Affect Reaction Time Research Articles

Direct comparison of the cognitive effects of acute alcohol with the morning after a normal night's drinking

The aim of this study was to compare performance measures after acute alcohol consumption (intoxication) with the performance the day after a normal night's drinking (hangover). Eighty-four social drinkers took part in two studies that followed a counterbalanced repeated measure design. Fifteen men and 33 women were tested the morning (09:00, 11:00 or 13:00 h) following normal/usual alcohol consumption and the morning after no alcohol consumption; the order of testing was counterbalanced. In a second study, 36 participants (18 men and 18 women) were tested after receiving alcohol to attain a blood alcohol concentration of 0.08%, and after no alcohol administration, the order of testing was counterbalanced. In both studies, participants completed a task battery of memory, reaction time and attention tasks. Alcohol had no effect on the free recall task and the spatial attention task. Alcohol consumption, either acute or the next day, significantly affected reaction time, divided attention, selective attention and Stroop interference. The impairments during intoxication and hangover were of comparable magnitude. Performance on tasks of delayed recognition and irregular interstimulus reaction time was worse during hangover when compared with intoxication. It is evident that awareness needs to be raised that performance the morning after alcohol consumption is at the same level if not worse than when participants are at the legal limit for driving (0.08% blood alcohol concentration).

Ventromedial frontal lobe damage disrupts the accuracy, but not the speed, of value-based preference judgments

The ventromedial frontal lobe (VMF) plays a role in decision making, but its precise function remains unclear. Several lines of evidence suggest that VMF is involved in representing the economic value of options. A prior study from our lab has shown that patients with lesions to the VMF are less consistent than controls in making simple preference judgments between stimuli presented in pairs. Here, we followed up that observation in a larger sample, using more sensitive tasks, and examining the category-specificity of this effect. Patients with damage to VMF (N=15) were compared to patients with frontal damage sparing that region (N=8) and to demographically matched healthy control participants (N=23). Five separate preference tasks were administered, requiring subjects to indicate their preference for 12 stimuli presented two at a time, in all possible combinations. Categories included fruits, vegetables, colors, landscapes, and puppies. Choices were analyzed for internal consistency, and decision times were measured. Three control tasks with the same format, but requiring perceptual judgments, were also administered. VMF patients were significantly more erratic than both non-VMF and healthy control participants in their preference judgments across all stimulus categories. However, decision times, and the relationship between decision time and relative value, were similar to that seen in control participants. The groups did not differ in perceptual judgment performance. These findings add further weight to the claim that VMF plays a critical role in simple value-based decision-making under conditions of certainty. This region appears to be necessary for consistent choices across a variety of stimulus categories, supporting the view that human VMF represents the (relative) value of decision options rather generally. That such damage impairs decision ‘accuracy’ without affecting reaction time has implications for theories of the role of VMF in decision-making, arguing that this region may be critical for linking a particular value to a particular option.

Venom, speed, and caution: effects on performance in a visual search task

Previous reports of faster responses to threatening compared to benign stimuli in visual search tasks have argued that threatening targets are faster to engage and slower to disengage attention than benign targets. This study reinterprets previous findings and resolves inconsistencies in the literature by replacing the theory of differential disengagement of attention with one of differential caution. It also examines whether visual attentional mechanisms are sensitive to more than just the threatening versus benign categorical status of the targets and introduces a novel measure (a caution score) that appears to be sensitive to the level of threat implied by the target image, but immune to other stimulus features (target-distracter similarity and threat status of distracters) known to affect reaction time. As well as locating threatening targets faster than benign targets, participants were also faster, more accurate, and more cautious to detect lethal spiders compared to nonlethal spiders and even more cautious again if the spiders were presented on a person's hand. These results suggest that mechanisms of attention and threat evaluation interact during visual search tasks, producing behaviour that is sensitive to the target's implied threat level and the context in which that target is presented.

