamus is a minute collection of nuclei situated
just below the thalamus. These nuclei are distinguished microscopically, and they include
the median eminence, the peri-and para-ventricular nuclei, the preoptic nuclei, the
arcuate nucleus and many others.
HYPOTHALAMIC-RELEASING HORMONES include
Thyrotropin-releasing hormone (TRH), Luteinizing hormone (LH), and somatostatin (growth
hormone release-inhibiting factor, SRIF).
The PITUITARY. The pituitary is the pea-like body sitting
in the pituitary fossa at the base of the skull. PITUITARY PEPTIDES include
Adrenocorticotropin (ACTH), Beta-Endorphin, Vasopressin and Oxytocin. The
hypothalamic-pituitary-adrenal axis is central to many aspects of the stress response.
The AMYGDALA. (plural for amygdalum). The amygdalum is a
nucleus the shape of an almond situated deep in each temporal lobe. The two nuclei
constitute the amygdala and are part of the limbic system, the so-called affective brain,
associated with emotionally-based behavior. The amygdala within the limbic system connects
to the cerebral cortex, to the thalamus and hypothalamus, and to the brainstem and spinal
cord. The amygala is important for the mediation of normal responses to fear-evoking or
anxiety-producing stimuli. Epileptic seizures where the abnormal neuronal discharge
involves the amygdalum can be manifested by severe sensations of fear and memories of
events full of fear. Autonomic changes can accompany this fear with increases in heart
rate and blood pressure, dialation of the pupils and pallor. "A majority of the
peptides that have been localised with neurons of the brain are found within either
neuronal cells bodies or terminals of the amygdala" (Gray). These include
cortocotropin-releasing factor (CRF), neurotensin, Enkephalin, Somatostatin and Substance
P.
Next we review the systems where neuropeptides are
particularly involved.
THE GASTR0-INTESTINAL SYSTEM.
GUT-BRAIN PEPTIDES give us the concept of the MINIBRAIN in
the intestinaltract. They include vasoactive intestinal polypeptide (VIP), Cholecystokinin
(CCK), Substance P, Neurotensin, Methionine enkephalin, Leucine enkephalin, Insulin and
Glucagon.
GASTRO-INTESTINAL (GI) FUNCTION. The stomach and intestines
have been known for a long time to have a large nerve supply, mainly of non-medullated
sympathetic fibers and medullated preganglionic fibers of the parasympathetic. Nerve
fibers between two layers of smooth circular muscle form the plexus of Auerbach. From
there they pass to the submucosa of the gut to form the plexus of Meissner.
Details of the enteric nervous system are now described
with brain peptides effecting GI transit (motility), and this gives the concept ot the
MINIBRAIN in the gut. Many neuropeptides are involved: the Opioids, Bombesin, CRF,
Thyrotropin-releasing hormone (TRH), Somatostatin, Calcitonin, Neurotensin and Substance
P. Opium and opiates such as morphine have been known since antiquity to inhibit
gastro-intestinal transit. Endogenous (naturally produced) opioid peptides like
beta-Endorphin act on gut motility, mainly inhibiting it. CRF is a critical mediator of
stress responses acting on the hypothalamus as described above. It has been shown
experimentally to inhibit transit in the small intestine and to stimulate it in the colon.
Biofeedback techniques can be helpful in reducing stress, plus modulating neuropeptide
activity, and thereby regulating the motility of the gut, and altering patterns of
motility.
The CARDIO-VASCULAR SYSTEM.
CARDIO-VASCULAR REGULATION. Adreno-cortico-trophic hormone
(ACTH) has important effects on blood pressure and sodium metabolism. Chronic treatment
with ACTH can cause hypertension and sodium retention. ACTH is primarily synthesized in
the anterior pituitary and its major role is the regulation of the adrenal cortex, but its
role within the CNS is unclear. (see below in mood-regulation). Vasopressin can cause
excitation of the sympathetic system. Endogenous opioid peptides appear to confer
protection against the arrhythmias that arise during stress, (Verrier). Indeed, many
investigators have shown that these opioids play a role in modulating the cardiovascular
response to circulatory stressors, (Frantz and Liang).
The IMMUNE SYSTEM.
