Independent category and spatial encoding in parietal cortex.

The posterior parietal cortex plays a central role in spatial functions, such as spatial attention and saccadic eye movements. However, recent work has increasingly focused on the role of parietal cortex in encoding nonspatial cognitive factors such as visual categories, learned stimulus associations, and task rules. The relationship between spatial encoding and nonspatial cognitive signals in parietal cortex, and whether cognitive signals are robustly encoded in the presence of strong spatial neuronal responses, is unknown. We directly compared nonspatial cognitive and spatial encoding in the lateral intraparietal (LIP) area by training monkeys to perform a visual categorization task during which they made saccades toward or away from LIP response fields (RFs). Here we show that strong saccade-related responses minimally influence robustly encoded category signals in LIP. This suggests that cognitive and spatial signals are encoded independently in LIP and underscores the role of parietal cortex in nonspatial cognitive functions.