White-matter commissures: a clinically focused anatomical review

Abstract

PurposeThe objective of this review is to provide a structured approach to the main white matter commissures, their anatomic and radiological definition and disease implications.MethodsThe Pubmed database and The JAMA Network were used for the literature review and the following terms were searched using Sort by: Best Match and Sort by: Most Recent: telencephalic commissure, forebrain commissure anatomy, fornix anatomy, commissure of fornix, posterior commissure, corpus callosum, commissural agenesis, Probst bundle, corpus callosum disorders review, corpus callosum diseases review, Marchiafava–Bignami, Alzheimer’s disease and Forel commissure; 36 papers were selected, one excluded due to the language barrier.ResultsThe interhemispheric communication in the brain is achieved via the brain commissures, bundles of white matter linking the two cerebral hemispheres. Anterior white commissure (AWC)—related with olfactory and non-visual communication, hippocampal commissure—main efferent pathway of the hippocampus, connecting the hippocampal formation to structures beyond the temporal lobe, crucial in declarative memory formation and consolidation—and the corpus callosum (CC)—from the anterior commissure to the hippocampal commissure—are the main telencephalic commissures. Supramammilary commissure, posterior commissure, supraoptic commissure and habenular commissure are diencephalic commissures—unknown function, probably related to involuntary eye movements. Commissural agenesis (AWC is absent or impossible to recognize), Alzheimer’s Disease (hippocampal commissure may contribute for disease dissemination) and agenesis of corpus callosum are some of the disturbances that involve the telenchephalic commissures.ConclusionsA comprehensive understanding of the clinic–anatomic correlation is pivotal to understand the pathology and therefore improve our diagnostic accuracy and treatment options, in the background of all patient management.