Peripheral Visual Stimuli Research Articles

Investigating the impact of early deafness on learned action-effect contingency for action linked to peripheral sensory effects

Investigating peripheral visual processing in individuals with early auditory deprivation is a critical research area in the field of neuroscience, since it helps understanding the phenomenon of sensory adaptation and brain plasticity after sensory loss. Prior research has already demonstrated that the absence of auditory input, which is crucial to detect events occurring out of the central egocentric visual space, leads to an improved processing of visual and tactile stimuli occurring in peripheral regions of the sensory space. Nevertheless, no prior studies have explored whether such enhanced processing also takes place within the domain of action, particularly when individuals are required to perform actions that produce peripheral sensory outcomes. To test this hypothesis, we recruited 15 hearing (31 ± 3.3 years) and 15 early deaf adults (42 ± 2.6 years) for a neuro-behavioral experiment involving: 1) a behavioral task where participants executed a simple motor action (i.e., a button press) and received a visual feedback either in the center or in a peripheral region of the visual field, and 2) the electrophysiological recording of brain electrical potentials (EEG). We measured and compared neural activity preceding the motor action (the readiness potentials) and visual evoked responses (the N1 and P2 ERP components) and found that deaf individuals did not exhibit more pronounced modulation of neural responses when their motor actions resulted in peripheral visual stimuli compared to their hearing counterparts. Instead they showed a reduced modulation when visual stimuli were presented in the center. Our results suggest a redistribution of attentional resources from center to periphery in deaf individuals during sensorimotor coupling.

A novel intervention for treating adults with ADHD using peripheral visual stimulation

ObjectiveStimulation of the peripheral visual field has been previously reported as beneficial for cognitive performance in ADHD. This study assesses the safety and efficacy of a novel intervention involving peripheral visual stimuli in managing attention deficit hyperactivity disorder (ADHD).MethodsOne hundred and eight adults, 18–40 years old, with ADHD, were enrolled in a two-month open-label study. The intervention (i.e., Neuro-glasses) consisted of standard eyeglasses with personalized peripheral visual stimuli embedded on the lenses. Participants were assessed at baseline and at the end of the study with self-report measures of ADHD symptoms (the Adult ADHD Self-Report Scale; ASRS), and executive functions (The Behavior Rating Inventory of Executive Function Adult Version; BRIEF-A). A computerized test of continuous performance (The Conners’ Continuous Performance Test-3; CPT-3) was tested at baseline with standard eyeglasses and at the end of study using Neuro-glasses. The Clinical Global Impression-Improvement scale (CGI-I) was assessed at the intervention endpoint. Safety was monitored by documentation of adverse events.ResultsThe efficacy analysis included 97 participants. Significant improvements were demonstrated in self-reported measures of inattentive symptoms (ASRS inattentive index; p = 0.037) and metacognitive functions concerning self-management and performance monitoring (BRIEF-A; p = 0.029). A continuous-performance test (CPT-3) indicated significant improvement in detectability (d’; p = 0.027) and reduced commission errors (p = 0.004), suggesting that the Neuro-glasses have positive effects on response inhibition. Sixty-two percent of the participants met the response criteria assessed by a clinician (CGI-I). No major adverse events were reported.ConclusionNeuro-glasses may offer a safe and effective approach to managing adult ADHD. Results encourage future controlled efficacy studies to confirm current findings in adults and possibly children with ADHD.Clinical trial registration: https://www.clinicaltrials.gov/, Identifier NCT05777785.

Enhanced memory for central visual and auditory elements experienced during a stressful episode

Acute psychosocial stress has been shown to benefit memory for central visual elements of a stressful episode. Here, we aimed at investigating whether this effect is accompanied by improved visual memory for the committee members in a modified version of the Trier Social Stress Test (TSST). Specifically, we tested participants´ recognition memory for accessories located on the bodies of the committee members, as well as their faces. Moreover, we investigated how stress influences memories for the content of the verbal interactions. That is, we studied how well participants remembered factual information associated with the main stress source, like name, age, and position of the committee members, as well as how accurately they could recite the exact wording of phrases used by them. In a counterbalanced 2 × 2 design, 77 men and women took part either in a stressful or non-stressful version of the TSST. While stressed participants better remembered personal information about the committee members than non-stressed participants, no differences in memory for the correct wording of phrases could be observed. Furthermore, in line with our hypothesis, stressed participants better remembered central, but not peripheral visual stimuli, compared to non-stressed participants, while, contrary to our expectations, stress did neither affect memory for objects located on the bodies of the committee members nor their faces. Our results are in line with the theory of enhanced memory binding under stress and extend previous results regarding improved memory for central visual elements encoded under stress to auditory learning material associated with the stressor.

