Children with developmental coordination disorder (DCD) can adapt to perceptible and subliminal rhythm changes but are more variable

Children with DCD demonstrate impairments in bimanual finger tapping during self-paced tapping and tapping in synchrony to different frequencies. In this study, we investigated the ability of children with DCD to adapt motorically to perceptible or subliminal changes of the auditory stimuli without a change in frequency, and compared their performance to typically developing controls (TDC). Nineteen children with DCD between ages 6–11 years (mean age ± SD = 114 ± 21 months) and 17 TDC (mean age ± SD = 113 ± 21 months) participated in this study. Auditory perceptual threshold was established. Children initially tapped bimanually to an antiphase beat and then to either a perceptible change in rhythm or to gradual subliminal changes in rhythm. Children with DCD were able to perceive changes in rhythm similar to TDC. They were also able to adapt to both perceptible and subliminal changes in rhythms similar to their age- and gender- matched TDC. However, these children were significantly more variable compared with TDC in all phasing conditions. The results suggest that the performance impairments in bilateral tapping are not a result of poor conscious or sub-conscious perception of the auditory cue. The increased motor variability may be associated with cerebellar dysfunction but further behavioral and neurophysiological studies are needed.     

Evaluating feedback time delay during perturbed and unperturbed balance in handstand

Feedback delays in balance are often assessed using muscle activity onset latencies in response to discrete perturbations. The purpose of the study was to calculate EMG latencies in perturbed handstand, and determine if delays are different to unperturbed handstand. Twelve national level gymnasts completed 12 perturbed and 10 unperturbed (five eyes open and five closed) handstands. Forearm EMG latencies during perturbed handstands were assessed against delay estimates calculated via: cross correlations of wrist torque and COM displacement, a proportional and derivative model of wrist torque and COM displacement and velocity (PD model), and a PD model incorporating a passive stiffness component (PS-PD model). Delays from the PD model (161 ± 14 ms) and PS-PD model (188 ± 14 ms) were in agreement with EMG latencies (165 ± 14 ms). Cross correlations of COM displacement and wrist torque provided unrealistically low estimates (5 ± 9 ms). Delays were significantly lower during perturbed (188 ± 14 ms) compared to unperturbed handstand (eyes open: 207 ± 12 ms; eyes closed: 220 ± 19 ms). Significant differences in delays and model parameters between perturbed and unperturbed handstand support the view that balance measures in perturbed testing should not be generalised to unperturbed balance.     

Immediate truth – Temporal contiguity between a cognitive problem and its solution determines experienced veracity of the solution

A temporal contiguity hypothesis for the experience of veracity is tested which states that a solution candidate to a cognitive problem is more likely to be experienced as correct the faster it succeeds the problem. Experiment 1 varied the onset time of the appearance of proposed solutions to anagrams (50 ms vs. 150 ms) and found for both correct and incorrect candidates that faster appearing solutions were more frequently judged as being correct, although participants were not aware of the difference in onset delay. Experiment 2 replicated this effect with mathematical equations, shorter onset latencies (0 ms vs. 50 ms), and a reversed sequence (presenting first the solution and then the problem). Experiment 3 showed that the probability of judging a word as the solution of a remote associate insight problem decreases linearly with increasing onset delay (50 ms, 150 ms, 300 ms). Possible neurobiological-cognitive explanations for this effect are proposed.     

Similar changes in muscle fiber phenotype with differentiated consequences for rate of force development: Endurance versus resistance training

Resistance training has been shown to positively affect the rate of force development (RFD) whereas there is currently no data on the effect of endurance training on RFD. Subjects completed ten weeks of either resistance training (RT, n = 7) or endurance cycling (END, n = 7). Pre and post measurements included biopsies obtained from m. vastus lateralis to quantify fiber phenotype and fiber area and isokinetic dynamometer tests to quantify maximal torque (Nm) and RFD (Nm/s) at 0–30, 0–50, 0–100 and 0–200 ms during maximal isometric contraction for both knee extensors and flexors. Both groups increased the area percentage of type IIa fibers (p < .01) and decreased the area percentage of type IIx fibers (p = .05), whereas only RT increased fiber size (p < .05). RT significantly increased eccentric, concentric and isometric strength for both knee extensors and flexors, whereas END did not. RT increased 200 ms RFD (p < .01) in knee flexor RFD and a tendency towards an increase at 100 ms (p < .1), whereas tendencies towards decreases were observed for the END group at 30, 50 and 100 ms (p < .1), resulting in RT having a higher RFD than END at post (p < .01). In conclusion, resistance training may be very important for maintaining RFD, whereas endurance training may negatively impact RFD.     

