Movement segmentation and visual perturbation increase developmental differences in motor control and learning.

We examined the developmental differences in motor control and learning of a two-segment movement. One hundred and five participants (53 female) were divided into three age groups (7-8 years, 9-10 years and 19-27 years). They performed a two-segment movement task in four conditions (full vision, fully disturbed vision, disturbed vision in the first movement segment and disturbed vision in the second movement segment). The results for movement accuracy and overall movement time show that children, especially younger children, are more susceptible to visual perturbations than adults. The adults' movement time in one of the movement segments could be increased by disturbing the vision of the other movement segment. The children's movement time for the second movement segment increased when their vision of the first movement segment was disturbed. Disturbing the vision of the first movement segment decreased the percentage of central control of the second movement in younger children, but not in the other two age groups. The children's normalized jerk was more easily increased by visual perturbations. The children showed greater improvement after practice in the conditions of partial vision disturbance. As the participants' age increased, practice tended to improve their feedforward motor control rather than their feedback motor control. These results suggest that children's central movement control improves with age and practice. We discuss the theoretical implications and practical significance of the differential effects of visual perturbation and movement segmentation upon motor control and learning from a developmental viewpoint.

Low frequency steady-state brain responses modulate large scale functional networks in a frequency-specific means.

Neural oscillations are essential for brain functions. Research has suggested that the frequency of neural oscillations is lower for more integrative and remote communications. In this vein, some resting-state studies have suggested that large scale networks function in the very low frequency range (<1 Hz). However, it is difficult to determine the frequency characteristics of brain networks because both resting-state studies and conventional frequency tagging approaches cannot simultaneously capture multiple large scale networks in controllable cognitive activities. In this preliminary study, we aimed to examine whether large scale networks can be modulated by task-induced low frequency steady-state brain responses (lfSSBRs) in a frequency-specific pattern. In a revised attention network test, the lfSSBRs were evoked in the triple network system and sensory-motor system, indicating that large scale networks can be modulated in a frequency tagging way. Furthermore, the inter- and intranetwork synchronizations as well as coherence were increased at the fundamental frequency and the first harmonic rather than at other frequency bands, indicating a frequency-specific modulation of information communication. However, there was no difference among attention conditions, indicating that lfSSBRs modulate the general attention state much stronger than distinguishing attention conditions. This study provides insights into the advantage and mechanism of lfSSBRs. More importantly, it paves a new way to investigate frequency-specific large scale brain activities.

Practice and nap schedules modulate children's motor learning.

Night- or day-time sleep enhances motor skill acquisition. However, prominent issues remained about the circadian (time-of-day) and homeostatic (time since last sleep) effects of sleep on developmental motor learning. Therefore, we examined the effects of nap schedules and nap-test-intervals (NTIs) on the learning of finger tapping sequences on computer keyboards. Children aged 6-7, 8-9, and 10-11 years explicitly acquired the short and long tapping orders that share the same movement strings (4-2-3-1-4, 4-2-3-1-4-2-3-1-4). Following a constant 8- or 10-hr post-learning period in one of the four NTIs (2, 4, 5, 7 hr), children in the morning napping groups, the afternoon napping groups, or the waking group performed the original long sequence in retention test (4-2-3-1-4-2-3-1-4) and the mirrored-order sequence in transfer test (1-3-2-4-1-3-2-4-1). Age and treatment differences in the movement time (MT, ms) and sequence accuracy (SA, %) were compared during skill learning and in retrieval tests. Results suggest that practice or nap affects MT and SA in a greater extent for the younger learners than for the older learners. The circadian effects might not change nap-based skill learning. Importantly, the longer NTIs resulted in superior retention performance than the shorter ones, suggesting that children require a relatively longer post-nap period to form motor memory. Finally, nap-based motor learning was more marked in skill retention than in skill transfer. Brain development may play an important role in motor learning. Our discussion centers on memory consolidation and its relevance for skill acquisition from early to late childhood.