Reading strategies in Spanish developmental dyslexics

Cross-linguistic studies suggest that the orthographic system determines the reading performance of dyslexic children. In opaque orthographies, the fundamental feature of developmental dyslexia is difficulty in reading accuracy, whereas slower reading speed is more common in transparent orthographies. The aim of the current study was to examine the extent to which different variables of words affect reaction times and articulation times in developmental dyslexics. A group of 19 developmental dyslexics of different ages and an age-matched group of 19 children without reading disabilities completed a word naming task. The children were asked to read 100 nouns that differed in length, frequency, age of acquisition, imageability, and orthographic neighborhood. The stimuli were presented on a laptop computer, and the responses were recorded using DMDX software. We conducted analyses of mixed-effects models to determine which variables influenced reading times in dyslexic children. We found that word naming skills in dyslexic children are affected predominantly by length, while in non-dyslexics children the principal variable is the age of acquisition, a lexical variable. These findings suggest that Spanish-speaking developmental dyslexics use a sublexical procedure for reading words, which is reflected in slower speed when reading long words. In contrast, normal children use a lexical strategy, which is frequently observed in readers of opaque languages.

Factors affecting cognitive function of opiate-dependent patients

Background A wide range of studies found that opiate-dependent patients suffer from cognitive impairment due to a number of different factors. However, this issue has never been examined systematically. Thus, the aim of the present study is to provide a comprehensive analysis of factors that might contribute to cognitive impairment of opiate-dependent patients and specifically differentiates between various cognitive abilities as these might be impacted differently. Methods Based on a comprehensive review of the literature with regard to previous findings and suggestions about which factors might affect cognitive functioning, we assessed a wide variety of variables related to substance use and opiate-dependence as well as demographic and socioeconomic variables. Cognitive functioning was assessed through a neuropsychological test-battery. Results We found that the duration of opiate dependence and maintenance treatment, as well as additional substance consumption (alcohol, amphetamines, and cocaine) are the main variables contributing to cognitive impairment in the domains of attention and executive function. Comorbid depressive symptoms negatively affected reaction times. There was no evidence for the role of demographic variables like age and education on cognitive functioning. Conclusions Our findings suggest that it might be important in the treatment of opiate dependence to address the consumption of additional substances and to closely monitor the negative effects of maintenance treatment on cognitive functioning.

Speed/Accuracy Trade-Off between the Habitual and the Goal-Directed Processes

Instrumental responses are hypothesized to be of two kinds: habitual and goal-directed, mediated by the sensorimotor and the associative cortico-basal ganglia circuits, respectively. The existence of the two heterogeneous associative learning mechanisms can be hypothesized to arise from the comparative advantages that they have at different stages of learning. In this paper, we assume that the goal-directed system is behaviourally flexible, but slow in choice selection. The habitual system, in contrast, is fast in responding, but inflexible in adapting its behavioural strategy to new conditions. Based on these assumptions and using the computational theory of reinforcement learning, we propose a normative model for arbitration between the two processes that makes an approximately optimal balance between search-time and accuracy in decision making. Behaviourally, the model can explain experimental evidence on behavioural sensitivity to outcome at the early stages of learning, but insensitivity at the later stages. It also explains that when two choices with equal incentive values are available concurrently, the behaviour remains outcome-sensitive, even after extensive training. Moreover, the model can explain choice reaction time variations during the course of learning, as well as the experimental observation that as the number of choices increases, the reaction time also increases. Neurobiologically, by assuming that phasic and tonic activities of midbrain dopamine neurons carry the reward prediction error and the average reward signals used by the model, respectively, the model predicts that whereas phasic dopamine indirectly affects behaviour through reinforcing stimulus-response associations, tonic dopamine can directly affect behaviour through manipulating the competition between the habitual and the goal-directed systems and thus, affect reaction time.

One night of sleep deprivation affects reaction time, but not interference or facilitation in a Stroop task

The Stroop color-naming task is one of the most widely studied tasks involving the inhibition of a prepotent response, regarded as an executive function. Several studies have examined performance on versions of the Stroop task under conditions of acute sleep deprivation. Though these studies revealed effects on Stroop performance, the results often do not differentiate between general effects of sleep deprivation on performance and effects specifically on interference in the Stroop task. To examine the effect of prolonged wakefulness on performance on the Stroop task, we studied participants in a 40-h “constant routine” protocol during which they remained awake in constant conditions and performed a Stroop color-naming task every two hours. We found that reaction time was slowest when the color and word did not match (incongruent), fastest when the color and word did match (congruent), and intermediate when participants named the color of the non-word stimulus (neutral). Performance on all three trial types degraded significantly as a function of time awake. Extended wakefulness did not significantly change the additional time needed to respond when the color and word did not match (Stroop interference), nor did it change the amount of facilitation when color and word matched. These results indicate that one night of sleep deprivation influences performance on the Stroop task by an overall increase in response time, but does not appear to impact the underlying processes of interference or facilitation. The results suggest that the degree to which an “executive function” is affected by sleep deprivation may depend on the particular executive function studied and the degree to which it is subserved by the prefrontal cortex.

