Tactile Reaction Time Research Articles

Cerebral Cortical Activity During Academic Stress Amongst Undergraduate Medical Students at Kampala International University (Uganda).

BackgroundStress among medical students is related to their academic lifespan; however, information on brain health among medical students from developing countries continues to be scarce. The objective of this study was to establish perceived academic stress levels, assess the ability to cope with stress, and investigate its effects on the visual reaction time (VRT), audio reaction time (ART), and tactile reaction time (TRT) in the somatosensory cortex among medical students of Uganda.MethodsThis was a cross-sectional study conducted among preclinical (n = 88) and clinical (n = 96) undergraduate medical students at Kampala International University Western Campus. A standard Perceived Stress Scale (PSS) was used to categorize stress into low, moderate, and severe while the ability to cope with stress was categorized into below average, average, above average, and superior stresscoper (SS). Data on reaction time were acquired through VRT, ART, and TRT using the catch-a-ruler experiment, and this was analyzed using SPSS version 20.ResultsThis study shows that preclinical students are more stressed than clinical students (PSS prevalence for low stress = preclinical; clinical: 40, 60%). Moderate stress was 48.4 and 51.6% while high perceived stress was 75 and 25% among preclinical and clinical students. Among male and female students in preclinical years, higher TRT and VRT were found in clinical students showing that stress affects the tactile and visual cortical areas in the brain, although the VRT scores were only significantly (P = 0.0123) poor in male students than female students in biomedical sciences. Also, highly stressed individuals had higher TRT and ART and low VRT. SS had high VRT and ART and low TRT in preclinical students, demonstrating the importance of the visual cortex in stress plasticity. Multiple regression showed a close relationship between PSS, ability to cope with stress, age, and educational level (P < 0.05), demonstrating the importance of social and psychological support, especially in the biomedical sciences.ConclusionPreclinical students suffer more from stress and are poorer SS than clinical students. This strongly impairs their cortical regions in the brain, thus affecting their academic productivity.

Knowledge of collision modulates defensive multisensory responses to looming insects in arachnophobes.

We investigated the role of contextual knowledge in defensive responses to visual stimuli (spiders and butterflies) looming toward the hand. Human participants responded to tactile stimuli delivered to the same hand at 6 possible locations during an insect's approach. Tactile reaction times were faster when looming stimuli were closer to the hand, especially for spiders, and faster when insects loomed on a collision path than on a near-miss path. This latter finding suggests that human reactions to looming stimuli are not merely automatic reflexes but that contextual knowledge about the trajectory of looming objects is included in predicting their impact. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Accurate reaction time methods demonstrate similar results from different sensory modalities

Over the past few decades, there has been a significant number of reports that suggested that reaction times for different sensory modalities were different – e.g., that visual reaction time was slower than tactile reaction time. A recent report by Holden and colleagues stated that (1) there has been a significant historic upward drift in reaction times reported in the literature, (2) that this drift or degradation in reaction times could be accounted for by inaccuracies in the methods used and (3) that these inaccurate methods led to inaccurate reporting of differences between visual and tactile based reaction time testing. The Holden study utilized robotics (i.e., no human factors) to test visual and tactile reaction time methods but did not assess how individuals would perform on different sensory modalities. This study utilized three different sensory modalities: visual, auditory, and tactile, to test reaction time. By changing the way in which the subjects were prompted and measuring subsequent reaction time, the impact of sensory modality could be analyzed. Reaction time testing for two sensory modalities, auditory and visual, were administered through an Arduino Uno microcontroller device, while tactile-based reaction time testing was administered with the Brain Gauge. A range of stimulus intensities was delivered for the reaction times delivered by each sensory modality. The average reaction time and reaction time variability was assessed and a trend could be identified for the reaction time measurements of each of the sensory modalities. Switching the sensory modality did not result in a difference in reaction time and it was concluded that this was due to the implementation of accurate circuitry used to deliver each test. Increasing stimulus intensity for each sensory modality resulted in faster reaction times. The results of this study confirm the findings of Holden and colleagues and contradict the results reported in countless studies that conclude that (1) reaction times are historically slower now than they were 50 years ago and (2) that there are differences in reaction times for different sensory modalities (vision, hearing, tactile). The implications of this are that utilization of accurate reaction time methods could have a significant impact on clinical outcomes and that many methods in current clinical use are basically perpetuating poor methods and wasting time and money of countless subjects or patients.

