“Vision in the service of action begins with the eyes, but then that information has to be transformed into motor commands,” said senior author Mriganka Sur, Paul E. and Lilah Newton Professor of Neuroscience in the Department of Brain and Cognitive Sciences. “This is the place where that planning begins.”
Sur said the study may help to explain a particular problem in some people who have suffered brain injuries or stroke, called “hemispatial neglect.” In such cases, people are not able to act upon or even perceive objects on one side of their visual field. Their eyes and bodies are fine, but the brain just doesn’t produce the notion that there is something there to trigger action. Some studies have implicated damage to the PPC in such cases.
In the new study, the research team pinpointed the exact role of the PPC in mice and showed that it contains a mix of neurons attuned to visual processing, decision-making and action.
“This makes the PPC an ideal conduit for flexible mapping of sensory signals onto motor actions,” said Gerald Pho, a former graduate student in the Sur lab who is now at Harvard University. Pho is co-lead author with Michael Goard, a former MIT postdoctoral fellow now at UC Santa Barbara.