Trained modulation of sensorimotor rhythms can affect reaction time

Objective Brain–computer interface (BCI) technology might be useful for rehabilitation of motor function. This speculation is based on the premise that modifying the EEG will modify behavior, a proposition for which there is limited empirical data. The present study examined the possibility that voluntary modulation of sensorimotor rhythm (SMR) can affect motor behavior in normal human subjects. Methods Six individuals performed a cued-reaction task with variable warning periods. A typical variable foreperiod effect was associated with SMR desynchronization. SMR features that correlated with reaction times were then used to control a two-target cursor movement BCI task. Following successful BCI training, an uncued reaction time task was embedded within the cursor movement task. Results Voluntarily increasing SMR beta rhythms was associated with longer reaction times than decreasing SMR beta rhythms. Conclusions Voluntary modulation of EEG SMR can affect motor behavior. Significance These results encourage studies that integrate BCI training into rehabilitation protocols and examine its capacity to augment restoration of useful motor function.

Neural mechanisms for the effect of prior knowledge on audiovisual integration

Converging evidence indicates that prior knowledge plays an important role in multisensory integration. However, the neural mechanisms underlying the processes with which prior knowledge is integrated with current sensory information remains unknown. In this study, we measured event-related potentials (ERPs) while manipulating prior knowledge using a novel visual letter recognition task in which auditory information was always presented simultaneously. The color of the letters was assigned to a particular probability of being associated with audiovisual congruency (e.g., green = high probability (HP) and blue = low probability (LP)). Results demonstrate that this prior began affecting reaction times to the congruent audiovisual stimuli at about the 900th trial. Consequently, the ERP data was analyzed in two phases: the “early phase” (<trial 600) and the “late phase” (>trial 900). The effects of prior knowledge were revealed through difference waveforms generated by subtracting the ERPs for the congruent audiovisual stimuli in the LP condition from those in the HP condition. A frontal-central probability effect (90–120 ms) was observed in the early phase. A right parietal-occipital probability effect (40–96 ms) and a frontal-central probability effect (170–200 ms) were observed in the late phase. The results suggest that during the initial acquisition of the knowledge about the probability of congruency, the brain assigned more attention to audiovisual stimuli for the LP condition. Following the acquisition of this prior knowledge, it was then used during early stages of visual processing and modulated the activity of multisensory cortical areas.

Do Ski Helmets Affect Reaction Time to Peripheral Stimuli?

Ski helmet use has steadily increased worldwide over the last 10 years in part as a result of preventive helmet campaigns but also in part as a result of increased media coverage after fatal injuries involving celebrities. However, a commonly reported reason for nonuse is impaired vision. The aim of this pilot study was to investigate whether ski helmet use affects reaction time to peripheral stimuli. A randomized controlled trial using the Compensatory-Tracking-Test (CTT) was conducted in a laboratory situation. This test measures reaction time to peripheral stimuli during a tracking task and was carried out by 10 males and 10 females (age: 22.1 ± 2.5 years) during 4 conditions in a randomized order: (A) with a ski cap; (B) with a ski helmet; (C) with a ski cap and ski goggles; and (D) with a ski helmet and ski goggles. Friedman-tests revealed significant differences in reaction times (ms) between the 4 conditions (p=.031). The lowest mean reaction time (± standard error) was measured for cap only use (477.3 ± 16.6), which was not different than helmet-only use (478.5 ± 19.1, p=0.911). However, reaction time was significantly longer for cap + goggles use (514.1 ± 20.8, p=0.005) and for helmet + goggles use (497.6 ± 17.3, p=0.017) when compared to cap-only use. Our results showed that ski helmet use did not increase reaction time to peripheral stimuli. This information should be implemented in future preventive campaigns to increase helmet use in skiers and snowboarders.

