Psychology Study Material: Structures Within the Limbic System

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Limbic System

Evolutionarily the structure of limbic system is rather old.

Limbic System
  • The limbic system, often referred to as the “emotional brain” , is found buried within the cerebrum.
  • At the border of the brainstem and cerebral hemispheres it is a doughnut-shaped system of neural structures; associated with emotions e. g. fear and aggression and drives like hunger and sex; regulates body temperature, blood sugar level and blood pressure.

Structures Within the Limbic System

  • Hippocampus
  • Amygdala
  • Hypothalamus


  • Two almond-shaped neural clusters in the limbic system that are linked with emotions.
  • They are related with aggression and fear.


The hippocampus is the part of the limbic system that is important for memory and learning.


  • One of the smallest structures in the brain.
  • The neural structure lying below (hypo) the thalamus; Composed of several nuclei. Small bundles of neurons that regulate physiological processes involved in motivated behaviour e. g. hunger, thirst, regulation of body temperature.
  • Hypothalamus acts as the body՚s Thermostat.
  • Helps govern the endocrine system via the pituitary gland.
  • Is linked to emotions.


Hypothalamus maintains the body՚s internal equilibrium e. g. looking for food when energy levels are low, causing constriction of the blood vessels when body temperature falls.


  • Largest part of the human brain, associated with higher brain functions such as thought and action.
  • Occupies 2/3 of the brain՚s total mass
  • Consists of two symmetrical halves or hemispheres; The right cerebral hemisphere controls the left side of the body and vice versa.
  • The hemispheres are connected by Corpus Callosum, a thick mass of nerve fibres.
  • Cerebrum regulates the brain՚s higher cognitive and emotional functions.

Cerebral Cortex

  • Coming from the Latin word for “bark” , cortex means covering, or sheath; the cortex is a sheet of tissue making up the outer layer of the brain.
  • About 1/10 of an inch in thickness, the cortex is composed of some 30 billion nerve cells and 300 trillion synaptic connections.
  • It is the body՚s ultimate control and information-processing centre.

The cerebral cortex is greatly convoluted in humans. These convolutions include:

  • Sulci (singular Sulcus) i.e.. small grooves.
  • Gyri (singular Gyrus) i.e.. large grooves also called “Fissures” .

Grey Matter

  • Cerebral cortex mostly consists of glia (glial cells) , cell bodies, dendrites and
  • interconnecting neurons: they give the cerebral cortex a grayish brown appearance, commonly known as ′ Grey Matter ″ .

White Matter

  • Beneath the cerebral cortex lie millions of axons that connect the neurons of the cerebral cortex to those located elsewhere in the brain.
  • The large myelin gives tissue an opaque white appearance known as “White Matter” .