In collaboration with Dana Boatman, Ph.D., we are studying the brain regions that are responsible for understanding spoken words and parts of words. In a paper published in Clinical Neurophysiology we compared the activation of human auditory cortex during discrimination of spoken syllables vs. discrimination of tones. We found that these tasks were associated with an event-related augmentation of gamma band (80-100 Hz) power over posterior superior temporal gyrus, a brain region that is known to be responsible for processing auditory information. Furthermore, we found that the gamma augmentation was greater and more widespread during spoken syllables than during tones. Future studies will explore this phenomenon in greater detail, in part to verify how closely gamma augmentation reflects the timing, complexity and difficulty of auditory processing. If the relationship between gamma activity and processing demands is a close one, it will strengthen our ability to study the brain mechanisms of other cognitive functions, including language. Dr. Boatman has an NIH grant to study cortical mechanisms of central auditory processing, including our collaborative research on gamma augmentation and its relationship with other electrophysiological indices of cortical activation during auditory processing, e.g. the mismatch negativity. |