Obesity Reduces Cognitive and Motor Functions across the Lifespan.

Due to a sedentary lifestyle, more and more people are becoming obese nowadays. In addition to health-related problems, obesity can also impair cognition and motor performance. Previous results have shown that obesity mainly affects cognition and motor behaviors through altering brain functions and musculoskeletal system, respectively. Many factors, such as insulin/leptin dysregulation and inflammation, mediate the effect of obesity and cognition and motor behaviors. Substantial evidence has suggested exercise to be an effective way to improve obesity and related cognitive and motor dysfunctions. This paper aims to discuss the association of obesity with cognition and motor behaviors and its underlying mechanisms. Following this, mechanisms of exercise to improve obesity-related dysfunctions are described. Finally, implications and future research direction are raised.

Steady-state BOLD Response to Higher-order Cognition Modulates Low-Frequency Neural Oscillations.

Steady-state responses (SSRs) reflect the synchronous neural oscillations evoked by noninvasive and consistently repeated stimuli at the fundamental or harmonic frequencies. The steady-state evoked potentials (SSEPs; the representative form of the SSRs) have been widely used in the cognitive and clinical neurosciences and brain-computer interface research. However, the steady-state evoked potentials have limitations in examining high-frequency neural oscillations and basic cognition. In addition, synchronous neural oscillations in the low frequency range (<1 Hz) and in higher-order cognition have received a little attention. Therefore, we examined the SSRs in the low frequency range using a new index, the steady-state BOLD responses (SSBRs) evoked by semantic stimuli. Our results revealed that the significant SSBRs were induced at the fundamental frequency of stimuli and the first harmonic in task-related regions, suggesting the enhanced variability of neural oscillations entrained by exogenous stimuli. The SSBRs were independent of neurovascular coupling and characterized by sensorimotor bias, an indication of regional-dependent neuroplasticity. Furthermore, the amplitude of SSBRs may predict behavioral performance and show the psychophysiological relevance. Our findings provide valuable insights into the understanding of the SSRs evoked by higher-order cognition and how the SSRs modulate low-frequency neural oscillations.

Visuomotor control in continuous response time tasks across different age groups.

The goal was to examine whether visuomotor control and choice response time shared age-related developmental trajectories, and if prior computer experience played an important role in control processes. Children (6-7, 8-9, 10-11 yr.), younger adults (24 yr.) and older adults (76 yr.) performed the cursor pointing and choice response time (CRT) tasks with a computer mouse. Participants moved the mouse cursor back and forth to click two targets on the screen as fast and accurately as possible. In the CRT, based on visual stimuli, participants moved and clicked one of the three targets on the screen as fast and accurately as possible; the time between stimulus onset and clicking the correct target was recorded as the choice response time. Visuomotor performance increased with age to younger adulthood but was worse in the older adult group. CRT performance was also positively related to age among the groups of children, with scores leveling off in the young adult group. Computer experience was statistically significantly related only to visuomotor control, but not to CRT. Optimal CRT performance required only sub-optimal visuomotor control. Cognitive and sensory age declines may be related to the poorer CRT performance in the oldest age group.

Brain mechanisms of mental processing: from evoked and spontaneous brain activities to enactive brain activity.

Within the context of the computer metaphor, evoked brain activity acts as a primary carrier for the brain mechanisms of mental processing. However, many studies have found that evoked brain activity is not the major part of brain activity. Instead, spontaneous brain activity exhibits greater intensity and coevolves with evoked brain activity through continuous interaction. Spontaneous and evoked brain activities are similar but not identical. They are not separate parts, but always dynamically interact with each other. Therefore, the enactive cognition theory further states that the brain is characterized by unified and active patterns of activity. The brain adjusts its activity pattern by minimizing the error between expectation and stimulation, adapting to the ever-changing environment. Therefore, the dynamic regulation of brain activity in response to task situations is the core brain mechanism of mental processing. Beyond the evoked brain activity and spontaneous brain activity, the enactive brain activity provides a novel framework to completely describe brain activities during mental processing. It is necessary for upcoming researchers to introduce innovative indicators and paradigms for investigating enactive brain activity during mental processing.

