The perception of temporal structure and auditory evoked brain activity.
The processing and perception of auditory signals depends on the temporal structure of stimulus characteristics. We studied 26 healthy subjects who participated in psychophysical experiments and in electrophysiological recordings of auditory evoked potentials from C2, C3, C4, T3 and T4. Stimuli consisted of tone series presented binaurally as tones or gaps with a base duration of 100 ms. In the psychophysical experiments, difference thresholds as indicators of temporal discrimination performance were significantly lower for tones than for gaps. In the electrophysiological recordings, gaps often failed to elicit N100 components. Tones produced shortest component latencies with largest amplitudes. In addition, brain activity was strongest at C2, and showed a symmetrical fall-off over both hemispheres. N100 components had significantly longer latencies and smaller amplitudes when they were evoked by the end of the gap (i.e. with the continuation of the tone) than by tones. Our data illustrate how the temporal structure of auditory stimuli affects neuronal responses of the brain. Similar effects were observed in psychophysical and electrophysiological experiments, and we were able to demonstrate a direct relationship between subjective sensory thresholds and auditory evoked brain activity.
Skrandies
W
W
Institute of Physiology, Justus-Liebig University, Giessen, Germany.
Rammsayer
T
T
D000328:Adult; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D004007:Dichotic Listening Tests; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010898:Pitch Perception / Q000502:physiology*; D011571:Psychoacoustics; D011930:Reaction Time / Q000502:physiology; D012684:Sensory Thresholds / Q000502:physiology; D013998:Time Perception / Q000502:physiology*