The Effect of Preference of Music on Reaction Time

A series of 4 collective, exploratory case studies were conducted in order to determine the effect of different genres on reaction time. The Brain Gauge System was used to measure raw reaction time via a tactile reaction time test, testing three different conditions: no music, preferred genre, classical music. The subjects listened to 10 minute increments of music on noise-cancelling headphones and took the tactile reaction time test once before listening and twice (2 minute and 8 minute mark) while the music was playing. Results indicated that there was a general trend of increased reaction time (i.e., decreased performance) with music playing in the background. An ANOVA test was performed, with a resulting p-value of 0.411. While statistical analysis proved the results to be insignificant, the trends found in the case studies indicate that listening to music worsens your reaction time. Furthermore, preferred types of music do not have a significant effect on reaction time. Consistent with literature, this indicates that music in general is a form of distraction, regardless of preference and genre. Further in-depth studies need to be conducted with a larger sample size in order to expand upon these preliminary findings.

Altered Peripersonal Space and the Bodily Self in Schizophrenia: A Virtual Reality Study.

Self-disturbances such as an anomalous perception of one's own body boundary are central to the phenomenology of schizophrenia (SZ), but measuring the spatial parameters of the hypothesized self-other boundary has proved to be challenging. Peripersonal space (PPS) refers to the immediate zone surrounding the body where the self interacts physically with the environment; the space that corresponds to hypothesized self-other boundary. PPS is represented by enhanced multisensory integration and faster reaction time (RT) for objects near the body. Thus, multisensory RT tasks can be used to estimate self-other boundary. We aimed to quantify PPS in SZ using an immersive virtual reality visuotactile RT paradigm. Twenty-four participants with SZ and 24 demographically matched controls (CO) were asked to detect tactile vibration while watching a ball approaching them, thrown by either a machine (nonsocial condition) or an avatar (social condition). Parameters of PPS were estimated from the midpoint of the spatial range where the tactile RT decreased most rapidly (size) and the gradient of the RT change at this midpoint (slope). Overall, PPS was smaller in participants with SZ compared with CO. PPS slope for participants with SZ was shallower than CO in the social but not in nonsocial condition, indicating an increased uncertainty of self-other boundary across an extended zone in SZ. Social condition also increased false alarms for tactile detection in SZ. Clinical symptoms were not clearly associated with PPS parameters. These findings suggest the context-dependent nature of weakened body boundary in SZ and underscore the importance of reconciliating objective and subjective aspects of self-disturbances.

Acute Impact of Mindfulness Meditation on Cognitive Performance

The beneficial effects of mindfulness meditation on higher-order cognitive performance as well as physiological parameters, such as decreased cortisol levels, blood pressure, pulse rate, and reaction time, have been studied extensively. However, most of these studies have been conducted over a relatively long term, comparing subjects who meditate on a regular basis with those who have never meditated. In this study, the acute effects of mindfulness meditation are investigated by examining the differences between tactile reaction time and temporal-order judgement (TOJ) obtained before and after a 10-minute meditation session in several case studies. Additionally, the participants reported their mood and stress levels in a survey before and after the meditation session. The results demonstrate that mindfulness meditation improves performance on the tactile reaction time and TOJ tasks, and it also promotes a peaceful state of mind.