Efficient use of peripheral information for temporal prediction

We adapt to the environment by predicting subsequent events. Generally, intervals between predictions and events make it difficult to predict the events accurately. Previous studies reported that using peripheral information is useful for maintaining predictions of subsequent events; however, it remains unclear how this information maintains the accuracy of the prediction. I presented peripheral visual stimuli in a discrimination task and manipulated the number of times these stimuli were presented while participants were waiting for a task-relevant visual stimulus, and compared participants’ response times and event-related brain potentials in Experiment 1. In addition, the influence of the difficulty of predicting the task-relevant visual stimulus was examined in Experiment 2. In both experiments, contingent negative variation (CNV) amplitude immediately before the task-relevant visual stimulus appeared was larger under the condition where many peripheral visual stimuli were presented, and the response time was shorter under this condition. In addition, the largest CNV amplitude under this condition was elicited by the third peripheral visual stimulus, followed in order by the first and second peripheral visual stimuli. These results show that we can predict the timing of events that occur with a delay after the prediction by using peripheral information. Moreover, this peripheral information is processed according to the importance of predicting a task-relevant stimulus, and attentional resources are allocated efficiently. These results provide evidence of the predictive function for temporal prediction of using peripheral information and the allocation of cognitive resources.

Visual and Auditory Spatial Localization in Younger and Older Adults.

Visual and auditory localization abilities are crucial in real-life tasks such as navigation and social interaction. Aging is frequently accompanied by vision and hearing loss, affecting spatial localization. The purpose of the current study is to elucidate the effect of typical aging on spatial localization and to establish a baseline for older individuals with pathological sensory impairment. Using a verbal report paradigm, we investigated how typical aging affects visual and auditory localization performance, the reliance on vision during sound localization, and sensory integration strategies when localizing audiovisual targets. Fifteen younger adults (N = 15, mean age = 26 years) and thirteen older adults (N = 13, mean age = 68 years) participated in this study, all with age-adjusted normal vision and hearing based on clinical standards. There were significant localization differences between younger and older adults, with the older group missing peripheral visual stimuli at significantly higher rates, localizing central stimuli as more peripheral, and being less precise in localizing sounds from central locations when compared to younger subjects. Both groups localized auditory targets better when the test space was visible compared to auditory localization when blindfolded. The two groups also exhibited similar patterns of audiovisual integration, showing optimal integration in central locations that was consistent with a Maximum-Likelihood Estimation model, but non-optimal integration in peripheral locations. These findings suggest that, despite the age-related changes in auditory and visual localization, the interactions between vision and hearing are largely preserved in older individuals without pathological sensory impairments.

Persian emotion elicitation film set and signal database

Emotions are associated to human central and peripheral nervous system activity and visual stimulus has the potential to invoke emotions. In the field of emotion analysis and recognition, films are widely used due to their similarity to real-life situations and various film sets have been collected in different languages. In this work, we present the PEEFS (Persian Emotion Elicitation Film Set) collection. According to the authors’ knowledge, Persian Emotion Elicitation Film Set (PEEFS) is the first emotion elicitation Persian film set that has been collected and validated by an 88-person population using an online server-based website created in this work. We have watched 84 most-watched Iranian films to trim emotional segments, and the final set consists of 21 film clips, duration from 20 to 100 s, with discrete labeling based on six basic emotions and ratings in two dimensions of arousal and valence. These 21 film clips have the highest intensity at each target emotion. In addition, emotion scores of the film clips are also included. This database can be used to stimulate emotions and to design automatic emotion recognition systems at different levels. In this work, a signal database has been provided by recording 2 channels of forehead EEG (Fp1 and Fp2) and 8 peripheral signals that include ECG lead II, GSR, trapezius and zygomatic EMG (tEMG and zEMG), vertical EOG (vEOG), finger pulse, Respiratory signal and skin temperature, using the PEEFS film set and selected film clips from the previous English and French databases.

