NIH Researchers Discover Brain Area Crucial for Recognizing Visual Events

fMRI scans reveal activity changes in the fSTS.

Photo: Richard Krauzlis

NIH researchers report that a brain region in the superior temporal sulcus (fSTS) is crucial for processing and making decisions about visual information. The findings, which could provide clues to treating visual conditions from stroke, appeared recently in the journal Neuron. The study was funded by NEI and NIMH.

“The human visual system recognizes, prioritizes and categorizes visual objects and events,” said Dr. Richard Krauzlis, chief of NEI’s section on eye movements and selective attention and senior author of the study. “We were surprised to learn that the fSTS is a crucial link in this story-building process, passing information from an evolutionarily ancient region in the midbrain to highly specialized regions of the visual cortex.”

While aspects of visual processing begin in the eye, crucial steps in visual attention start in the superior colliculus, a part of the midbrain that handles a variety of sensory input. Neuronal activity in the superior colliculus tells the brain to notice an event in the visual field and decide if it is significant.

Using fMRI, researchers found that some fSTS neurons fired in response to specific images, a property found only in areas of the brain that manage high-level processing. Without the contribution of the superior colliculus, many of these object-specific neurons in the fSTS failed to fire in response to their favored object.

These findings are particularly relevant to a condition known as visual neglect, which can occur in people after a stroke or other brain injury that affects brain areas involved in visual attention. People with visual neglect can see all the objects and events in their visual field, but often aren’t aware of the events on the affected side, especially when the visual field is cluttered.