Claustrum

Part of speech: noun

Pronunciation: /ˈklɔːstɹəm/

Definitions

1. A complex structure in the brain consisting of gray matter that links different cortical regions to facilitate communication and sensory integration
2. An important neural component found in the brain that interconnects various areas of the cortex and aids in the processing of sensory information
3. A brain structure composed of gray matter that connects assorted cortical areas for effective communication and integration of sensory experiences

Etymology: Latin "claustrum" meant "a bolt" or "bar", a device for fastening a door, and it is closely related to "claudere", "to shut". The same Latin noun also gave English "cloister", a word that once meant an enclosed space, and the two are doublets: separate English words descended from one Latin source. "Cloister" arrived through Old French, which softened and reshaped the Latin form, while "claustrum" was taken into English directly without that adaptation. The borrowed form was applied to the brain's thin layer of grey matter, the claustrum, which lies deep within the cerebral hemispheres beside the insula. The sense is figurative: the structure is a thin sheet of neurons sitting closed in between other regions, so the bar-and-bolt image of enclosure was carried over to it.