Effects of Vowel Length on Gaze Durations in Silent and Oral Reading

Vowel length is known to affect reaction times in single word reading. Eye movement studies involving silent sentence reading showed that phonological information of a word can be acquired even before it is fixated. However, it remained an open question whether vowel length directly influences oculomotor control in sentence reading. In the present eye tracking study, subjects read sentences that included target words of varying vowel length and frequency. In Experiment 1, subjects read silently for comprehension, whereas Experiment 2 involved oral reading. Experiments 3 and 4 additionally included an articulatory suppression task and a foot tapping task. Results indicated that in conditions that did not require additional articulation (Experiments 1 and 4) gaze durations were increased for words with long vowels compared to words with short vowels. Conditions that required simultaneous articulation (Experiments 2 and 3) did not yield a vowel length effect. The results point to an influence of phonetic properties on oculomotor control during silent reading around the time of the completion of lexical access.

What is 'anti' about anti-reaches? Reference frames selectively affect reaction times and endpoint variability.

Reach movement planning involves the representation of spatial target information in different reference frames. Neurons at parietal and premotor stages of the cortical sensorimotor system represent target information in eye- or hand-centered reference frames, respectively. How the different neuronal representations affect behavioral parameters of motor planning and control, i.e. which stage of neural representation is relevant for which aspect of behavior, is not obvious from the physiology. Here, we test with a behavioral experiment if different kinematic movement parameters are affected to a different degree by either an eye- or hand-reference frame. We used a generalized anti-reach task to test the influence of stimulus-response compatibility (SRC) in eye- and hand-reference frames on reach reaction times, movement times, and endpoint variability. While in a standard anti-reach task, the SRC is identical in the eye- and hand-reference frames, we could separate SRC for the two reference frames. We found that reaction times were influenced by the SRC in eye- and hand-reference frame. In contrast, movement times were only influenced by the SRC in hand-reference frame, and endpoint variability was only influenced by the SRC in eye-reference frame. Since movement time and endpoint variability are the result of planning and control processes, while reaction times are consequences of only the planning process, we suggest that SRC effects on reaction times are highly suited to investigate reference frames of movement planning, and that eye- and hand-reference frames have distinct effects on different phases of motor action and different kinematic movement parameters.

Effects of trifluoromethylphenylpiperazine (TFMPP) on interhemispheric communication

'Party Pills' containing trifluoromethylphenylpiperazine (TFMPP) and benzylpiperazine are legally available in many countries and marketed as safe alternatives to other illicit substances such as methamphetamine and methylenedioxymethamphetamine (or Ecstasy). They have gained huge popularity around the world, especially amongst young adults. However, there is no information currently available describing the acute neurophysiological effects of these psychoactive drugs in humans. The purpose of this study is to investigate the effects of TFMPP on central information processing speed in humans. A randomised, double blind, placebo-controlled study using electroencephalography (EEG) was carried out to investigate the effects of TFMPP on interhemispheric transfer time (IHTT). Healthy, right-handed males (age: 25 ± 5.6 years) were given placebo (n = 15) or TFMPP (0.94 mg/kg, oral, n = 15) and tested both pre- and 2 h post-drug administration. High-density EEG recordings (128 channels which were re-referenced using an average reference to make 129 electrodes) were used to record event-related potentials. The N160 component was defined as the biggest negative peak in the range between 140 and 220 ms after the event. The IHHTs were analysed by deducting the N160 latency obtained in the contralateral hemisphere from the N160 latency obtained in the hemisphere ipsilateral to stimulus signal. Statistical analysis using a split-plot design analysis of variance revealed that TFMPP significantly reduced the IHTT but did not affect reaction time. No statistically significant changes were observed in the placebo group. This study is the first to report the neurophysiological effects of TFMPP in humans and suggests that TFMPP may affect transmitter systems involved in speeding of interhemispheric communication in the male brain.

