EEG camouflage project: To see or not to see: camouflage and human processes of detection

This data set contains behavioural and EEG output data from one experiment. It also includes pre-processing and analysis scripts, scripts used for running the experiment

An fMRI study of parietal cortex involvement in the visual guidance of locomotion

Locomoting through the environment typically involves anticipating impending changes in heading trajectory in addition to maintaining the current direction of travel. We explored the neural systems involved in the “far road” and “near road” mechanisms proposed by Land and Horwood (1995) using simulated forward or backward travel where participants were required to gauge their current direction of travel (rather than directly control it). During forward egomotion, the distant road edges provided future path information, which participants used to improve their heading judgments. During backward egomotion, the road edges did not enhance performance because they no longer provided prospective information. This behavioral dissociation was reflected at the neural level, where only simulated forward travel increased activation in a region of the superior parietal lobe and the medial intraparietal sulcus. Providing only near road information during a forward heading judgment task resulted in activation in the motion complex. We propose a complementary role for the posterior parietal cortex and motion complex in detecting future path information and maintaining current lane positioning, respectively. (PsycINFO Database Record (c) 2010 APA, all rights reserved

Reduced relative volume in motor and attention regions in developmental coordination disorder: a voxel-based morphometry study.

Background and Objectives: Developmental coordination disorder (DCD) is a prevalent childhood movement disorder, impacting the ability to perform movement skills at an age appropriate level. Although differences in grey matter (GM) volumes have been found in related developmental disorders, no such evidence has been linked with DCD to date. This cross-sectional study assessed structural brain differences in children with and without DCD. Methods: High-resolution structural images were acquired from 44 children aged 7.8–12 years, including 22 children with DCD (≤16th percentile on MABC-2; no ADHD/ASD), and 22 typically developing controls (≥20th percentile on MABC-2). Structural voxel-based morphology analysis was performed to determine group differences in focal GM volumes. Results: Children with DCD were found to have significant, large, right lateralised reductions in grey matter volume in the medial and middle frontal, and superior frontal gyri compared to controls. The addition of motor proficiency as a covariate explained the between-group GM volume differences, suggesting that GM volumes in motor regions are reflective of the level of motor proficiency. A positive correlation between motor proficiency and relative GM volume was also identified in the left posterior cingulate and precuneus. Conclusions: GM volume reductions in premotor frontal regions may underlie the motor difficulties characteristic of DCD. It is possible that intervention approaches targeting motor planning, attention, and executive functioning processes associated with the regions of reduced GM volume may result in functional improvements in children with DCD

Optimal use of visual information in adolescents and young adults with developmental coordination disorder

Recent reports offer contrasting views on whether or not the use of online visual control is impaired in individuals with developmental coordination disorder (DCD). This study explored the optimal temporal basis for processing and using visual information in adolescents and young adults with DCD. Participants were 22 adolescents and young adults (12 males and 10 females; M = 19 years, SD = 3). Half had been diagnosed with DCD as children and still performed poorly on the movement assessment battery for children (DCD group; n = 11), and half reported typical development (TD group; n = 11) and were age- and gender-matched with the DCD group. We used performance on a steering task as a measure of information processing and examined the use of advance visual information. The conditions varied the duration of advance visual information: 125, 250, 500, 750, and 1,000 ms. With increased duration of advance visual information, the TD group showed a pattern of linear improvement. For the DCD group, however, the pattern was best described by a U-curve where optimal performance occurred with about 750 ms of advance information. The results suggest that the DCD group has an underlying preference for immediate online processing of visual information. The exact timing for optimal online control may depend crucially on the task, but too much advance information is detrimental to performance

The involvement of the fronto-parietal brain network in oculomotor sequence learning using fMRI.

The basis of motor learning involves decomposing complete actions into a series of predictive individual components that form the whole. The present fMRI study investigated the areas of the human brain important for oculomotor short-term learning, by using a novel sequence learning paradigm that is equivalent in visual and temporal properties for both saccades and pursuit, enabling more direct comparisons between the oculomotor subsystems. In contrast with previous studies that have implemented a series of discrete ramps to observe predictive behaviour as evidence for learning, we presented a continuous sequence of interlinked components that better represents sequences of actions. We implemented both a classic univariate fMRI analysis, followed by a further multivariate pattern analysis (MVPA) within a priori regions of interest, to investigate oculomotor sequence learning in the brain and to determine whether these mechanisms overlap in pursuit and saccades as part of a higher order learning network. This study has uniquely identified an equivalent frontal-parietal network (dorsolateral prefrontal cortex, frontal eye fields and posterior parietal cortex) in both saccades and pursuit sequence learning. In addition, this is the first study to investigate oculomotor sequence learning during fMRI brain imaging, and makes significant contributions to understanding the role of the dorsal networks in motor learning

Cortical functioning in children with developmental coordination disorder:a motor overflow study

This study examined brain activation in children with developmental coordination disorder (DCD) to reveal areas that may contribute to poor movement execution and/or abundant motor overflow. Using functional magnetic resonance imaging, 13 boys with DCD (mean age = 9.6 years ±0.8) and 13 typically developing controls (mean age = 9.3 years ±0.6) were scanned performing two tasks (finger sequencing and hand clenching) with their dominant hand, while a four-finger motion sensor recorded contralateral motor overflow on their non-dominant hand. Despite displaying increased motor overflow on both functional tasks during scanning, there were no obvious activation deficits in the DCD group to explain the abundant motor overflow seen. However, children with DCD were found to display decreased activation in the left superior frontal gyrus on the finger-sequencing task, an area which plays an integral role in executive and spatially oriented processing. Decreased activation was also seen in the left inferior frontal gyrus, an area typically active during the observation and imitation of hand movements. Finally, increased activation in the right postcentral gyrus was seen in children with DCD, which may reflect increased reliance on somatosensory information during the execution of complex fine motor tasks

