Peter Brotchie1, 2, Shaun Seixas3, Shoane Ip4, Mathew Hughes3, Graeme Jackson4
1MRI, Geelong Hospital, Geelong, Victoria, Australia; 2Radiology, University of Melbourne, Melbourne, Victoria, Australia; 3Brain and Psychological Research Centre, Swinburne University of Technology, Melbourne, Victoria, Australia; 4Melbourne Brain Centre, Brain Research Institute, Melbourne, Victoria, Australia
Posterior parietal cortex (PPC) has long been known to be involved in spatial processing, forming a key element of the where pathway in visual processing. However, its role in navigation has not been well documented with functional imaging studies. In this study we have looked at the role of PPC in navigation using a delayed response paradigm to assess the persistent activity that is known to be present in the neurons of the posterior parietal cortex (PPC) in delayed response tasks. In order to detect orientation specific activity, we used repetition suppression of the subects orientation with respect to a virtual environment. We found increased activity predominantly in area PFm of the left PPC that was orientation specific, but present only when the subject was planning a change in orientation. The findings indicate a specialised region in PPC that plans for upcoming changes in orientation.