Multisensory integration in children with Developmental Coordination Disorder

This study examines how multisensory stimuli affect the performance of children with Developmental Coordination Disorder (DCD) on a choice reaction time (CRT) task. Ten children with DCD, identified using the Movement Assessment Battery for Children-2, aged 7–10 years (4F, M = 8 y 3 m, SD = 17 m) and 10 typically developing peers (TDC) (5F, M = 8 y 4 m, SD = 17 m) reached to unimodal (auditory (AO), visual (VO)) and bimodal (audiovisual (AV)) stimuli at one of three target locations. A multisensory (AV) stimulus reduced RTs for both groups (p < 0.001, η² = 0.36). While the children with DCD had a longer RT in all conditions, the AV stimulus produced RTs in children with DCD (494 ms) that were equivalent to those produced by the TDC to the VO stimulus (493 ms). Movement Time (DCD = 486 ms; TDC = 434 ms) and Path Length (DCD = 25.6 cm; TDC = 24.2 cm) were longer in children with DCD compared to TDC as expected (p < 0.05). Only the TDC benefited from the AV information for movement control, as deceleration time of the dominant hand was seen to decrease when moving to an AV stimulus (p < 0.05). Overall, data shows children with DCD do benefit from a bimodal stimulus to plan their movement, but do not for movement control. Further research is required to understand if this is a result of impaired multisensory integration.     

Masked cross-modal priming turns on a glimpse of the prime

We examined if cross-modal priming (print to speech) was greater for participants who were aware of the presence of letters in the experiment. Experiment 1 determined that word primes displayed at 47 ms were adequately masked. In Experiment 2 (a, b) with primes displayed at 47 ms masked priming occurred for within-mode printed targets but not for spoken ones. Experiment 3, with spoken targets, presented primes at two different durations (59, 71 ms) and priming was found for participants who reported seeing letters but not for those who did not. The results are discussed in terms how the link between prime and target representations might be strengthened even by cursory awareness of the prime and what this tells us about priming.     

Evaluation of cognitive behavior among deaf subjects with video game as intervention

Previous research on video gaming mainly focused on negative impact on users. In this study, the positive impact of action video gaming among congenitally deaf subjects is investigated. Subjects possessed high level of visual information processing capacity. A 96 h of action video game play resulted in the improvement of mean reaction time (mRT) (post = 413.21 ms, pre = 453.39 ms) and certain cognitive functions. Higher heart rate variability (HRV) subjects demonstrated faster and significant improvement in mRT (p < 0.0045) after intervention. The α and β EEG band powers were found increased in parietal (6.33%, 4.28%) and occipital (8.38%, 38%) lobes respectively. The θ band power increased in frontal (32%) and parietal (13%) lobes. These results can reflect enhancement in certain cognitive performances such as visual perception, attention, memory, and motor skills. The ratio index β/(α + θ) increased in frontal and occipital lobes while β/θ increased in frontal and temporal lobes. These results may also suggest improvements in attention processing capacity and neural activity. These results implies improvements in certain aspects of cognition among deaf subjects. However, to validate these results a further study on larger number of samples with advanced computerized cognitive battery testing can be employed.     

Rescuing stimuli from invisibility: Inducing a momentary release from visual masking with pre-target entrainment

At near-threshold levels of stimulation, identical stimulus parameters can result in very different phenomenal experiences. Can we manipulate which stimuli reach consciousness? Here we show that consciousness of otherwise masked stimuli can be experimentally induced by sensory entrainment. We preceded a backward-masked stimulus with a series of rapid visual events presented at 12 Hz for 800 ms. Peaks in visual sensitivity (d′) were observed when the target appeared at the time that the next entraining stimuli would have occurred. Observers’ sensitivity for identical masked near-threshold stimuli increased by factors as large as 55%, but only at this precise moment in time. These data thus reveal that awareness of near-threshold stimuli can be manipulated by entrainment to rhythmic events, supporting the functional role of induced oscillations in underlying cortical excitability, and suggest a plausible mechanism of temporal attention.     