The Effect of Increasing Music Volume on Reaction Time

The purpose of this study was to investigate the impact that music volume has on reaction time. The significance of this study is that music volume is often suggested to be one of the factors and/or distractions that lead young drivers under the age of 25 to experience a high rate of vehicular accidents, and the goal of this study was to quantitatively assess the effect of increasing music volume on the reaction time of subjects in this demographic. Tactile reaction time, using the Brain Gauge, was used to record simple reaction time and choice reaction time data for 20 college students while the Neil Diamond classic “Sweet Caroline” was played at approximately 0dB, 20dB, 40dB, and 80dB. The results demonstrate a significant increase in simple reaction time with increased music volume and shows that louder music impacts an individual’s capacity to react to a stimulus. Although the study was not conducted while the individual was driving, the results strongly suggest that high music volume could significantly impair a driver’s response time.

Auditory roughness elicits defense reactions

Auditory roughness elicits aversion, and higher activation in cerebral areas involved in threat processing, but its link with defensive behavior is unknown. Defensive behaviors are triggered by intrusions into the space immediately surrounding the body, called peripersonal space (PPS). Integrating multisensory information in PPS is crucial to assure the protection of the body. Here, we assessed the behavioral effects of roughness on auditory-tactile integration, which reflects the monitoring of this multisensory region of space. Healthy human participants had to detect as fast as possible a tactile stimulation delivered on their hand while an irrelevant sound was approaching them from the rear hemifield. The sound was either a simple harmonic sound or a rough sound, processed through binaural rendering so that the virtual sound source was looming towards participants. The rough sound speeded tactile reaction times at a farther distance from the body than the non-rough sound. This indicates that PPS, as estimated here via auditory-tactile integration, is sensitive to auditory roughness. Auditory roughness modifies the behavioral relevance of simple auditory events in relation to the body. Even without emotional or social contextual information, auditory roughness constitutes an innate threat cue that elicits defensive responses.

Methodological Problems With Online Concussion Testing.

Reaction time testing is widely used in online computerized concussion assessments, and most concussion studies utilizing the metric have demonstrated varying degrees of difference between concussed and non-concussed individuals. The problem with most of these online concussion assessments is that they predominantly rely on consumer grade technology. Typical administration of these reaction time tests involves presenting a visual stimulus on a computer monitor and prompting the test subject to respond as quickly as possible via keypad or computer mouse. However, inherent delays and variabilities are introduced to the reaction time measure by both computer and associated operating systems that the concussion assessment tool is installed on. The authors hypothesized systems that are typically used to collect concussion reaction time data would demonstrate significant errors in reaction time measurements. To remove human bias, a series of experiments was conducted robotically to assess timing errors introduced by reaction time tests under four different conditions. In the first condition, a visual reaction time test was conducted by flashing a visual stimulus on a computer monitor. Detection was via photodiode and mechanical response was delivered via computer mouse. The second condition employed a mobile device for the visual stimulus, and the mechanical response was delivered to the mobile device's touchscreen. The third condition simulated a tactile reaction time test, and mechanical response was delivered via computer mouse. The fourth condition also simulated a tactile reaction time test, but response was delivered to a dedicated device designed to store the interval between stimulus delivery and response, thus bypassing any problems hypothesized to be introduced by computer and/or computer software. There were significant differences in the range of responses recorded from the four different conditions with the reaction time collected from visual stimulus on a mobile device being the worst and the device with dedicated hardware designed for the task being the best. The results suggest that some of the commonly used visual tasks on consumer grade computers could be (and have been) introducing significant errors for reaction time testing and that dedicated hardware designed for the reaction time task is needed to minimize testing errors.

Do sounds near the hand facilitate tactile reaction times? Four experiments and a meta-analysis provide mixed support and suggest a small effect size

