Download Definition of the limbic system

AROUSAL
Prof. Dr. Elham Al-Jammas
May 2015
L11
AROUSAL
Is a state of being excited or alarmed or the establishment
& maintenance of an awake state which involve a
complex mechanism (mental& physical) ,that prepare the
organism to deal with emergency situation & danger.
The electrophysiological studies showed that both the thalamus &
the cortex fire rhythmical burst of neuronal activities at a rate of
20-40c/s .During sleep the bursts are slow & not synchronized
,the higher the synchronization the higher the level of wakefulness.
Stupor or coma indicates absence of arousal.
Intense emotion usually involves physiological arousal caused by
the activation of the sympathetic division of the autonomic nervous
system that manifest by:
-Rapid heartbeat & increased blood pressure.
-Rapid breathing .
-pupil dilate
-Dryness of mouth & throat
-feeling weak & even faint with sinking feeling in the stomach.
-excessive sweating
- trembling
-poor concentration
-blood sugar level increases
As the emergency situation subside the parasympathetic take
overall these activities are triggered in the brain in the Limbic
system.
Definition of the limbic system:
Is the neuronal circuit that controls the emotional behavior, drive
&motivation.
The limbic system :is a set of brain structures including the
hippocampus, amygdala, anterior thalamic nuclei, septum, limbic
cortex and fornix, which seemingly support a variety of functions
including emotion, behavior, long term memory, and olfaction
The limbic system is the set of brain structures that forms the inner
border of the cortex
HIPPOCAMPUS AND ASSOCIATED STRUCTURES:
Required for the formation of long-term memories and implicated in maintenance of
cognitive maps.
Amygdala: Involved in signaling the cortex of motivationally significant stimuli such as
those related to reward and fear in addition to social functions such as mating.
Fornix carries: signals from the hippocampus to the mammillary bodies and septal
nuclei.
Mammillary body: Important for the formation of memory;
Cingulate gyrus: Autonomic functions regulating heart rate, blood pressure and
cognitive and attentional processing
Dentate gyrus: thought to contribute to new memories and to regulate happiness.
Piriform cortex: The function of which relates to the olfactory system.
Nucleus accumbens: Involved in reward, pleasure, and addiction
Orbitofrontal cortex: Required for decision making.
FUNCTION OF LIMBIC SYSTEM
Limbic System: The Center of Emotions
The limbic system operates by influencing the endocrine system
and the autonomic nervous system. It is highly interconnected with
the nucleus accumbens, the brain's pleasure center, which plays a
role in sexual arousal and the "high" derived from certain
recreational drugs. These responses are heavily modulated by
dopaminergic projections from the limbic system. The limbic
system is also tightly connected to the prefrontal cortex. Some
scientists contend that this connection is related to the pleasure
obtained from solving problems. To cure severe emotional
disorders, this connection was sometimes surgically severed, a
procedure of psychosurgery, called a prefrontal lobotomy (this is
actually a misnomer). Patients who underwent this procedure often
became passive and lacked all motivation
Emotion involves the entire nervous system, of course. But there
are two parts of the nervous system that are especially significant:
.The limbic system and the autonomic nervous system
One of its most important effects is causing the adrenal glands
(which sit on top of the kidneys) to release epinephrine (aka
adrenalin) into the blood stream. Epinephrine is a powerful
hormone that causes various parts of the body to respond in much
the same way as the sympathetic nervous system. Being in the
blood stream, it takes a bit longer to stop its effects. This is why,
when you get upset, it sometimes takes a while before you can
!calm yourself down again
The sympathetic nervous system also takes in information, mostly
concerning pain from internal organs. Because the nerves that
carry information about organ pain often travel along the same
paths that carry information about pain from more surface areas of
the body, the information sometimes get confused. This is called
referred pain, and the best known example is the pain some people
feel in the left shoulder and arm when they are having a heart
attack.
The other part of the autonomic nervous system is called the parasympathetic nervous
system. It has its roots in the brainstem and in the spinal cord of the lower back. Its
function is to bring the body back from the emergency status that the sympathetic
nervous system puts it into some of the details of parasympathetic arousal include...
pupil constriction
activation of the salivary glands
stimulating the secretions of the stomach
stimulating the activity of the intestines
stimulating secretions in the lungs
constricting the bronchial tubes
decreasing heart rate
The parasympathetic nervous system also has some sensory abilities: It receives
information about blood pressure, levels of carbon dioxide in the blood, and so on.
THE INVERTED-U THEORY
The inverted U theory has been around for as long as the arousal/performance
relationship has been studied. It simply states that the relationship between
performance and arousal is curvilinear as opposed to linear, and takes the form
of an inverted-U. it seems relatively clear that the nature of the relationship
between athletic performance and arousal takes the form of the inverted U, it is
not clear why this occurs.
DRIVE THEORY
The great contribution of drive theory is that it helps to explain the relationships •
between learning and arousal, and between performance and arousal. Many young
athletes are just beginning the process of becoming skilled performers. The effect
of arousal upon a beginner may be different from its effect upon a skilled performer
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