Quantification of gaze reaction time in infants with Pediatric Perimeter.

PurposeWe quantified the eye/head (gaze) reaction time in infants to establish a normative database for the Pediatric Perimeter device. Additionally, we tested the hypothesis that gaze reaction time will reduce with age.MethodsA cross-sectional study was conducted. Healthy infants between 3 to 10 months of age were recruited. Peripheral visual field stimuli (hemifield and quadrant stimuli) were presented in the Pediatric Perimeter device. Infant’s gaze to these stimuli was observed, documented in real time, and video recorded for offline analysis.ResultsA total of 121 infants were tested in three age group bins [3–5 months, n = 44; >5–7 months, n = 30 and >7–10 months, n = 47]. Overall, 3–5 months old had longer reaction time when compared to the older infants particularly for stimuli presented in the quadrants (Kruskal-Wallis, p<0.038). A significantly asymmetric difference (p = 0.025) in reaction time was observed between the upper (median = 820ms, IQR = 659-1093ms) and lower quadrants (median = 601ms, IQR = 540-1052ms) only for the 3–5 months old infants.ConclusionThis study provides the normative gaze reaction time of healthy infants. With increase in age, there is reduction in reaction time and disappearance of reaction time asymmetry in quadrant stimuli. The longer reaction time for upward gaze could be due to delayed maturation of neural mechanisms and/or decreased visual attention.

EFFECTS OF VARYING FACEMASK REINFORCEMENT ON REACTION TIME AND TARGET DETECTION IN NCAA FOOTBALL PLAYERS

PURPOSE: Football helmet facemasks have been shown to differentially alter visual field. We have previously shown that peripheral vision reaction time (PRT) and target detection are hindered while wearing football headgear. However, whether different levels of facemask reinforcement alter ability to respond to peripheral visual stimuli is unknown. The purpose of this study was to examine the effects of varying facemask reinforcement on PRT and target detection in collegiate football players. METHODS: Division 1 NCAA football players with normal/corrected to normal vision participated. In a randomized manner, participants completed peripheral reaction time tests for the following conditions: Baseline/no helmet (BL), Light reinforced (L), Medium reinforced (M), Heavy reinforced (H), and Extra-heavy reinforced (XH) face masks. For each condition, a 60 s PRT test was completed on a Dynavision D2 visuomotor board. Subjective perception of how levels of reinforcement would affect field performance was assessed with a 7-point Likert scale questionnaire. RESULTS: Regardless of reinforcement, all facemask conditions resulted in significantly slower average PRT and lower target hits compared to BL (p < 0.05). No differences for PRT or target hits were observed between L, M, or H conditions. PRT was significantly slower for the XH condition versus L (p = 0.003), M (p = 0.001), H (p = 0.004). Additionally, target hits were significantly lower for the XH condition versus L (p = 0.010), M (p = 0.009), H (p = 0.016). Subjectively, participants believed that the H and XH facemasks would make their performance worse on the field compared to L or M (p < 0.05). CONCLUSIONS: Wearing a helmet irrespective of facemask reinforcement worsens PRT and target detection. However, only extra-heavy facemask reinforcement potentiates impairments in the ability to detect and respond to peripheral stimuli. Since unobstructed vision on the field is important for safety and performance, these findings may have important implications on equipment regulations for safety in collegiate football.

