Biomedical subjects

Karen Davranche

Publications and source records attributed to Karen Davranche.

5 recordsLinked to original sources

PubMed2006

Physical exercise facilitates motor processes in simple reaction time performance: an electromyographic analysis.

The aim of the current study was to assess the effects of physical exercise on simple reaction time performance. Participants performed a simple reaction time task twice, one time during physical exercise and another time without exercise. Electromyographic signals were recorded from the thumb of the responding hand to fraction reaction time in pre-motor and motor time. The results showed that exercise shortened motor time but failed to affect pre-motor time. This pattern of findings is consistent with previous studies examining the effects of physical exercise on choice reaction time.

Adult↗

PubMed2006

A distributional analysis of the effect of physical exercise on a choice reaction time task.

The aim of this study was to examine the facilitating effects of physical exercise on the reaction process. Eleven participants with specific expertise in decision-making sports performed a choice reaction time task during moderate sub-maximal exercise (90% of their ventilatory threshold power). Participants were tested at rest and while cycling. During exercise, the participants were faster, without being more variable. We suggest that the effect of exercise on cognitive performance was due to a major generalized improvement of the whole distribution of response time and, although the benefit effect was small, it was consistent throughout the entire range of reaction times.

Adult↗

PubMed2005

Information processing during physical exercise: a chronometric and electromyographic study.

Choice reaction time (RT) is shorter when participants perform a choice task at the same time as a sub-maximal exercise than when they are at rest. The purpose of the present study was to determine whether such an exercise affects response execution or whether it alters processes located upstream from the neuro-muscular level. To this end, the electromyographic (EMG) activity of the response agonists was analysed in a between-hand choice RT task performed either concurrently with a pedalling task or at rest. Visual stimulus intensity was also manipulated so as to determine whether exercise further affects early sensory processes. Results shows that exercise affected the time interval elapsing from the onset of the contraction of the response agonists to the mechanical response, thereby indicating that this variable modifies the peripheral motor processes involved in response execution. EMG signal analyses further revealed that the cortico-spinal command is more efficient during exercise than at rest. In addition, exercise was shown to interact with visual stimulus intensity on the time between stimulus and voluntary EMG onset and to increase the critical flicker fusion frequency threshold, thereby indicating that exercise modifies the peripheral sensory processes involved in early sensory operations. The decomposition of RT, with respect to the EMG activity of response agonists, sheds light on the processes affected by exercise and suggests that exercise affects both sensory processes and late motor processes.

Adult↗

PubMed2004

Facilitating effects of exercise on information processing.

The aim of this study was to examine the facilitating effects of moderate physical exercise on the reaction process to gain a better understanding of the interaction between physiological and cognitive processes. Sixteen participants with specific expertise in decision-making sports performed a double task consisting of choice reaction time while cycling. Signal quality, stimulus-response compatibility and time uncertainty were manipulated. Participants were tested at rest and while cycling at 20% and at 50% of their maximal aerobic power. A mood assessment questionnaire and a critical flicker fusion test were administered before and after the choice reaction time task. The results showed that moderate-intensity exercise (50% maximal aerobic power) improves cognitive performance and that low-intensity exercise (20% maximal aerobic power) enables participants to compensate the negative dual-task effect.

Adult↗

PubMed2002

Effects of a low dose of transdermal nicotine on information processing.

The objective of this research was to assess the effect of a low dose of nicotine (7 mg/24 h), administered through a transdermal device, on the cognitive processes of subjects who were slightly dependent smokers. Sixteen smokers were chosen as subjects using a French version of Fagerström's Test of Nicotine Dependence. Under suboptimal alertness conditions the subjects were faced with a choice reaction time (CRT) task. Two conditions of signal quality (intact or degraded) and two conditions of fore period (FP) (short or long) were used during two different experimental sessions (nicotine or placebo). At the same time, the subjects filled in a mood questionnaire and took part in a critical flicker fusion (CFF) determination test. The results obtained suggest that nicotine improves the subjective state of alertness of the subjects and enables them, despite the suboptimal state, to maintain a constant performance level during a CRT task. Neither an effect of nicotine on the CFF nor any interaction between the nicotine, the signal quality or the duration of the FP were observed. The conclusion to be drawn from the results is that nicotine has an enabling effect, but the results do not allow the determination of the precise site of this effect among the different stages of information processing.

Administration, Cutaneous↗