2. Limbic System
• Limbic: Border
• Refers to a ring of gray
matter on the medial
aspect of the cerebral
hemispheres.
• Neuronal circuit that
controls emotional
behavior and motivational
drives.
5. Functions of Limbic System
• Feeding chewing and licking
• Emotions fear, sweating, Pupillary dilatation
• Autonomic function heart rate, B.P, respiratory rate
• Rage and placidity
• Regulation of biological rhythm Body temp, urine vol, electrolyte balance
• Maternal behavior Prolactin release, Lactation
• Motivation Reward and Punishment
• Sexual functions
6. Hypothalamus
• Para-ventricular N Punishment center
• Pre-optic & anterior N Parasympathetic control
• Posterior & lateral N Sympathetic control
Rage center
• Lateral hypothalamic N Punishment center
Hunger center
Thirst center
• Ventro-medial hypothalamic N Satiety center
Reward center
7. Hippocampus
• Elongated portion of cerebral
cortex
• One end abuts the amygdaloid
nuclei
• Other end fuse with
parahippocampal gyrus
• Almost any type of sensory
experience can cause
activation of hippocampus that
initiate behavioral reaction
• Hyperexcitable three nerve
cell layer response persist
for many seconds after the
stimulus is over
8. Hippocampus
• Roles
– Learning (bilateral lesion, cant learn even names)
– Memory
– Evolutionary role (smell things to eat)
– Decision making for life and death
– It helps control corticosteroid production.
• Lesion
– Anterograde amnesia
– No long term memory establishment
9. Amygdala
• Complex of multiple small nuclei
• Located immediately beneath the cerebral
cortex in each temporal lobe
• Transmit signals to:
1. Back to same cortical areas
2. Into hippocampus
3. Into septum
4. Into thalamus
5. Into hypothalamus
10. Regions of Amygdala
• Large basolateral region: Provides
direct input to basal ganglia and motor
system.
• Small corticomedial group of nuclei:
Related to olfactory cortex especially in
lower animals.
• Medial and central nuclei: Connected
to hypothalamus
11.
12.
13. Functions of the Amygdala
• Behavioral awareness areas Window of limbic system
• wide afferent connections with visual, auditory association areas.
• Wide efferent connections
• Effects of stimulation Coordinated behavioral, autonomic and
endocrine responses
• Feeding and drinking,
• Fighting behavior,
• Mating and maternal care
• Responses to physical or emotional stresses
• Relate environmental stimuli to coordinated behavioral responses
14. Kluver-Bucy Syndrome
• Results from bilateral destruction of temporal lobes
or amygdala.
• Characteristics:
– Increase in sexual activity
– Compulsive tendency to place objects in mouth
– is not afraid of anything
– has extreme curiosity about everything
– forgets rapidly
• Although similar lesions in human beings are rare
15. Limbic cortex
• Cerebral association area for control of behavior
• This ring of limbic cortex
• Most poorly understood portion
• Essentially all behavioral patterns can be elicited by stimulation of
specific portions of the limbic cortex.
• Ablation of some limbic cortical areas can cause persistent changes in
an animal’s behavior
16.
17. Limbic cortex
• Posterior orbital frontal cortex Exert tremendous inhibitory
as well as expressive influences on emotion and generalized arousal
• Anterior temporal cortex gustatory and olfactory behavioral
associations
• Parahippocampal gyri Tendency for complex auditory
associations as well as complex thought associations derived from
Wernicke’s area of the posterior temporal lobe
• Middle and Posterior cingulate cortex Sensorimotor
behavioral associations
18. Mamillary bodies
• They are connected to other parts of the
brain
• Act as a relay for impulses coming from
the amygdalae and hippocampi, via the
mamillo-thalamic tract to the thalamus.
• This circuit, from amygdalae to
mammillary bodies, and then on to the
thalamus, is part of the larger 'Papez
circuit‘
• They, along with the anterior and
dorsomedial nuclei in the thalamus, are
involved with the processing of memory.
