The pathways for intelligible speech: multivariate and univariate perspectives.
Bottom Line: We have demonstrated that the left anterior superior temporal sulcus (STS) responds preferentially to intelligible speech (Scott SK, Blank CC, Rosen S, Wise RJS. 2000.In contrast, in classifications using local "searchlights" and a whole brain analysis, we find greater classification accuracy in posterior rather than anterior temporal regions.Thus, we show that the precise nature of the multivariate analysis used will emphasize different response profiles associated with complex sound to speech processing.
Affiliation: Institute of Cognitive Neuroscience, MRC Cognition and Brain Sciences Unit, Cambridge CB2 7EF, UK.Show MeSH
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Mentions: Classification was conducted using an ROI consisting of the entire bilateral temporal cortex, including PAC and a control region, the inferior occipital gyrus. Cross validation using the run structure demonstrated that this ROI correctly classified 0.74 (proportion correct) of volumes of (clear vs. rot), and 0.79 of volumes of (NV vs. rotNV) correctly (chance level 0.50; Fig. 6Ai,Bi); and in both cases, classification was significantly greater than chance (clear vs. rot: t(11) = 5.961, P < 0.001; NV vs. rotNV: t(11) = 9.949, P < 0.001) when Bonferroni correcting for 2 tests (P = 0.025). There was no evidence that the inferior occipital gyrus performed at a level greater than chance (clear vs. rot: P = 0.812; NV vs. rotNV: P = 0.967). Having demonstrated above-chance classification using the bilateral temporal cortex in both intelligibility classifications, we extracted the weight vector from a classifier trained using both runs of data for each intelligibility classification.Figure 6.
Affiliation: Institute of Cognitive Neuroscience, MRC Cognition and Brain Sciences Unit, Cambridge CB2 7EF, UK.