Strengthened functional connectivity in the brain during muscle fatigue.

Fatigue caused by sustaining submaximal-intensity muscle contraction(s) involves increased activation in the brain such as primary motor cortex (M1), primary sensory cortex (S1), premotor and supplementary motor area (PM&SMA) and prefrontal cortex (PFC). The synchronized increases in activation level in these cortical areas suggest fatigue-related strengthening of functional coupling within the motor control network. In the present study, this hypothesis was tested using the cross-correlation based functional connectivity (FC) analysis method. Ten subjects performed a 20-minute intermittent (3.5s ON/6.5s OFF, 120 trials total) handgrip task using the right hand at 50% maximal voluntary contraction (MVC) force level while their brain was scanned by a 3 T Siemens Trio scanner using echo planar imaging (EPI) sequence. A representative signal time course of the left M1 was extracted by averaging the time course data of a 2-mm cluster of neighboring voxels of local maximal activation foci, which was identified by a general linear model. Two FC activation maps were created for each subject by cross-correlating the time course data of the minimal (the first 10 trials) and significant (the last 10 trials) fatigue stages across all the voxels in the brain to the corresponding representative time course. Histogram and quantile regression analysis were used to compare the FC between the minimal and significant fatigue stages and the results showed a significant increase in FC among multiple cortical regions, including right M1 and bilateral PM&SMA, S1 and PFC. This strengthened FC indicates that when muscle fatigue worsens, many brain regions increase their coupling with the left M1, the primary motor output control center for the right handgrip, to compensate for diminished force generating capability of the muscle in a coordinated fashion by enhancing the descending command for greater muscle recruitment to maintain the same force.

Transfer effects of manipulating temporal constraints on learning a two-choice reaction time task with low stimulus-response compatibility.

Recent research using deliberate amplification of spatial errors to increase motor learning leads to the question of whether amplifying temporal errors may also facilitate learning. We investigated transfer effects caused by manipulating temporal constraints on learning a two-choice reaction time (CRT) task with varying degrees of stimulus-response compatibility. Thirty-four participants were randomly assigned to one of the three groups and completed 120 trials during acquisition. For every fourth trial, one group was instructed to decrease CRT by 50 msec. relative to the previous trial and a second group was instructed to increase CRT by 50 msec. The third group (the control) was told not to change their responses. After a 5-min. break, participants completed a 40-trial no-feedback transfer test. A 40-trial delayed transfer test was administered 24 hours later. During acquisition, the Decreased Reaction Time group responded faster than the two other groups, but this group also made more errors than the other two groups. In the 5-min. delayed test (immediate transfer), the Decreased Reaction Time group had faster reaction times than the other two groups, while for the 24-hr. delayed test (delayed transfer), both the Decreased Reaction Time group and Increased Reaction Time group had significantly faster reaction times than the control. For delayed transfer, both Decreased and Increased Reaction Time groups reacted significantly faster than the control group. Analyses of error scores in the transfer tests indicated revealed no significant group differences. Results were discussed with regard to the notion of practice variability and goal-setting benefits.

Inhibitory control differentiates rare target search performance in children.

Age-related differences in rare-target search are primarily explained by the speed-accuracy trade-off, primed responses, or decision making. The goal was to examine how motor inhibition influences visual search. Children pressed a key when a rare target was detected. On no-target trials, children withheld reactions. Response time (RT), hits, misses, correct rejection, and false alarms were measured. Tapping tests assessed motor control. Older children tapped faster, were more sensitive to rare targets (higher d'), and reacted more slowly than younger ones. Girls outperformed boys in search sensitivity but not in RT. Motor speed was closely associated with hit rate and RT. Results suggest that development of inhibitory control plays a key role in visual detection. The potential implications for cognitive-motor development and individual differences are discussed.

