Which region of the brain sends information to the cortex in order to initiate a saccade?

• A. Inferior colliculus
• B. Superior colliculus
• C. MGN
• D. Hippocampus

Answer: (B)

Saccades are driven by a circuit that links midbrain structures with the cortex, using a pathway that turns sensory input into a motor command for eye movement. The superior colliculus is a key midbrain hub with a retinotopic map that translates visual input into a saccade command. It not only initiates the motor signal that ultimately drives the brainstem saccade generators, but it also sends signals upward to the cortex via thalamic relays (to frontal eye fields). This cortico-subcortical loop allows the cortex to participate in planning and initiating the eye movement, with the superior colliculus providing the critical information to engage the cortical areas involved in voluntary control.

The other regions don’t participate in this specific pathway to initiate a saccade: the inferior colliculus is part of the auditory pathway, the medial geniculate nucleus is the auditory relay in the thalamus, and the hippocampus is involved in memory.