Impact of acute open-skill exercise on inhibitory control and brain activation: A functional near-infrared spectroscopy study.

There is a growing body of literature demonstrating that a single bout of exercise benefits executive cognitive function. While the acute effect of closed-skill exercises like walking, running, and cycling has been well investigated, it is less clear how open-skill exercise impacts executive function and brain activation. Therefore, we compared the acute effects of an open-skill exercise on inhibitory control and brain activation with those of a closed-skill exercise using functional near-infrared spectroscopy (fNIRS). Twenty-four young right-hand dominant adults (9 women) completed three interventions: badminton, running, and a seated rest control condition for 10 min each. The intensities of badminton and running were comparable. During each intervention, oxygen uptake and heart rate were monitored. A Stroop task composed of neutral and incongruent conditions was administrated before and after each intervention. An fNIRS system recorded hemodynamics in the prefrontal cortex to evaluate brain activation during the Stroop task. Performance on the Stroop task was significantly improved after badminton, specifically in the incongruent condition relative to in the neutral condition. On the other hand, neither running nor seated rest affected performance in the Stroop task. The fNIRS measures indicated that badminton and running had no significant influence on brain activation. These results show that a single bout of open-skill exercise enhances inhibitory control without increasing brain activation compared to closed-skill exercise, suggesting that an acute open-skill exercise induces neural efficiency.

Implicit expectation modulates multisensory perception.

Stimulus statistics can induce expectations that in turn can influence multisensory perception. In three experiments, we manipulate perceptual history by biasing stimulus statistics and examined the effect of implicit expectations on the perceptual resolution of a bistable visual stimulus that is modulated by sound. First, we found a general effect of expectation such that responses were biased in line with the biased statistics and interpret this as a bias towards an implicitly expected outcome. Second, expectation did not influence the perception of all types of stimuli. In both Experiment 1 and Experiment 2, integrated audio-visual stimuli were affected by expectation but visual-only and unintegrated audio-visual stimuli were not. In Experiment 3 we examined the sensory versus interpretational effects of expectation and found that contrary to our predictions, an expectation of audio-visually integrated stimuli was associated with impaired multisensory integration compared to visual-only or unintegrated audio-visual stimuli. Our findings suggest that perceptual experience implicitly creates expectations that influence multisensory perception, which appear to be about perceptual outcomes rather than sensory stimuli. Finally, in the case of resolving perceptual ambiguity, the expectation effect is an effect on cognitive rather than sensory processes.

Aptitude and attitude: predictors of performance during and after basic laparoscopic skills training.

BACKGROUND: Manual dexterity and visual-spatial ability are considered key to the development of superior laparoscopic skills. Nevertheless, these abilities do not reliably explain all the variance found in the technical performance of surgical trainees. Consequently, we must look beyond these abilities to improve our understanding of laparoscopic skills and to better identify/develop surgical potential earlier on. PURPOSE: To assess the individual and collective impact of physical, cognitive, visual, and psychological variables on performance during and after basic simulation-based laparoscopic skills training. METHOD: Thirty-four medical students (laparoscopic novices) completed a proficiency-based laparoscopic skills training program (using either a 2D or 3D viewing mode). This was followed by one testing session, a follow-up testing session with new (yet similar) tasks, and a series of physical, cognitive, visual, and psychological measures. RESULTS: The statistical models that best predicted variance in training performance metrics included four variables: viewing mode (2D vs 3D), psychological flexibility, perceived task demands, and manual dexterity (bimanual). In subsequent testing, a model that included viewing mode and manual dexterity (assembly) best predicted performance on the pre-practiced tasks. However, for a highly novel, spatially complex laparoscopic task, performance was best predicted by a model that comprised viewing mode, visual-spatial ability, and perceived task demands. At follow-up, manual dexterity (assembly) alone was the best predictor of performance on new (yet similar) tasks. CONCLUSION: By focussing exclusively on physical/cognitive abilities, we may overlook other important predictors of surgical performance (e.g. psychological variables). The present findings suggest that laparoscopic performance may be more accurately explained through the combined effects of physical, cognitive, visual, and psychological variables. Further, the results suggest that the predictors may change with both task demands and the development of the trainee. This study highlights the key role of psychological skills in overcoming initial training challenges, with far-reaching implications for practice.

The effects of recent perceptual history on stream-bounce perception.

