Evidence That Primary Visual Cortex Is Required for Image, Orientation, and Motion Discrimination by Rats
A. Summary of lesion boundaries. Medial extrastriate visual cortex (areas V2-MM and V2-ML as defined by (Paxinos and Watson, 1998)) was almost completely damaged and the damage was bilaterally symmetrical. There was bilateral sparing in the most anterior sections; the lesion began bilaterally at the same level in V2MM, sparing the most anterior tip of V2-ML bilaterally. Moving posterior, the lesion completely encompassed V2MM and V2ML bilaterally. Overall, 93% of V2MM was damaged and 88% of V2ML was damaged, bilaterally. The extent of V1 damage was mainly to the medial edge of V1. However, at the most posterior portion of the lesion, the V1 damage was more substantial as V1 moves more medially in this region to replace V2MM. Nonetheless, the V1 damage was less than 5% in total. V2-L (the portion that is lateral to V1) was never damaged. B. Sample section through lesion illustrating quality and extent of the damage attained by ibotenic acid injection.