A kinematic analysis of the association between impulsivity and manual aiming control

Hand differences in aiming task: A complementary spatial approach and analysis of dynamic brain networks with EEG

Left and right-hand exhibit differences in the execution of movements. Particularly, it has been shown that manual goal-directed aiming is more accurate with the right hand than with the left, which has been explained through the shorter time spent by the right hand in the feedback phase (FB). This explanation makes sense for the temporal aspects of the task; however, there is a lack of explanations for the spatial aspects. The present study hypothesizes that the right hand is more associated with the FB, while the left hand is more strongly associated with the pre-programming phase (PP). In addition, the present study aims to investigate differences between hands in functional brain connectivity (FBC). We hypothesize an increase in FBC of the right hand compared to the left hand. Twenty-two participants performed 20 trials of the goal-directed aiming task with both hands. Overall, the results confirm the study's hypotheses. Although the right hand stopped far from the target at the PP, it exhibited a lower final position error than the left hand. These findings imply that during the FB, the right hand compensates for the higher error observed in the PP, using the visual feedback to approach the target more closely than the left hand. Conversely, the left hand displayed a lower error at the PP than the right. Also, the right hand displayed greater FBC within and between brain hemispheres. This heightened connectivity in the right hand might be associated with inhibitory mechanisms between hemispheres.

Reduced motor planning underlying inhibition of prepotent responses in children with ADHD

To flexibly regulate their behavior, children's ability to inhibit prepotent responses arises from cognitive and motor mechanisms that have an intertwined developmental trajectory. Subtle differences in planning and control can contribute to impulsive behaviors, which are common in Attention Deficit and Hyperactivity Disorder (ADHD) and difficult to be assessed and trained. We adapted a Go/No-Go task and employed a portable, low-cost kinematic sensor to explore the different strategies used by children with ADHD or typical development to provide a prepotent response (dominant condition) or inhibit the prepotent and select an alternative one (non-dominant condition). Although no group difference emerged on accuracy levels, the kinematic analysis of correct responses revealed that, unlike neurotypical children, those with ADHD did not show increased motor planning in non-dominant compared to dominant trials. Future studies should investigate whether motor control could help children with ADHD compensate for planning difficulties. This strategy might make inhibition harder in naturalistic situations that involve complex actions. Combining cognitive and kinematic measures is a potential innovative method for assessment and intervention of subtle differences in executive processes such as inhibition, going deeper than is possible based on accuracy outcomes alone.

Self-Controlled Feedback and Learner Impulsivity in Sequential Motor Learning

Many studies have attributed self-controlled feedback benefits associated with motor learning to learners' greater information processing during practice. However, individual learner characteristics like their impulsivity can also influence how people engage cognitively during learning. We investigated possible dissociations between the types of interaction in self-controlled knowledge of results (KR) and learner impulsivity levels in learning a sequential motor task. Ninety volunteers responded to the self-restraint section of the Barkley deficits in executive functioning scale, and those 60 participants with the highest ( n = 30) and lowest ( n = 30) impulsivity scores practiced a motor task involving sequential pressing of four keys in predetermined absolute and relative times. We further divided participants into four experimental groups by assigning the high- and low-impulsivity groups to two forms of KR—self-controlled absolute and yoked. Study results showed no interaction effect between impulsivity and self-controlled KR, and, contrary to expectation, self-controlled KR did not benefit learning, independently of impulsivity. However, low-impulsivity participants performed better than high-impulsivity participants on the absolute dimension of the transfer task, while high-impulsivity learners were better at the relative dimension. Cognitive characteristics of automatic and reflexive processing were expressed by the strategies used to direct attention to relative and absolute task dimensions, respectively. Low-impulsivity learners switched their attention to both dimensions at the end of practice, while high-impulsivity learners did not switch their attention or directed it only to the relative dimension at the end of the practice. These results suggest that the cognitive styles of high- and low-impulsive learners differentially favor learning distinct dimensions of a motor task, regardless of self-controlled KR.

Translation, Adaptation, and Validation of the Brazilian Version of the Dickman Impulsivity Inventory (Br-DII)

Impulsivity has mainly been described as a negative or dysfunctional characteristic associated with several disorders. However, impulsivity is not only related to dysfunctional outcomes and may explain individual differences in optimal human functioning as well. The Dickman Impulsivity Inventory (DII) is a self-report instrument measuring both the dysfunctional and the functional aspects of impulsivity. In this study, we performed the translation and cultural adaptation of the DII to the Brazilian context and analyzed its psychometric properties. Translation and cultural adaptation followed a rigorous process, which relied on an expert panel in the cross-cultural adaptation of psychological instruments. Data from 405 undergraduate students were obtained for the Brazilian version of the DII (Br-DII). The 23 items of the Br-DII was considered unsuitable according to model fit indices of the Confirmatory Factor Analysis (both for Oblique and Orthogonal models). Exploratory Factor Analysis showed an 18 items version of the Br-DII to be suitable (CFI = 0.92; TLI = 0.90, and RMSEA = 0.057). The DII's 18 items version also showed adequate Cronbach's alpha, intraclass correlation coefficient, and convergent and discriminant validity with the BIS-11. Therefore, the Br-DII demonstrated reliability and validity in the measurement of functional and dysfunctional impulsivity.