Audiovisual integration improves task performance in AD and bvFTD

AbstractBackgroundComplex analysis of sensory inputs, such as auditory scene analysis and spatial localisation, is impaired in Alzheimer’s disease (AD) and behavioural variant frontotemporal dementia (bvFTD). Multisensory integration research demonstrates that synchronous stimulation in one sense (e.g. vision) can modify processing of suboptimal sensory inputs from another sense (e.g. hearing) in the healthy brain. However, the potential benefit of multisensory stimulation to reduce common symptoms in dementia has not been fully examined.MethodPatients living with AD (n = 20) or bvFTD (n = 12), and healthy age‐matched controls (n = 18) were recruited to perform three brief cognitive tasks: 1. Cocktail party effect, identify a name spoken in a noisy environment; 2. Spatial ventriloquism, discriminate the location of an auditory stimulus (left/right of centre); and 3. Detect a suboptimal visual stimulus. Task performance was compared between unisensory, audiovisual congruent, and audiovisual incongruent conditions, and between groups.Result1. Identification of spoken names in a noisy auditory environment was significantly worse for both patient groups than controls. All groups performed significantly better when viewing an accompanying video of congruent lip movements. The AD group showed some improvement for incongruent videos that cued the onset of the spoken name. 2. Auditory spatial discrimination was significantly worse in the AD group than controls, but both groups were significantly biased by the locations of the accompanying visual stimulus. The bvFTD group was only influenced by spatially incongruent visual stimulation. 3. Detection of a near‐threshold peripheral visual stimulus was improved by a synchronous auditory stimulus, irrespective of spatial congruency, in the bvFTD and control groups. In the AD group, only spatially congruent or neutral auditory stimuli benefitted visual stimulus detection.ConclusionCongruent audiovisual stimulation improves the ability of people living with AD or bvFTD to understand voices in a noisy environment, locate auditory sounds, and detect unreliable visual events. Congruency of audiovisual stimulation in different domains (e.g. semantic, spatial) provides evidence for disease‐specific stratification of multisensory integration profiles. As such, multisensory integration provides a mechanism to improve reliability of sensory inputs and the potential to alleviate symptoms in daily life if tailored according to disease.

Triggering microsaccades by foveal motor error is sufficient to modulate peripheral visual sensitivity: neural and perceptual evidence

Visual processing is frequently interspersed with saccades, which are associated with strong peri-movement changes in neural and perceptual sensitivity. With fixed gaze, for controlled experiments on processes like covert attention, microsaccades still occur. During the past two decades, it became clear that microsaccades are not random (Hafed and Clark, 2002; Engbert and Kliegl, 2003), but instead exhibit predictable correlations with enhanced or decreased peripheral visual sensitivity (in multiple brain areas) and perception. These time-locked changes appear at eccentricities 1-2 orders of magnitude larger than the eye movement endpoints themselves. However, it remains unclear whether it is microsaccades, perhaps through their motor preparatory activity, that causally influence visual sensitivity, or whether visual sensitivity is itself modulated independently of microsaccades, maybe through oscillatory brain-state fluctuations; in this case, it is such modulations that “leak” into the motor system and trigger microsaccades. Here, motivated by (Hafed and Clark, 2002), in which no attentional effects were present in the absence of microsaccades, we tested the former hypothesis. We used real-time retinal image stabilization to introduce foveal motor errors at fixation (~0.06 deg) and causally drive microsaccades in an experimentally-controlled direction. We then presented peripheral (>5 deg) visual stimuli congruent or incongruent with microsaccade direction and recorded monkey superior colliculus (SC) activity. We found enhanced visual sensitivity and faster reaction times for microsaccade-congruent stimuli as a result of causally-generated microsaccades. In humans, we adapted a known task for pre-saccadic perceptual sensitivity (Rolfs & Carrasco, 2012) for microsaccades: subjects fixated, and we shifted the fixation spot by ~0.18 deg right or left to trigger microsaccades; the actual perceptual task (contrast comparison) was done for stimuli at 7 deg. Peripheral contrast sensitivity was enhanced before experimentally-manipulated microsaccades congruent with stimulus location, consistent with the neurophysiological results. Thus, foveal motor activity is sufficient to influence peripheral visual sensitivity.

Associations Between Neonatal Cry Acoustics and Visual Attention During the First Year.

It has been suggested that early cry parameters are connected to later cognitive abilities. The present study is the first to investigate whether the acoustic features of infant cry are associated with cognitive development already during the first year, as measured by oculomotor orienting and attention disengagement. Cry sounds for acoustic analyses (fundamental frequency; F0) were recorded in two neonatal cohorts at the age of 0–8 days (Tampere, Finland) or at 6 weeks (Cape Town, South Africa). Eye tracking was used to measure oculomotor orienting to peripheral visual stimuli and attention disengagement from central stimuli at 8 months (Tampere) or at 6 months (Cape Town) of age. Only a marginal positive correlation between fundamental frequency of cry (F0) and visual attention disengagement was observed in the Tampere cohort, but not in the Cape Town cohort. This correlation indicated that infants from the Tampere cohort with a higher neonatal F0 were marginally slower to shift their gaze away from the central stimulus to the peripheral stimulus. No associations between F0 and oculomotor orienting were observed in either cohort. We discuss possible factors influencing the current pattern of results suggesting a lack of replicable associations between neonatal cry and visual attention and suggest directions for future research investigating the potential of early cry analysis in predicting later cognitive development.