IMMUNE FUNCTION. There is strong evidence for a functional
effect of opioids on the immune system. Opioid peptides have an effect onreceptor sites of
many subgroups of leucocytes (white blood cells) including natural killers (NK) cells,
monocytes, macrophages, mast cells, lymphocytes and thymocytes which are all involved in
reactions to infections, and in auto-immune disease processes, such as multiple sclerosis.
Natural killer (NK) cells are thought to play an important
role as tumor cell scavengers and also in transplant rejection. NK cell activity has been
shown in humans to be enhanced by exercise (Brahmi et al.).
The COGNITIVE - EMOTIONAL SYSTEM
Neuropeptides have effects which overlap several systems
and therefore repetition is inevitable when we review some of the chemical control
mechanisms of mood, behavior and reactions to stressors.
The age-old drug from the poppy, opium, gives a
"pleasurable" or antidepressant effect. Substances produced in the body which
give"pleasure" are therefore called opioids. ENDOGENOUS OPIOID PEPTIDES have
been implicated as being either causative or curative agents in a variety of mental
disorders. Stress, opioid peptides (endorphins) and cardiac arrhythymias are often
inter-related, and this aspect of the cardio-vascular system is well-known as suitable for
biofeedback treatment.
Stress stimulates the secretion of corticopin-releasing-
factor (CRF) from the hypothalamus. CRF is carried down the pituitary stalk and stimulates
secretion of ACTH and beta-endorphin into the periphery. CRF produces activation of the
sympathetic nervous system resulting in secretion of epinephrine (adrenaline) and
nor-epinephrine from the adrenal medulla.
Leu-and met-enkephalin are co-secreted along with
epinephrine and nor-epinephrine from the adrenal medulla into the bloodstream. Also,
inhibitory feedback pathways go from the pituitary to the adrenal and cortisol in the
blood stream can inhibit the hypothalamus as well as ACTH and endophins in the pituitary.
ENDOCRINE REGULATION for the prevention of stress and/or
depression involves the hypothalamic-pituitary-adrenal axis.
Corticotrophin-releasing factor (CRF) is the hypothalamic
releasing hormone that controls the hypothalamic-pituitary-adrenal axis (HPA axis). Stress
increases ACTH and glucocortisol concentrations. Apparently the activation of the HPA axis
by stress is due to the release of several neuro-modulators including CRF, Arginine,
Vasopressin, Oxytocin, Angiotensin II, Vasoactive intestinal peptide (VIP). Epinephrine,
and Norepinephrine.
Corticotrophin-releasing factor (CRF), however, is THE
major regulator of ACTH.
Patients suffering from major depression, when not
medicated, are as a group hypercorticolemic (too much cortisol in the blood), and they may
therefore be chronically over (hyper) secreting CRF. The possible mechanisms involving CRF
and the pathogenesis of depression are numerous and await detection. Biofeedfack as a
treatment can help the symptom by modifying the behavior.
4. THE BRAIN AS A SYSTEM OF ADAPTATION
There is a plethora of data generated in the last decade on
the various physiological alterations that occur after exposure to stressful stimuli. This
shows how the brain functions for adaptation. It is important for biofeedback
professionals to have some understanding of these alterations, because the technique of
biofeedback teaches the subject to modify his/her responses to stressors in order to
maintain psycho-physiological balance when battered by these stimuli.
The hypothalamic-pituitary-adrenal (HPA) axis has been the
focus of many investigations on the manifestations of the stress response ever since Hans
Selye described in 1936 the hypertrophy of the adrenal gland and the atrophy of lymph
glands in response to chronic stress. With the discovery of corticotropin-releasing factor
(CRF) by Vale and co-workers in 1981, the hypothalamic component of this axis became
available for investigation.
The HPA axis is a multistep integrated process involving
several CNS sites (cerebral cortex, amygdala, locus caeruleus, hippocampus, etc). In the
hypothalamus these signals are transduced to humoral-type messages, release and release-
inhibiting hormones. These travel a short distance to the anterior pituitary where they
are funneled into the general circulation and travel to their appropriate target organs.
The responses that these signals engender have major influences on blood pressure,
reproductive function and energy mobilization. In addition the various neuroendocrine axes
are also influenced by a variety of feedback control loops. These feedback controls can be
of both a fast and a slow nature and involve both central and peripheral sites (Ritchie
and Nemeroff). In major depression, corticotropin-releasing factor ( CRF) is most likely
hypersecreted (see above).
