Making faces in the brain

Artificially activating the right neurons at the right time causes visual perception of a face. This new result shows that such neurons directly underlie the recognition of complex objects. Direct electrophysiological recordings and fMRI scanning experiments in an area of the primate cerebral cortex called inferior temporal (IT) cortex have shown that this area responds selectively to highly complex visual stimuli, such as faces, leading to the hypothesis that this brain region is involved in object recognition. Now direct proof for this hypothesis has been obtained, with the discovery of a direct link between face-selective neurons and face perception. Electrical microstimulation of clusters of face-selective neurons in IT cortex induces a strong bias in the monkey's decisions towards the face category. As well as linking neural activity in the IT cortex and object recognition, this work sets the stage for future research into the neural code for object shape.