Article Figures & Data
Figures
- Figure 1.
Cortical regions more active during synchronous speaking than solo speaking and listening. This conjunction analysis shows voxels more active during synchronous speaking (with both live and recorded voice) than either speaking alone or passive listening (Synch-Live + Synch-Rec > Speak ∩ Synch-Live + Synch-Rec > Listen. Activated regions include the anterior and posterior auditory processing streams and medial regions on the superior temporal plane. Colors represent voxel T values.
- Figure 2.
Cortical regions more active during synchronous speaking than solo speaking and listening, shown for Synch-Live and Synch-Rec separately. This conjunction analysis shows voxels more active during synchronous speaking, displaying activation for Synch-Live and Synch-Rec separately. Voxels in red represent significant voxels (p < 0.005, cluster corrected) for Synch-Live. Blue voxels represent significant voxel for Synch-Rec. Purple voxels represent significance in both conjunctions. Activated regions were largely overlapping, although activity in right inferior frontal gyrus was only detected for the Synch-Live condition. A statistical test for differences between Synch-Live and Synch-Rec is reported in the next section.
- Figure 3.
Parametric effect of closer synchrony. Pericentral regions showed increased activity on trials where synchrony between talkers was closer (p < 0.005, uncorrected).
- Figure 4.
Regions that showed greater activity during synchrony with a live voice (Synch-Live) compared with a recorded voice (Synch-Rec). Several regions showed increased activity during live synchrony compared with recorded synchrony, including the right temporal pole, inferior frontal gyrus, supramarginal gyrus, and bilateral parahippocampal gyrus, extending into hippocampus and lingual gyrus (p < 0.005, cluster corrected).
- Figure 5.
Release of auditory suppression during live synchronous speaking. Red voxels represent increased activity during speech that is produced synchronously with a live person (a–c) as defined by the conjunction of Synch-Live > Synch-Rec ∩ Synch-Live > Diff-Live. The profile of activity in this region (d) indicates that this activity reflects an absence of suppression that typically occurs during speech production. The conditions are colored to indicate significant differences: red bars are significantly greater than blue bars; bars of the same color did not differ significantly. Significance was set at a Bonferroni-corrected level of α = 0.005 for all 10 pairwise tests. Error bars indicate SEM.
- Figure 6.
Effects related to synchronous speaking. Functional connectivity (measured with PPI) from RSTG/IPL and RIFG, as well as the parametric effect of closer synchrony, all converged in right somatosensory cortex. Both rendered images show the same activity, from two different angles. Left image is sectioned to show overlap of results in somatosensory cortex.
- Figure 7.
Schematic diagram of brain areas recruited by synchronized speaking. Arrows indicate pairs of regions that showed increased correlated activity during two-way (Synch-Live) synchronous speaking compared with one-way (Synch-Rec) synchronous speaking. Increased accuracy was parametrically related to activity in postcentral gyrus bilaterally during live synchronous speaking. The right temporal pole showed release of speech-induced suppression during live synchronous speaking.
Tables
Voxels Region x y z T (peak voxel) 323 STG −30 −34 13 5.03 228 STG 42 −28 −5 4.70 1 IFG 44 15 23 2.95 ↵aCoordinates in MNI space.
Voxels Region x y z T (peak voxel) 317 STG −63 −31 10 5.23 169 STG 57 −31 16 4.36 ↵aCoordinates in MNI space.
Voxels Region x y z T (peak voxel) 229 STG 42 −28 −5 5.5 268 STG −63 −4 4 4.48 31 IFG (opercularis) 48 17 7 3.64 ↵aCoordinates in MNI space.
Voxels Region x y z T 33 Superior frontal gyrus 24 −13 67 5.39 23 Postcentral gyrus 24 −43 64 4.73 36 Posterior cingulate cortex 12 −52 28 4.6 12 Rolandic operculum 57 −13 19 4.41 36 Postcentral gyrus 66 −10 40 4.33 22 Insula 36 −1 19 4.24 63 Postcentral gyrus −54 −16 49 4.15 22 Precentral gyrus −27 −16 61 4.1 10 Rolandic operculum 36 −28 25 3.93 15 Middle occipital gyrus −42 −79 34 3.87 14 Rolandic operculum −39 −10 16 3.81 15 Precuneus 18 −70 28 3.77 10 Middle temporal gyrus −39 −58 22 3.54 14 Postcentral gyrus −33 −37 55 3.28 10 Putamen 30 −7 1 3.24 ↵aCoordinates in MNI space.
Voxels Region x y z T Z 76 IFG 48 23 13 5.37 4.05 106 Temporal pole 36 20 −29 5.1 3.92 84 Parahippocampal/lingual gyrus −18 −43 −5 5.03 3.88 78 Parahippocampal gyrus 18 −34 −5 4.46 3.58 73 Supramarginal/angular gyrus 66 −28 31 3.79 3.18 ↵aCoordinates in MNI space.
Voxels Region x y z T Z 109 Posterior cingulate/corpus callosum −3 −31 10 5 3.87 100 Temporal pole 48 17 −23 4.86 3.8 ↵aCoordinates in MNI space.
Voxels Region x y z T 59 Temporal pole 39 20 −25 4.24 ↵aCoordinates in MNI space.
Voxels Region x y z T (peak voxel) 44 Frontal white matter 21 29 25 4.58 34 IFG (opercularis) 45 17 13 3.92 27 Middle frontal gyrus −33 20 52 4.10 24 Inferior occipital gyrus 47 −76 −5 4.02 23 Insula 48 −7 4 4.00 ↵aCoordinates in MNI space. These regions showed increased functional connectivity with the right temporal pole during Synch-Live trials, compared with Synch-Rec trials. p < 0.005, uncorrected (20 voxel extent threshold).
