The amygdala is an almond-shaped, grey-matter structure located in the inferior portion of temporal lobe in each cerebral hemisphere. It is bigger in male than in female. It receives afferent fibers from the medulla oblongata and sends efferent nerve projections to the hypothalamus and thalamic reticular nucleus. It is also known as the amygdaloid body.
Function
Along with the hippocampus, the amygdala belongs to the limbic system. Thus, functionally, it is associated with long-term memory, playing an important role in storing memories linked to emotional events. Stimulation of the amygdala in humans leads to changes in mood, ranging from fear and rage to rest and relaxation . It is also associated with sexual hormones response, having receptors for both testosterone and estrogen.
Anatomical Description
The amygdala stretches medially to the inferior surface of the cortex of temporal lobe in both cerebral hemisphere. This is why it is also considered to be part of the cortex as well as a nuclear structure which has migrated into the white matter. It lies right below the putamen and anterior to the tail of the caudate nucleus. The fibers of the pyramidal tract run posteriorly and medially to the amygdala. The corticomedial half of it is considered to be part of the paleocortex, while the deeper portion is characterized as a nuclear complex.
Below, lateral view of left cerebral hemisphere, showing the position of the amygdala in relation to basal ganglia structures (putamen and caudate nucleus) and pyramidal tract.
Frontal view of the aforesaid grey nuclei in a coronal section of the forebrain (cerebrum)
