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1. Limbic System
Limbic lobe
Associated subcortical nuclei

2. Limbic System
• First described by Paul Broca in 1878
• Was called as the Visceral Brain by Mclean
in 1949
• It is called limbic lobe as it forms a ring
around the Corpus Callosum

4. Structures Included In The
Limbic System
• Limbic lobe-Cingulate gyrus
Isthmus
Hippocampal gyrus
Uncus
Related Subcortical Nuclei
Amygdala
Septal nuclei
Hypothalamus
Anterior thalamic nuclei

5. Afferent Connections
• Autonomic afferents from spinal cord and
brain stem
• Reticular formation to various parts of the
limbic system
• Visceral as well as some somatic sensations
from the body wall,mouth, smell ,taste and
from eyes and ears.(Hippocampus)

6. Efferent Connections
• Efferent fibres to autonomic centres in the brain-
stem directly or through the hypothalamus
• Efferent fibres to the reticular formation
• From hippocampus to the hypothalamus and the
anterior nucleus of the thalamus
• Few to and fro connections to the neocortex
• Interconnections between parts of the limbic
system

7. Circuits within Limbic system
Papez Circuit
Hippocampus via Fornix Mamillary
Body
Cingulate Anterior nucleus
gyrus of thalamus

8. Basolateral Circuit
Amygdaloid Stria terminalis Dorsomedial N.
Complex of thalamus
Hypothalmus
(Lat. Vent med N)
Orbitoinsulotemporal cortex

9. Functions
• Control of visceral and autonomic functions
• Perception of smell
• Emotional exteriorisation-Fear,Rage,Placidity
• Behavioral responses
• Sexual behavior
• Feeding behavior
• Memory and learning
• Biological rhythm

10. Emotion
• It is an aroused condition with intense feeling,
autonomic activation and related behavior
• Mental component-Cognition, Affect,
Conation
• Physical Component-Changes in viscera and
skeletal muscles.(Coordinated activity of
autonomic and somatic nervous system)

11. Fear & Rage
• Flight / Avoidance reaction –Sweating
pupillary dilation,Bending and turning head
from side to side.
• Fight/Rage-Hissing spitting, growling,
pilorection, pupillary dilation,biting and
clawing.

12. Rage
• Removal of neocortex
• Destruction of ventromedial hypothalamic nucleus
• Stimulation of amygdaloid nucleus
• Stimulation around posterolateral hypothalamus
• Androgen injection
• Amygdaloid destruction causes placidity
Subsequent destruction of ventromedial nucleus of
hypothalamus converts it to rage.

13. Sham Rage
• Caused by removal of brain rostral to the
thalamus in animals.
• Symptoms of fear and rage are seen
accompanied by the sympathetic changes.

14. Sexual Behavior
• Stimulation of neocortex,anterior
hypothalamus and median forebrain bundle
causes hypersexuality
Destruction of piriform cortex causes
hypersexuality.

15. Kluver Bucy Syndrome
• Shown by Kluver and Bucy in 1938.
• Removal of temporal lobe causes
• Placidity
• Hypersexuality
• Psychic blindness

16. Reward & Punishment
• Hess Technique
• Reward areas-Lateral hypothalamus,
Septum, Tegmentum, Dorsal area of pons,
medial forebrain bundle
• Punishment Areas-Posterior hypothalamus,
dorsal parts of midbrain
• These also play a role in motivation and
addiction