The amygdala is a structure in the forebrain that resembles a walnut both in size and shape. The amygdala is surrounded by white matter. The amygdala is part of a functional system in the brain called the limbic system which deals with emotional responses to events, objects and people based on memory and sensory input. The limbic system also includes other structures called the hippocampus, mammillary bodies and cingulate gyrus.
The amygdala connects to the parietal lobes which process sensory information and to the hippocampus which is involved in memory. The amygdala is responsible for determining emotional responses to sensory input - when you see a face, smell a flower or hear a piece of music, it is the amygdala that is involved in your emotional response. For this reason it is often called the gateway to the emotions.
Damage to the pathways between the parietal lobes and the amygdala can cause people to fail to recognise the significance of people and objects. Hyperstimulation, for example in certain types of seizures, can cause states of emotional overload that resemble spiritual experiences. Some neuro-psychiatrists postulate that certain pathways exist in the amygdala which control religious experience.
The Amygdala also plays a role in depression, feelings of hopelessness and anxiety. Multiple sclerosis lesions in the white matter surrounding the amygdala probably influence emotional lability and depression.
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