Effects of time-compressed speech training on multiple functional and structural neural mechanisms involving the left superior temporal gyrus

Time-compressed speech is an artificial form of rapidly presented speech. Training with time compressed speech in a second language leads to adaptation toward time-compressed speech in a second language and toward time compressed speech in different languages. However, the effects of training with time-compressed speech of a second language (TCSSL) on diverse cognitive functions and neural mechanisms beyond time compressed speech-related activation are unknown. We investigated the effects of 4 weeks of training with TCSSL on the fractional amplitude of spontaneous low-frequency fluctuations (fALFF) of 0.01–0.08 Hz, resting-state functional connectivity (RSFC) with the left superior temporal gyrus (STG), fractional anisotropy (FA), and regional gray matter volume (rGMV) of young adults by magnetic resonance imaging. There were no significant differences in change of performance of measures of cognitive functions or second language skills after training with TCSSL compared with that of the active control group. However, compared with the active control group, training with TCSSL was associated with increased fALFF, RSFC, and FA and decreased rGMV involving areas in the left STG. These results lacked evidence of a far transfer effect of time compressed speech training on a wide range of cognitive functions and second language skills in young adults. However, these results demonstrated effects of time compressed speech training on gray and white matter structures as well as on resting-state intrinsic activity and connectivity involving the left STG, which plays a key role in listening comprehension

Lenticular nucleus correlates of general self-efficacy in young adults

General self-efficacy (GSE) is an important factor in education, social participation, and medical treatment. However, the only study that has investigated the direct association between GSE and a neural correlate did not identify specific brain regions, rather only assessed brain structures, and included older adult subjects. GSE is related to motivation, physical activity, learning, the willingness to initiate behaviour and expend effort, and adjustment. Thus, it was hypothesized in the present study that the neural correlates of GSE might be related to changes in the basal ganglia, which is a region related to the abovementioned self-efficacy factors. This study aimed to identify the brain structures associated with GSE in healthy young adults (n = 1204, 691 males and 513 females, age 20.7 ± 1.8 years) using regional grey matter density and volume (rGMD and rGMV), fractional anisotropy (FA) and mean diffusivity (MD) analyses of magnetic resonance imaging (MRI) data. The findings showed that scores on the GSE Scale (GSES) were associated with a lower MD value in regions from the right putamen to the globus pallidum; however, there were no significant association between GSES scores and regional brain structures using the other analyses (rGMD, rGMV, and FA). Thus, the present findings indicated that the lenticular nucleus is a neural correlate of GSE

Regional homogeneity, resting-state functional connectivity and amplitude of low frequency fluctuation associated with creativity measured by divergent thinking in a sex-specific manner

Brain connectivity is traditionally thought to be important for creativity. Here we investigated the associations of creativity measured by divergent thinking (CMDT) with resting-state functional magnetic imaging (fMRI) measures and their sex differences. We examined these relationships in the brains of 1277 healthy young adults. Whole-brain analyses revealed a significant interaction between verbal CMDT and sex on (a) regional homogeneity within an area from the left anterior temporal lobe (b) on the resting state functional connectivity (RSFC) between the mPFC and the left inferior frontal gyrus and (c) on fractional amplitude of low frequency fluctuations (fALFF) in several distinct areas, including the precuneus and middle cingulate gyrus, left middle temporal gyrus, right middle frontal gyrus, and cerebellum. These interactions were mediated by positive correlations in females and negative correlations in males. These findings suggest that greater CMDT in females is reflected by (a) regional coherence (regional homogeneity) of brain areas responsible for representing and combining concepts as well as (b) the efficient functional connection (RSFC) between the key areas for the default state of cognitive activity and speech production, and (c) greater spontaneous neural activity (fALFF) during the resting of brain areas involved in frontal lobe functions, default cognitive activities, and language functions. Furthermore, these findings suggest that the associations between creativity and resting state brain connectivity patterns are different between males and females

Ongoing Activity in Temporally Coherent Networks Predicts Intra-Subject Fluctuation of Response Time to Sporadic Executive Control Demands

