Effects of stimulus frequency and duration on somatosensory discrimination responses

Abstract

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.

Common or Redundant Neural Circuits for Duration Processing across Audition and Touch

“…The sMMN response over the frontal midline scalp is also representative of what has been shown in previous literature (Kekoni et al , 1997; Shinozaki et al , 1998; Spackman et al , 2007, 2010). The sMMN waveform has two phases: an earlier negative peak at ∼145ms followed by a positive peak at ∼235ms.…”

“…For the somatosensory MMN the timing and scalp distribution has been shown to be quite similar, but the initial negative deflection is also followed by a relative positivity (see e.g. Spackman et al , 2007). Here participants viewed a silent movie with subtitles during stimulus delivery and were told to ignore the auditory and somatosensory stimuli.…”

“…It has, however, been similarly elicited for many different stimulus properties such as a duration (Akatsuka et al , 2005; Spackman et al , 2007), frequency (Kekoni et al , 1997), and location (Shinozaki et al , 1998). As with the aMMN, the sMMN component correlates with the ability to discriminate between standard and deviant stimuli (Spackman et al , 2007). The MMN is elicited by the infrequent occurrence of a “deviant” stimulus within the context of a frequently occurring “standard” stimulus.…”

Audio-Tactile Integration and the Influence of Musical Training

“…Previous studies on the tactile MMN often found two event related components, with the first one peaking around 100–200 ms and the later one peaking around 170–270 ms [15]–[17], [41], [42]. Likewise, we find also two components in the tactile condition of the present study.…”

Evidence for neural encoding of Bayesian surprise in human somatosensation

“…Consistently, a fronto-parietal negative shift between 100 and 200 ms contralateral to the side of stimulation has been observed for unexpected stimuli (Akatsuka et al, 2007b;Kekoni et al, 1997;Kida et al, 2004;NeuroImage 62 (2012) 177-188 Restuccia et al, 2007;Shinozaki et al, 1998;Spackman et al, 2007Spackman et al, , 2010, while some studies additionally reported earlier mismatch responses 60 to 90 ms after stimulus onset (Akatsuka et al, 2007a(Akatsuka et al, , 2007bGötz et al, 2011). Further, in analogy to other sensory modalities, somatosensory oddball stimuli that capture the observer's attention elicit a parietal positive response at about 300 ms post-stimulus, commonly referred to as P300 (Restuccia et al, 2009;Tarkka et al, 1996).…”