Do not throw out the baby with the bath water: choosing an effective baseline for a functional localizer of speech processing
Article first published online: 17 FEB 2013
© 2013 The Authors. Brain and Behavior published by Wiley Periodicals, Inc.
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Brain and Behavior
Volume 3, Issue 3, pages 211–222, May 2013
How to Cite
Brain and Behavior 2013; 3(3):211–222.
- Issue published online: 13 MAY 2013
- Article first published online: 17 FEB 2013
- Manuscript Accepted: 15 JAN 2013
- Manuscript Revised: 23 DEC 2012
- Manuscript Received: 31 JUL 2012
- Israel Science Foundation. Grant Number: 513/11
- Marie Curie International Reintegration Grant. Grant Number: DNLP 231029
|brb3129-sup-0001-FigS1.tif||image/tif||848K||Figure S1. Temporal characteristics of a STS response to speech and reversed speech. (A) Group-averaged time course of BOLD activation for Speech (red) and Reversed (green) in left and right aSTS. ROIs were defined by Speech versus SCN (P < 0.001, uncorrected), (B) Half-maximum decay time of the BOLD response for speech and reversed speech. Bars denote group average, error bars represent 1 standard error of the mean. In similar fashion to pSTS results (Fig. 5), no significant difference was found between speech and reversed speech decay times, (C) Half-maximum decay times are plotted for speech against reversed speech in each participant. Dots under the gray line (x > y) are ones where reversed speech decays faster than speech. This is evident only in a few subjects in left aSTS, again, similarly to pSTS. aSTS, anterior superior temporal sulcus; ROIs, region of interests; SCN, signal correlated noise; pSTS, posterior superior temporal sulcus.|
|brb3129-sup-0002-FigS2.tif||image/tif||6272K||Figure S2. Reversed speech removes activation in language regions regardless of P-value. Axial slices of four individual participants, depicting significant response for Speech versus SCN contrast (left column) and Speech versus Reversed speech contrast (right columns), under different threshold levels. Notice that even for less stringent thresholds, Speech versus Reversed speech fails to detect activation in language regions which are readily picked up by the Speech versus SCN contrast. SCN, signal correlated noise.|
|brb3129-sup-0003-FigS3.tif||image/tif||468K||Figure S3. Time courses of BOLD responses in three individual participants. Data were collected from ROI voxels identified by Speech > SCN contrast (P < 0.001, uncorrected). Activations are normalized to the baseline of rest signal level. Red = Speech, green = Reversed speech, blue = SCN. BOLD responses for speech and reversed speech rise similarly during initial stimulus presentation, but then decay more rapidly in the reversed condition. This effect was found mainly in the left IFG. ROI, region of interest; SCN, signal correlated noise; IFG, inferior frontal gyrus.|
|brb3129-sup-0004-FigS4.tif||image/tif||1488K||Figure S4. Group analysis results. Group activation patterns shown for Speech versus SCN (left panel) and Speech versus Reversed (right panel), displayed on the left hemisphere (n = 12, P < 0.001, uncorrected). Activations are shown in color rendered unto the SPM5 single subject brain template. Notice the absence of activation in left IFG for Speech versus Reversed, demonstrating that the difference in efficiency between the baselines is evident even at the group level. SCN, signal correlated noise; IFG, inferior frontal gyrus.|
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