Spackman, Lynne and Boyd, Stewart and Towell, Anthony (2007) Effects of stimulus frequency and duration on somatosensory discrimination responses. Experimental Brain Research, 177 (1). pp. 21-30. ISSN 0014-4819
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Official URL: http://dx.doi.org/10.1007/s00221-006-0650-0
Somatosensory processing of duration and frequency changes was investigated using event-related potentials to vibrotactile stimuli. Intermittent vibration to the fingertips of either hand was presented using a two-stimulus odd-ball paradigm (deviant P = 0.10). One group (N = 12, 18–38 years) was presented with stimulus pairs of 20/70, 50/150 and 170/250 ms. A second group (N = 10, 19–34 years) was tested using frequency pairs of 200/70 Hz. A psychophysical study examined the subjects’ ability to discriminate between different stimulus pairs. A clear negative shift in the response to the deviant stimulus was recorded with all the stimulus conditions used in both experiments. Both frequency changes and duration increments/decrements revealed an initial negativity in the subtraction waveform with a mean onset of 90–170 ms and a following positivity, both of which were dependent on the duration of the stimulus used. A significant decrease in the amplitude of both components was observed with the 170/250 ms pairing, coinciding with a positive correlation between individual discrimination performance and amplitude. These results support the existence of a somatosensory mismatch response with features similar to those of the aMMN and highlight the relevance of the somatosensory-specific positivity. Results from the duration experiment also resolve some of the discrepancies between previous studies.
|Additional Information:||Online ISSN 1432-1106|
|Research Community:||University of Westminster > Social Sciences, Humanities and Languages, School of|
|Deposited On:||31 May 2007|
|Last Modified:||30 Oct 2009 12:00|
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