Neuromagnetic correlates of intra- and extra-dimensional set-shifting

Set-shifting is essential to cognitive flexibility and relies on frontal lobe function. Previous studies have mostly focused on feedback processes following shifting rather than set-shifting itself. We designed an MEG paradigm without feedback to directly investigate the neural correlates of set-shifting. Adults (n = 16) matched one of two coloured images with a third stimulus, the target, by either the colour or shape dimension of the target. Half of the shift trials involved colour-to-colour or shape-to-shape (intra-dimensional: ID) shifting and the other half involved colour-to-shape or shape-to-colour (extra-dimensional: ED) shifting. MEG was continuously recorded on a 151 channel CTF system. We used beamforming to analyze responses to the first (shift) and the third (repeat) trials in each set. These trials were contrasted separately for ID and ED sets. Shift versus repeat trials showed larger MEG activations for intra-dimensional shifting in the right inferior frontal gyrus (BA 47), left medial frontal gyrus (BA 10) and right superior frontal gyrus (BA 9) as early as 100 ms, and in left middle frontal gyrus (BA 11) between 250–500 ms. Activations related to extra-dimensional shifting were detected in left inferior frontal gyrus (BA 44), left middle frontal gyrus (BA 11), and right middle frontal gyrus (BA 46) between 100 ms and 350 ms, followed by superior frontal gyrus (BA 8/BA 10) between 250–500 ms. Intra-dimensional and extra-dimensional shifting also activated bilateral and right parietal areas, respectively. This study establishes the location and timing of frontal and parietal activations during an intra-dimensional versus extra-dimensional shifting task.     

Cyclic variations in sustained human performance

Biological rhythms play a prominent role in the modulation of human physiology and behavior. [Smith, K., Valentino, D., & Arruda, J. (2003). Rhythmic oscillations in the performance of a sustained attention task. Journal of Clinical and Experimental Neuropsychology, 25, 561-570] suggested that sustained human performance may systematically fluctuate in a cyclic manner with periods of 1.5 min and 5.2 min. The current series of investigations sought to manipulate those periodicities by altering task difficulty, administering caffeine, and testing on a more ecologically valid task. Strong evidence of a 1.5 min periodicity was found across studies. Most participants did not demonstrate the 5.2 min periodicity. Moreover, the 1.5 min periodicity was resistant to task manipulations and appeared in similar levels across conditions in all three experiments. These rhythms may be indicative of an endogenous system that modulates sustained attention in humans. Evidence supporting this idea and implications of the research are discussed.     

Global shape integration and illusory form perception in the absence of awareness

Previous research on perceptual organization operations still provides contradictory evidence on whether the integration of sparse local elements into coherently unified shapes and the construction of the illusory form are accomplished without the need of awareness. In the present study, three experiments were conducted in which participants were presented with masked (Experiment 1, SOA = 27 ms; Experiment 2; SOA = 53 ms) and unmasked (Experiment 3) primes consisting of geometric shapes (a square or a diamond) that could be congruent or incongruent with subsequent probe stimuli (square vs. diamond). Furthermore, the primes were divided into: a grouping condition (where local elements may group together into global shapes), an illusory condition (where the arrangement of local elements produced illusory shapes) and a hybrid condition (where both operations were presented simultaneously). While no priming effects were found for the shortest SOA (27 ms), both grouping and illusory primes produced significant priming effects in the longer SOA (53 ms). On the other hand, results in Experiment 3 (unmasked) showed strong priming effects for the grouping of the inducers in both the grouping and the hybrid conditions, and also a significant but weaker priming effect for the illusory condition. Overall, our results support the possibility of the integration of local visual features into a global shape in the absence of awareness and, likewise, they suggest an early –subliminal– construction of the illusory shape, implying that feedback projections from higher to lower visual areas are not crucial in the construction of the illusory form.     

