rhinal

Rhinal is an anatomical term used as an adjective to describe structures related to the rhinal region of the brain, a part of the rhinencephalon associated with olfactory processing and memory. In neuroanatomical usage, rhinal most often refers to the rhinal cortex, which includes the perirhinal and entorhinal cortices located along the rhinal sulcus on the medial temporal lobe. The rhinal region is closely linked to the olfactory cortex and serves as a hub integrating sensory information with memory networks.

Anatomy and connections: The perirhinal cortex lies along the parahippocampal gyrus, surrounding the rhinal sulcus, while the entorhinal cortex sits adjacent to the hippocampus. These areas receive and relay multimodal sensory input to and from the hippocampal formation, and they interface with broader neocortical regions to support memory processing, recognition, and the association of objects with prior experiences.

Functions: The rhinal cortices participate in higher-order olfactory processing and memory functions. The perirhinal cortex is implicated in object recognition and familiarity judgments, while the entorhinal cortex acts as a major gateway between the neocortex and hippocampus, supporting episodic memory formation and spatial coding.

Clinical relevance: Degeneration or damage to rhinal regions, particularly the entorhinal and perirhinal cortices, is associated with memory impairment and aging. These areas are among the early sites affected in Alzheimer's disease, and epileptic activity in the rhinal region can contribute to memory disturbances.

See also: Rhinencephalon, entorhinal cortex, perirhinal cortex, hippocampus, piriform cortex.