Mapping neural dynamics underlying saccade preparation and execution and their relation to reaction time and direction errors.

Our ability to control and inhibit automatic behaviors is crucial for negotiating complex environments, all of which require rapid communication between sensory, motor, and cognitive networks. Here, we measured neuromagnetic brain activity to investigate the neural timing of cortical areas needed for inhibitory control, while 14 healthy young adults performed an interleaved prosaccade (look at a peripheral visual stimulus) and antisaccade (look away from stimulus) task. Analysis of how neural activity relates to saccade reaction time (SRT) and occurrence of direction errors (look at stimulus on antisaccade trials) provides insight into inhibitory control. Neuromagnetic source activity was used to extract stimulus‐aligned and saccade‐aligned activity to examine temporal differences between prosaccade and antisaccade trials in brain regions associated with saccade control. For stimulus‐aligned antisaccade trials, a longer SRT was associated with delayed onset of neural activity within the ipsilateral parietal eye field (PEF) and bilateral frontal eye field (FEF). Saccade‐aligned activity demonstrated peak activation 10ms before saccade‐onset within the contralateral PEF for prosaccade trials and within the bilateral FEF for antisaccade trials. In addition, failure to inhibit prosaccades on anti‐saccade trials was associated with increased activity prior to saccade onset within the FEF contralateral to the peripheral stimulus. This work on dynamic activity adds to our knowledge that direction errors were due, at least in part, to a failure to inhibit automatic prosaccades. These findings provide novel evidence in humans regarding the temporal dynamics within oculomotor areas needed for saccade programming and the role frontal brain regions have on top‐down inhibitory control.

Effects of Protective American Football Headgear on Peripheral Vision Reaction Time and Visual Target Detection in Division I NCAA Football Players.

The purpose of this study was to examine the effects of protective football headgear on peripheral vision reaction time and visual target detection. Twenty-five Division I NCAA football players (age = 20.5 yrs ± 0.9, height = 185.9 cm ± 6.8, body mass = 99.2 kg ± 19.2, BMI = 29.6 ± 4.5) participated. In a crossover counterbalanced study design, subjects participated in one visit with three conditions: Baseline (BL) without headgear, helmet only (HO), helmet with an eye shield (HE). Subjects completed a 1-min peripheral vision reaction time test for each condition separated by 3-min recovery periods. Tests were administered using a 64 light Dynavision D2 Visuomotor board. Target detection (total hit score) was higher during BL than HO (p < 0.001) and HE (p < 0.001). Average (p < 0.001), peak (p < 0.001), minimum (p < 0.001), and median (p < 0.001) peripheral reaction times were faster during BL than HO and HE. No significant differences were observed for any measures between HO and HE conditions (p > 0.05). Findings indicate that protective football headgear impaired reaction time to peripheral visual stimuli. The addition of an eye shield to the helmet had a small non-significant effect on reaction time and target detection. These results may hold important implications in helmet design and player safety.

Effects of stimulus position on the classification of miniature asymmetric VEPs for brain-computer interfaces.

The speed of visual brain-computer interfaces (BCIs) has been greatly improved in recent years. However, traditional visual BCI paradigm requires users to directly gaze at the intensive flickering items, which would cause severe problems in practical applications, such as visual fatigue and excessive visual resources consumption. A promising solution is to use small visual stimuli outside the central visual area to encode instructions, which had been demonstrated to be effective in our previous study. This study aims to further investigate the effects of stimulus position on the classification of miniature asymmetric visual evoked potentials (aVEPs). Small peripheral visual stimuli were designed with different eccentricities (1° and 2°) and directions (0°, 45°, 90°, 135°, 180°, -135°, -90°, and -45°) to induce different kinds of miniature aVEPs. Five subjects participated in this experiment. Discriminative canonical pattern matching (DCPM) was used to classify all possible pairs of miniature aVEPs. Study results showed that visual stimuli with less eccentricity could induce more distinct miniature aVEPs. The highest single-trial accuracy achieved was about 83% for the binary classifications of miniature aVEPs pairs corresponding to (1°, -135°) Vs (1°, 0°), (1°, -45°) Vs (1°, -135°) and (1°, -45°) Vs (1°, 180°). This finding is very important for the design and development of the miniature aVEPs-based BCIs.

