amygdale

The amygdala, also referred to as amygdale in some languages, is a small, almond-shaped cluster of nuclei located in the anterior medial temporal lobe. It is a core component of the limbic system and plays a central role in the processing of emotions, especially fear and threat, as well as the formation of emotionally charged memories.

Anatomy and circuits: The amygdala comprises several nuclei organized into broad functional groups, commonly described as the basolateral complex, the centromedial complex, and the cortical/medial nuclei. The basolateral complex receives diverse sensory inputs from cortical and thalamic regions and assigns affective value to stimuli. The centromedial complex provides major outputs to the hypothalamus and brainstem to regulate autonomic and hormonal responses. The cortical and medial nuclei contribute to olfactory processing and social behavior. The amygdala maintains extensive connections with the prefrontal cortex, hippocampus, thalamus, and other limbic structures, enabling rapid appraisal of emotional significance. The extended amygdala includes connections with the bed nucleus of the stria terminalis, linking acute and sustained threat processing.

Functions: The amygdala is involved in fear conditioning, emotional learning, and the rapid appraisal of emotional salience. It modulates attention and memory consolidation for emotionally memorable events, in large part through interactions with the hippocampus and neuromodulatory systems. The medial amygdala contributes to processing social and olfactory cues, while the basolateral and centromedial regions coordinate behavioral and physiological responses.

Clinical relevance: Altered amygdala activity is associated with anxiety disorders, PTSD, phobias, and mood disorders. Neuroimaging often shows hyperresponsivity to emotional stimuli, and lesions can disrupt fear conditioning and affective behavior.