Guilherme Menezes Lage

Impulsivity and the 5-HTTLPR Polymorphism in a Non-Clinical Sample

Background Impulsivity has been associated with serotonergic system functions. However, few researchers have investigated the relationship between a polymorphism in the promoter of the serotonin transporter gene (5-HTTLPR) and the different components of impulsivity in a non-clinical population. The aim of this study was to investigate the relationship between a polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) and the different components of impulsivity in a non-clinical population. Methodology/Principal Findings We administered two neuropsychological tests, the Continuous Performance Task and the Iowa Gambling Task, to 127 healthy participants to measure their levels of motor, attentional and non-planning impulsivity. Then, these participants were grouped by genotype and gender, and their scores on impulsivity measures were compared. There were no significant differences between group scores on attentional, motor and non-planning impulsivity. Conclusions/Significance Our results suggest that 5-HTTLPR genotype is not significantly associated with subsets of impulsive behavior in a non-clinical sample when measured by neuropsychological tests. These findings are discussed in terms of the sensitivity of neuropsychological tests to detect impulsivity in a non-clinical population and the role of gender and race in the relationship between the 5-HTTLPR and impulsivity.

Relative Age Effect in Olympic Taekwondo Athletes

Relative age effects refer to the effects of age differences among individuals who have been grouped together for a performance activity. This study aimed to investigate the relative age effect on Olympic Taekwondo athletes, in several Olympic Games, and in both sexes. The study sample consisted of 291 athletes who had competed in Atlanta, Sydney, and Beijing Olympic Games. The relative age effect was examined for the general distribution of athletes by quartile, for each of the individuals, and for male and female athletes. There were no discernable effects of relative age on Olympic Taekwondo athletes.

Repetition and variation in motor practice: A review of neural correlates.

Random practice results in more effective motor learning than either constant or blocked practice. Recent studies have investigated the effects of practice schedules at the neurophysiological level. This study aims to conduct a literature review of the following issues: (a) the differential involvement of premotor areas, the primary motor cortex, the dorsolateral prefrontal cortex and the posterior parietal cortex in different types of practice; (b) changes in the participation of these areas throughout practice; and (c) the degree of support that current neurophysiological findings offer to strengthen the behavioral proposition that distinct cognitive processes are generated by different practice schedules. Data from 10 studies that investigated associations between practice structures and neurobiological substrates were analyzed. The participation of the indicated areas was found to depend on practice structure and varied during the learning process. Greater cognitive engagement was associated with random practice. In conclusion, distinct neural processes are engendered by different practice conditions. The integration of behavioral and neurophysiological findings promotes a more comprehensive view of the phenomenon.

Association between the Catechol O-Methyltransferase (COMT) Val158met Polymorphism and Different Dimensions of Impulsivity

Background Impulsivity is a multidimensional construct which has been associated with dopaminergic neurotransmission. Nonetheless, until this moment, few studies addressed the relationship between different types of impulsivity and the single nucleotide polymorphism caused by a substitution of valine (val) with methionine (met) in the 158 codon of the Catechol-o-Methyltransferase gene (COMT-val158met). The present study aimed to investigate the association between val158met COMT polymorphism and impulsive behavior measured by two neuropsychological tests. Methodology/Principal Findings We administered two neuropsychological tests, a Continuous Performance Task and the Iowa Gambling Task were applied to 195 healthy participants to characterize their levels of motor, attentional and non-planning impulsivity. Then, subjects were grouped by genotype, and their scores on impulsivity measures were compared. There were no significant differences between group scores on attentional and motor impulsivity. Those participants who were homozygous for the met allele performed worse in the Iowa Gambling Task than val/val and val/met subjects. Conclusions/Significance Our results suggest that met allele of val158met COMT polymorphism is associated with poor performance in decision-making/cognitive impulsivity task. The results reinforce the hypothesis that val and met alleles of the val158met polymorphism show functional dissociation and are related to different prefrontal processes.

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

Two characteristics usually found in impulsive behavior are deficits in response inhibition and the inability to delay gratification. The former behavior is called motor impulsivity, and the second is called cognitive impulsivity. This study investigates the association of motor and cognitive impulsivity with manual aiming control. We administered two neuropsychological tests to 81 healthy participants to measure their levels of motor and cognitive impulsivity. A manual aiming motor task was also applied. Subsequently, from the initial group of 81 participants, two subgroups of 27 individuals were selected by their scores on (1) motor impulsivity and (2) cognitive impulsivity, and their motor performances were compared. While a group was comprised by the top 33.3% high-impulsive participants, the other was comprised by the bottom 33.3% low-impulsives participants. The results indicate that motor impulsivity is more related to motor control than cognitive impulsivity. Differences between motor impulsivity groups were found in the duration of the primary submovement, peak velocity, score of response inhibition errors and incorrect hits score. It was found that in situations in which the temporal and spatial demands to the motor system were high, the impulsivity had a functional, adaptive effect on motor control.