It is also possible that the precipitous fall in CRF, in
ACTH and in cortisol levels in maternal plasma at the time of delivery leaves the HPA axis
uncompensated, and postpartum depression may develop because of sudden changes.
The locus caeruleus is important in the process of
adaptation to the environment because it is rich in nor-epinephrine, (nor-adrenaline). The
locus caeruleus (literally the "blue spot") is so-called because of
melanin-pigment granules found in human infants and increasing with age. It has a very
rich blood supply enabling this nor-epinephrive to be rapidly transported over the body.
It is a microscopic nucleus in the floor of the 4th ventricle in the upper pons, near
structures that regulate respiration with changes in the relative carbon dioxide and
oxygen content of the blood.
It is important to understand something of the neuropeptide
involvement in STRESS. Since stress is the result of an individual's response to
stressors, we can see that the brain is the organ of adaptation, acting through its
neuro-humoral network. Neuropeptides are part of this network. They mediate the regulation
of the neuroendocrine and the autonomic responses to stress.
The neuropeptides identified in this network include :
(1)Corticotropin-releasing-factor (CRF); (2) thyrotropin-releasing factor (TRF); (3)
Bombesin and related peptides: and (4) Somatostatin-related peptides. All 4 groups of
these peptides effect both the sympathetic and the parasympathetic systems. For example,
CRF increases the plasma concentration of glucose and glucagon, increases cardiac output,
heart rate and blood pressure, decreases kidney and mesenteric blood flow, gastric
motility and acid secretion, and inhibits ovulation, (Brown). TRF and Somatostatin-related
peptides have cardiorespiratory, metabolic, gastrointestinal and pancreatic effects
demonstrated in animal experiments (Brown). "Bombesin acts within the CNS to decrease
regulatory heat production and oxygen consumption during cold exposure" (Brown). Thus
Bombesin slows an animal's metabolism.
The brain reacts in many ways to drinking behavior,
drinking bouts and signals that initiate or terminate drinking. For example, Angiotensin
II is a neuropeptide with three physiological mechanisms appropriate to a response to
water loss. (a) vasoconstriction (b) increased release of aldosterone and (c) increased
release of antidiuretic hormone.
5. MOOD RELATED TO PATHO-PHYSIOLOGY
Dr. Eliot Stellar, a physiological psychologist, author of
the well-known books "Physiological Psychology" in 1950 and "The
Neurobiology of Motivation and Reward" in 1985, illuminated the interdependence of
psychology and physiology. This interdependence may seem self-evident but must be
understood in detail.
Mood and emotional reactions are sensitively related to our
physiological well-being or our pathological ill-state. Everyone is aware that sleep and
food intake effect mood. Thus a sleep deprived person is "grumpy", irritable and
lacks judgement. People are less aware that sleep deprivation can cause seizures; that
over-activity (hyperfunction) of the thyroid gland can lead to thyrotoxic emotional
lability; and that under-activity (hypo-function) of the thyroid gland (myxedema) can lead
to "myxedema madness". With an insulin tumor, a patient may develop bursts of
irrational behavior. A phaeochromocytoma is a tumor of certain cells of the adrenal
medulla. The tumors secrete an excess of adrenaline and noradrenaline but because the
output may be continuous or paroxysmal, the clinical features vary greatly. Apart from
hypertension, anxiety and fear can be severe in attacks, (Lishman, 1987). Depression is
frequent after influenza and other viral infections. Episodes of abnormal behavior may
occur in patients with epilepsy, unrelated in time to a seizure.
Other evidence of mood related to pathology includes
depression in Parkinson's disease, the on-off drug effects in the treatment of Parkinson's
disease; chemical imbalance in manic-depression; pre-menstrual syndrome; depression in
cerebral arteriosclerosis; drug-related mood changes; hallucinatory drugs; oxygen lack
causes loss of judgement; sensory deprivation illusions; vitamin deficiences cause lack of
energy; and toxic disorders like lead poisoning are associated with low IQ.
Changes in personality are frequently observed due to
cerebral tumors (mainly frontal), to head injury, to cerebrovascular disorders, to senile
dementia, and to presenile dementia (Alzheimer's disease). All these disorders show that
disfunction in any organ, including the brain, changes mood, emotions and behavior.
