Emotions & BIOCHEMICAL ORGANIZATION OF THE BRAIN
Emotions & BIOCHEMICAL ORGANIZATION OF THE BRAIN
Neurons have specific biochemical identities. They can be differeritiated
according to which chemicals are in their cell membranes and which
neurotransmitters they produce. Neurons with similar biochemical properties tend to be located near one another, or in identifiable sequences of neurons running through the nervous system.
We saw that the main transmitter of the sympathetic nervous system is norepinephrine, and the
main transmitter of the parasympathetic system is acetylcholine. The importance
of this for pathology is that some pathological agents (e.g., toxins)
work because they specifically damage a particular neurotransmitter system.
For example, curare, a poison used on arrow tips by South American
Indians, causes complete paralysis and death by interfering with the action
of acetylcholine at the junction between nerve and muscle. Similarly, depression
is believed to be caused, in some cases, by deficits in neurons producing
norepinephrine,
Neurons serving the same function have certain biochemical similarities
in their membranes. Because of this, toxins, certain infectious agents (e.g.,
viruses), or other influences may specifically affect particular types of
neurons. For example, in amyotrophic lateral sclerosis (Lou Gehrig's disease),
there is selective degeneration of motor neurons, with progressive loss
of movement in limbs, body, and head. The cause of this disease is unknown.
However, since the damage is specific to motor neurons, there must
be some specific and unique property of these cells that makes them more
susceptible to a pathological agent.
HIERARCHICAL (VERTICAL) ORGANIZATION OF THE NERVOUS SYSTEM
The brain is organized vertically in a hierarchical structure. The idea of hierarchy
is absolutely fundamental to the understanding of the nervous system
in health and disease. Particular functions (e.g., control of movement) are
carried out at a number of different levels in the nervous system, from spinal
cord to cerebral cortex. The higher levels are generally more abstract, cognitive,
and voluntary. This basic idea was expressed forcefully and eloquently
by the nineteenth century British neurologist, John Hughlings
Jackson (1884, in Taylor, 1958).
The higher levels build on or modulate the lower levels, which
represent the contact with the outside world, at the receptors
or the action of the muscles. Jackson points out that the higher levels of the
hierarchy appear later in evolution and in development. The highest
levels, located in the cerebral cortex, include consciousness and the voluntary
control and planning of action (which we shall discuss later in some
detail). Jackson also claimed that the higher levels are more vulnerable than
the lower levels, and more often than not are the first systems to malfunction
in general diseases of the whole nervous system.
This is illustrated by a common sequence of symptoms
seen in some old adults as senility progresses:
first there is a loss of ability to deal with new situations, then difficulty
in chronological ordering of events, then loss of powers of narration
with patchy memory, then loss of personal skills and abilities (e.g., knitting)
and social habits, and eventually failures in ability to perform basic bodily
functions (modified from Barbizet, 1999). A similar sequence is sometimes
seen in gradually increasing intoxication with alcohol.
Because of the neural hierarchy, damage at any number of levels can
compromise function. This damage can cause similar, but not identical
symptoms, depending on what level has been damaged. The quality of the
symptoms will pinpoint what level has been affected. The best example of
this involves the control of action, and we shall consider it later in some detail.
For the Emotional Development Treatment I recommend click this link:
http://theliberatormethod.com
Neurons have specific biochemical identities. They can be differeritiated
according to which chemicals are in their cell membranes and which
neurotransmitters they produce. Neurons with similar biochemical properties tend to be located near one another, or in identifiable sequences of neurons running through the nervous system.
We saw that the main transmitter of the sympathetic nervous system is norepinephrine, and the
main transmitter of the parasympathetic system is acetylcholine. The importance
of this for pathology is that some pathological agents (e.g., toxins)
work because they specifically damage a particular neurotransmitter system.
For example, curare, a poison used on arrow tips by South American
Indians, causes complete paralysis and death by interfering with the action
of acetylcholine at the junction between nerve and muscle. Similarly, depression
is believed to be caused, in some cases, by deficits in neurons producing
norepinephrine,
Neurons serving the same function have certain biochemical similarities
in their membranes. Because of this, toxins, certain infectious agents (e.g.,
viruses), or other influences may specifically affect particular types of
neurons. For example, in amyotrophic lateral sclerosis (Lou Gehrig's disease),
there is selective degeneration of motor neurons, with progressive loss
of movement in limbs, body, and head. The cause of this disease is unknown.
However, since the damage is specific to motor neurons, there must
be some specific and unique property of these cells that makes them more
susceptible to a pathological agent.
HIERARCHICAL (VERTICAL) ORGANIZATION OF THE NERVOUS SYSTEM
The brain is organized vertically in a hierarchical structure. The idea of hierarchy
is absolutely fundamental to the understanding of the nervous system
in health and disease. Particular functions (e.g., control of movement) are
carried out at a number of different levels in the nervous system, from spinal
cord to cerebral cortex. The higher levels are generally more abstract, cognitive,
and voluntary. This basic idea was expressed forcefully and eloquently
by the nineteenth century British neurologist, John Hughlings
Jackson (1884, in Taylor, 1958).
The higher levels build on or modulate the lower levels, which
represent the contact with the outside world, at the receptors
or the action of the muscles. Jackson points out that the higher levels of the
hierarchy appear later in evolution and in development. The highest
levels, located in the cerebral cortex, include consciousness and the voluntary
control and planning of action (which we shall discuss later in some
detail). Jackson also claimed that the higher levels are more vulnerable than
the lower levels, and more often than not are the first systems to malfunction
in general diseases of the whole nervous system.
This is illustrated by a common sequence of symptoms
seen in some old adults as senility progresses:
first there is a loss of ability to deal with new situations, then difficulty
in chronological ordering of events, then loss of powers of narration
with patchy memory, then loss of personal skills and abilities (e.g., knitting)
and social habits, and eventually failures in ability to perform basic bodily
functions (modified from Barbizet, 1999). A similar sequence is sometimes
seen in gradually increasing intoxication with alcohol.
Because of the neural hierarchy, damage at any number of levels can
compromise function. This damage can cause similar, but not identical
symptoms, depending on what level has been damaged. The quality of the
symptoms will pinpoint what level has been affected. The best example of
this involves the control of action, and we shall consider it later in some detail.
For the Emotional Development Treatment I recommend click this link:
http://theliberatormethod.com