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Decoding Accuracy in Supplementary Motor Cortex Correlates with Perceptual Sensitivity to Tactile Roughness.

Kim J, Chung YG, Park JY, Chung SC, Wallraven C, Bülthoff HH, Kim SP - PLoS ONE (2015)

Bottom Line: The searchlight MVPA revealed four brain regions showing significant decoding results: the supplementary motor area (SMA), contralateral postcentral gyrus (S1), and superior portion of the bilateral temporal pole (STP).We found that only the SMA showed a significant correlation between neuronal decoding accuracy and JND across individuals; Participants with a smaller JND (i.e., better discrimination ability) exhibited higher decoding accuracy from their voxel response patterns in the SMA.Our findings suggest that multivariate voxel response patterns presented in the SMA represent individual perceptual sensitivity to tactile roughness and people with greater perceptual sensitivity to tactile roughness are likely to have more distinct neural representations of different roughness levels in their SMA.

View Article: PubMed Central - PubMed

Affiliation: Department of Brain and Cognitive Engineering, Korea University, Seoul, Republic of Korea.

ABSTRACT
Perceptual sensitivity to tactile roughness varies across individuals for the same degree of roughness. A number of neurophysiological studies have investigated the neural substrates of tactile roughness perception, but the neural processing underlying the strong individual differences in perceptual roughness sensitivity remains unknown. In this study, we explored the human brain activation patterns associated with the behavioral discriminability of surface texture roughness using functional magnetic resonance imaging (fMRI). First, a whole-brain searchlight multi-voxel pattern analysis (MVPA) was used to find brain regions from which we could decode roughness information. The searchlight MVPA revealed four brain regions showing significant decoding results: the supplementary motor area (SMA), contralateral postcentral gyrus (S1), and superior portion of the bilateral temporal pole (STP). Next, we evaluated the behavioral roughness discrimination sensitivity of each individual using the just-noticeable difference (JND) and correlated this with the decoding accuracy in each of the four regions. We found that only the SMA showed a significant correlation between neuronal decoding accuracy and JND across individuals; Participants with a smaller JND (i.e., better discrimination ability) exhibited higher decoding accuracy from their voxel response patterns in the SMA. Our findings suggest that multivariate voxel response patterns presented in the SMA represent individual perceptual sensitivity to tactile roughness and people with greater perceptual sensitivity to tactile roughness are likely to have more distinct neural representations of different roughness levels in their SMA.

No MeSH data available.


Correlations between behavioral and neural decoding accuracies for roughness discrimination.The 13 participants’ neural decoding accuracies are plotted over the JND values in the behavioral experiments. The solid lines show robust fits of linear relationships.
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pone.0129777.g004: Correlations between behavioral and neural decoding accuracies for roughness discrimination.The 13 participants’ neural decoding accuracies are plotted over the JND values in the behavioral experiments. The solid lines show robust fits of linear relationships.

Mentions: Having found specific brain regions that provided useful information for roughness classification as presented above, we investigated how regional classification accuracy of individual participants varied with their perceptual roughness discriminative sensitivity (JND). Data from 13 participants were used in this analysis; data from three were excluded (participants 6, 7, and 10). The pairwise correlation analysis revealed a significant correlation between JND and decoding accuracy in the SMA (r = -0.756, p < 0.01), but not in other regions: contralateral S1 (r = -0.245, p = 0.42), contralateral STP (r = -0.486, p = 0.09), and ipsilateral STP (r = -0.195, p = 0.52) (Fig 4). The negative correlation in the SMA indicated that a higher decoding accuracy from the SMA was obtained in those participants who showed a smaller JND value (i.e., better roughness discrimination). Another correlation analysis of decoding accuracy with percentage of correct answers did not show any significant correlation for all the searchlight clusters (all r < 0.3, p > 0.32).


Decoding Accuracy in Supplementary Motor Cortex Correlates with Perceptual Sensitivity to Tactile Roughness.

Kim J, Chung YG, Park JY, Chung SC, Wallraven C, Bülthoff HH, Kim SP - PLoS ONE (2015)

Correlations between behavioral and neural decoding accuracies for roughness discrimination.The 13 participants’ neural decoding accuracies are plotted over the JND values in the behavioral experiments. The solid lines show robust fits of linear relationships.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4465937&req=5

pone.0129777.g004: Correlations between behavioral and neural decoding accuracies for roughness discrimination.The 13 participants’ neural decoding accuracies are plotted over the JND values in the behavioral experiments. The solid lines show robust fits of linear relationships.
Mentions: Having found specific brain regions that provided useful information for roughness classification as presented above, we investigated how regional classification accuracy of individual participants varied with their perceptual roughness discriminative sensitivity (JND). Data from 13 participants were used in this analysis; data from three were excluded (participants 6, 7, and 10). The pairwise correlation analysis revealed a significant correlation between JND and decoding accuracy in the SMA (r = -0.756, p < 0.01), but not in other regions: contralateral S1 (r = -0.245, p = 0.42), contralateral STP (r = -0.486, p = 0.09), and ipsilateral STP (r = -0.195, p = 0.52) (Fig 4). The negative correlation in the SMA indicated that a higher decoding accuracy from the SMA was obtained in those participants who showed a smaller JND value (i.e., better roughness discrimination). Another correlation analysis of decoding accuracy with percentage of correct answers did not show any significant correlation for all the searchlight clusters (all r < 0.3, p > 0.32).

Bottom Line: The searchlight MVPA revealed four brain regions showing significant decoding results: the supplementary motor area (SMA), contralateral postcentral gyrus (S1), and superior portion of the bilateral temporal pole (STP).We found that only the SMA showed a significant correlation between neuronal decoding accuracy and JND across individuals; Participants with a smaller JND (i.e., better discrimination ability) exhibited higher decoding accuracy from their voxel response patterns in the SMA.Our findings suggest that multivariate voxel response patterns presented in the SMA represent individual perceptual sensitivity to tactile roughness and people with greater perceptual sensitivity to tactile roughness are likely to have more distinct neural representations of different roughness levels in their SMA.

View Article: PubMed Central - PubMed

Affiliation: Department of Brain and Cognitive Engineering, Korea University, Seoul, Republic of Korea.

ABSTRACT
Perceptual sensitivity to tactile roughness varies across individuals for the same degree of roughness. A number of neurophysiological studies have investigated the neural substrates of tactile roughness perception, but the neural processing underlying the strong individual differences in perceptual roughness sensitivity remains unknown. In this study, we explored the human brain activation patterns associated with the behavioral discriminability of surface texture roughness using functional magnetic resonance imaging (fMRI). First, a whole-brain searchlight multi-voxel pattern analysis (MVPA) was used to find brain regions from which we could decode roughness information. The searchlight MVPA revealed four brain regions showing significant decoding results: the supplementary motor area (SMA), contralateral postcentral gyrus (S1), and superior portion of the bilateral temporal pole (STP). Next, we evaluated the behavioral roughness discrimination sensitivity of each individual using the just-noticeable difference (JND) and correlated this with the decoding accuracy in each of the four regions. We found that only the SMA showed a significant correlation between neuronal decoding accuracy and JND across individuals; Participants with a smaller JND (i.e., better discrimination ability) exhibited higher decoding accuracy from their voxel response patterns in the SMA. Our findings suggest that multivariate voxel response patterns presented in the SMA represent individual perceptual sensitivity to tactile roughness and people with greater perceptual sensitivity to tactile roughness are likely to have more distinct neural representations of different roughness levels in their SMA.

No MeSH data available.