A neurosurgeon is planning a procedure that requires access to a structure located deep in the center of the brain, directly between the two cerebral hemispheres. A medical image shows this target structure as a large, C-shaped arch of white matter. Based on this description of its position and shape, which structure is the surgeon targeting?

A neuroscientist is examining a medical image that displays a view of the brain as if it were sliced down the middle from front to back. They identify a prominent, C-shaped arc of dense fibers situated deep within the cerebrum, forming a bridge between the two distinct cerebral halves. Based on this specific location and appearance, which structure is being observed?