Ocular drift reflects volitional action preparation.

Human cognitive behavior is predictive rather than reflexive because of volitional action preparation. Recent studies have shown that the covert process of volitional action preparation can be decoded from overt fixational eye movements of fixational/microsaccades and pupil dilation. Ocular drift, the slowest fixational eye movements, is also under the active neural control, but its relationship with cognitive behavior is unknown. Here, we examined whether ocular drift also reflects volitional action preparation. We analyzed ocular drift while adult humans maintained fixation on a central visual stimulus as they prepared to generate a volitional saccade. We adopted the antisaccade paradigm in which subjects generate a targeting saccade toward the opposite direction of a peripheral visual stimulus. Our findings are the following five points. First, ocular drift was slower when subjects prepared for targeting saccade initiation than when such preparation was unnecessary. Second, ocular drift was slowed down with elapsed time from fixation initiation, which was associated with the facilitation of targeting saccade initiation. Third, ocular drift was further slowed on correct antisaccade trials than when subjects failed to suppress targeting saccades toward peripheral stimuli. Fourth, such correlation with antisaccade performance was observed immediately after fixation initiation in ocular drift, but it emerged more slowly in the other fixational eye movements. Fifth, subjects with unstable fixation because of faster ocular drift had poorer antisaccade performance. We suggest that fixation stability measured by ocular drift can be used to decode the covert process of volitional action preparation along with the other fixational eye movements.

Modeling Saccadic Action Selection: Cortical and Basal Ganglia Signals Coalesce in the Superior Colliculus.

The distributed nature of information processing in the brain creates a complex variety of decision making behavior. Likewise, computational models of saccadic decision making behavior are numerous and diverse. Here we present a generative model of saccadic action selection in the context of competitive decision making in the superior colliculus (SC) in order to investigate how independent neural signals may converge to interact and guide saccade selection, and to test if systematic variations can better replicate the variability in responses that are part of normal human behavior. The model was tasked with performing pro- and anti-saccades in order to replicate specific attributes of healthy human saccade behavior. Participants (ages 18–39) were instructed to either look toward (pro-saccade, well-practiced automated response) or away from (anti-saccade, combination of inhibitory and voluntary responses) a peripheral visual stimulus. They generated express and regular latency saccades in the pro-saccade task. In the anti-saccade task, correct reaction times were longer and participants occasionally looked at the stimulus (direction error) at either express or regular latencies. To gain a better understanding of the underlying neural processes that lead to saccadic action selection and response inhibition, we implemented 8 inputs inspired by systems neuroscience. These inputs reflected known sensory, automated, voluntary, and inhibitory components of cortical and basal ganglia activity that coalesces in the intermediate layers of the SC (SCi). The model produced bimodal reaction time distributions, where express and regular latency saccades had distinct modes, for both correct pro-saccades and direction errors in the anti-saccade task. Importantly, express and regular latency direction errors resulted from interactions of different inputs in the model. Express latency direction errors were due to a lack of pre-emptive fixation and inhibitory activity, which aloud sensory and automated inputs to initiate a stimulus-driven saccade. Regular latency errors occurred when the automated motor signals were stronger than the voluntary motor signals. While previous models have emulated fewer aspects of these behavioral findings, the focus of the simulations here is on the interaction of a wide variety of physiologically-based information integration producing a richer set of natural behavioral variability.

A rapid visuomotor response on the human upper limb is selectively influenced by implicit motor learning.

