The mind’s eye

Activity in the temporoparietal junction (TPJ) of the human brain could be the signature of visual perception, according to a study published online this week in Nature Neuroscience. These results suggest that signals in the TPJ support conscious awareness.

Previous work suggested that the TPJ is critical for detecting salient or unexpected stimuli, and damage to this area can result in spatial neglect, a deficit in the control of attention.

Michael Beauchamp and colleagues worked with patients who had electrodes implanted into their brains for surgical treatment of epilepsy. They stimulated an area in the early visual system of each person’s brain with low intensity electrical pulses that sometimes evoked the perception of a flash of light and sometimes did not. They found that people only reported seeing a light on occasions when there was also a response in the TPJ. The authors found that disruption of signals in the TPJ decreased the detectability of a barely visible visual target, further linking this brain area to visual perception.