Cerebral blood flow during rest associates with general intelligence and creativity

White matter structures associated with empathizing and systemizing in young adults

Empathizing is defined as the drive to identify the mental states of others in order to predict their behavior and respond with an appropriate emotion. Systemizing is defined as the drive to analyze a system in terms of the rules that govern it to predict its behavior. We undertook voxel-by-voxel investigations of regional white matter volume (rWMV) and fractional anisotropy (FA) of diffusion tensor imaging to discover the WM structural correlates of empathizing, systemizing, and their difference (D score: systemizing-empathizing). Whole brain analyses of covariance revealed that across both sexes, the D score was negatively correlated with rWMV in the WM area in the bilateral temporal lobe, near the right inferior frontal gyrus, near the ventral medial prefrontal cortex, and near the posterior cingulate cortex and positively correlated with FA in an area involving the superior longitudinal fasciculus. Post-hoc analyses revealed that these associations were generally formed by both the correlation between WM structures and empathizing as well as the opposite correlation between WM structures and systemizing. A significant effect of interaction between sex and the D score on rWMV, which was mainly observed because of a positive correlation between rWMV and empathizing in females and a negative correlation between rWMV and systemizing in females, was found in an area close to the right inferior parietal lobule and temporoparietal junction. Our results suggest that WM structures involving the default mode network and the mirror neuron system support empathizing, and that a WM structure relating to the external attention system supports systemizing. Further, our results revealed an overlap between positive/negative WM structural correlates of empathizing and negative/positive WM structural correlates of systemizing despite little correlation between empathizing and systemizing, which supports the previously held idea that there is a trade-off between empathizing and systemizing in the brain.

Regional gray matter density is associated with achievement motivation: evidence from voxel-based morphometry

Achievement motivation can be defined as a recurrent need to improve one's past performance. Despite previous functional imaging studies on motivation-related functional activation, the relationship between regional gray matter (rGM) morphology and achievement motivation has never been investigated. We used voxel-based morphometry and a questionnaire (achievement motivation scale) to measure individual achievement motivation and investigated the association between rGM density (rGMD) and achievement motivation [self-fulfillment achievement motivation (SFAM) and competitive achievement motivation (CAM) across the brain in healthy young adults (age 21.0 ± 1.8 years, men (n = 94), women (n = 91)]. SFAM and rGMD significantly and negatively correlated in the orbitofrontal cortex (OFC). CAM and rGMD significantly and positively correlated in the right putamen, insula, and precuneus. These results suggest that the brain areas that play central roles in externally modulated motivation (OFC and putamen) also contribute to SFAM and CAM, respectively, but in different ways. Furthermore, the brain areas in which rGMD correlated with CAM are related to cognitive processes associated with distressing emotions and social cognition, and these cognitive processes may characterize CAM.

The rCBF brain mapping in adolescent ADHD comorbid developmental coordination disorder and its changes after MPH challenging

BACKGROUND

Comorbid developmental coordination disorder (DCD) in the patients with attention-deficit hyperactivity disorder (ADHD) often complicated the treatment strategy. Methylphenidate (MPH) improves the coordination problem in patients with ADHD.

AIM

The study intended to investigate the pathophysiology and the mechanisms of MPH in comorbid DCD of the adolescents with ADHD.

METHODS

Brain images using technetium-99m ethyl cysteinate dimmer ((99m)Tc-ECD) single photon emission computed tomography (SPECT) were done in 10 drug-naïve adolescents with ADHD without DCD and 5 adolescents with ADHD comorbid DCD. The baseline rCBF and changes of rCBF after 10 mg MPH challenge between two groups were compared using statistical parametric mapping (SPM99) analysis.

RESULTS

Lower rCBF of bilateral frontal lobe, inferior parental lobe, and increased rCBF of right posterior cingulate gyrus, anterior lobe of cerebellum were found in ADHD comorbid DCD group compared to ADHD without DCD group. Decreased rCBF in the right occipital, inferior temporal lobe was found in ADHD comorbid DCD group after MPH while ADHD alone group revealed increased rCBF in bilateral occipital lobe.

CONCLUSIONS

The results help us understand the pathophysiology of DCD in ADHD adolescents. The different rCBF response to MPH provides a clue for future intervention of DCD in ADHD adolescents.

Effects of working memory training on functional connectivity and cerebral blood flow during rest

Working memory (WM) training (WMT) alters the task-related brain activity and structure of the external attention system (EAS). We investigated whether WMT also alters resting-state brain mechanisms, which are assumed to reflect intrinsic brain activity and connectivity. Our study subjects were subjected to a 4-week WMT program and brain scans before and after the intervention for determining changes of functional connectivity and regional cerebral blood flow during rest (resting-FC/resting-rCBF). Compared with no-intervention, WMT (a) increased resting-FC between the medial prefrontal cortex (mPFC) and precuneus, which are key nodes of the default mode network (DMN), (b) decreased resting-FC between mPFC and the right posterior parietal cortex/right lateral prefrontal cortex (LPFC), which are key nodes of the EAS, and (c) increased resting-rCBF in the right LPFC. However, the training-related decreases in resting-FC between the key DMN node and the nodes of EAS were only observed when the whole brain signal was regressed out in individual analyses, and these changes were not observed when the whole brain signal was not regressed out in individual analyses. Further analyses indicated that these differences may be mediated by a weak but a widespread increase in resting-FC between the nodes of EAS and activity of multiple bilateral areas across the brain. These results showed that WMT induces plasticity in neural mechanisms involving DMN and the EAS during rest and indicated that intrinsic brain activity and connectivity can be affected by cognitive training.