Testing a dual-process model of avoidant defenses

Research suggests that the defensive strategy used by people who score high on attachment-related avoidance when they encounter interpersonal threats involves two stages: automatic vigilance followed by effortful avoidance. In two studies we varied stimulus exposure times and cognitive load to determine how attention is regulated by avoidant individuals. Results indicate that avoidant individuals were vigilant toward contempt faces when the faces were presented for 100 ms but quickly disengaged from them when the faces were presented for 750 ms. Moreover, avoidant participants could disengage from contempt faces presented for 750 ms while rehearsing a simple 1-digit number, but not when rehearsing a 7-digit number, suggesting that avoidant disengagement is a cognitively effortful process. Theoretical and practical implications are discussed.     

Beat gestures modulate auditory integration in speech perception

Spontaneous beat gestures are an integral part of the paralinguistic context during face-to-face conversations. Here we investigated the time course of beat-speech integration in speech perception by measuring ERPs evoked by words pronounced with or without an accompanying beat gesture, while participants watched a spoken discourse. Words accompanied by beats elicited a positive shift in ERPs at an early sensory stage (before 100 ms) and at a later time window coinciding with the auditory component P2. The same word tokens produced no ERP differences when participants listened to the discourse without view of the speaker. We conclude that beat gestures are integrated with speech early on in time and modulate sensory/phonological levels of processing. The present results support the possible role of beats as a highlighter, helping the listener to direct the focus of attention to important information and modulate the parsing of the speech stream.     

Inhibitory mechanisms in single negative priming from ignored and briefly flashed primes: The key role of the inter-stimulus interval

The influence of interstimulus intervals (ISIs) on priming effects was investigated using a single-prime negative priming (NP) paradigm. In all experiments, a brief (16 ms), centrally displayed prime (a Chinese character, to be ignored) appeared, followed by a pattern mask and then a centrally displayed target (another semantically related or unrelated Chinese character); the task required semantic categorization (animate/inanimate) of the target. An ISI could occur either between prime and mask (Experiments 1 and 5) or between mask and target (Experiments 2–4). The results revealed NP when a 470 ms ISI occurred between prime and mask (Experiments 1 and 5) and when a 700 ms ISI occurred between mask and target (Experiments 3 and 4). In contrast, when a long prime-target SOA was maintained but the mask-target ISI was shortened, NP disappeared (Experiment 4). The results indicated that a persisting mask/distractor (without ISI) located in the same position as the following target interfered with the buildup of inhibition, but an ISI between prime and mask or mask and target eliminated this interference, and that inhibition processes induced by an ignore instruction were implemented faster with an ISI placed between prime and mask than with an ISI placed between mask and target.     

Tracking simple and complex sequences

We address issues of synchronization to rhythms of musical complexity. In two experiments, synchronization to simple and more complex rhythmic sequences was investigated. Experiment 1 examined responses to phase and tempo perturbations within simple, structurally isochronous sequences, presented at different base rates. Experiment 2 investigated responses to similar perturbations embedded within more complex, metrically structured sequences; participants were explicitly instructed to synchronize at different metrical levels (i.e., tap at different rates to the same rhythmic patterns) on different trials. We found evidence that (1) the intrinsic tapping frequency adapts in response to temporal perturbations in both simple (isochronous) and complex (metrically structured) rhythms, (2) people can synchronize with unpredictable, metrically structured rhythms at different metrical levels, with qualitatively different patterns of synchronization seen at higher versus lower levels of metrical structure, and (3) synchronization at each tapping level reflects information from other metrical levels. The latter finding provides evidence for a dynamic and flexible internal representation of the sequence's metrical structure.     

