Cortical motor areas are activated early in a characteristic sequence during post-movement processing

Movement time differentiates extraverts from introverts

Five experiments investigated whether cognitively based spatial S-R correspondence effects or “compatibility” effects can occur in simple reaction time (SRT) tasks and if so, which factors might be responsible for their occurrence and size. In Experiment 1, responses were cued before each trial, but made only after presentation of a Go signal. There were considerably faster responses with spatial correspondence of Go signal and response, demonstrating that response certainty does not prevent a compatibility effect. Experiment 2, a SRT task with “extra” trials requiring responses with the same or the opposite hand, indicated a major determinant of this effect to be the keeping of two task-relevant responses in a state of readiness. Experiment 3 provided preliminary evidence for “inertia” effects—that is, for stronger correspondence effects with frequent than with infrequent alternations between left-hand and right-hand blocks. Experiment 4 showed that correspondence effects can be obtained by using a within-hand response repertoire. Experiment 5, a replication of Experiment 3 with within-hand responses, found further evidence for inertia effects. For all experiments, reaction time distribution analyses were carried out to gain insight into the temporal dynamics of correspondence effects. Altogether the results strongly suggest that most if not all correspondence effects had a cognitive rather than an anatomical origin. This raises some doubts about conclusions from prior attempts to measure interhemispheric transmission costs by means of SRT tasks.

The purpose of this study was to test the hypothesis that an increase in the number of alternatives in the choice reaction time task would lengthen the reaction time in the inunediately preceding simple reaction time task because of higher attentional preparation demand. The simple reaction time task involved an auditory click and was performed between the warning light and the visual choice reaction time task. The hypothesis was confirmed. The increase in simple reaction time as a function of information load of the subsequent choice reaction time task was explained in terms of an increased amount of conunitment of limited-capacity attentional system and was interpreted as signifying that there is at least partial parallel processing of the two tasks. The relation of these results to some recent data on the effect of expectancy and limited-capacity short-term memory was discussed.

BackgroundConverging evidence comparing barefoot (BF) and shod (SH) running highlights differences in foot-strike patterns and somatosensory feedback, among others. Anecdotal evidence from SH runners attempting BF running suggests a greater attentional demand may be experienced during BF running. However, little work to date has examined whether there is an attentional cost of BF versus SH running.ObjectiveThis exploratory study aimed to examine whether an acute bout of BF running would impact simple reaction time (SRT) compared to SH running, in a sample of runners naïve to BF running.MethodsEight male distance runners completed SRT testing during 10 min of BF or SH treadmill running at 70% maximal aerobic speed (17.9 ± 1.4 km h−1). To test SRT, participants were required to press a hand-held button in response to the flash of a light bulb placed in the center of their visual field. SRT was tested at 1-minute intervals during running. BF and SH conditions were completed in a pseudo-randomized and counterbalanced crossover fashion. SRT was defined as the time elapsed between the light bulb flash and the button press. SRT errors were also recorded and were defined as the number of trials in which a button press was not recorded in response to the light bulb flash.ResultsOverall, SRT later in the exercise bouts showed a statistically significant increase compared to earlier (p < 0.05). Statistically significant increases in SRT were present at 7 min versus 5 min (0.29 ± 0.02 s vs. 0.27 ± 0.02 s, p < 0.05) and at 9 min versus 2 min (0.29 ± 0.03 s vs. 0.27 ± 0.03 s, p < 0.05). However, BF running did not influence this increase in SRT (p > 0.05) or the number of SRT errors (17.6 ± 6.6 trials vs. 17.0 ± 13.0 trials, p > 0.05).DiscussionIn a sample of distance runners naïve to BF running, there was no statistically significant difference in SRT or SRT errors during acute bouts of BF and SH running. We interpret these results to mean that BF running does not have a greater attentional cost compared to SH running during a SRT task throughout treadmill running. Literature suggests that stride-to-stride gait modulation during running may occur predominately via mechanisms that preclude conscious perception, thus potentially attenuating effects of increased somatosensory feedback experienced during BF running. Future research should explore the present experimental paradigm in a larger sample using over-ground running trials, as well as employing different tests of attention.