Association between the catechol-O-methyltransferase (COMT) Val158Met polymorphism and manual aiming control in healthy subjects

BACKGROUND

Prefrontal dopamine is catabolized by the catechol-O-methyltransferase (COMT) enzyme. Current evidence suggests that the val/met single nucleotide polymorphism in the COMT gene can predict the efficiency of executive cognition in humans. Individuals carrying the val allele perform more poorly because less synaptic dopamine is available.

METHODOLOGY/PRINCIPAL FINDINGS

We investigated the influence of the COMT polymorphism on motor performance in a task that requires different executive functions. We administered a manual aiming motor task that was performed under four different conditions of execution by 111 healthy participants. Participants were grouped according to genotype (met/met, met/val, val/val), and the motor performance among groups was compared. Overall, the results indicate that met/met carriers presented lower levels of peak velocity during the movement trajectory than the val carriers, but met/met carriers displayed higher accuracy than the val carriers.

CONCLUSIONS/SIGNIFICANCE

This study found a significant association between the COMT polymorphism and manual aiming control. Few studies have investigated the genetics of motor control, and these findings indicate that individual differences in motor control require further investigation using genetic studies.

Sex differences in dimensions of impulsivity in a non-clinical sample

Impulsivity has been more closely associated with men than with women because men are more often involved in illegal behaviors. The few studies that have investigated sex differences in impulsivity have used self-report questionnaires and have obtained contradictory results. Two computerized behavioral tests were administered to 125 healthy undergraduate students (75 women, M age 23.8 yr.; 50 men, M age 25.0 yr.). Men exhibited higher scores on motor impulsivity, but there were no significant differences between men and women on attentional and non-planning impulsivity scores. These findings are discussed in terms of the relationship between impulsivity and low- and high-order control.

A kinematic analysis of manual aiming control on euthymic bipolar disorder

Motor deficits in tasks that require force steadiness or scaling of movement velocity have been found in bipolar disorder (BD). A potential explanation for these results is the abnormal functioning of the frontostriatal circuitry. We designed this study to investigate the possible impairments in a manual aiming task. Participants comprised 15 euthymic BD patients and 15 healthy controls, who performed 100 trials of a goal-directed manual movement with a non-inking pen on a digitizing tablet. Four different conditions of execution were required. The control condition appeared on the computer screen in 70% of the trials, and the other three conditions, (a) distractor, (b) inhibition of response and (c) higher index of difficulty, each appeared in 10% of the trials. Compared to the controls, the BD patients were less fluent in their movements, relied more heavily on visual feedback to control their manual movements and presented a lower spatial accuracy. We found that motor deficits in euthymic BD were observed in the kinematic analysis of manual aiming. Our findings are consistent with the hypothesis of abnormal functioning of the frontostriatal circuitry in euthymic BD.

The Iowa Gambling Task (IGT) in Brazil: a systematic review

Background: Decision-making is a complex, multidimensional cognitive function that requires the choice between two or more options and also the predictive analysis of its consequences. One of the tools most widely used to assess decision-making in neuropsychological research is the Iowa Gambling Task (IGT). Objective: To conduct a systematic review of articles reporting empirical IGT studies based in Brazil. Method: Articles were obtained from multiple journal databases including ISI Web of Knowledge, Scopus, SciELO, LILACS, and Scholar Google. Results: Thirty-six studies were included in this review and divided into four categories according to main subject matter (psychiatry & personality; demographic & cultural variables; medical/clinic; and psychometric properties & test administration standardization). In general, there was a significant growth in research employing IGT (Χ² = 17.6, df = 5, p = 0.0003), but this growth was restricted to a few geographic areas of Brazil. The psychiatry & personality subject matter was the most abundant, accounting for 14 publications (39% of the total sample). Conclusion: Since its first adaptation to Brazilian Portuguese in 2006, a growing interest in decision-making as measured by the IGT can be observed, with psychiatry & personality topics representing a large portion of the scientific inquiry to date. Nevertheless, in order to extend the initial results of Brazilian IGT decision-making research, more studies are necessary - across a more diverse range of topics, including demographic & cultural variables, and psychometric properties & test administration standardization, the areas least studied -, as is the dissemination of the IGT to more regions of the country.