We examine perceptual disambiguation and crossmodal interactions by considering the effect of recent perceptual history on stream-bounce perception. First, we tested the assumption that the audio-visual stream-bounce effect (visual-only trials mostly stream, whereas audio-visual trials mostly bounce) reflects some intrinsic preference for streaming that is broken by sound. Instead, we found that for naïve observers, visual-only stimuli are bistable and bias free. In intermixed trials, sound acts as a polarizing factor (rather than a bounce-inducing factor) and has as much effect on visual-only trials as it does on audio-visual trials. Second, temporal context exerts a comparative influence and exposure to audio-visual stimuli influences responses to visual-only stimuli and vice-versa. Finally, there is a serial dependence in responses and the current stimulus (unisensory or multisensory) is interpreted with a bias to recent interpretations. Recent perceptual history exerts a substantial influence on the perception of stream-bounce stimuli. This influence occurs in the unisensory case and is in line with an extensive literature on visual bistability; it extends to the multisensory case, and there are interactions between the 2 cases. Our combined findings support a role for top-down interpretational influences in the stream-bounce effect and stream-bounce perception more generally. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

The Lightness/Pitch Crossmodal Correspondence Modulates the Rubin Face/Vase Perception.

We examine whether crossmodal correspondences (CMCs) modulate perceptual disambiguation by considering the influence of lightness/pitch congruency on the perceptual resolution of the Rubin face/vase (RFV). We randomly paired a black-and-white RFV (black faces and white vase, or vice versa) with either a high or low pitch tone and found that CMC congruency biases the dominant visual percept. The perceptual option that was CMC-congruent with the tone (white/high pitch or black/low pitch) was reported significantly more often than the perceptual option CMC-incongruent with the tone (white/low pitch or black/high pitch). However, the effect was only observed for stimuli presented for longer and not shorter durations suggesting a perceptual effect rather than a response bias, and moreover, we infer an effect on perceptual reversals rather than initial percepts. We found that the CMC congruency effect for longer-duration stimuli only occurred after prior exposure to the stimuli of several minutes, suggesting that the CMC congruency develops over time. These findings extend the observed effects of CMCs from relatively low-level feature-based effects to higher-level object-based perceptual effects (specifically, resolving ambiguity) and demonstrate that an entirely new category of crossmodal factors (CMC congruency) influence perceptual disambiguation in bistability.

Laparoscopic skills training: the effects of viewing mode (2D vs. 3D) on skill acquisition and transfer.

BACKGROUND: Three-dimensional (3D) visual displays have been suggested to aid laparoscopic skills training by providing the depth cues not present in traditional two-dimensional (2D) displays. However, few studies have robustly investigated the impact of viewing mode (2D vs. 3D) on learning outcomes. PURPOSE: To examine how viewing mode (2D vs. 3D) impacts the acquisition and transferability of basic laparoscopic skills by comparing performance between transfer and control groups on a complete proficiency-based training program. METHOD: A counterbalanced between-subjects design was employed. Each participant was randomly allocated to one of four groups, comprising two transfer groups (trained in one viewing mode and tested in the alternate mode: the 2D → 3D and 3D → 2D groups) and two control groups (trained and tested in one viewing mode: the 2D → 2D and 3D → 3D groups). Participants completed proficiency-based training in six laparoscopic training tasks. Testing included two further repetitions of all tasks under test conditions. Objective performance measures included the total number of repetitions to reach proficiency, and total performance scores (i.e. time + error penalties across all repetitions) in training and testing. RESULTS: The groups trained in 3D demonstrated superior training performance (i.e. less time + errors) and took fewer repetitions to reach proficiency than the groups trained in 2D. The groups tested in 3D also demonstrated superior test performance compared to those tested in 2D. However, training mode did not yield significant test differences between the groups tested in 2D (i.e. 2D → 2D vs. 3D → 2D), or between the groups tested in 3D (i.e. 3D → 3D vs. 2D → 3D). CONCLUSION: Novices demonstrate superior performance in laparoscopic skills training using a 3D viewing mode compared to 2D. However, this does not necessarily translate to superior performance in subsequent testing or enhanced learning overall. Rather, test performance appears to be dictated by the viewing mode used during testing, not that of prior training.

The vergence horopter.

The horopter is defined by the criterion with which it is measured; these include the apparent frontoparallel plane, the region of binocular single vision, and identical visual direction. Another criterion is one that "the positions of the points are such that none provides a stimulus for fusional movement of the eyes". Measuring the horopter using this criterion is the aim of the current paper. Based on previous research investigating corresponding points, we predicted the vergence horopter should trace an arc similar to the empirical horizontal horopter. We further predicted based on the characteristics of vergence eye movements in the periphery, that the range of horizontal disparities that do not elicit a vergence movement would increase with eccentricity. In experiment 1 we conducted the first measurements of the vergence horopter along the horizontal plane of regard and sagittal planes. We found that the vergence horopter consists of a stable range of disparities that do not increase with eccentricity. In experiment 2, we measured Panum's fusional range for the same eccentricities and elevations to determine the placement of the vergence horopter within the fusional ranges. In the horizontal plane, the vergence horopter sits centrally within Panum's fusional range. In the vertical plane, the data are suggestive that the vergence horopter is less slanted than the corresponding fusional range.