BackgroundThe aim of the study was to assess the attentional requirements of steady state treadmill walking in human subjects using a dual task paradigm. The extent of decrement of a secondary (cognitive) RT task provides a measure of the attentional resources required to maintain performance of the primary (locomotor) task. Varying the level of difficulty of the reaction time (RT) task is used to verify the priority of allocation of attentional resources.Methods11 healthy adult subjects were required to walk while simultaneously performing a RT task. Participants were instructed to bite a pressure transducer placed in the mouth as quickly as possible in response to an unpredictable electrical stimulation applied on the back of the neck. Each subject was tested under five different experimental conditions: simple RT task alone and while walking, recognition RT task alone and while walking, walking alone. A foot switch system composed of a pressure sensitive sensor was placed under the heel and forefoot of each foot to determine the gait cycle duration.ResultsGait cycle duration was unchanged (p > 0.05) by the addition of the RT task. Regardless of the level of difficulty of the RT task, the RTs were longer during treadmill walking than in sitting conditions (p < 0.01) indicating that an increased amount of resources are required for the maintainance of walking performance on a treadmill at a steady state. No interaction (p > 0.05) was found between the attentional demand of the walking task and the decrement of performance found in the RT task under varying levels of difficulty. This finding suggests that the healthy subjects prioritized the control of walking at the expense of cognitive performance.ConclusionWe conclude that treadmill walking in young adults is not a purely automatic task. The methodology and outcome measures used in this study provide an assessment of the attentional resources required by walking on the treadmill at a steady state.

Does hypnotic susceptibility influence information processing speed and motor cortical preparatory activity?

Reaction times and anticipatory skills of karate athletes

The fronto-cerebellar functional network has been proposed to subserve cognitive processing speed. This study aims to elucidate how the long-range frontal-to-cerebellar effective connectivity contributes to faster speed. In total, 60 healthy participants were randomly allocated to three five-daily sessions of transcranial magnetic stimulation conditions, namely intermittent theta-burst stimulation (iTBS, excitatory), continuous theta-burst stimulation (CTBS, inhibitory), or a sham condition. The sites of the stimulations were the right pre-supplementary motor area (RpSMA), medial cerebellar vermis VI (MCV6), and vertex, respectively. Performances in two reaction time tasks were recorded at different time points. Post-stimulation speeds revealed marginal decreases in the simple but not complex task. Nevertheless, participants in the excitatory RpSMA and inhibitory MCV6 conditions showed direct and negative path effects on faster speeds compared to the sham condition in the simple reaction time (SRT) task (β = -0.320, p = 0.045 and β = -0.414, p = 0.007, respectively). These path effects were not observed in the SDMT task. RpSMA and MCV6 were involved in promoting the path effects of faster reaction times on simple cognitive task. This study offers further evidence to support their roles within the long-range frontal-to-cerebellar connectivity subserving cognitive processing speed. The enhancement effects, however, are likely limited to simple rather than complex mental operations.

Ear differences in simple reaction time: The influence of attentional factors

Patients with Parkinson's disease exhibit a number. of abnormalities that seem more marked in circumstances in which stimulus and response are predictable in advance. In this article, we consider the prolonged movement onset latencies exhibited by Parkinsonian subjects in the tracking of predictable targets and in the simple reaction time (RT) task. It has been suggested that the performance impairments on both these tasks stem from a common planning deficit. We argue that the Parkinsonian tendency to refrain from predictive tracking cannot be ascribed to an inability to anticipate due to a planning deficit. The data are better accommodated by our alternative thesis that when Parkinsonians' response initiation lags behind that of normal subjects, this is a result of a strategic adaptation to an impairment of the accuracy of movements guided by an internal representation of the target. Our conclusion, that the primary impairment of predictive tracking is one of inaccurate movement execution rather than delayed response initiation, precludes postulation of the same deficit as a source of the selective prolongation of simple RT sometimes found in Parkinson's disease. Moreover, an analysis of the processing demands of the two tasks shows that the predictability that characterizes each of them is quite different in nature. Hence, the impairments in predictive tracking and simple RT tasks are unlikely to stem from a single mechanism that is defective in Parkinson's disease.