Do anticholinergics affect reaction time? A possible impact on the course of rehabilitation

To assess if oxybutynin and tolterodine have an effect on simple reaction time in healthy volunteers. Simple reaction time was evaluated before and 90 minutes after the oral administration of oxybutynin and tolterodine in a cross-over design. Twenty seven healthy volunteers, aged 26 to 48 years, were included in the study. The electromyographic activity of the flexor digitorum superficialis muscle that was used for the response was recorded, and premotor time was measured. The mean age of the study group was 33.1 ± 7.4 years. Mean premotor times before oxybutynin and before tolterodine administration were statistically non-significant. Mean premotor times after the administration of oxybutynin and tolterodine were significantly longer than the initial premotor times (p = 0.003). The results of the study showed that oxybutynin and tolterodine prolonged the simple reaction time. The prolonged simple reaction time may suggest a perceptive impairment. The potential for perceptive impairment as a side effect of oxybutynin and tolterodine might suggest a negative impact on the rehabilitation interventions and the activities of daily living because of central nervous system effects.

The accuracy and limitations of a new meter used to measure aqueous carbon dioxide

The OxyGuard CO 2 Analyzer is a novel meter that can directly measure aqueous CO 2 gas pressure using a water-resistant gas-permeable membrane and infra-red absorption cell. The pCO 2 is converted to a concentration via a solubility factor determined from the calibration procedure and a thermistor. We undertook to independently validate the precision and utility of this meter. Water flow over the probe membrane was a key determinant of the reaction time. At water velocities of ≥30 cm s −1 the time to 99% span was 6–7 min, while at 0 cm s −1 it was 55–60 min. Temperature and CO 2(aq) concentration did not appreciably affect reaction time. The meter had a precision of ±0.5 mg L −1 CO 2(aq), and high linearity (correlation 0.99–1.01) above 1 mg L −1 in both freshwater and seawater. The standard meter will not be useful for measuring low concentrations such as atmospheric CO 2 levels, but will be useful in situations where accurate pH and carbonate alkalinity determinations are difficult to obtain, such as saline waters and waters of high organic loadings.

Functional disconnection of the substantia nigra pars compacta from the pedunculopontine nucleus impairs learning of a conditioned avoidance task

The pedunculopontine tegmental nucleus (PPTg) targets nuclei in the basal ganglia, including the substantia nigra pars compacta (SNc), in which neuronal loss occurs in Parkinson’s disease, a condition in which patients show cognitive as well as motor disturbances. Partial loss and functional abnormalities of neurons in the PPTg are also associated with Parkinson’s disease. We hypothesized that the interaction of PPTg and SNc might be important for cognitive impairments and so investigated whether disrupting the connections between the PPTg and SNc impaired learning of a conditioned avoidance response (CAR) by male Wistar rats. The following groups were tested: PPTg unilateral; SNc unilateral; PPTg–SNc ipsilateral (ipsilateral lesions in PPTg and SNc); PPTg–SNc contralateral (contralateral lesions in PPTg and SNc); sham lesions (of each type). SNc lesions were made with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine HCl (MPTP, 0.6 μmol); PPTg lesions with ibotenate (24 nmol). After recovery, all rats underwent 50-trial sessions of 2-way active avoidance conditioning for 3 consecutive days. Rats with unilateral lesions in PPTg or SNc learnt this, however rats with contralateral (but not ipsilateral) combined lesions in both structures presented no sign of learning. This effect was not likely to be due to sensorimotor impairment because lesions did not affect reaction time to the tone or footshock during conditioning. However, an increased number of non-responses were observed in the rats with contralateral lesions. The results support the hypothesis that a functional interaction between PPTg and SNc is needed for CAR learning and performance.

Control of sensorimotor variability

PURPOSE. Studies of reaction time distributions provide a useful quantitative approach to understand decision processes at the neural level and at the behavioral level. A strong relationship between the spread of latencies and the median is generally accepted even though there has been no attempt to disentangle experimentally these two parameters. Here we test the ability to independently control the median and the variability in reaction times. METHODS. Reaction times were measured in human subjects instructed to make a discrimination between a target and a distractor in a 2AFC task. In a first experiment, saccadic latencies were measured. In a second experiment, we used manual response reaction times. In each experiment subjects were trained to produce four different reaction time distributions. A reinforcing feedback was given depending on both the variability and the median of the latency distributions. RESULTS. When low variability was reinforced the standard deviation of reaction time distributions were reduced by a factor of two and when high variability was reinforced, the standard deviation returned to baseline level. Our procedure independently affected the spread and the median of the distribution patterns. By fitting the latency distributions using the Reddi and Carpenter LATER model, we found that these effects could be simulated by changing the distribution of the noise affecting the decision process. Our results demonstrate that learned contingencies can affect reaction time variability and support the view that the so-called noise level in decision processes can undergo long-term changes.

