Depression: SPATIAL ORGANIZATION OF THE BRAIN
Depression &
The SPATIAL ORGANIZATION OF THE BRAIN
The brain is spatially organized. That is, neurons very close to one another in the brain are likely to perform the same functions. This spatial organize the catecholamine theory of depression, which holds that a deficiency in the neurotransmitter norepinephrine in certain parts of the brain is the cause of depression.
SUPPORTIVE TISSUE AND STRUCTURES IN THE BRAIN
Although there are billions of neurons in the brain, most of the volume of
the brain is made up of supportive tissue and structures. These include cells
(glia cells) mixed in among the neurons and is responsible
for the maintenance of neurons, blood vessels, and the protective mention
of the nervous system allows a neurologist to determine the location of
damage in the nervous system by just examining symptoms. Most damage
to the nervous system affects a moderately well-defined area, as would
clearly be the case for strokes, bullet wounds, or tumors. In general, both the
brain and spinal cord are organized so that motor functions are in the front,
and sensory functions in the back, Therefore, the damage involved in most
sensory disorders occurs further back in the nervous system than that involved
in motor disorders.
The nervous system contains areas in which nerve cell bodies are concentrated,
called gray matter, and areas in which axons are concentrated into
tracts, called white matter, because of the white myelin surrounding many
axons. Tissue damage can occur in either or both regions. Functionally, we
can think of the areas of gray matter as processing centers where neurons
interact, and the tracts as the connections among the gray areas. Cell bodies
of neurons are larger in diameter than their axons, and they tend to be
spread further apart. A nerve tract, on the other hand, is a highly concentrated
group of axons, usually serving one or a few functions. This has an
important consequence for pathology. Since many forms of injury to the
nervous system (e.g., small strokes) cause small, spatially well-defined lesions,
they are more likely to totally interrupt a fiber tract than to totally destroy
an area of gray matter that performs a specific function. Put simply,
some disorders can be accounted for in terms of severing the "wires" connecting
two areas. These disorders have been called disconnection syndromes
(Geschwind, 1995).
LATERAL (HORIZONTAL) ORGANIZATION OF THE BRAIN
The human brain, more than the brain of any other species, is differentiated
on a left-right basis. Among all vertebrates, the left half of the brain receives
most of the input from the right side of the body, arid the left half controls
action primarily on the right side. This "contralateral" projection is of powerful
diagnostic value. In almost all cases, if weakness, paralysis, or loss of
sensation on one side of the body results from damage to the brain, the damage
is on the side of the brain opposite to the afflicted body part.
There is a qualitative difference in the functioning of the two human cerebral
hemispheres. The full significance of this difference is best illustrated by
a very special man-made pathology, the split-brain syndrome. (For the rest
of this chapter, assume that all statements refer to right-handers, unless
otherwise indicated, for left-handers are much less consistent than right handers
in hemispheric organization.)
A surgical procedure has been found to reduce certain uncontrollable and
very frequent brain seizures (a particularly severe form of epilepsy). In these
cases, the seizure activity goes back and forth from one side of the brain to
the other. The treatment, pioneered by Joseph Bogen, separates the two
cerebral hemispheres by cutting the corpus callosum and a few other structures
that serve as the main connections between
the two hemispheres. (This, of course, produces a massive disconnection syndrome.)
Bogen's patients were carefully studied by Roger Sperry and his
students (Gazzaniga, 1990; Levy, 1992; Sperry, 1994). In brief, the results
were striking: the patients appeared to have two consciousness in one
head. The left brain was the only half that could speak, and it had a much
more sophisticated understanding of language. The right brain was superior
to the left brain in tasks involving spatial abilities and the recognition of
complex forms that are difficult to describe in words. (e.g., faces) (Levy,
1972, 1980).
The differences between the hemispheres are well illustrated by the performance
of the right hand (left hemisphere) and left hand (right hemisphere)
in copying simple figures. The drawings of the right
hand suggest a general deficit in the organization of the spatial world. The
three-dimensional aspect of the figures is lost, whereas it is preserved in the
drawings by the left hand. One way to summarize the hemispheric differences
is to say that the left hemisphere is better at analyzing inputs and
breaking inputs or outputs into sequences over time, while the right hemisphere
is better at synthesizing components into wholes and making spatial
representations.
These differences have many implications for psychopathology. Language
disorders are much more common with left hemisphere damage (for
right-handers), while disorders in getting around in space or recognizing
faces and other complex configurations occur much more frequently with
right hemisphere damage.
