The role of frontal and parietal cortex in the performance of gifted and average adolescents in a mental rotation task

The spectral profile of cortical activation during a visuospatial mental rotation task and its correlation with working memory

Introduction

The search for a cortical signature of intelligent behavior has been a longtime motivation in Neuroscience. One noticeable characteristic of intelligence is its association with visuospatial skills. This has led to a steady focus on the functional and structural characteristics of the frontoparietal network (FPN) of areas involved with higher cognition and spatial behavior in humans, including the question of whether intelligence is correlated with larger or smaller activity in this important cortical circuit. This question has broad significance, including speculations about the evolution of human cognition. One way to indirectly measure cortical activity with millisecond precision is to evaluate the event-related spectral perturbation (ERSP) of alpha power (alpha ERSP) during cognitive tasks. Mental rotation, or the ability to transform a mental representation of an object to accurately predict how the object would look from a different angle, is an important feature of everyday activities and has been shown in previous work by our group to be positively correlated with intelligence. In the present work, we evaluate whether alpha ERSP recorded over the parietal, frontal, temporal, and occipital regions of adolescents performing easy and difficult trials of the Shepard–Metzler’s mental rotation task, correlates or are predicted by intelligence measures of the Weschler’s intelligence scale.

Methods

We used a database obtained from a previous study of intellectually gifted (N = 15) and average intelligence (N = 15) adolescents.

Results

Our findings suggest that in challenging task conditions, there is a notable difference in the prominence of alpha event-related spectral perturbation (ERSP) activity between various cortical regions. Specifically, we found that alpha ERSP in the parietal region was less prominent relative to those in the frontal, temporal and occipital regions. Working memory scores predict alpha ERSP values in the frontal and parietal regions. In the frontal cortex, alpha ERSP of difficult trials was negatively correlated with working memory scores.

Discussion

Thus, our results suggest that even though the FPN is task-relevant during mental rotation tasks, only the frontal alpha ERSP is correlated with working memory score in mental rotation tasks.

Interhemispheric asymmetry profile and cognitive functions in adolescents with average and high intelligence

Background. The neuropsychological approach suggests that differences in cognitive processes are associated with the variability of combinations of signs of partial dominance of certain brain structures, manifested in the form of individual laterality profiles. However, the problem of identifying and studying the relationship between interhemispheric asymmetry and cognitive functions in adolescents with a high level of intelligence remains not fully resolved, which determines the relevance of this study.The aim of the research was to describe the relationship between the type of profile of interhemispheric asymmetry with the characteristics of cognitive functions in adolescents with average and high levels of intelligence.Materials and methods. The sample included 52 people aged 12–15 years: 26 adolescents with high level intelligence (main group), 26 adolescents with an average level of intelligence (control group). The following research methods were used: Wechsler test (WISC-IV), method for studying the profile of interhemispheric asymmetry (Khomskaya E.D., Efimova I.V.); method “Correction test” by B. Bourdon; method ”Story on a given topic”.Results. The majority of adolescents with a high level of intelligence revealed the severity of right-lateral features, which were traced in the manual, auditory and visual spheres of sensorimotor asymmetry. At the same time, the severity of right-lateral and ambilateral features is accompanied by more pronounced indicators of the development of cognitive functions. Adolescents with the type of profile of interhemispheric asymmetry “Left-handed” were characterized by an insufficient level of attention stability and a reduced ability for detailed speech utterance, regardless of the level of intelligence.Conclusions. The data obtained show that the peculiarity of individual profiles of interhemispheric asymmetry determines the uneven development of a number of mental functions in adolescence and the different readiness of brain mechanisms to support various cognitive processes. We assume that the results of the work will expand the understanding of the role of interhemispheric asymmetry of the brain in the organization of cognitive functions in adolescents with a high level of intelligence.

Enhanced effective connectivity from the middle frontal gyrus to the parietal lobe is associated with impaired mental rotation after total sleep deprivation: An electroencephalogram study

Sleep deprivation impairs cognitive functions, including attention, memory, and decision-making. Studies on the neuro-electro-physiological mechanisms underlying total sleep deprivation (TSD) that impairs spatial cognition are limited. Based on electroencephalogram (EEG) and Exact Low Resolution Brain Electromagnetic Tomography (eLORETA), this study focused on the effects of TSD on mental rotation and the cognitive neural mechanisms underlying its damage. Twenty-four healthy college students completed mental rotation tasks while resting and after 36 h of TSD; their EEG data were simultaneously recorded. The amplitude of P300 component associated with mental rotation was observed and localized through source reconstruction, while changes in effective connectivity between multiple brain regions associated with mental rotation cognitive processing were calculated using isolated effective coherence (iCoh) of eLORETA. Compared with the baseline before TSD, the amplitude of the P300 component related to mental rotation decreased. The task-state data of P300 were localized to the source of the difference in ERP current density, and it was found that the brain regions related to the difference in the decrease in P300 amplitude included the superior parietal lobule, precuneus, prefrontal lobe, and other related regions. Effective connectivity analysis found that TSD enhanced the effective connectivity from the left middle frontal gyrus to the left superior parietal lobule, left inferior parietal lobule, and left precuneus under the identical condition. Pearson correlation analysis showed a positive correlation between the decrease in accuracy of mental rotation and increase in effective connectivity. Thus, our study suggests that TSD impairs the ability of the mental rotation, showing a decrease in P300 amplitude and an enhanced effective connectivity between the middle frontal gyrus and the parietal lobe in the task state.

Task-domain and hemisphere-asymmetry effects in cisgender and transmale individuals

The present research examined the extent to which transmale individuals’ functional brain organization resembles that of their assigned sex or gender identity. Cisgender-female, cisgender-male, and transmale participants, who were assigned female sex but did not have a female gender identity, were compared in terms of effects that have been observed in cisgender individuals: task-domain effects, in which males perform better than females on spatial tasks and females perform better than males on verbal tasks; and hemisphere-asymmetry effects, in which males show larger differences between the left and right hemispheres than females. In addition, the present research measured participants’ intelligence in order to control for potential moderating effects. Participants performed spatial (mental rotation) and verbal (lexical decision) tasks presented to each hemisphere using a divided-visual field paradigm, and then completed an intelligence assessment. In the mental-rotation task, cismale and transmale participants performed better than cisfemale participants, however this group difference was explained by intelligence scores, with higher scores predicting better performance. In the lexical-decision task, cismale and transmale participants exhibited a greater left-hemisphere advantage than cisfemales, and this difference was not affected by intelligence scores. Taken together, results do not support task-domain effects when intelligence is accounted for; however, they do demonstrate a hemisphere-asymmetry effect in the verbal domain that is moderated by gender identity and not assigned sex.