Table 2.

Principal component analysis of increased and decreased activity

Cumulative variance (%)pc varianceResponsepc1pc2pc3pc4
pc144.210302810.1629294SupragranularIncreased0.1929690.4848809−0.3123310.0005789
pc271.032468850.0988484Decreased0.4076718−0.2051530.1687933−0.0543012
pc392.994438190.080937GranularIncreased0.1661080.2601034−0.3648693−0.0260106
pc496.894476430.0143729Decreased0.33999260.21395660.2859596−0.5156428
pc598.606216370.0063083InfragranularIncreased0.05127690.4105422−0.0402117−0.1843402
pc699.614621240.0037163Decreased0.4235365−0.2734356−0.2119353−0.3806003
pc799.838045860.0008234M1Increased0.0843040.1439821−0.10925860.3450707
pc899.946895530.0004011Decreased0.3603517−0.01479260.06826320.2510888
pc999.97104968.90E-05VPMIncreased0.19679740.2950371−0.25422390.0260476
pc1099.989967686.97E-05Decreased0.14899340.30888440.71764820.0854539
pc1199.997767992.87E-05POMIncreased−0.12736020.35533210.12618170.2783481
pc121008.23E-06Decreased0.5072061−0.1907687−0.01882020.5329833
  • Analysis of significant increased and decreased responses across all areas studied showed that two principal components (pcs) were able to explain a large portion of the sample's variance. The first component included mostly decreased activity from all S1 layers, M1, and POM, and increased activity in VPM. The second component included increased activity in all S1 layers, VPM, and POM, and decreased activity in VPM and all S1 layers. The presence of such a large portion of variance explained solely by two components indicates that common concurrent patterns of increased and decreased activity occur at all times in the TCLs, suggesting a distributed mode of processing during active tactile discrimination.