The brain represents the space immediately surrounding the body differently to more distant parts of space. Direct evidence for this ‘peripersonal space’ representation comes from neurophysiological studies in monkeys, which show distance-dependent responses to visual stimuli in neurons with spatially coincident tactile responses. Most evidence for peripersonal space in humans is indirect: spatial- and distance-dependent modulations of reaction times and error rates in behavioural tasks. In one task often used to assess peripersonal space, sounds near the body have been argued to speed reactions to tactile stimuli. We conducted four experiments attempting to measure this distance-dependent audiotactile interaction. We found no distance-dependent enhancement of tactile processing in error rates or task performance, but found some evidence for a general speeding of reaction times by 9.5 ms when sounds were presented near the hand. A systematic review revealed an overestimation of reported effect sizes, lack of control conditions, a wide variety of methods, post hoc removal of data, and flexible methods of data analysis. After correcting for the speed of sound, removing biased or inconclusive studies, correcting for temporal expectancy, and using the trim-and-fill method to correct for publication bias, meta-analysis revealed an overall benefit of 15.2 ms when tactile stimuli are accompanied by near sounds compared to sounds further away. While this effect may be due to peripersonal space, response probability and the number of trials per condition explained significant proportions of variance in this near versus far benefit. These confounds need to be addressed, and alternative explanations ruled out by future, ideally pre-registered, studies.

A study on visual, audio and tactile reaction time among medical students at Kampala International University in Uganda.

Reaction time (RT) is an indicator of neural activity, however, its variation due to visual (VRT), audio (ART) and tactile (TRT) in African medical students has not been investigated. The aim of the study was to determine relationships between VRT, ART and TRT amongst medical students in Uganda. This was a cross sectional study, the body mass index (BMI) and RT (i.e. VRT, ART and TRT) were determined using weighing scale with standiometer and the catch a ruler experiment respectively. A questionnaire was administered to collect information on participant's lifestyle patterns and analysis was done using SPSS Version 20. The mean (± SEM) VRT, ART and TRT in the study were found to be 0.148 ± 0.002s, 0.141 ± 0.002s and 0.139 ± 0.003s respectively. A strong correlation between TRT and ART was found to exist in the youthful Ugandan medical student's population. Furthermore, significant differences in ART and VRT were observed with sex, although these were absent amongst preclinical and clinical students, showing the importance of sex in RT. The low VRT and ART in Ugandan medical students is indicative of a healthy somatosensory connectivity, thus of academic importance.

Vestibular modulation of peripersonal space boundaries.

Human-environment interactions are mediated through the body and occur within the peripersonal space (PPS), the space immediately adjacent to and surrounding the body. The PPS is taken to be a critical interface between the body and the environment, and indeed, body-part specific PPS remapping has been shown to depend on body-part utilization, such as upper limb movements in otherwise static observers. How vestibular signals induced by whole-body movement contribute to PPS representation is less well understood. In a series of experiments, we mapped the spatial extension of the PPS around the head while participants were submitted to passive whole-body rotations inducing vestibular stimulation. Forty-six participants, in three experiments, executed a tactile detection reaction time task while task-irrelevant auditory stimuli approached them. The maximal distance at which the auditory stimulus facilitated tactile reaction time was taken as a proxy for the boundary of peri-head space. The present results indicate two distinct vestibular effects. First, vestibular stimulation speeded tactile detection indicating a vestibular facilitation of somatosensory processing. Second, vestibular stimulation modulated audio-tactile interaction of peri-head space in a rotation direction-specific manner. Congruent but not incongruent audio-vestibular motion stimuli expanded the PPS boundary further away from the body as compared to no rotation. These results show that vestibular inputs dynamically update the multisensory delineation of PPS and far space, which may serve to maintain accurate tracking of objects close to the body and to update spatial self-representations.

Approaching threat modulates visuotactile interactions in peripersonal space

The region surrounding our body (i.e. peripersonal space) is coded in a multimodal representation by fronto-parietal bimodal neurons integrating tactile stimuli on the body with nearby visual stimuli. This has often been suggested to serve a defensive purpose, which we propose could be mediated through visuotactile predictions. An approaching threat would then be of particular interest to peripersonal space processing. To investigate this, we asked participants to respond as fast as possible to a tactile stimulus on the hand, while looking at an animation of an approaching or receding spider or butterfly. Tactile stimulation was applied at one of 25 possible time points during the animation. Tactile reaction times were faster when an approaching stimulus was closer to the hand at the time of tactile presentation. Critically, this effect of distance on reaction times was larger when participants saw an approaching spider compared to an approaching butterfly, but only for participants who were afraid of spiders. This finding demonstrates that the perceived threat of an approaching stimulus modulates visuotactile interactions in peripersonal space and is consistent with the idea that visuotactile predictions are important for defensive purposes and maintaining bodily integrity.