Use of Stroop Test for Sports Psychology Study: Cross-Over Design Research.

Background: In sports psychology research, the Stroop test and its derivations are commonly used to investigate the benefits of exercise on cognitive function. The measures of the Stroop test and the computed interference often have different interclass correlation coefficients (ICC). However, the ICC is never reported in cross-over designs involving multiple variances associated with individual differences. Objective: We investigated the ICC of the Stroop neutral and incongruent tests and interference (neutral test-incongruent test), and reverse Stroop task using the linear mixed model. Methods: Forty-eight young adults participated in a cross-over design experiment composed of 2 factors: exercise mode (walking, resistance exercise, badminton, and seated rest as control) and time (pre- and post-tests). Before and after each intervention, participants completed the Stroop neutral and incongruent, and the reverse-Stroop neutral and incongruent tests. We analyzed for each test performance and interference and calculated ICC using the linear mixed model. Results: The linear mixed model found a significant interaction of exercise mode and time for both the Stroop and reverse-Stroop tasks, suggesting that exercise mode influences the effect of acute exercise on inhibitory function. On the other hand, there was no significant effect of exercise mode for both the Stroop and reverse-Stroop interference. The results also revealed that calculating both the Stroop and reverse-Stroop interference resulted in smaller ICCs than the ICCs of the neutral and incongruent tests for both the Stroop and reverse-Stroop tasks. Conclusion: The Stroop and reverse-Stroop interferences are known as valid measures of the inhibitory function for cross-sectional research design. However, to understand the benefits of acute exercise on inhibitory function comprehensively by cross-over design, comparing the incongruent test with the neutral test also seems superior because these tests have high reliability and statistical power.

The Relationship Between Illusory Crescents and the Stream/Bounce Effect.

We conducted two experiments to evaluate Meyerhoff and Scholl's (2018, Cognition 170, 88-94) hypothesis that illusory crescents contribute to resolutions in audiovisual stream/bounce displays. In Experiment 1, we measured illusory crescent size in the launching effect as a function of speed, overlap, and sound. In Experiment 2, we tabulated stream and bounce responses to similar stimuli with the same speed, sound, and overlap conditions as Experiment 1. Our critical manipulation of target speed spanned the range of values from typical stream/bounce investigations of ∼5 degrees/s up to the target speeds employed by Meyerhoff and Scholl ∼38 degrees/s. We replicated Meyerhoff and Scholl's findings at higher speeds, but not at slower speeds. Critically, we found that speed influenced crescent size judgements and bouncing responses in opposite directions. As target speed increased, illusory crescent size increased (Experiment 1), but the overall percentage of bounce responses decreased (Experiment 2). Additionally, we found that sound failed to enhance illusory crescent size at slower speeds but promotes bouncing responses at all speeds. The disassociation of the effects of speed and sound on illusory crescents with those effects on reported streaming/bouncing in similar displays provides compelling evidence against Meyerhoff and Scholl's hypothesis. Therefore, we conclude that illusory crescents do not account for the pattern of responses attributed to the stream/bounce effect.

Comparison of the effects of running and badminton on executive function: A within-subjects design.

Multiple cross-sectional studies have shown that regular complex exercises, which require cognitive demands (e.g., decision making) and various motions, are associated with greater positive effects on executive functions compared to simple exercises. However, the evidence of a single bout of complex exercises is mixed, and investigations on the acute effect of complex exercise using a well-controlled within-subjects research design are few. Therefore, we compared the acute effects of complex exercise on inhibitory functions with those of simple running. Twenty young adults performed three interventions, which were running, badminton, and seated rest as a control condition for 10 min each. During each intervention, oxygen consumption and heart rate were monitored. A Stroop test and a reverse-Stroop test were completed before and after each intervention. The intensities of the badminton and running were equivalent. Badminton significantly improved performance on the Stroop task compared to seated rest; however, running did not enhance performance on the Stroop task relative to seated rest. A single bout of complex exercise elicits a larger benefit to inhibitory function than a single bout of simple exercise. However, the benefit of complex exercise may vary depending on the type of executive functions.

Temporal dynamics of a perceptual decision.