Impairment of fine motor dexterity in mild cognitive impairment and Alzheimer’s disease dementia: association with activities of daily living

Objective: Cognitive impairment is a hallmark of mild cognitive impairment (MCI) and Alzheimer’s disease dementia (AD). Although the cognitive profile of these patients and its association with activities of daily living (ADLs) is well documented, few studies have assessed deficits in fine motor dexterity and their association with ADL performance. The objective of this research paper is to evaluate fine motor dexterity performance among MCI and AD patients and to investigate its association with different aspects of ADLs. Methods: We assessed normal aging controls, patients with multiple- and single-domain amnestic MCI (aMCI), and patients with mild AD. Fine motor dexterity was measured with the Nine-Hole Peg Test and cognitive functioning by the Mattis Dementia Rating Scale. We analyzed the data using general linear models. Results: Patients with AD or multiple-domain aMCI had slower motor responses when compared to controls. AD patients were slower than those with single-domain aMCI. We found associations between cognition and instrumental ADLs, and between fine motor dexterity and self-care ADLs. Conclusion: We observed progressive slowing of fine motor dexterity along the normal aging-MCI-AD spectrum, which was associated with autonomy in self-care ADLs.

The relative age effect in combat sports: an analysis of olympic judo athletes, 1964-2012

This study assessed the relative age effect (RAE) in judo athletes who participated in the Olympic Games from 1964 to 2012. The names and birth-dates of the Olympic judo athletes were collected from open-access websites. Data from male (n = 1,762) and female (n = 665) competitors were analyzed separately. Chi-squared tests were performed to investigate REA in medalists, and by weight categories and sexes. When the analyses used semesters to divide the period when the athletes were born, a RAE was found in male heavyweight athletes and male medallists. Thus, in a selected group of judo athletes who had participated at the highest competitive level, RAEs were present in both athletes who won Olympic medals and heavyweight athletes in the male group.

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.

Sensorimotor performance in euthymic bipolar disorder: the MPraxis (PennCNP) analysis

BACKGROUND Sensorimotor deficits are an important phenomenological facet observed in patients with bipolar disorder (BD). However, there is little research on this topic. We hypothesize that the MPraxis test can be used to screen for motor impairments in BD aiming movements. METHOD The MPraxis, which is a quick and easy-to-apply computerized test, measures sensorimotor control. During the test, the participant must move the computer mouse cursor over an ever-shrinking green box and click on it once. We predict that the MPraxis test is capable of detecting differences in sensorimotor performance between patients with BD and controls. We assessed 21 euthymic type I BD patients, without DSM-IV-TR Axis I comorbidity, and 21 healthy controls. RESULTS AND CONCLUSIONS Compared to the controls, the patients with BD presented a lower response time in their movements in all conditions. Our results showed sensorimotor deficits in BD and suggested that the MPraxis test can be used to screen for motor impairments in patients with euthymic BD.

Atividade física e desempenho em tarefas de funções executivas em idosos saudáveis: dados preliminares

CONTEXTO: A atividade fisica parece exercer um efeito positivo sobre varios processos cognitivos em idosos. Entretanto, pouco se sabe sobre o impacto da atividade fisica sequencial, como a danca, sobre as funcoes executivas dos idosos. OBJETIVO: Avaliar a relacao entre o tipo de atividade fisica praticada e o desempenho em tarefas de funcoes executivas em idosos. METODOS: Participaram do estudo 35 idosos entre 60 e 69 anos de idade. O grupo controle (GC) foi composto por idosos sedentarios; o grupo ativos (GA) foi composto por idosos praticantes de atividade fisica; o grupo danca (GD) foi composto por idosos praticantes de atividade fisica identica ao GA acrescido da pratica de danca senior. Apos uma triagem inicial, todos os participantes foram submetidos a testes de funcoes executivas. RESULTADOS: Comparado aos demais grupos, o GD apresentou melhor desempenho em termos de (1) planejamento, medida essa observada no teste da Torre de Londres e (2) controle inibitorio, por meio do teste de Stroop. CONCLUSOES: Os resultados preliminares encontrados sugerem uma especificidade da atividade fisica sobre o desempenho de determinadas funcoes executivas. A perspectiva e de que com uma maior amostra esses achados sejam mantidos.