A novel device to measure tactile reaction time

Introduction: Reaction Time has been widely used as one of the measures of mental chronometry since very long. Most of the work has been done with visual and auditory reaction time. Till now reaction time has never been measured by giving tactile stimuli. Hence we have designed a new device to provide different tactile stimuli and to simultaneously measure the time taken by the subject to respond to it. Probably for the first time in the history of mental chronometry Tactile Choice Reaction Time has been compared between males and females. Methods and Materials: The study was conducted among 53 male and 34 female healthy subjects who were between the age group of 18- 24 years. A new instrument has been designed by the author of this article to deliver tactile stimuli on the skin of the subject and to measure the reaction time for that particular sensory modality. Result: All the reaction times were found to be significantly faster in males than in females except for fine touch. For fine touch although the RT is faster in males but the difference is not statistically significant. Conclusion: Present study has reconfirmed the gender differences in case of tactile choice reaction time also. It is going to be really interesting with the use of this new device to find out the relationship of various Tactile Choice Reaction Times with these conditions.

Social Modulation of Peripersonal Space Boundaries

The space around the body, i.e., peripersonal space (PPS), is conceived as a multisensory-motor interface between body and environment. PPS is represented by frontoparietal neurons integrating tactile, visual, and auditory stimuli occurring near the body. PPS is plastic, because it extends by using a tool to reach far objects. Although interactions with others occur within PPS, little is known about how social environment modulates it. Here, we show that presence and interaction with others shape PPS representation. Participants performed a tactile detection task on their face while concurrent task-irrelevant sounds approached toward or receded from their face. Because a sound affects touch when occurring within PPS, we calculated the critical distance where sounds speeded up tactile reaction time as a proxy of PPS boundaries. Experiment 1 shows that PPS boundaries shrink when subjects face another individual, as compared to a mannequin, placed in far space. Experiment 2 and 3 show that, after playing an economic game with another person, PPS boundaries between self and other merge, but only if the other behaved cooperatively. These results reveal that PPS representation is sensitive to social modulation, showing a link between low-level sensorimotor processing and high-level social cognition.

Preferential processing of tactile events under conditions of divided attention

Differences in transduction and transmission latencies of visual, auditory and tactile events cause corresponding differences in simple reaction time. As reaction time is usually measured in unimodal blocks, it is unclear whether such latency differences also apply when observers monitor multiple sensory channels. We investigate this by comparing reaction time when attention is focused on a single modality, and when attention is divided between multiple modalities. Results show that tactile reaction time is unaffected by dividing attention, whereas visual and auditory reaction times are significantly and asymmetrically increased. These findings show that tactile information is processed preferentially by the nervous system under conditions of divided attention, and suggest that tactile events may be processed preattentively.

Losing one's hand: visual-proprioceptive conflict affects touch perception.

BackgroundWhile the sense of bodily ownership has now been widely investigated through the rubber hand illusion (RHI), very little is known about the sense of disownership. It has been hypothesized that the RHI also affects the ownership feelings towards the participant's own hand, as if the rubber hand replaced the participant's actual hand. Somatosensory changes observed in the participants' hand while experiencing the RHI have been taken as evidence for disownership of their real hand. Here we propose a theoretical framework to disambiguate whether such somatosensory changes are to be ascribed to the disownership of the real hand or rather to the anomalous visuo-proprioceptive conflict experienced by the participant during the RHI.Methodology/Principal FindingsIn experiment 1, reaction times (RTs) to tactile stimuli delivered to the participants' hand slowed down following the establishment of the RHI. In experiment 2, the misalignment of visual and proprioceptive inputs was obtained via prismatic displacement, a situation in which ownership of the seen hand was doubtless. This condition slowed down the participants' tactile RTs. Thus, similar effects on touch perception emerged following RHI and prismatic displacement. Both manipulations also induced a proprioceptive drift, toward the fake hand in the first experiment and toward the visual position of the participants' hand in the second experiment.Conclusions/SignificanceThese findings reveal that somatosensory alterations in the experimental hand resulting from the RHI result from cross-modal mismatch between the seen and felt position of the hand. As such, they are not necessarily a signature of disownership.

