Association between hemodynamic activity and motor performance in six-month-old full-term and preterm infants: a functional near-infrared spectroscopy study.

This study aimed to assess task-induced activation in motor cortex and its association with motor performance in full-term and preterm born infants at six months old. A cross-sectional study of 73 six-month-old infants was conducted (35 full-term and 38 preterm infants). Motor performance was assessed using the Bayley Scales of Infant Development third edition-Bayley-III. Brain hemodynamic activity during motor task was measured by functional near-infrared spectroscopy (fNIRS). Motor performance was similar in full-term and preterm infants. However, differences in hemodynamic response were identified. Full terms showed a more homogeneous unilateral and contralateral activated area, whereas in preterm-born the activation response was predominantly bilateral. The full-term group also exhibited a shorter latency for the hemodynamic response than the preterm group. Hemodynamic activity in the left sensorimotor region was positively associated with motor performance measured by Bayley-III. The results highlight the adequacy of fNIRS to assess differences in task-induced activation in sensorimotor cortex between groups. The association between motor performance and the hemodynamic activity require further investigation and suggest that fNIRS can become a suitable auxiliary tool to investigate aspects of neural basis on early development of motor abilities.

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.

The 5-HTTLPR polymorphism, impulsivity and suicide behavior in euthymic bipolar patients.

BACKGROUND: Suicide behavior is very frequent in Bipolar Disorder (BD) and they are both closely associated with impulsivity. Furthermore they are, impulsivity, BD and suicide behavior, associated with serotonergic function, at least partially, under genetic determinism and somewhat associated with the serotonin transporter gene polymorphism, the 5-HTTLPR. We aimed to assess different impulsivity components in BD sub-grouped by suicidal attempt and healthy controls. We hypothesized that the non-planning/cognitive impulsivity, could be more closely associated with suicidal behavior. We further associated 5-HTTLPR genotypes with neuropsychological results to test the hypothesis that this polymorphism is associated with cognitive impulsivity. METHOD: We assessed 95 euthymic bipolar patients sub-grouped by suicidal attempt history in comparison with 94 healthy controls. All subjects underwent a laboratory assessment of impulsivity (Continuous Performance Test and Iowa Gambling Test). Furthermore the genotyping of 5-HTTLPR was performed in all subjects. RESULTS: We found that bipolar patients are more impulsive than healthy controls in all impulsivity dimensions we studied. Furthermore bipolar patients with a suicide attempt history have a greater cognitive impulsivity when compared to both bipolar patients without such a history as well when compared to healthy controls. No association was found between 5-HTTLPR genotypes and neuropsychological measures of impulsive behavior. LIMITATIONS: The sample studied can be considered small and a potentially confounding variable - medication status - was not controlled. CONCLUSION: A lifetime suicide attempt seems associated with cognitive impulsivity independently of the socio-demographic and clinical variables studied as well with 5-HTTLPR genotype. Further studies in larger samples are necessary.