It remains unclear whether activation kinetics in the motor cortex area is affected by training. The purpose of the present study was to examine the effect of training on the motor cortex activation. To accomplish this, the correlation between maximal voluntary contraction and motor cortex (M1) activity was examined. Differences in the motor cortex activation between two groups during exercise were examined in 14 male volunteer participants (M age 25.2 yr., SD = 1.4): seven highly trained athletes (VO2max = 60 ml/kg/min.; maximal voluntary contraction > 55 kg, M MVC = 63.6 kg, SD = 4.2) and seven nonathletes (VO2max < 45 ml/ kg/min.; MVC < 50.0 kg, M MVC = 4 3.5 kg, SD = 5.2). Participants were familiarized with the study protocol during which they performed a maximal voluntary static handgrip test. Specifically, M1 activation was measured by near-infrared spectroscopy throughout a handgrip exercise in which participants performed a sustained middle-intensity handgrip exercise (50% of maximal voluntary contraction) until voluntary exhaustion. In the Athlete group, activation in the M1 at voluntary exhaustion fell below the resting value. In the Nonathlete group, activation in the M1 was elevated throughout the exercise. Results suggest that motor signals from the motor cortex area correlate with exercise training status, especially during fatiguing exercise.

P.3.c.025 Change of cognitive functions in switching of risperidone for chronic schizophrenic patients

Aim:The purpose of this comparative study was to evaluate cognitive function in end-stage renal disease (ESRD) patients in comparison with age, sex, and level of education-matched control.Materials and Methods:This is a cross-sectional study involving 80 ESRD patients receiving maintenance hemodialysis treatment and recruited conservatively at the nephrology unit of our hospital. Eighty apparently healthy control, that were matched with the patients for age, sex and education, were also recruited. Following exclusion of depression and severe functional disability, a computer-assisted neuropsychological test, the FePsy, was used to assess memory, psychomotor speed, concentration and attention using simple auditory and visual reaction time tasks, recognition memory tests (RMTs), finger tapping task, and binary choice task (BCT) for both the ESRD patients and controls.Results:ESRD patients performed worse on simple auditory and visual reaction time tasks (P < 0.05), RMTs (P < 0.05), finger tapping task (P < 0.05), BCT, and computerized visual search task (P < 0.05).Conclusion:Performance in memory, psychomotor tasks, concentration, and attention tasks were found to be reduced among patients with ESRD compared with age, sex and level of education-matched control.

The influence of set on a simple reaction time task was examined by comparing the differences of psychological factors between a group of subjects who expected and experienced a fixed foreperiod Control condition: 12 subjects) and another group of subjects who were instructed to expect variable foreperiods but experienced the same fixed foreperiod (Instruction condition: 11 subjects), using the index of contingent negative variation (CNV). The foreperiod of simple reaction time task in each condition was fixed at 3 sec. Subjects were required to respond to 2 blocks of 24 trials, and each instruction was presented between blocks. On the second block CNV amplitudes were higher in the instruction condition as was every CNV component (early late, and whole component). The set created by anticipating variable foreperiods seems to increase cerebral activity, arousal, and attention during simple reaction time tasks.

Performance on some complex and difficult tasks has been shown to be negatively affected for some time after an acute dose of alcohol has been cleared from the system. However, Dauncey reported impairment of a relatively simple reaction time task 3 hr after a dose of alcohol, when the blood alcohol concentration was at or near 0. This impairment was positively related to the subject's drinking history. A replication using the same task found a linear dose/impairment relationship during intoxication. A second simple reaction time task and a vigilance task showed a trend toward impairment, but only a divided attention task was significantly affected during intoxication. There was no significant effect of dose on any of these tests during a "morning after" session. The results are discussed in relation to the differences in method between Dauncey and this study.