Neural Circuitry: Architecture and Function-A Fiber Dissection Study.

Objective: White fiber dissection using a gyrus-based approach was performed to study the various associations, commissural, and projection fiber bundles of the brain.

Methods: Ten previously frozen and formalin-fixed cadaveric human brains were included. The fiber dissection techniques described by Klingler were used. The primary dissection tools were thin handmade wooden spatulas and curved metallic spatulas with tips of various sizes. The fibers were studied by the naked eye and with the use of magnification. The various fiber bundles were studied using a gyrus-based approach. The dissection was performed through each named gyrus, and the fiber tracts encountered during dissection were identified, and their relationship to other adjacent fiber bundles was studied.

Results: From our dissections, the white fibers of the brain were divided architecturally into 5 groups-4 horizontal groups and 1 vertical group. The 4 horizontal groups were the superficial, middle, deep, and central groups. The association fibers constituted the superficial, middle, and deep groups. The commissural fibers formed the central group, and the projection fibers formed the vertical group. The course of the fiber bundles and their functional co-relationship were determined.

Conclusions: When planning the surgical trajectory, knowledge of the location of white matter tracts is essential to help minimize the occurrence of postoperative deficits. Fiber dissection using the Klingler technique is useful in gaining an understanding of the complex 3-dimensional nature of these white matter tracts and can provide a valuable resource in neurosurgical training.