A voxel-based morphometry study of gray and white matter correlates of a need for uniqueness

People appear to derive intrinsic satisfaction from the perception that they are unique, special, and separable from the masses, which is referred to as a need for uniqueness (NFU). NFU is a universal human trait, along with a tendency to conform to the beliefs and attitudes of others and social norms. We used voxel-based morphometry and a questionnaire to determine individual NFU and its association with brain structures in healthy men (94) and women (91; age, 21.3 ± 1.9 years). Individual NFU was associated with smaller gray matter volume of a cluster that included areas in (a) the left middle temporal gyrus, left superior temporal gyrus, and left superior temporal sulcus (STS); (b) the dorsal part of the anterior cingulate gyrus and the anterior part of the middle cingulate gyrus; and (c) the right inferior frontal gyrus and the ventral part of the precentral gyrus. Individual NFU was also associated with larger white matter concentration of a cluster that mainly included the body of the corpus callosum. These findings demonstrated that variations in NFU reflect the gray and white matter structures of focal regions. These findings suggest a biological basis for individual NFU, distributed across different gray and white matter areas of the brain.

Evidence for a left-over-right inhibitory mechanism during figural creative thinking in healthy nonartists

As a complex mental process, creativity requires the coordination of multiple brain regions. Previous pathological research on figural creativity has indicated that there is a mechanism by which the left side of the brain inhibits the activities of the right side of the brain during figural creative thinking, but this mechanism has not been directly demonstrated. In this study, we used functional magnetic resonance imaging (fMRI) to demonstrate the existence of this inhibitory mechanism in young adults (15 women, 11 men, mean age: 22 years) that were not artists. By making comparisons between brain activity during creative and uncreative tasks, we found increased activity in the left middle and inferior frontal lobe and strong decreases in activity in the right middle frontal lobe and the left inferior parietal lobe. As such, these data suggest that the left frontal lobe may inhibit the right hemisphere during figural creative thinking in normal people. Moreover, removal of this inhibition by practicing artistry or through specific damage to the left frontal lobe may facilitate the emergence of artistic creativity.

The association between resting functional connectivity and creativity

The analysis of functional connectivity at rest (rFC) enables us to know how brain regions within and between networks interact. In this study, we used resting-state functional magnetic resonance imaging and a creativity test of divergent thinking (DT) to investigate the relationship between creativity measured by DT and rFC. We took the medial prefrontal cortex (mPFC) to be the seed region and investigated correlations across subjects between the score of the DT test and the strength of rFC between the mPFC and other brain regions. Our results showed that the strength of rFC with the mPFC significantly and positively correlated with creativity as measured by the DT test in the posterior cingulate cortex (PCC). These results showed that higher creativity measured by DT is associated with rFC between the mPFC and the PCC, the key nodes of the default mode network (DMN). Increased rFC between these regions is completely opposite from that is generally expected from the association between higher creativity and reduced deactivation in DMN during an externally directed attention-demanding task shown in our previous study but is similar to the pattern seen in relatives of schizophrenia. These findings are comparable to the previously reported psychological associations between schizotypy and creativity.

Regional gray and white matter volume associated with Stroop interference: evidence from voxel-based morphometry

During Stroop tasks, subjects experience cognitive interference when they resolve interferences such as identifying the ink color of a printed word while ignoring the word's identity. Stroop paradigms are commonly used as an index of attention deficits and a tool for investigating the functions of the frontal lobes and other associated structures. Despite these uses and the vast amount of attention given to Stroop paradigms, the regional gray matter volume/regional white matter volume (rGMV/rWMV) correlates of Stroop interference have not yet been identified at the whole brain level in normal adults. We examined this issue using voxel-based morphometry in right-handed healthy young adults. We found significant negative relationships between the Stroop interference rate and rGMV in the anterior cingulate cortex (ACC), right inferior frontal gyrus, and cerebellum. Furthermore, we found relationships between the Stroop interference rate and rWMV in bilateral anatomical clusters that extended around extensive WM regions in the dorsal part of the frontal lobe. These findings are the first to reveal rGMV/rWMV that underlie the performance of the Stroop task, a widely used psychological paradigm at the whole brain level. Of note, our findings support the notion that ACC contributes to Stroop performance and show the involvement of regions that have been implicated in response inhibition and attention.