Auditory localisation of conventional and electric cars: Laboratory results and implications for cycling safety

When driven at low speeds, cars operating in electric mode have been found to be quieter than conventional cars. As a result, the auditory cues which pedestrians and cyclists use to assess the presence, proximity and location oncoming traffic may be reduced, posing a safety hazard. This laboratory study examined auditory localisation of conventional and electric cars including vehicle motion paths relevant for cycling activity. Participants (N = 65) in three age groups (16–18, 30–40 and 65–70 year old) indicated the location and movement direction (approaching versus receding) of cars driven at 15, 30 and 50 km/h in two ambient sound conditions (low and moderate). Results show that low speeds, higher ambient sound level and older age were associated with worse performance on the location and motion direction tasks. In addition, participants were less accurate at determining the location of electric and conventional car sounds emanating from directly behind the participant. Implications for cycling safety and proposals for adding extra artificial noise or warning sounds to quiet (electric) cars are discussed.     

Sequential modulations of poorer-strategy effects during strategy execution: An event-related potential study in arithmetic

When participants accomplish cognitive tasks, they obtain poorer performance if asked to execute a poorer strategy than a better strategy on a given problem. These poorer-strategy effects are smaller following execution of a poorer strategy relative to following a better strategy. To investigate ERP correlates of sequential modulations of poorer-strategy effects, we asked participants (n = 20) to accomplish a computational estimation task (i.e., provide approximate products to two-digit multiplication problems like 38 × 74). For each problem, they were cued to execute a better versus a poorer strategy. We found event-related potentials signatures of sequential modulations of poorer-strategy effects in two crucial windows (i.e., between 200 and 550 ms and between 850 and 1250 ms) associated with executive control mechanisms and allowing conflict monitoring between the better and the cued strategy. These results have important implications on theories of strategies as they suggest that sequential modulations of poorer-strategy effects involve earlier as well as later mechanisms of cognitive control during strategy execution.     

Finger forces in fastball baseball pitching

Forces imparted by the fingers onto a baseball are the final, critical aspects for pitching, however these forces have not been quantified previously as no biomechanical technology was available. In this study, an instrumented baseball was developed for direct measurement of ball reaction force by individual fingers and used to provide fundamental information on the forces during a fastball pitch. A tri-axial force transducer with a cable having an easily-detachable connector were installed in an official baseball. Data were collected from 11 pitchers who placed the fingertip of their index, middle, ring, or thumb on the transducer, and threw four-seam fastballs to a target cage from a flat mound. For the index and middle fingers, resultant ball reaction force exhibited a bimodal pattern with initial and second peaks at 38–39 ms and 6–7 ms before ball release, and their amplitudes were around 97 N each. The ring finger and thumb produced single-peak forces of approximately 50 and 83 N, respectively. Shear forces for the index and middle fingers formed distinct peak at 4–5 ms before release, and the peaks summed to 102 N; a kinetic source for backspin on the ball. An additional experiment with submaximal pitching effort showed a linear relationship of peak forces with ball velocity. The peak ball reaction force for fastballs exceeded 80% of maximum finger strength measured, suggesting that strengthening of the distal muscles is important both for enhancing performance and for avoiding injuries.     

When hearing the bark helps to identify the dog: Semantically-congruent sounds modulate the identification of masked pictures

We report a series of experiments designed to assess the effect of audiovisual semantic congruency on the identification of visually-presented pictures. Participants made unspeeded identification responses concerning a series of briefly-presented, and then rapidly-masked, pictures. A naturalistic sound was sometimes presented together with the picture at a stimulus onset asynchrony (SOA) that varied between 0 and 533 ms (auditory lagging). The sound could be semantically congruent, semantically incongruent, or else neutral (white noise) with respect to the target picture. The results showed that when the onset of the picture and sound occurred simultaneously, a semantically-congruent sound improved, whereas a semantically-incongruent sound impaired, participants’ picture identification performance, as compared to performance in the white-noise control condition. A significant facilitatory effect was also observed at SOAs of around 300 ms, whereas no such semantic congruency effects were observed at the longest interval (533 ms). These results therefore suggest that the neural representations associated with visual and auditory stimuli can interact in a shared semantic system. Furthermore, this crossmodal semantic interaction is not constrained by the need for the strict temporal coincidence of the constituent auditory and visual stimuli. We therefore suggest that audiovisual semantic interactions likely occur in a short-term buffer which rapidly accesses, and temporarily retains, the semantic representations of multisensory stimuli in order to form a coherent multisensory object representation. These results are explained in terms of Potter’s (1993) notion of conceptual short-term memory.