How do humans learn to adapt their motor actions to achieve task success? Recent behavioral and patient studies have challenged the classic notion that motor learning arises solely from the errors produced during a task, suggesting instead that explicit cognitive strategies can act in concert with the implicit, error-based, motor learning component. In this study, we show that the earliest wave of directionally tuned neuromuscular activity that begins within ~100 ms of peripheral visual stimulus onset is selectively influenced by the implicit component of motor learning. In contrast, the voluntary neuromuscular activity associated with reach initiation, which evolves ~100-200 ms later, is influenced by both the implicit and explicit components of motor learning. The selective influence of the implicit, but not explicit, component of motor learning on the directional tuning of the earliest cascade of neuromuscular activity supports the notion that these components of motor learning can differentially influence descending motor pathways. NEW & NOTEWORTHY Motor learning can be driven both by an implicit error-based component and an explicit strategic component, but the influence of these components on the descending pathways that contribute to motor control is unknown. In this study, we show that the implicit component selectively influences a reflexive circuit that rapidly generates a visuomotor response on the human upper limb. Our results show that the substrates mediating implicit and explicit motor learning exert distinct influences on descending motor pathways.

Detection of visual stimuli on monocular peripheral head-worn displays

ObjectiveTo compare people's ability to detect peripherally presented stimuli on a monocular head-worn display (HWD) versus a conventional screen. BackgroundVisual attention capture has been systematically investigated, but not with respect to HWDs. How stimulus properties affect attention capture is likely to be different on an HWD when compared to a traditional computer display. MethodParticipants performed an ongoing perceptual task and attempted to detect stimuli that were displayed peripherally on either a computer monitor or a monocular HWD. ResultsParticipants were less able to detect peripheral stimuli when the stimuli were presented on a HWD than when presented on a computer monitor. Moreover, the disadvantage of the HWD was more pronounced when peripheral stimuli were less distinct and when the stimuli were presented further into the periphery. ConclusionPresenting stimuli on a monocular head-worn display reduces participants' ability to notice peripheral visual stimuli compared to presentation on a normal computer monitor. This effect increases as stimuli are presented further in the periphery, but can be ameliorated to a degree by using high-contrast stimuli. ApplicationThe findings are useful for designers creating visual stimuli intended to capture attention when viewed on a peripherally positioned monocular head-worn display.

Fixating at far distance shortens reaction time to peripheral visual stimuli at specific locations.

The purpose of the present study was to examine whether the fixation distance in real three-dimensional space affects manual reaction time to peripheral visual stimuli. Light-emitting diodes were used for presenting a fixation point and four peripheral visual stimuli. The visual stimuli were located at a distance of 45cm and at 25° in the left, right, upper, and lower directions from the sagittal axis including the fixation point. Near (30cm), Middle (45cm), Far (90cm), and Very Far (300cm) fixation distance conditions were used. When one of the four visual stimuli was randomly illuminated, the participants released a button as quickly as possible. Results showed that overall peripheral reaction time decreased as the fixation distance increased. The significant interaction between fixation distance and stimulus location indicated that the effect of fixation distance on reaction time was observed at the left, right, and upper locations but not at the lower location. These results suggest that fixating at far distance would contribute to faster reaction and that the effect is specific to locations in the peripheral visual field. The present findings are discussed in terms of viewer-centered representation, the focus of attention in depth, and visual field asymmetry related to neurological and psychological aspects.

Spatial modulation of motor-sensory recalibration in early deaf individuals.

Audition dominates other senses in temporal processing, and in the absence of auditory cues, temporal perception can be compromised. Moreover, after auditory deprivation, visual attention is selectively enhanced for peripheral visual stimuli. In this study, we assessed whether early hearing loss affects motor-sensory recalibration, the ability to adjust the timing of an action and its sensory effect based on the recent experience. Early deaf participants and hearing controls were asked to discriminate the temporal order between a motor action (a keypress) and a visual stimulus (a white circle) before and after adaptation to a delay between the two events. To examine the effects of spatial modulation, we presented visual stimuli in both central and peripheral visual fields. Results showed overall higher temporal JNDs (Just Noticeable Difference) for deaf participants as compared to hearing controls suggesting that the auditory information is important for the calibration of motor-sensory timing. Adaptation to a motor-sensory delay induced distinctive effect in the two groups of participants, with hearing controls showing a recalibration effect for central stimuli only whereas deaf individuals for peripheral visual stimuli only. Our results suggest that auditory deprivation affects motor-sensory recalibration and that the mechanism underlying motor-sensory recalibration is susceptible to spatial modulation.