For many people, mood is associated with the
"mind". However they can understand that the brain is as much part of the body
as all the other organs, such as heart, lungs, thyroid. They can see that disfunction of
any of these organs can cause psychological disfunction. Because the brain regulates the
other organs through feedback mechanisms, it is pivotal in psychology. The
"mind"is a concept and from the physiological point of view its workings are
those of the brain.
Biofeedback treatment is directed to the brain mechanisms
that control all our physiological functions. When this biofeedback treatment is
inappropriate for patients because of their significant cognitive deterioration,
biofeedback may be offered to their relatives suffering from reactive anxiety and
distress.
6. THE BRAIN CONTROLS ACTIVITY.
Charles SHERRINGTON, the founder of modern motor
physiology, wrote that : "To move is all mankind can do and for such, the sole
executant is muscle, whether in whispering a syllable or in felling a forest".
Here the CNS operates through the peripheral nervous
system. "Spinal interneurons constitute an important set of networks for processing
both peripheral inputs and commands descending from higher brain centers"
(Sherrington)
Both too little (hypo) and too much (hyper) activity can be
pathological. HYPOACTIVITY is one of the hallmarks of clinical depression. The
patho-physiology of depression is described in detail in the book:"Neuropeptides and
Psychiatric disorders" edited by Charles B. Nemeroff.
Inability to "get going" can be pathologically
based as in Parkinson's disease where patients have great difficulty in initiating a
movement, for example walking; here the dopamine metabolism is disturbed. Many patients
with Parkinsonism suffer from depression because their musculature does not respond to
their desires; actual slowing of thinking processes may also be involved. On the other
hand inability to "get going" may be psychologically based through lack of
motivation or sensory deprivation on a socio-economic background.
HYPERACTIVITY with its corollary of defective attention in
childhood is in many cases a contemporary phenomenon caused by excessive
television-watching, an environment of "sound-bites" and methods of education.
Hyperactivity associated with various forms of neurological
retardation is associated with lack of neuronal inhibition and poor control of responses.
The LIMBIC CHILDREN is a concept (Fischer-Williams ) that
arose from the clinical observation of certain patients with "retardation"on an
organic neurological basis. These subjects, children and young adults, have frequent mood
changes with outbursts of uncontrolled activity, disturbed behavior and abnormal
"drives". The limbic system regulates emotions and the activities of the frontal
cerebral cortex through many anatomo-physiological pathways. When there is a lack of
feedback control from the limbic system to the frontal cortex (where judgement is formed
and social activity is analysed), these subjects show inappropriate hyperactivity. A more
correct term would be "a-limbic children" because the condition indicates that
the limbic structures never developed their functions or were lost through early disease.
Information on the neuropeptides operating in the limbic system (particularly of the
amygdala which are part of the limbic system) is now detailed.
THE BRAIN NEEDS FEEDING WITH BLOOD. Clearly, brain function
depends on a healthy supply of blood. This subject, however, will not be discussed in this
chapter. except to say that the heart can be likened to a pump, the blood vessels to a
garden hose, and the brain to a garden.
7. STIMULUS - RESPONSE MECHANISMS
In biofeedback, there is a primary concern with two
mechanisms: first, when the subject or patient becomes continuously aware of the stimulus
of certain physiological activities, such as muscle tone or heart rate, and second when
the subject has incentives or rewards for changing or controlling the feedback and
therefore learns to control voluntarily the physiological response associated with the
feedback. The continuous information fed back to the subject brings to consciouness
something which has not previously been registered at a conscious level. Consequently
information travels a different neuronal pathway.
It is therefore important to understand the principle of
divergence and convergence of information, and some of the complex neuronal systems that
can modify or modulate behavior. For example a great deal of information arrives
(converges) at the retinal nerve cells. This information is compacted (reduced) and then
passed down the visual pathways. At the occipital cortex it is received by cells with very
specialized functions, so that the information is sorted out (teased out) and diverges to
individual groups of cells. However the brain has learned to converge vision and the
"normal" individual sees one picture. Psycho-physiological techniques can teach
an individual to separate or to converge sensations.
