A deep groove called the fissure divides the left and right cerebral hemispheres.

The deep groove that divides the left and right cerebral hemispheres is called the longitudinal fissure. This deep groove runs from the front to the back along the midline of the brain, separating it into two halves. Each half, or hemisphere, of the brain is responsible for different functions. For example, in most people, the left hemisphere is dominant for language and speech, while the right hemisphere is more involved in visual and spatial processing.