Cognitive strategies for spatial memory of navigation: studies combining virtual reality and brain imaging

This talk will deal with the neural basis of spatial memory during navigation. When navigating or trying to remember a traveled path the brain uses different cognitive strategies. It can use, among others, an egocentric, (topo-kinesthétic), memory of the travel involving kinaesthetic memories of the route and episodic memory, but it can also use allocentric, (topo-graphic), map like, memories. Different brain systems are involved in these strategies and they develop during ontogeny. I will describe studies using virtual reality in normal subjects and patient with hippocampal lesions. In addition I will describe results obtained with fMRI and intracranial recordings in epileptic patients which identify the brain areas involved in these strategies. Virtual reality allows us to selectively identify the brain areas involved in such tasks as perspective change, manipulation of reference frames, decision making and some aspects of social interaction such as empathy etc. The paradigms we have designed for these fundamental studies can also be used for diagnosis of these deficits in Schizophrenia, autism, and other psyhchiatric or neurological diseases. They could also be used for remediation in these diseases or others like agoraphobia. A new field is now opened in which neuroscientists, neurologists, psychiatrists, otolaryngologists and roboticians can cooperate to try to compensate for this category of deficits in patients, during development or aging.