A unilateral lesion of the superior colliculus would most directly impair which function?
- A Reflex saccadic eye movements to contralateral visual field stimuli ✓
- B Vertical gaze
- C Pupillary light reflex
- D Convergence reflex
Correct answer: A. Reflex saccadic eye movements to contralateral visual field stimuli
Explanation
The superior colliculus mediates reflex saccadic (fast) eye movements toward unexpected visual stimuli in the contralateral visual field; this is the orienting reflex. Bilateral superior colliculus lesions disrupt vertical gaze (Parinaud syndrome). The pupillary light reflex involves the pretectal area (olivary pretectal nucleus), not the superior colliculus. Convergence is a midbrain function mediated by the nucleus of Perlia.
Reference: BD Chaurasia's Human Anatomy, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.