Previous research suggests that cognitive factors acting in a top-down manner influence the perceptual interpretation of ambiguous stimuli. To examine the temporal unfolding of these influences as a perceptual decision evolves, we have implemented a modified version of the stream-bounce display. Our novel approach allows us to track responses to stream-bounce stimuli dynamically over the entire course of the motion sequence rather than collecting a subjective report after the fact. Using a trackpad, we had participants control a cursor to track a stream-bounce target actively from start to end and measured tracking speed throughout as the dependent variable. Our paradigm replicated the typical effect of visual-only displays being associated with a streaming bias and audiovisual displays with a bouncing bias. Our main finding is a significant behavioral change preceding a perceptual decision that then predicts that decision. Specifically, for trials in which the sound was presented, tracking speeds were significantly slower starting 500 ms before the point of coincidence and presentation of the sound for bounce compared to stream responses. We suggest that behavioral response may reflect a cognitive expectation of a perceptual outcome that then biases action and the interpretation of sensory input to favor that forthcoming percept in a manner consistent with both the predictive-coding and common-coding theoretical frameworks. Our approach provides a novel behavioral corroboration of recent imaging studies that are suggestive of early brain activity in perception and action.

Lightness/pitch and elevation/pitch crossmodal correspondences are low-level sensory effects.

We tested the sensory versus decisional origins of two established audiovisual crossmodal correspondences (CMCs; lightness/pitch and elevation/pitch), applying a signal discrimination paradigm to low-level stimulus features and controlling for attentional cueing. An audiovisual stimulus randomly varied along two visual dimensions (lightness: black/white; elevation: high/low) and one auditory dimension (pitch: high/low), and participants discriminated either only lightness, only elevation, or both lightness and elevation. The discrimination task and the stimulus duration varied between subjects. To investigate the influence of crossmodal congruency, we considered the effect of each CMC (lightness/pitch and elevation/pitch) on the sensitivity and criterion of each discrimination as a function of stimulus duration. There were three main findings. First, discrimination sensitivity was significantly higher for visual targets paired congruently (compared with incongruently) with tones while criterion was unaffected. Second, the sensitivity increase occurred for all stimulus durations, ruling out attentional cueing effects. Third, the sensitivity increase was feature specific such that only the CMC that related to the feature being discriminated influenced sensitivity (i.e. lightness congruency only influenced lightness discrimination and elevation congruency only influenced elevation discrimination in the single and dual task conditions). We suggest that these congruency effects reflect low-level sensory processes.

The Effect of Transient Location on the Resolution of Bistable Visual and Audiovisual Motion Sequences.

We examined the attention and inference accounts of audiovisual perception using the stream/bounce display, a visual stimulus wherein two identical objects move toward each other, completely superimpose, then move apart. This display has two candidate percepts: stream past each other or bounce off each other. Presented without additional visual or auditory transients, the motion sequence tends to yield the streaming percept, but when coupled with a tone or flash at the point of coincidence, the response bias flips toward bouncing. We explored two competing accounts of this effect: the attentional hypothesis and the inference hypothesis. Participants watched a series of motion sequences where a transient, when present, occurred at the moment of coincidence either colocalised with the motion sequence (congruent presentation) or on the opposite side of the display (incongruent presentation). Assuming the spotlight or zoom lens metaphor, an attentional account predicts that incongruent presentations should be associated with a higher percentage of bouncing responses than congruent presentations, while the inferential account predicts the opposite effect. No effect was found for tone-only trials. However, in trials containing a visual transient, results showed higher proportions of bounce responses within congruent over incongruent presentations, favouring the inference hypothesis over a spotlight or zoom lens attentional account.

The impact of crosstalk on three-dimensional laparoscopic performance and workload.

This is the first study to explore the effects of crosstalk from 3D laparoscopic displays on technical performance and workload. We studied crosstalk at magnitudes that may have been tolerated during laparoscopic surgery. Participants were 36 voluntary doctors. To minimize floor effects, participants completed their surgery rotations, and a laparoscopic suturing course for surgical trainees. We used a counterbalanced, within-subjects design in which participants were randomly assigned to complete laparoscopic tasks in one of six unique testing sequences. In a simulation laboratory, participants were randomly assigned to complete laparoscopic 'navigation in space' and suturing tasks in three viewing conditions: 2D, 3D without ghosting and 3D with ghosting. Participants calibrated their exposure to crosstalk as the maximum level of ghosting that they could tolerate without discomfort. The Randot® Stereotest was used to verify stereoacuity. The study performance metric was time to completion. The NASA TLX was used to measure workload. Normal threshold stereoacuity (40-20 second of arc) was verified in all participants. Comparing optimal 3D with 2D viewing conditions, mean performance times were 2.8 and 1.6 times faster in laparoscopic navigation in space and suturing tasks respectively (p< .001). Comparing optimal 3D with suboptimal 3D viewing conditions, mean performance times were 2.9 times faster in both tasks (p< .001). Mean workload in 2D was 1.5 and 1.3 times greater than in optimal 3D viewing, for navigation in space and suturing tasks respectively (p< .001). Mean workload associated with suboptimal 3D was 1.3 times greater than optimal 3D in both laparoscopic tasks (p< .001). There was no significant relationship between the magnitude of ghosting score, laparoscopic performance and workload. Our findings highlight the advantages of 3D displays when used optimally, and their shortcomings when used sub-optimally, on both laparoscopic performance and workload.

