Limbic system, introduction, parts, function and diseases , guyton nervous system

2. LIMBIC SYSTEM
YASIR REHMAN
DPT (SECOND YEAR)
ROLL NO.2

3. LEARNING OBJECTIVES
 Limbic system
 Functions of limbic system
 Different parts of limbic system
 Functions of various parts of hypothalamus
 Malfunction of limbic system

4. LIMBIC SYSTEM
 Limbus - ring
 The part of cortex and subcortical structure
that form ring around brain stem.
 Earlier called--- Rhinencephalon ---related
to Olfaction.

5. LIMBIC SYSTEM
 Limbic means the structure which lies on medical
rim of brain between cerebral cortex and
hypothalamus.
 Limbic system is a set of brain structures including
hippocampus, amygdala, anterior thalamic nuclei and
limbic cortex.

6. LIMBIC SYSTEM

7. LIMBIC SYSTEM
 Not a separate structure but a ring of forebrain structures that
surrounds the brain stem.
RESPONSIBLE FOR
 Emotions
 long term memory
 olfaction
 inborn behavioral patterns related to survival and
 perpetuation of species
 plays important role in motivation and learning

8. HYPOTHALAMUS
 Output signals from the hypothalamus
 Brainstem
 Diencephalon and Cerebrum
 Infundibulum– The Pituitary Gland
 Hypothalamus represents less than 1% of the brain mass

9. HYPOTHALAMIC FUNCTIONS
 Regulate Blood pressure , rate and force of heart beat,
digestive tract mobility, rate and depth of breathing and
many other visceral activities
 Perception of pleasure , fear and rage
 Regulation of body temperature
 Regulates feelings of hunger and satiety
 Regulates sleep and sleep cycle
 Endocrine function of the hypothalamus

10. Behavioral functions of
hypothalamus and
associated limbic structures
 Stimulation of lateral hypothalamus
 Ventromedial nucleus and surroundings
 Periventricular nuclei—3rd ventricle
 Sexual drive-anterior and posterior hypothalamus
 Effects of hypothalamic lesions

11. REWARD AND PUNISHMENT
FUNCTIONS OF LIMBIC SYSTEM
 REWARD CENTER
 Medial forebrain bundles, VMN,LHA
 Less potent reward centers reside in the septum and some basal
ganglial areas
 PUNISHMENT CENTERS
 Central gray surrounding the aqueduct of sylvius in the
mesencephalon and periventricular area.
 Less potent punishment areas are found in the amygdala and
hippocampus

12. REWARD AND PUNISHMENT
FUNCTIONS OF LIMBIC SYSTEM

13. REWARD AND PUNISHMENT
FUNCTIONS OF LIMBIC SYSTEM
 Rage and its association with the punishment centers
 Effect of tranquilizers on the reward or punishment centers
 Importance of reward or punishment in learning and
memory

14. ASSOCIATIVE LEARNING

15. MEMORY AND HIPPOCAMPUS
 Memory is the storage and retrieval of information
 The three principles of memory are :
 STORAGE - occurs in stages and is continually changing
 PROCESSING - accomplished by the hippocampus and the
surrounding structures
 MEMORY TRACES - chemical or structural changes that encode
memory

16. HIPPOCAMPUS
 Hippocampus and adjacent temporal and parietal structures are
called HIPPOCAMPAL FORMATIOM
 This formation has connections with cerebral cortex,
hypothalamus, septum, amygdala, limbic cortex and mammillary
bodies.
 Hippocampus is hyperexcitable
 Epileptic seizures
 Less layers in the hippocampal cortex

17. FUNCTIONS OF AMYGDALA
 The amygdala is the complex multiple small nuclei located
immediately beneath the cerebral cortex of medial anterior pole
of each temporal lobe.
 It has abundant directional connections with the hypothalamus
and the other parts of limbic system.
 Effects initiated from the amygdala and send through the
hypothalamus—mostly autonomic functions.

18. FUNCTIONS OF AMYGDALA
 Direct stimulations of amygdala results in several types of
involuntary movements.
 Bilateral ablation of amygdala (KLUWER –BUCY
SYNDROME)
 Not afraid of everything
 Extreme curiosity about everything
 Forgets rapidly
 Tendency to place everything in mouth and eating objects
 Strong sexual drives.

19. FUNCTIONS OF LIMIBIC CORTEX
 Cerebral association areas for control of behavior