Evidence for a pre-match 'mental translation' on a form-matching task

PURPOSE AND APPROACH. The aim was to explore whether there is a pre-match ‘mental translation’, analogous to ‘mental rotation’ and ‘mental scaling’, on a Same-Different simultaneous form-matching task. The basic approach was to vary the environmental separation of the forms, while holding constant everything else that might affect reaction time. METHOD. On a Same-Different task, subjects were presented with two forms flanking a fixation triangle, all shown in the same depth-plane. Distance (simulated) to the forms was varied. Viewing was in stereo. Total visual angle spanned by the centers of the bases of the two forms, in each eye, was held (essentially, effectively) constant as distance to the forms (and so environmental separation) varied. The forms and fixation triangle were shown resting on a bar that spanned a textured enclosure; the top of the bar crossed at eye-level and the bar was anchored to the floor of the enclosure by struts. The top half of the back of the enclosure was open, with the forms silhouetted against a blank field. So: form edge-information and gaze angle were both held constant as distance to the forms (and so environmental separation) varied, and there was no backing surface. In Experiment I, the forms were shown for 400msc; in Experiment II, the forms were shown for 300msc, and the Same-Different discrimination was made slightly easier. RESULTS AND CONCLUSION. In Experiment I, reaction time rose with increases in environmental separation (n = 34, p < .01, R-squared = .9295; Same trials). Results for the 16 subjects run so far in Experiment II also indicate a rise in reaction time with increases in environmental separation (p = .029; Same trials). In both cases, the slopes suggest a fast process. In sum, the results are evidence that comparisons of the forms were preceded by a fast ‘mental translation’, analogous to ‘mental rotation’ and ‘mental scaling’, with the locations of the forms coded in a non-retinal frame of reference.

Planning and control of hand orientation in grasping movements

Humans grasp objects in a way that facilitates the intended use of the object. We examined how humans grasp a circular control knob in order to turn it in different directions and by different extents. To examine the processes involved in anticipatory planning of grasps, we manipulated advance information about the location of the control knob and the target of the knob-turn. The forearm orientation at the time of grasping depended strongly on the knob-turn, with the direction of the knob-turn having a stronger effect than the extent of the knob-turn. However, the variability of the forearm orientations after the knob-turn remained considerable. Anticipatory forearm orientations began early during the grasping movement. Advance information had no influence on the trajectory of the grasp but affected reaction times and the duration of the grasp. From the results, we conclude that (1) grasps are selected in anticipation of the upcoming knob rotation, (2) the desired hand location and forearm orientation at the time of grasping are specified before the onset of the grasp, and (3) an online programming strategy is used to schedule the preparation of the knob-turn during the execution of the grasp.

Everyday use of the computer mouse extends peripersonal space representation

Auditory and tactile stimuli are integrated within a limited space around the body to form an auditory peripersonal space (APPS). Here we investigate whether the APPS representation around the hand can be extended through the use of a common technological tool such as the computer mouse. When using a mouse, an action occurring in the space around the hand has a distal effect in the space defined by the computer screen; thus, the mouse virtually links near and far space. Does prolonged experience with the mouse durably extend APPS representation to the far space? We examined 16 habitual mouse users to determine whether a sound presented near the right hand or near the computer screen affected reaction times to a tactile target at the hand. When subjects sat in front of the computer, without holding the mouse, they responded faster to tactile stimuli when sounds were presented near the hand rather than near the screen, consistent with a normal segregation of APPS around the hand. In contrast, when subjects either actively used or even passively held the mouse, the difference between the effects of near and far sounds disappeared, thus showing an extension of the APPS toward the far space. This effect was selective for the effector used to operate the mouse: if tactile stimuli were presented on the left hand, rarely used to act upon the mouse, a sound presented near the hand speeded up reactions times when subjects both held and did not hold the mouse in their left hand.