Sensitivity and Bias in the Resolution of Stream-Bounce Stimuli.

The audiovisual stream-bounce effect refers to the resolution of ambiguous motion sequences as streaming or bouncing depending on the presence or absence of a sound. We used a novel experimental design and signal detection theory (SDT) to determine its sensory or decisional origins. To account for issues raised by Witt et al. on the interpretation of SDT results, we devised a pure signal detection (as opposed to signal discrimination) paradigm and measured participants' sensitivity and criterion when detecting a weak tone concurrent with objectively streaming or bouncing visual displays. We observed no change in sensitivity but a significant change in criterion with participants' criterion more liberal with bouncing targets than for streaming targets with. In a second experiment, we tasked participants with detecting a weak tone in noise while viewing an ambiguous motion sequence. They also indicated whether the targets appeared to stream or bounce. Participants' reported equivalent, mostly bouncing responses for hit and false alarm trials, and equivalent, mostly streaming responses for correct rejection and miss trials. Further, differences in participants' sensitivity and criterion measures for detecting tones in subjectively streaming compared to subjectively bouncing targets were inconsistent with sensory factors. These results support a decisional account of the sound-induced switch from mostly streaming to mostly bouncing responses in audiovisual stream-bounce displays.

Low-Level Motion Characteristics Do Not Account for Perceptions of Stream-Bounce Stimuli.

The stream-bounce effect refers to a bistable motion stimulus that is interpreted as two targets either "streaming" past or "bouncing" off one another, and the manipulations that bias responses. Directional bias, according to Bertenthal et al., is an account of the effect proposing that low-level motion integration promotes streaming, and its disruption leads to bouncing, and it is sometimes cited either directly in a bottom-up fashion or indirectly under top-down control despite Sekuler and Sekuler finding evidence inconsistent with it. We tested two key aspects of the hypothesis: (a) comparable changes in speed should produce comparable disruptions and lead to similar effects; and (b) speed changes alone should disrupt integration without the need for additional more complex changes of motion. We found that target motion influences stream-bounce perception, but not as directional bias predicts. Our results support Sekuler and Sekuler and argue against the low-level motion signals driving perceptual outcomes in stream-bounce displays (directly or indirectly) and point to higher level inferential processes involving perceptual history and expectation. Directional bias as a mechanism should be abandoned and either another specific bottom-up process must be proposed and tested or consideration should be given to top-down factors alone driving the effect.

The viewpoint-specific failure of modern 3D displays in laparoscopic surgery.

PURPOSE: Surgeons conventionally assume the optimal viewing position during 3D laparoscopic surgery and may not be aware of the potential hazards to team members positioned across different suboptimal viewing positions. The first aim of this study was to map the viewing positions within a standard operating theatre where individuals may experience visual ghosting (i.e. double vision images) from crosstalk. The second aim was to characterize the standard viewing positions adopted by instrument nurses and surgical assistants during laparoscopic pelvic surgery and report the associated levels of visual ghosting and discomfort. METHODS: In experiment 1, 15 participants viewed a laparoscopic 3D display from 176 different viewing positions around the screen. In experiment 2, 12 participants (randomly assigned to four clinically relevant viewing positions) viewed laparoscopic suturing in a simulation laboratory. In both experiments, we measured the intensity of visual ghosting. In experiment 2, participants also completed the Simulator Sickness Questionnaire. RESULTS: We mapped locations within the dimensions of a standard operating theatre at which visual ghosting may result during 3D laparoscopy. Head height relative to the bottom of the image and large horizontal eccentricities away from the surface normal were important contributors to high levels of visual ghosting. Conventional viewing positions adopted by instrument nurses yielded high levels of visual ghosting and severe discomfort. CONCLUSIONS: The conventional viewing positions adopted by surgical team members during laparoscopic pelvic operations are suboptimal for viewing 3D laparoscopic displays, and even short periods of viewing can yield high levels of discomfort.