S-R Compatibility Effects without Response Uncertainty

Movement time differentiates extraverts from introverts

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

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.

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.

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.

A longitudinal study of reaction time performance in long-evans rats

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

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.

Non-aging fore-periods and simple reaction time

Focused attention deficits in patients with Alzheimer’s disease and mild cognitive impairment

Deficits in inhibitory force control in young adults with ADHD

Alzheimer's disease (AD) is characterized by progressive decline in memory, language and other cognitive functions. Deficits in attentional processes have also been suggested. A simple reaction time (RT) task was used to assess global attention in AD. The length and consistency of a warning signal given prior to the response stimulus were manipulated to determine if patients with AD and age-matched controls benefit from predictability in RT tasks. Overall reaction time was slower in the AD group than in the and control group. Both groups demonstrated significant improvement in RT with long warning signals compared to short warning signals, but only the control group benefited from the consistency of the warning.

Complaints of feeling unfocused and being unable to concentrate are common during smoking cessation, and such feelings may contribute to a subtle erosion of the motivation to quit. A heterogeneous sample of 21 established smokers (10 women, 11 men) completed this double-blind, placebo-controlled study to test the hypothesis that nicotine replacement during cessation therapy (using a 21-mg nicotine patch) would improve performance on tasks sensitive to nicotine deprivation. Participants were trained to stable performance on simple reaction time, mathematical processing, Sternberg memory, rapid visual-information processing, grammatical reasoning, and the Stroop Color-Word (Stroop) tasks. They received smoking cessation counseling and were randomly assigned to nicotine patch and placebo patch groups. Performance was assessed prior to cessation, and early (days 2 and 3) and late (days 5 through 7) in the first cessation week. The hypothesis was not supported. Increased accuracy was associated with the patch only for grammatical reasoning. No reaction time differences were found in the simple reaction time, grammatical reasoning, and mathematical processing tasks. Reaction time was faster in the placebo group on the more difficult portions of those tasks requiring sustained attention (rapid visual-information processing, Stroop Color-Word, and Sternberg memory tasks). These results differ substantially from those obtained when young adults are allowed to smoke or chew nicotine gum after relatively brief periods of deprivation. Evidence that smoking may interfere with cognition is accumulating; these results support this view. The subjective performance decrements noted by many smokers during cessation may be related to overall negative affect, rather than to direct effects on cognition and attention.

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.