Error accumulation when steering toward curves

To steer a vehicle, humans must process incoming signals that provide information about their movement through the world. These signals are used to inform motor control responses that are appropriately timed and of the correct magnitude. However, the perceptual mechanisms determining how drivers process visual information remain unclear. Previous research has demonstrated that when steering toward a straight road-line, drivers accumulate perceptual evidence (error) over time to initiate steering action (Accumulator framework), rather than waiting for perceptual evidence to surpass time-independent fixed thresholds (Threshold framework). The more general case of steering around bends (with a requirement that the trajectory is adjusted to match the road curvature ahead) provides richer continuously varying information. The current experiment aims to establish whether the Accumulator framework provides a good description of human responses when steering toward curved road-lines. Using a computer-generated steering correction paradigm, drivers (N=11) steered toward intermittently appearing curved road-lines that varied in position and radius with respect to the driver’s trajectory. A Threshold framework predicted that steering responses would be of fixed magnitude and at fixed absolute errors across conditions regardless of the rate of error development. Conversely, the Accumulator framework predicted that drivers should respond to larger absolute errors when the error signal developed at a faster rate. Results were consistent with an Accumulator framework in a manner that supports previous investigations and the computational modelling literature. We propose that accumulation of perceptual evidence captures human behaviour in a variety of steering contexts that drivers face in the real world

A Utility Maximization Model of Pedestrian and Driver Interactions

The UM model accounts for the traffic interactions in road users by applying the principle of the utility maximization, discrete motor primitives, and evidence accumulation

Evidence for hyperactivity in the superior colliculus in Attention-Deficit/Hyperactivity Disorder

Objectives The superior colliculus (SC) is a sub-cortical midbrain structure involved in attentional shifts and distractibility. As distractibility is often atypical within ADHD, it is possible SC functionality in ADHD is also atypical. Indeed, a recent theory suggests distractibility observed within ADHD could be attributed to dysfunction, specifically hyperactivity, of the SC (Overton, 2008). This experiment aimed to explore whether SC responses to visual stimulation were associated with ADHD traits. We predicted a positive correlation between ADHD traits and SC responses. Methods The present study uses fMRI to examine the relationship between SC responsiveness and inattention-ADHD traits, assessed with the ASRS questionnaire. Seventeen typically developed adults, who ranged along the continuum of inattention-ADHD traits, were shown radial motion and static dot stimuli presented unilaterally in the left or right hemifield, while they performed a central rapid colour counting task. Results Responses in the left and right SC to motion versus static stimuli presented in the right hemifield, showed significant positive correlations with ADHD inattention traits (left hemisphere: r=.50 p=.020, right hemisphere: r=.45 p=.035), with those exhibiting higher levels of inattention traits showing larger motion responses compared to static. However, when the same stimuli were presented in the left hemifield, there was no significant correlation between left or right SC responses to motion versus static stimuli and ADHD inattention traits. Whole brain analyses also revealed positive associations between the left hemisphere early visual cortex response to right hemifield motion versus static stimuli and ADHD inattention traits. Again, no similar results were found for left hemifield presentation. Conclusions The results found preliminary support the initial hypothesis that those with higher levels of inattention traits showed increased SC activity to motion distractors compared to static, suggesting SC dysfunction may underlie some ADHD distractibility. Interestingly, such results only occurred to right hemifield distractors, which may reflect the hemifield differences in spatial attention previously observed within ADHD

The effect of interactive virtual reality on pain perception: a systematic review of clinical studies

Purpose: The aim of this systematic review was to evaluate the effect of immersive and non-immersive interactive virtual reality on pain perception in patients with a clinical pain condition. Methods: The following databases were searched from inception: Medline (Ovid), PsychInfo, CINAHL, Cochrane library and Web of Science. Two reviewers screened reports and extracted the data. A third reviewer acted as an arbiter. Studies were eligible if they were randomized controlled trials, quasi-randomized trials, and uncontrolled trials. Crossover and parallel-group designs were included. Risk of bias was assessed for all included studies. Results: Thirteen clinical studies were included. The majority of studies investigated a sample of participants with chronic pain. Six were controlled trials and seven uncontrolled studies. Findings from controlled research suggest that interactive virtual reality may reduce pain associated with ankylosing spondylitis and post-mastectomy, but results are inconsistent for patients with neck pain. Findings from uncontrolled studies suggest that interactive virtual reality may reduce neuropathic limb pain, and phantom limb pain, but had no effect on nonspecific chronic back pain. Conclusions: There is a need for more rigorous randomized control trials in order to conclude on the effectiveness of the use of virtual reality for the management of pain.Implications for rehabilitationInteractive virtual reality has been increasingly used in the rehabilitation of painful conditions.Interactive virtual reality using exergames may promote distraction from painful exercises and reduce pain post-mastectomy and in patients with ankylosing spondylitis.Interactive virtual representation of limbs may reduce neuropathic and phantom limb pain. Interactive virtual reality has been increasingly used in the rehabilitation of painful conditions. Interactive virtual reality using exergames may promote distraction from painful exercises and reduce pain post-mastectomy and in patients with ankylosing spondylitis. Interactive virtual representation of limbs may reduce neuropathic and phantom limb pain.</p