Amigdalele

Amigdalele, or amygdalae in English, are a pair of almond-shaped nuclei located in the medial temporal lobes and are central components of the limbic system. Each hemisphere contains one amygdala, and together they form a bilateral network that processes emotional information and assigns significance to stimuli.

Anatomy and connections: The amygdala comprises several nuclei grouped into major complexes, most notably the basolateral complex, which receives sensory input and assigns emotional value; the centromedial complex, which projects to brainstem and hypothalamic regions to coordinate autonomic and hormonal responses; and the cortical and medial nuclei. The amygdala has extensive connections with the hippocampus, prefrontal and orbitofrontal cortices, insula, thalamus, hypothalamus, and various brainstem centers, supporting integrated emotional processing, memory, and behavior.

Function: The amygdala evaluates the emotional salience of stimuli, participates in fear conditioning and threat assessment, and modulates reward-related learning. It helps generate affective states and coordinates physiological responses via the hypothalamus. The amygdala also contributes to social and emotional processing, including recognition of facial expressions, and interacts with memory systems to tag experiences with emotional meaning.

Development and lateralization: In humans, amygdalae are present from infancy and continue to mature into adolescence, with some evidence of functional lateralization. The right amygdala is often linked to rapid, automatic threat processing, while the left may be more involved in detailed evaluation, though findings vary.

Clinical significance: Altered amygdala activity or structure is associated with anxiety disorders, phobias, PTSD, and mood disorders. Bilateral lesions can disrupt fear learning (Kluver–Bucy syndrome). In epilepsy, targeted damage to the amygdala can affect affective responses. Functional imaging frequently records amygdala activation during emotional tasks.

Etymology: The name derives from Greek amygdale, meaning almond.