For the Anxiety or Depression Treatment I recommend click this link:
http://theliberatormethod.com
The SPATIAL ORGANIZATION OF THE BRAIN
The brain is spatially organized. That is, neurons very close to one another in the brain are likely to perform the same functions. This spatial organize the catecholamine theory of depression, which holds that a deficiency in the neurotransmitter norepinephrine in certain parts of the brain is the cause of depression.
SUPPORTIVE TISSUE AND STRUCTURES IN THE BRAIN
Although there are billions of neurons in the brain, most of the volume of
the brain is made up of supportive tissue and structures. These include cells
(glia cells) mixed in among the neurons and is responsible
for the maintenance of neurons, blood vessels, and the protective mention
of the nervous system allows a neurologist to determine the location of
damage in the nervous system by just examining symptoms. Most damage
to the nervous system affects a moderately well-defined area, as would
clearly be the case for strokes, bullet wounds, or tumors. In general, both the
brain and spinal cord are organized so that motor functions are in the front,
and sensory functions in the back, Therefore, the damage involved in most
sensory disorders occurs further back in the nervous system than that involved
in motor disorders.
The nervous system contains areas in which nerve cell bodies are concentrated,
called gray matter, and areas in which axons are concentrated into
tracts, called white matter, because of the white myelin surrounding many
axons. Tissue damage can occur in either or both regions. Functionally, we
can think of the areas of gray matter as processing centers where neurons
interact, and the tracts as the connections among the gray areas. Cell bodies
of neurons are larger in diameter than their axons, and they tend to be
spread further apart. A nerve tract, on the other hand, is a highly concentrated
group of axons, usually serving one or a few functions. This has an
important consequence for pathology. Since many forms of injury to the
nervous system (e.g., small strokes) cause small, spatially well-defined lesions,
they are more likely to totally interrupt a fiber tract than to totally destroy
an area of gray matter that performs a specific function. Put simply,
some disorders can be accounted for in terms of severing the "wires" connecting
two areas. These disorders have been called disconnection syndromes
(Geschwind, 1995).
LATERAL (HORIZONTAL) ORGANIZATION OF THE BRAIN
The human brain, more than the brain of any other species, is differentiated
on a left-right basis. Among all vertebrates, the left half of the brain receives
most of the input from the right side of the body, arid the left half controls
action primarily on the right side. This "contralateral" projection is of powerful
diagnostic value. In almost all cases, if weakness, paralysis, or loss of
sensation on one side of the body results from damage to the brain, the damage
is on the side of the brain opposite to the afflicted body part.
There is a qualitative difference in the functioning of the two human cerebral
hemispheres. The full significance of this difference is best illustrated by
a very special man-made pathology, the split-brain syndrome. (For the rest
of this chapter, assume that all statements refer to right-handers, unless
otherwise indicated, for left-handers are much less consistent than right handers
in hemispheric organization.)
A surgical procedure has been found to reduce certain uncontrollable and
very frequent brain seizures (a particularly severe form of epilepsy). In these
cases, the seizure activity goes back and forth from one side of the brain to
the other. The treatment, pioneered by Joseph Bogen, separates the two
cerebral hemispheres by cutting the corpus callosum and a few other structures
that serve as the main connections between
the two hemispheres. (This, of course, produces a massive disconnection syndrome.)
Bogen's patients were carefully studied by Roger Sperry and his
students (Gazzaniga, 1990; Levy, 1992; Sperry, 1994). In brief, the results
were striking: the patients appeared to have two consciousness in one
head. The left brain was the only half that could speak, and it had a much
more sophisticated understanding of language. The right brain was superior
to the left brain in tasks involving spatial abilities and the recognition of
complex forms that are difficult to describe in words. (e.g., faces) (Levy,
1972, 1980).
The differences between the hemispheres are well illustrated by the performance
of the right hand (left hemisphere) and left hand (right hemisphere)
in copying simple figures. The drawings of the right
hand suggest a general deficit in the organization of the spatial world. The
three-dimensional aspect of the figures is lost, whereas it is preserved in the
drawings by the left hand. One way to summarize the hemispheric differences
is to say that the left hemisphere is better at analyzing inputs and
breaking inputs or outputs into sequences over time, while the right hemisphere
is better at synthesizing components into wholes and making spatial
representations.
These differences have many implications for psychopathology. Language
disorders are much more common with left hemisphere damage (for
right-handers), while disorders in getting around in space or recognizing
faces and other complex configurations occur much more frequently with
right hemisphere damage.
For the Anxiety or Depression Treatment I recommend click this link:
http://theliberatormethod.com