Limbic System: Overview, Definition, Function, Meaning, Diagram

What Is A Limbic System?

Encircling the upper part of the brainstem and the corpus callosum is a ring of structures on the inner border of the cerebrum and floor of the diencephalon that constitutes the limbic system. It is a complicated system of structures lying deep in the brain, related to emotions, memory, and some forms of behavioural regulation.

The limbic system is also called the “emotional brain” because it plays a primary role in a range of emotions, including pain, pleasure, affection and anger. It also is involved in olfaction (smell) and memory. Together with the cerebrum, the limbic system also functions in memory, hence any damage to the limbic system causes memory impairment.

Components Of The Limbic System

The various components of the limbic system are:

Amygdala

• Functions of the amygdala include the processing of emotions related to fear, anger, and pleasure.

• It plays a key role in the formation of emotional memories.

Hippocampus

• The hippocampus participates in the procedure of forming new memories and navigation in space.

• It is the structure responsible for changing or transposing short-term into long-term memory.

Hypothalamus

• The hypothalamus controls the independent functions of hunger, thirst, and body temperature.

• It acts to control the secretion of hormones through the pituitary.

Thalamus

• The thalamus acts as the relay station for sensory and motor signals. It relays them through towards the cerebral cortex.

• Besides, it has also been engaged in the regulation of consciousness, sleep and alertness.

Functions of the Limbic System

The functions of the limbic system are:

Emotional Regulation

• The limbic system plays a vital role in controlling emotions and their responses.

• It makes us capable of using the right emotional responses when we undergo any situation.

Memory Formation

• The hippocampus and amygdala interconnect with each other to form and store memories, primarily emotional memory.

• This helps us remember past experiences and repeat or avoid certain experiences based on the outcome of those experiences.

Behaviour & Motivation

• The limbic system is involved in survival behaviours like eating, drinking and reproduction.

• It also is involved in motivational and reward-seeking behaviour.

Interaction with Other Brain Areas

The limbic system interacts with other brain areas in various ways:

Limbic–Cortex Interaction

• The limbic system interacts with the cerebral cortex to integrate emotion and cognition.

• This interplay gives rise to the expression of particular behaviours, that is, executive decisions.

Limbic Influence on ANS

• The autonomic nervous system is controlled by modulations from the limbic system, particularly the hypothalamus, which deviates from physiological responses to emotions.

• These modulations enable the body to respond appropriately to an emotional event.

Limbic System NEET MCQs (With Answers & Explanations)

Important questions asked in NEET from this topic are:

• Components of Limbic system

• Functions of the Limbic system

Practice Questions for NEET

Q1. Which of the following structures or regions is incorrectly paired with its function ?

1. Hypothalamus : production of releasing hormones and regulation of temperature, hunger and thirst

2. Limbic system : consists of fibre tracts that interconnect different regions of brain ; controls movement

3. Medulla oblongata : controls respiration and cardiovascular reflexes.

4. Corpus callosum : band of fibers connecting left and right cerebral hemispheres.

Correct answer: 2) Limbic system : consists of fibre tracts that interconnect different regions of brain ; controls movement

Explanation:

The limbic system is a set of brain structures involved in regulating emotions, motivation, and memory, influencing behaviour and emotional responses. It includes the amygdala, which processes emotions like fear and pleasure, the hippocampus, crucial for memory formation, and the hypothalamus, which controls basic functions like hunger and temperature regulation. Other components include the cingulate gyrus, involved in emotion processing and behaviour regulation, and the thalamus, which relays sensory information. The prefrontal cortex also interacts with the limbic system, linking emotions to decision-making and actions. Together, these structures help integrate emotions, motivation, and memory into our behaviour and experiences.

Hence the correct answer is option 2) Limbic system: consists of fibre tracts that interconnect different regions of the brain; and control movement

Q2. The amygdala is involved in

1. Learning and memory.

2. Control of reflex muscular activity

3. The experience of emotion and tying emotional meaning to the memories.

4. Control of the movements during voluntary motor activity

Correct answer: 3) The experience of emotion and tying emotional meaning to the memories.

Explanation:

One area of the brain that aids with emotion and memory association is the amygdala. It has a significant impact on emotions including happiness, rage, and terror. It also helps in the recall of emotionally charged events such as joyful or frightening ones. The limbic system which regulates emotions and memory includes the amygdala.

Hence, the correct answer is option 3)the experience of emotion and tying emotional meaning to the memories.

Q3. Mammillary bodies

1. are present behind the infundibulum.

2. are located within the septal area

3. almond-shaped structure located in the tip of the temporal lobe.

4. are located inside the temporal lobe.

Correct answer: 1) are present behind the infundibulum.

Explanation:

The mammillary bodies are a part of the limbic system and play an important role in memory processing and recollection. These small, rounded structures act as relay stations, transmitting signals between the hippocampus and the thalamus. These are present behind the infundibulum. They play a vital role in memory processing. Damage to the MBOs can cause various forms of anterograde amnesia (inability to form new memories) and retrograde amnesia (loss of previously formed memories).

Hence, the correct answer is option 1) are present behind the infundibulum.

Also Read:

• MCQs on Limbic System

• Sympathetic Nervous System

• Mechanism of Vision

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