The Study Of The Microsurgical Anatomy Of The Claustrum And Its Adjacent White Matter Fiber Tracts

Objective The goal in this study was to investigate the microsurgical anatomy of theclaustrum and its adjacent white matter fiber tracts, and to analyze the functional and clinicalimplications of the findings.Methods Ten formalin-fixed human brain hemispheres were dissected using theKlingler fiber dissection technique, with the aid of an operating microscope at×4～25magnification. The microsurgical anatomy of the claustrum and its adjacent white matter fibertracts was observered.Results The claustrum is a thin, irregular sheet of grey matter which is surrounded byseveral adjacent white matter fiber tracts. It lies below the general region of the insula, andabove the outer surface of the putamen, with a fibre tract on each side of it (the extreme andexternal capsulae). The extreme capsule, the external capsule, the uncinate fascicle, theinferior occipitofrontal fascicle are located respectively lateral, dorsal and medial, ventral tothe claustrum, and the sublenticular portion of the internal capsule which runs from medial tolateral is located posteroinferior to the claustrum. Macroscopically, we divide the claustruminto2parts: the dorsal claustrum and the ventral claustrum, which in humans the dorsalclaustrum is posterosuperior, and the ventral claustrum is anteroinferior. Although the fibersfrom the uncinate and inferior occipitofrontal fascicles traverse and fragment the ventralclaustrum, the fibers from the extreme capsule and the external capsule initiate from orterminate to the dorsal claustrum, and part of the fibers from the internal capsule traverse theposteroinferior pole of the claustrum. Although the extreme capsule connects the dorsalclaustrum and insular cortex, the external capsule connects the dorsal claustrum and somatosensory,motor cortex and inferior parietal lobe, and the sublenticular portion of theinternal capsule connects the dorsal claustrum and pontine, thalamus and auditory cortex. Theuncinate fascicle connects the ventral claustrum and orbitofrontal cortex and temporal pole,and the inferior occipitofrontal fascicle connects the ventral claustrum and inferior frontalgyrus and visual cortex of the occipital lobe. The ventral claustrum is related closely withseveral grey matter nucleus of basilad telencephalon such as the amygdala, nucleusaccumbens and substantia innominata.Conclusion The study of anatomy and function of the adjacent white matter fiber tractsof the claustrum may provide a new thread of the functional investigation of the claustrum.Furthermore, the white matter fiber tracts have the same importance as the functional areas ofthe cerebral cortex. it’s not only beneficial for us to explore the mechanism of brain cognitivefunction, but also beneficial for clinical diagnosis and treatment to improve theknowledgement and understanding of white matter fiber tracts of the white matter fiber tracts.