The Limbic System
What is limbic system?
The limbic system is composed of structures in the brain that deals with emotions (such as anger, happiness and fear as well as memories.
Location:
The limbic system located just beneath the cerebrum on both sides of the thalamus.
Parts of the limbic system;
1. Amygdala
2. Cingulate gyrus
3. Fornix
4. Hippocampus
5. Hypothalamus
6. Olfactory cortex
7. Thalamus
8. Mammillary body
Function:
Limbic system structures are involved in many of our emotions and motivations, particularly those that are related to survival. Such emotions include fear, anger, and emotions related to sexual behavior. The limbic system is also involved in feelings of pleasure that are related to our survival, such as those experienced from eating and sex.
Function And Structure Of Each Part Of The Limbic System;
1. Amygdala: Almond shaped mass of nuclei involved in emotional responses, hormonal secretions, and memory. The amygdala is responsible for fear conditioning or the associative learning process by which we learn to fear something.
2. Cingulate gyrus: A fold in the brain involved with sensory input concerning emotions and the regulation of aggressive behavior.
3 .Fornix: An arching, band of white matter axons (nerve fibers) that connect the hippocampus to the hypothalamus.
4.Hippocampus: A tiny nub that acts as a memory indexer — sending memories out to the appropriate part of the cerebral hemisphere for long-term storage and retrieving them when necessary.
5. Hypothalamus: About the size of a pearl, this structure directs a multitude of important functions. It wakes you up in the morning, and gets the adrenaline flowing. The hypothalamus is also an important emotional center, controlling the molecules that make you feel exhilarated, angry, or unhappy.
6. Olfactory Cortex :Receives sensory information from the olfactory bulb and is involved in the identification of odors.
7. Thalamus :A large, dual lobed mass of gray matter cells that relay sensory signals to and from the spinal cord and the cerebrum.
8. Mammilary bodies: The mammillary bodies combine with the diencephalon to form a portion of the limbic system. The mammillary bodies form the terminals of the anterior arches of the fornix. They carry electrical impulses from the brain and thalamus through to the spinal cord and on to the rest of the nervous system.
Lesions of limbic system:
Damage to the structures of limbic system results in conditions like Alzheimer’s disease, anterograde amnesia, ret rograde amnesia, and Kluver-Bucy syndrome.