<div><p>Can ongoing fMRI BOLD signals predict fluctuations in swiftness of a person’s response to sporadic cognitive demands? This is an important issue because it clarifies whether intrinsic brain dynamics, for which spatio-temporal patterns are expressed as temporally coherent networks (TCNs), have effects not only on sensory or motor processes, but also on cognitive processes. Predictivity has been affirmed, although to a limited extent. Expecting a predictive effect on executive performance for a wider range of TCNs constituting the cingulo-opercular, fronto-parietal, and default mode networks, we conducted an fMRI study using a version of the color–word Stroop task that was specifically designed to put a higher load on executive control, with the aim of making its fluctuations more detectable. We explored the relationships between the fluctuations in ongoing pre-trial activity in TCNs and the task response time (RT). The results revealed the existence of TCNs in which fluctuations in activity several seconds before the onset of the trial predicted RT fluctuations for the subsequent trial. These TCNs were distributed in the cingulo-opercular and fronto-parietal networks, as well as in perceptual and motor networks. Our results suggest that intrinsic brain dynamics in these networks constitute “cognitive readiness,” which plays an active role especially in situations where information for anticipatory attention control is unavailable. Fluctuations in these networks lead to fluctuations in executive control performance.</p></div

Distribution of response time (RT) for the Stroop task (A) and simple response task (B).

<p>Data of all subjects were concatenated.</p

All the independent components (ICs) extracted by the group ICA.

<p><i>I_q</i>: cluster quality index; MNI peak: Montreal Neurological Institute (MNI) coordinates of the highest peak position; DR: dynamic range; LH: low to high power ratio.</p><p>ICs were classified into TCNs or artifacts, and TCNs were labeled with anatomical names based on their spatial maps. AG: angular gyrus; AI: anterior insula; Amyg: amygdala; dACC: dorsal anterior cingulate cortex; dlPFC: dorsolateral prefrontal cortex; FEF: frontal eye field; FO: frontal operculum; IFG: inferior frontal gyrus; IPL: inferior parietal lobule; MFG: middle frontal gyrus; mPFC: medial prefrontal cortex; MTG: middle temporal gyrus; PCC: posterior cingulate cortex; SFG: superior frontal gyrus; SMA: supplementary motor area; SMG: supramarginal gyrus; SOG: superior occipital gyrus; SPL: superior parietal lobule; Op: operculum;</p><p>TCNs were divided into the following groups based on their spatial organization and their activation/deactivation to the task: cingulo-opercular network (CON), fronto-parietal network (FPN), default mode network (DMN), visual (VIS), auditory (AUD), sensorimotor (MOT), and subcortical (SC) networks.</p

Description of temporally coherent networks (TCNs) that were partially RT-predictive.

<p>Ten TCNs for which the activity at 0.0< <i>t</i> ≤ 3.0 s from the trial onset significantly explained response time (RT) variability. The format for composite visualization of each TCN is the same as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0099166#pone-0099166-g004" target="_blank">Figure 4</a>.</p

Functional network connectivity (FNC) between all temporally coherent networks (TCNs) for the ongoing activity time courses in the task sessions.

<p>The residual time course in each TCN of each subject was obtained by regressing out the average response from the back-reconstructed and preprocessed time course, leaving trial-to-trial fluctuation of the ongoing activity in the TCN. For each pair of TCNs, the correlation coefficient was calculated for each subject over sessions, subjected to Fisher’s <i>r</i>-to-<i>z</i> transformation, and averaged over subjects. The asterisks indicate significant connectivity over subjects (two-tailed one sample <i>t</i>-test, <i>p</i><0.001 with control of the false discovery rate [FDR] for all TCN pairs). The solid lines indicate the division of TCNs into network groups. The FNC matrices (see also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0099166#pone.0099166.s002" target="_blank">Figure S2</a>) also support the division of the FPN into dorsal and ventral parts <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0099166#pone.0099166-Kerns1" target="_blank">[64]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0099166#pone.0099166-Logan1" target="_blank">[29]</a>, as indicated by the dashed lines. See the note below <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0099166#pone-0099166-t001" target="_blank">Table 1</a> for the abbreviations.</p

Experimental paradigm.

<p>(A) The Stroop task for fMRI sessions. In each trial, subjects were required to indicate the position of a surrounding word that names the font color of the central word. All the words used were color–word incongruent. (B) Control task outside the scanner. Subjects were required to simply replicate the directions indicated by the arrows. (C) Distribution of inter-stimulus intervals (ISIs) across trials for both tasks.</p

Statistics for the response time (RT) predictivity of the nine temporally coherent networks (TCNs) at pre-trial time points (<i>t</i> = −6.0 to 0.0 s).

<p>Each cell shows the <i>t</i>-value (df = 47) of the two-tailed one sample <i>t</i>-test of the mean coefficient of RT-predictive ANCOVA model over subjects, with a braced false discovery rate (FDR)-corrected <i>p</i>-value.</p