Psychology Study Material: Structures Within the Limbic System

Doorsteptutor material for competitive exams is prepared by world's top subject experts: get questions, notes, tests, video lectures and more- for all subjects of your exam.

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

Amygdala

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

Hippocampus

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

Hypothalamus

  • 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.

Homeostasis

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.

Cerebrum

  • 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” .

Developed by: