Central to human cognition is the ability to interact adaptively with our visual environment by collecting and accumulating pertinent information to guide thoughts and behavior. Recent work has pinpointed the significant role of posterior parietal cortex (PPC) in supporting adaptive visual processing. Building upon two recent reviews on PPC and two sets of exciting preliminary findings on visual representation in human PPC involving attention and visual working memory (VWM), the present proposal aims to document the nature of visual processing in PPC with the same rigor and precision as those used to study visual representation in OTC. The overarching hypothesis here is that task-related factors play a more prominent role in shaping visual representation in PPC than OTC and the key to understand the intricate details of visual representation in PPC is through its interactions with task-related factors. Using fMRI pattern decoding and representational similarity analyses to document PPC representational structure in humans, the present proposal examines two fundamental aspects of adaptive visual processing: The contributions of attention and task to adaptive visual representation in PPC in Aim 1, and the nature of VWM representation in PPC in Aim 2. To understand the neural underpinnings of PPC visual processing, using voxel overlap analysis, in all the studies proposed, we will examine whether the same or distinct PPC neuronal populations contribute to different aspect of PPC visual processing. The proposed studies will provide for the first time an in-depth and systematic understanding of the nature of PPC visual representation in the human brain and its interaction with important task-related factors. They shall provide foundational knowledge regarding how adaptive visual processing is accomplished in the human brain.
A thorough understanding of PPC visual representation characteristics and their interactions with task factors can help us better understand the various constraints and limitations of visual processing during task performance. It can additionally help us formulate better treatment and rehabilitation plans to facilitate the recovery of PPC functions after lesion. Greater knowledge of PPC function can also provide guidance to the removal of possible PPC tissues due to epilepsy.