The effectiveness of physical activity interventions on communication and social functioning in autistic children and adolescents: A meta-analysis of controlled trials.

LAY ABSTRACT: Difficulty with communication and social functioning are two outstanding core symptoms of autism spectrum disorder, while there is no efficacious pharmacologic treatment available to deal with them. Traditional behavioral therapies usually require specialist therapist and be conducted in specific settings, increasing burdens on families and individuals with autism. Physical activity has long been found to promote physical and mental well-beings, and it is more affordable and versatile than traditional therapies. There is preliminary support for the use of physical activity interventions to improve communication and social functioning in individuals with autism. In this study, we quantitatively aggregate data from existing controlled trials to provide an up-to-date inquiry into the effectiveness of physical activity interventions on communication and social functioning in autistic children and adolescents. We included 12 trials involving 350 participants (8 trials reported communication outcomes and 11 trials reported social functioning outcomes) and found small to moderate benefits on communication and social functioning. Further analyses showed that the benefit of physical activity interventions is greater in younger participants. Results of this study suggest that physical activity interventions are effective to improve communication and social functioning in autistic children and adolescents, and early participation in the interventions can be more beneficial. Given their affordability, versatility, and efficacy, physical activity interventions could be considered a cost-effective option for autism spectrum disorder management in the future.

Developmental motor function plays a key role in visual search.

Adults often miss a disturbingly high percentage of rare targets in visual arrays. The mechanisms underlying this effect remain hotly debated. This study examines the effects of developing motor control on the speed and accuracy of visual search. Children detected targets that appeared rarely or frequently. Participants reported a target's presence or absence by either pressing a key or marking on recording sheets. The results replicated past reports of increased errors with reduced target prevalence in adults. A potential developmental trend in performance is linked to a measure of motor function. When the pressure to respond quickly was removed, search accuracy greatly improved for rare targets. A developmental account for the perceptual-motor mechanisms of prevalence effect is discussed.

The effectiveness of dance interventions on cognition in patients with mild cognitive impairment: A meta-analysis of randomized controlled trials.

This meta-analysis of randomized controlled trials (published or unpublished RCTs in English) examined the effectiveness of dance interventions compared to waitlist/active controls on cognitive functions in patients with mild cognitive impairment (MCI). Literature search was conducted on MEDLINE, EMBASE, CINAHL and related databases through 3 August 2019. Risk of bias was assessed with the PEDro scale regarding randomization, allocation concealment, group comparability, blinding, attrition and selective reporting. Five included RCTs (N = 358) used Latin, ballroom and aerobic dances (frequency: 1-3 session/week; intensity: light to moderate; time: 25-60 min/session; type: aerobic). Results show that dance interventions improve global cognition (SMD [95 % CI] = 0.48 [0.21, 0.74]), attention (SMD [95 % CI] = 0.33 [0.12, 0.54]), immediate (SMD [95 % CI] = 0.54 [0.38, 0.71]) and delayed recall (SMD [95 % CI] = 0.33 [0.01, 0.64]), and visuospatial ability (SMD [95 % CI] = 0.16 [0.01, 0.32]). Study limitations include a small number of RCTs and high heterogeneity in some cognitive domains. In summary, dance interventions improve some cognitive domains in MCI. (PROSPERO registration: CRD42019145418).

Neural correlates of the females' susceptibility to negative emotions: an insight into gender-related prevalence of affective disturbances.