Neuropsychological and Information Processing Performance and Its Relationship to White Matter Changes Following Moderate and Severe Traumatic Brain Injury: A Preliminary Study

Reductions in information processing speed have frequently been reported following moderate and severe traumatic brain injuries (TBIs), consistent with the effects of diffuse white matter damage. Although the corpus callosum (CC) is a common site for diffuse damage following TBI, the effects of this damage on information processing speed have not been adequately examined. This study assessed a TBI group and a matched control group on tests of attention, memory, fluency, and set shifting ability, together with reaction time (RT) tasks requiring the inter- and intrahemispheric processing of visual and tactile information. The RT tasks were designed to target the cognitive functions that are likely to be affected by diffuse white matter damage, including damage to the CC. The TBI group demonstrated deficits in verbal and visual fluency and verbal memory. They were also slower on the visual and tactile RT tasks, were more affected by task complexity, and slower on RT tasks requiring the interhemispheric transfer of information. In fact, one of the interhemispheric tactile RT tasks proved to be the most discriminating of all the cognitive and RT measures. MRIs completed on a subset of TBI participants indicated that the mean CC measurements were 5% to 19% smaller than a normative control group, with the most atrophied areas being the isthmus and anterior midbody. Although white matter atrophy was moderately related to visual and tactile RT performance, and total hippocampal volume related to memory performance, CC area was not related to many of the tasks that were designed to tap interhemispheric processing. None of the standard cognitive tests correlated with outcome in the TBI group, but 1 of the tactile RT measures was significantly related to 2 measures of outcome.

Neuropsychological and information processing deficits following mild traumatic brain injury.

Neuroradiological and neuropathological investigations have found evidence of diffuse brain damage in the frontal and temporal lobes, corpus callosum, and fornices in patients who have sustained a mild traumatic brain injury (TBI). However, neuropsychological assessments of these patients do not typically target many of the subtle information processing deficits that may arise from diffuse damage involving the frontotemporal regions of the brain as well as white matter pathology, including the corpus callosum. Consequently, we have a limited understanding of the deficits that may be attributable to temporary or permanent disruptions to these functional pathways. This study assessed a group of mild TBI patients (N = 40) and a matched control group (N = 40) on a number of standard neuropsychological tests of selective and sustained attention, verbal and non-verbal fluency, and verbal memory. In addition, reaction time (RT) tasks, requiring both the inter- and intra-hemispheric processing of visual and tactile information, were used to assess the functional integrity of the tracts that are likely to be affected by diffuse damage. In the 1st month after sustaining their injury, the mild TBI group demonstrated deficits in attention, non-verbal fluency, and verbal memory. They also demonstrated slower visual and tactile RTs, with the visual RTs of mild TBI patients being more affected by increased task difficulty and the need to transfer information across the corpus callosum, than did their matched controls.

Redundant target effect and intersensory facilitation from visual-tactile interactions in simple reaction time.

In a simple reaction time (RT) task, normal observers responded faster to simultaneous visual and tactile stimuli than to single visual or tactile stimuli. RT to simultaneous visual and tactile stimuli was also faster than RT to simultaneous dual visual or tactile stimuli. The advantage for RT to combined visual-tactile stimuli over RT to the other types of stimulation could be accounted for by intersensory neural facilitation rather than by probability summation. The direction of gaze (and presumably of visual attention) to space regions near to or far from the site of tactile stimulation had no effect on tactile RT. However, RT to single or dual tactile stimuli was fastest when observers could see the sites of tactile stimulation on their hands both directly and through a mirror at the same time. All these effects can be ascribed to the convergence of tactile and visual inputs onto neural centers which contain flexible multimodal representations of body parts.