Amygdala
Say it: uh-MIG-duh-luh
The amygdala is an almond-shaped cluster of nuclei deep in each temporal lobe that processes emotion, especially fear, and colors memories with feeling.
Also: amygdalae, amygdaloid body
Definition
What is the amygdala?
The amygdala is a small, almond-shaped group of nuclei (clusters of neuron cell bodies) buried in the front of each temporal lobe, just ahead of the hippocampus. There is one on each side of the brain, and both belong to the limbic system, the network of structures that handles emotion, motivation and memory.
The amygdala rapidly judges whether something we see, hear or smell matters emotionally, and it helps launch the body's reaction. When it detects a threat, it signals the hypothalamus and brainstem, which bring on the pounding heart, quick breathing and alertness of the fight-or-flight response through the sympathetic nervous system and stress hormones. It is central to fear learning, in which a harmless cue becomes linked to danger after only a few pairings, and it helps us recognize fear in other people's faces. It also shapes pleasure, anxiety and anger.
By attaching emotional meaning to events, the amygdala influences how firmly memories are stored, which is one reason emotionally charged moments are remembered so vividly. Its activity is studied closely in anxiety disorders and post-traumatic stress disorder, and the receptors in its fear circuits are a target in the search for new anti-anxiety drugs.
Word parts
Where does the word “amygdala” come from?
- amygdal-
- almondGreek amygdale, via Latin amygdala
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Related
Terms that go with it
- HippocampusThe hippocampus is a curved structure deep in each temporal lobe of the brain that is essential for forming new memories and finding our way around.
- Sympathetic nervous systemThe sympathetic nervous system is the division of the autonomic nervous system that readies the body for action, producing the fight-or-flight response.
- Cerebral cortexThe cerebral cortex is the thin, folded layer of gray matter covering the cerebrum, where perception, movement, language and thought are processed.
- CortisolCortisol is a steroid hormone made by the adrenal cortex that helps the body cope with stress, raises blood glucose and dampens inflammation.
- NeuronA neuron is a nerve cell, the basic signaling unit of the nervous system, which receives information and passes it on as electrical and chemical signals.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- OpenStax Biology 2e, 35.3 The Central Nervous System
- Queensland Brain Institute: The limbic system
- NCBI MeSH: Amygdala
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