Figure 1.
The ISC map and the GLM results for speech and non-speech sounds.
The intersubject correlation (ISC) map (top panels) and general linear model (GLM) results overlaid on a MNI305 template brain and viewed from the lateral and medial aspects of both hemispheres. The GLM maps show brain areas correlating with the speech sounds (middle panels) and non-speech sounds (bottom panels). The GLM maps are thresholded at FWE-corrected p<0.05, cluster size >10 voxels, the ISC map at FWE corrected p<0.01, cluster size >20 voxels. STG = superior temporal gyrus, MTG = middle temporal gyrus, IPL = inferior parietal lobule, SMG = supramarginal gyrus, TP = temporal pole, MFG = middle frontal gyrus, IFG = inferior frontal gyrus, Cun = Cuneus, PreCun = PreCuneus, CC = cingulate cortex, Amyg = amygdala, L = left hemisphere, R = right hemisphere.
Table 1.
Peak voxel coordinates (x, y, and z in MNI system) and anatomical labels for the ISC map.
Table 2.
Peak voxel coordinates (x, y, and z in MNI system) and anatomical labels for the GLM maps.
Figure 2.
Sorting of the ICs based on correlations with the ISC map.
The bar graph shows the independent components (ICs) organized in a descending order based on their spatial correlations with the intersubject correlation (ISC) map. The colors of the four most stimulus related extrinsic ICs (IC1–IC4) in the bar graph correspond to the colors in the independent component analysis (ICA) map illustrating their spatial distribution. The four ICs (IC5–IC8) that correlated temporally with two extrinsic ICs are also marked in the bar graph. The ISC and IC maps are thresholded at FWE corrected p<0.01, cluster size >20 voxels. L = left hemisphere, R = right hemisphere.
Table 3.
Peak voxel coordinates (x, y, and z in MNI system) and anatomical labels for IC1–IC8.
Figure 3.
The extrinsic independent components (ICs), IC1–IC4, are shown on the left and the intrinsic ICs, IC5–IC8 on the right. Extrinsic and intrinsic ICs are grouped with green boxes. Mean intersubject correlation values of the ICs time-courses are written below the IC number. Correlation values between the extrinsic and intrinsic ICs are displayed in the middle. The group-level t-maps are thresholded at FWE corrected p<0.01, cluster size >20 voxels and overlaid on an average of the subjects’ normalized anatomical images. MNI z-coordinates are presented beside the axial slices. L = left, R = right, r = mean Pearson correlation strength.
Figure 4.
Correlations between the time-courses of the independent components (ICs) and reactivity of the ICs to speech and non-speech sounds.
The correlation matrix for the time-courses of IC1–IC8 is presented on the left. The colour of each square represents the subjects’ mean correlation strengths. The colour key is given to the right of the matrix. The bar graph on the right presents mean beta value results from the analysis where the time-courses of the spatial ICs were subjected to a multiple regression analysis with the speech (brown) and non-speech (blue) regressors. * p<0.05, **p<0.005.
Figure 5.
A schematic summary of the extrinsic and intrinsic speech and non-speech networks.
The extrinsic areas are labeled with blue letters, the intrinsic with red letters. Areas of the speech network are marked by solid boxes, areas of the non-speech sound network by dotted boxes. The summary is based on the characteristics of independent components (ICs) IC1–IC8. Extrinsic areas are based on the correlation and overlap of the ICs with the intersubject correlation (ISC) map. Speech and non-speech brain areas are based on the similarity of the time-courses of the ICs to the speech and non-speech regressors, and on functional connectivity analysis. Abbreviations: MTG = middle temporal gyrus, IN = insula, SFG = superior frontal gyrus, SFGmed = superior frontal gyrus medial part, MFG = middle frontal gyrus, IFG = inferior frontal gyrus, TP = temporal pole, IPL = inferior parietal lobule, SMG = supramarginal gyrus, CC = cingulate cortex, Cun = Cuneus, PreCun = PreCuneus, ant = anterior, post = posterior, sup = superior, inf = inferior, trans = transitional.