Which layer of the primary visual cortex (V1) sends axons to the superior colliculus for control of saccadic eye movements?

Which layer of the primary visual cortex (V1) sends axons to the superior colliculus for control of saccadic eye movements?

• A. Layer 1
• B. Layer 4
• C. Layer 5
• D. Layer 6

Answer: (C)

Cortical control of rapid eye movements relies on outputs from the primary visual cortex to subcortical motor structures. In V1, the deep pyramidal neurons in layer five send long-range axons to subcortical targets, including the superior colliculus. This projection provides the pathway by which visual information processed in V1 can influence the saccadic system, since the superior colliculus is a key center for initiating and guiding eye movements. Layer six mainly sends feedback to the LGN, layer four is the main recipient of LGN input, and layers two and three handle cortical-cortical communication. The direct drive to the superior colliculus thus comes from layer five, making it the correct source of those axons.

Cortical control of rapid eye movements relies on outputs from the primary visual cortex to subcortical motor structures. In V1, the deep pyramidal neurons in layer five send long-range axons to subcortical targets, including the superior colliculus. This projection provides the pathway by which visual information processed in V1 can influence the saccadic system, since the superior colliculus is a key center for initiating and guiding eye movements. Layer six mainly sends feedback to the LGN, layer four is the main recipient of LGN input, and layers two and three handle cortical-cortical communication. The direct drive to the superior colliculus thus comes from layer five, making it the correct source of those axons.