The limbic system is composed of structures in the brain that deal with emotions (such as anger, happiness and fear) as well as memories. This article will address the limbic system, its parts and their functions in the human body.
Emotions, Memories and Instincts
Have you ever been angry? How about sad and happy? All of these are emotions, which are different mental reactions that are expressed by humans. Emotions are present in our daily lives and play a role in how we behave individually and socially. The limbic system is thought to control emotion and other brain functions related to our instincts and memories.
Let’s look deeper into the limbic system and its overall function in our bodies.
Parts of the Limbic System
The limbic system is the portion of the brain that deals with three key functions: emotions, memories and arousal (or stimulation). This system is composed of several parts, which are found above the brainstem and within the cerebrum. The limbic system connects parts of the brain that deal with high and low functions.
Let’s talk about the major parts of the limbic system. First, we have the thalamus, which is a portion of the brain that is responsible for detecting and relaying information from our senses, such as smell and vision. The thalamus is located within the brainstem and is part of the pathway of information into the cerebrum, which is the section of the brain that is responsible for thinking and movement.Next, we have the hypothalamus, which is a vital portion of the limbic system that is responsible for producing multiple chemical messengers, called hormones.
These hormones control water levels in the body, sleep cycles, body temperature and food intake. The hypothalamus is located beneath the thalamus.The cingulate gyrus, meanwhile, serves as a pathway that transmits messages between the inner and outer portions of the limbic system.
The amygdala is one of two almond-shaped clusters of nerve cells in the temporal (or side) lobe of the cerebrum. Both amygdalae are responsible for preparing the body for emergency situations, such as being ‘startled,’ and for storing memories of events for future recognition. Amygdalae assist in the development of memories, particularly those related to emotional events and emergencies. The amygdalae are also involved specifically with the development of the fear emotion and can be the cause of extreme expressions of fear, as in the case of panic. Additionally, the amygdalae play a major role in pleasure and sexual arousal and may vary in size depending on the sexual activity and maturity of the individual.
The hippocampus is another section of the temporal lobe that is responsible for converting short-term memories into long-termed memories. The hippocampus is thought to work with the amygdala for memory storage, and damage to the hippocampus may lead to amnesia (or memory loss).Finally, we have the basal ganglia, which are a collection of nerve cell bodies that are responsible for coordinating muscular movement in posture.
Specifically, the basal ganglia help to block unwanted movements from occurring and directly connect with the cerebrum for coordination.
Speculation on the Development of the Limbic System
The limbic system is thought to have developed from primitive mammalian brains during the course of human evolution. Therefore, many of the functions of the limbic system deal with instincts, rather than learned behaviors. (Note: This does not mean that memories will not play a role in learned behaviors, but it does mean that the primary functions will be instinctive.) Scientists debate about whether or not this system should be considered one unit biologically, since many of the original ideas that were used to develop this concept are considered outdated.
While they do not dispute the functions of the individual parts, many disagree about whether the pathways involved in these primitive functions are actually linked. However, the limbic system is still discussed in many traditional biology and physiology courses as part of the nervous system.
The limbic system is a set of structures in the brain that controls emotion, memories and arousal. It contains regions that detect fear, control bodily functions and perceive sensory information (among other things).
Scientists debate as to whether or not the system is truly one unit, but in most cases, it is treated as such in academic courses.
After you’ve completed this lesson, you should have the ability to:
- Identify the parts of the limbic system
- Describe the structure and function of the limbic system and its parts
- Explain the debate among scientists regarding the limbic system