While it was known that the visual system has a specialized region for perceiving motion, it wasn't known whether the auditory system has such a region--or whether sound location and motion are processed by the same circuitry. Previous studies of the capabilities of brain-damaged patients had found only that both their location and motion processing abilities were impaired, and animal and human neuroimaging studies had not been able to conclusively tease apart the two abilities.
Ducommun and her colleagues discovered the region by studying a woman who was to be operated on to alleviate intractable temporal lobe epilepsy. The operation would involve the removal of the affected regions of the right anterior temporal lobe and the right posterior superior temporal gyrus (STG).
Perceptual tests before the operation showed her ability to perceive sound location and motion to be normal. In those tests, the researchers played white noise through headphones and simulated movement of the noise source, asking the patient to detect the noise location and how it seemed to be moving. The patient could also identify sounds such as a piano, dog, water, sneezing, and a saw.
Also, the researchers electrically stimulated the brain region to be removed--using electrodes already in place to monitor epileptic activity. They found that such stimulation of the right posterior STG led the patient to r
Contact: Heidi Hardman