The "expectancy " wave of Grey Walter. Another
phenomenon may be relevant in this context. When two stimuli are associated and the
subject is instructed to terminate the second one by pressing a button, a low voltage
"intention" or "expectancy " wave develops and can be recorded in
normal subjects with DC recording on the scalp. It is termed the negative contingent wave
(Walter), and this electrical cortical event is important because it comes just before
action. Grey Walter once suggested that a disturbance of this "intention" wave
was related to the indecision sometimes seen in "neurotic" patients. It might be
related to the "jitters" described in some golf players just before the action
of putting.
Other phenomena may exist similar to those seen in patients
with "split brains", where the two hemispheres have been disconnected after
section of the corpus callosum and the anterior commissure in the treatment of intractable
epilepsy. Division (separation) of information has been demonstrated in regard to
perception, cognition, volition, learning and memory (Sperry). These phenomena allow one
to speculate that during biofeedback training, new linkage pathways may be established
between perception of the monitor measurements fed back and the unconcious physical
changes in whatever modality is being monitored at the time. The patient's body makes
physical changes in by-passing the ordinary sequence of volitional motor activity, just as
motor skills are acquired by constant repetition.
8.Biofeedback as a treatment modality in Neuropsychiatry
Neuropsychiatry is based on the "delicate balance
between our knowledge and understanding of the brain and our knowledge and understanding
of people", (Lishman). As a neuropsychiatrist, Dr. Lishman wrote: "I tend to see
patients with brain disease- - - and the decision we must often try to make is on whether
the problems we see in the clinic are "organic" or "functional"---
more precisely whether they derive from a primary brain malfunction or from difficulties
the patients are encountering in their lives," (Lishman). He wisely comments that
"we must sidestep the risk of becoming too far seduced by one or other pole of this
dual requirement". "Brain biochemistry - - with increasing relevance to
emotional and behavioral disorder" (Lishman), pharmacotherapy, psycho-pharmacology,
imaging of many areas in the brain including the limbic system during cognitive
activities, all open up exciting vistas for health therapists to explore.
For example, Lishman quoted Weinberger: "We can
visualize the increased blood flow to frontal regions when a normal subject engages in a
category sorting task and show that equivalent dynamic shifts are defective in the
schizophrenic brain". (Weinberger et al.)
We can ask other questions: is there a neurologic cause for
obsessive-compulsive disorder? (Insel). How much is pre-menstrual tension a neurochemical
dysfunction, and how much is it a psychological reaction to feedback mechanisms in normal
cyclical events? Similar questions arise with sleep disorders when observed with the
electroencephalogram (EEG) in the study of wake-sleep behavioral mechanisms.
9. Biofeedback as a treatment modality in RESTORATIVE
NEUROLOGY.
Biofeedback treatment is useful as an adjunct in the
therapy of neurological disorders. Criteria for sucessful treatment include basic
knowledge of brain function, and honest motivation of both patient and therapist with
reasonable self-knowledge. Expectations both of the patients and the therapist must be
realistic.
The sad consequences of not keeping this in mind are
described in the book: The Bitter Pill: Doctors, Patients and Failed Expectations, by
Martin R. Lipp. They can often be avoided by close co-ordination with other treatment
modalities and on-going co-operation with specialists in other fields.
Biofeedback is a technique to help reconnect the feedback
systems. We can"listen to our thalamus" (part of the limbic system, sometimes
designated as the emotional brain), we can use our dreams, our sensations, whatever
messages come from our "unconscious". Add to this, we can "use our
brain", meaning we can use our cerebral cortex to analyse our 10 emotions. This
control of thought and action (cognitive and behavioral activities) can lead to synthesis
and the acceptance of paradox.
Biofeedback can play an interventory role at many levels
within the nervous system. It can facilitate re-inhibition, activation, re-balancing ,
stabilization or re-assignment of function. Once a patient is properly evaluated
neurologically, biofeedback can be an adjunct or primary treatment of neurological
disorders. The criteria for the use of biofeedback is discussed in A Textbook of
Biological Feedback (Fischer-Williams, Nigl and Sovine) and in many chapters of this book.
For cost-effective results, the expectations of both the patient and the therapist must be
realistic. For long-lasting results, biofeedback effectiveness is often enhanced when
co-ordinated with other modalities (Fischer-Williams, 1993).
For a better future, we trust that there will be expansion
of methods of preventive medicine. This, however, depends on the health of therapists and
the imaginative education of the public.
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