Limbic System

The limbic system is the innermost part of the brain, which is located on both sides and below the thalamus. The limbic system comprises of complex set of brain structures. These brain structures are responsible for our emotional life. They are involved in many of our emotions including anger, fear, pleasure, happiness and many more. Some limbic system structures are even involved in memory.

The main limbic system structures are stated below:

Amygdala: Amygdala is an almond shaped set of neurons, which are involved in memory, emotional responses and hormonal secretions. It is located deep in the medial temporal lobe of the brain. It is responsible for determining what, which and where the memories are stored in the brain.

It is responsible for controlling autonomic responses associated with fear. It is also involved in the emotions related to sex like arousal. The abnormal functioning of amygdala may result in anxiety, autism, stress and depression.

Hippocampus: Hippocampus is a curved shaped part of the forebrain. It is located in the medial temporal lobe of the brain and is involved in formation of long-term memories. That is, it is responsible for converting the short-term things into long-term memories.

It is responsible for sending memories out to the appropriate part of the cerebral hemisphere for long-term storage and retrieving those memories when essential. Any damage caused to hippocampus may result in inability to build up new memories.

Thalamus: Thalamus also referred, as a relay station is a large, dual lobed mass of grey matter cells. It receives auditory, somatosensory and visual sensory signals and relays those signals to the cerebral cortex.

It is responsible for regulating motor functions. It connects the parts of the cerebral cortex involved in sensation and movement with other parts of the brain, which are also involved in sensation and movement.

Hypothalamus: Hypothalamus is a small region (size of a pearl) of the brain, which is located just below thalamus. It is responsible for regulating certain metabolic processes and autonomic functions.

It regulates sleep wake cycle, heart rate, hunger, thirst and blood pressure. It is also important for regulating hormones, body temperature, adrenal and pituitary glands. It is also involved in emotions like anger, unhappiness etc.

Cingulate gyrus: Cingulate gyrus is a fold in the brain located in the medial part of the brain between the cingulate sulcus and the sulcus of the corpus callosum. It is the integral part of the limbic system, which is responsible for coordinating sensory inputs with emotions.

The frontal part of this area is responsible for associating memories to smells, sights and pain. It is involved in regulation of aggressive behavior and emotional responses to pain. It regulates blood pressure and heart rate.

Olfactory Cortex: Olfactory Cortex is located within the medial temporal lobes. It is responsible for receiving sensory information from the olfactory bulb.

It is connected directly to amygdala and hippocampus and is concerned mainly with sense of smell. It is involved in the identification and awareness of odors.

Fornix: Fornix is a C-shaped bundle of fibers in the brain that connects hippocampus and hypothalamus. It is responsible for carrying signals from hippocampus to the mammillary bodies and septal nuclei.

Thus, the limbic system is responsible for regulating various functions in the body including hormonal secretions, memory storage, motivations, motor functions, autonomic functions, emotional responses and sensations.