Abstract | Somatosensory processing of duration and frequency changes was investigated using the somatosensory mismatch negativity (sMMN), a preattentively evoked somatosensory event-related potential analogous to the auditory mismatch negativity. Intermittent vibration to the fingertips of either hand was presented using a 2-stimulus oddball paradigm (deviant p = 0.10). One group (N = 12, 18–38 yr) was presented with stimulus pairs of 20/70, 50/150 and 170/250 ms. A second group (N = 10, 19–34 yr) was tested using frequency pairs of 200/70 Hz. A psychophysical study confirmed the subjects’ ability to discriminate between different stimulus pairs, with good discrimination between all stimuli except for the longest durations where the average probability was 50%. Both frequency changes and duration increments/decrements revealed sMMNs. Peak latency occurred between 120 and 200 ms and increased with longer durations. A significant decrease in amplitude was observed with the 170/250 ms pairing, coinciding with a positive correlation between individual discrimination performance and amplitude. This study reveals similarities between the auditory and sMMN and helps characterize the shared features of these responses. |
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