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Limbic system Haytham Eloqayli

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Limbic system Haytham Eloqayli

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    2. Limbic system limbic cortex: ring of cerebral cortex in each side of the brain. subcortical limbic structures

    3. Limbic system limbic cortex: orbitofrontal area subcallosal gyrus cingulate gyrus, parahippocampal gyrus temporal uncus.

    4. Limbic system

    5. Limbic system -function is poorly understood -functions as a transitional zone through which signals are transmitted from the brain cortex into the limbic system and in the opposite direction. -ablation of the limbic cortex release the limbic system from the inhibitory effect of the cerebral cortex. e.g Bilateral removal of orbital frontal cortex can cause insomnia

    6. Limbic system subcortical limbic structures hypothalamus Septum paraolfactory area anterior nucleus of the thalamus portions of the basal ganglia hippocampus amygdala.

    7. Limbic system Function of the limbic system Behavior and control of our behavior Emotions (nature of the sensations, pleasant or unpleasant) Learning and memory All these functions are controlled through the Reward and punishment function of the limbic system.

    8. Limbic system Reward and punishment function: Reward (satisfaction) e.g satisfiction after eating, drinking, success…etc Punishment (displeasure, fear, terror, pain..etc)

    9. Limbic system Reward Centers along the course of the medial forebrain bundle especially ventromedial and lateral hypothalamic nuclei Lateral nuclei of the hypothalamus (weak stimuli give a sense of reward and stronger ones a sense of punishment) e.g mild hunger reward of food but not finding the food can lead to rage (punishment)

    10. Limbic system Punishment Centers central gray area surrounding the aqueduct of Sylvius in the mesencephalon and the lateral hypothalamus (stronger stimuli). Less potent reward and punishment areas are found in many locations of the limbic system like the amygdala and hippocampus.

    11. Limbic system Learning and Memory Reward or Punishment ? Reinforcement and Habituation selecting the information that we learn (important memory) while throwing away the unimportant information. stimulus (experience) which cause either reward or punishmen is remembered (Reinforcement) stimulus (experience) that causes neither reward nor punishment is ignored (habituation)

    12. Specific areas of the limbic system Hypothalamus Hippocampus Amygdala

    13. Hypothalamus Functions Behavior, vegetative, endocrine Connections Vegetative:to the brain stem (mainly reticular areas) from these areas into the peripheral nerves of the autonomic nervous system Behavior: to the other limbic areas and higher areas of the diencephalon and cerebrum. Endocrine: to the posterior and the anterior lobes of the pituitary gland.

    14. Hypothalamus

    15. Hypothalamus

    16. Hypothalamus Vegetative: 1.Cardiovasculer regulation: both increase and decrease in blood pressure and heart rate. 2.Regulation of the body tempreture 3.Regulation of body water (through thirst center and ADH secretion) 4.Regulation of feeding. 5.Sexual drive

    17. Hypothalamus Lateral hypothalamus: thirst, hunger, increase level of activity (if strong rage, fear..etc) Ventromedial hypothalmus: satiety, decreased eating, tranquility. (functions opposite to the lateral hypothalmus) Supraoptic neuclei: secrete anti diurtic hormone (ADH (vasopressin)) in response to fluid concentration. Paraventricular neuclei: secrete oxytocin (utrine contraction at the end of pregnency and milk ejection).

    18. Hypothalamus Endocrine function To the posterior pituitery (neurohypophysis): -ADH, Oxytocin. -directly to the nerve endings To the anterior pituitery (adenohypophysis): -ACTH-RH, GH-RH, FSH-RH, LH-RH, TSH-RH, PIF (dopamin) -through the blood (portal system)

    19. Hypothalamus Behavior Through reward and punishment centers

    20. Hippocampus -part of the reward and punishment centers -important role in learning and memory Abnormalities -Mesial temporal sclerosis and temporal lobe epilepsy -Anterograde amnesia

    21. Amygdala The behavior awareness area which is responsible for the behavioral response appropriate to each occasion. Bilateral ablation of the amygdala result in Kluver-Busy Syndrome (loss of fear, curiosity, abnormal and increase sexual drive…etc).

    22. Limbic system

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