Considerable studies reported that females are more susceptible to affective disturbances such as depression, anxiety disorder, and phobia compared to males. Based on the close relation between emotional sensitivity and liability to affective disturbances (Hofer et al. [2006]: NeuroImage 32, 854-862; Spearing [2001]: Bipolar disorder, 2nd ed. Bethesda (MA): National institute of Mental Health), this study investigated the neural mechanism underlying the females' liability to affective disturbances by hypothesizing that females are more susceptible to negative emotions than males. Event-related potentials (ERPs) were recorded for highly negative (HN), moderately negative (MN), and neutral images in Experiment 1, and for highly positive, moderately positive, and neutral images in Experiment 2, whereas subjects (15 males and 15 females) performed a standard/deviant distinction task, irrespective of the emotional valence of deviants in both experiments. In addition to the prominent emotional reactions evoked by HN stimuli in both genders, Experiment 1 displayed conspicuous emotional responses of females to MN stimuli across N2 and P3 components, which were absent in males. In contrast, Experiment 2 demonstrated neither significant valence effect, nor significant valence by gender interaction effect at these components. Thus, although both genders are sensitive to HN stimuli, females, instead of males, are particularly susceptible to negative stimuli of lesser salience, and this female specific susceptibility does not exist to the positive stimuli. Therefore, females must be more susceptible to negative emotions in life settings, which may be one important mechanism underlying their higher prevalence of affective disturbances.

Explicit Aiming Strategy Decreases the Differences in Visuomotor Adaptation between Children and Young Adults.

We examined the visuomotor adaptation of children and adults with and without explicit aiming strategies. Younger children were slower and less smooth in visuomotor adaption than adults. Specifically, in the course of adaptation and re-adaptation, older children had better movement accuracy than adults, while their movement speed and smoothness were similar to those of the adults. Explicit aiming improved movement accuracy for all participants, but also facilitated movement smoothness for younger children. The contribution of explicit adjustment was greater for older children than for younger children. These results show the ongoing development of cognitive functions and movement experiences in children.

Effects of Meditation and Mind-Body Exercises on Older Adults' Cognitive Performance: A Meta-analysis.

BACKGROUND AND OBJECTIVES: Meditation and mind-body exercises are suggested to delay decline or enhance cognitive capabilities in older adults. However, their effectiveness remains uncertain. This study assessed the effectiveness of meditation and mind-body exercises to improve cognition in elderly people aged 60 years or above. Moderator variables were also explored. RESEARCH DESIGN AND METHODS: A databases search (MEDLINE, EMBASE, CINAHL, PsycINFO, Cochrane Library, Web of Science, CNKI, and Wangfang) was conducted from the first available date to January 10, 2018. Inclusion criteria include (a) human older adults aged 60 years or above, (b) meditation, Tai Chi, Qigong, or yoga intervention, (c) intervention should be structured, (d) inclusion of a control group, (e) at least one outcome measure of cognition was measured at baseline and post-training, and (f) peer-reviewed journal articles in English or Chinese. RESULTS: Forty-one studies (N = 3,551) were included in the meta-analysis. In general, meditation and mind-body exercises improve cognition in the elderly people (SMD = 0.34, 95% CI: 0.19 to 0.48), but the cognition-enhancing effects depend on the type of exercise. In addition, cognitive performance is only improved when the length of intervention is longer than 12 weeks, exercise frequency is 3-7 times/week, or duration of an exercise session is 45-60 min/session. DISCUSSION AND IMPLICATIONS: This study suggests that meditation and mind-body exercises are effective to improve cognition of older adults aged 60 years or above, and exercise parameters should be considered for intervention planning.

Dysfunctional preparatory processes in hazardous drinkers: An ERP study.

Alcohol drinking is associated with impaired cognitive and motor performance. This electrophysiological study examined the differences in the preparatory processes preceding motor imagery (visual and kinesthetic) and execution between hazardous drinkers and non-hazardous drinking controls. Twenty-two hazardous drinkers and 22 non-hazardous drinking controls were recruited to participate in the study. They were required to produce a 3-key response sequence physically or mentally 3 s after the appearance of a corresponding cue. Here we showed significantly smaller amplitudes of both early and late negative contingent variation in hazardous drinkers compared to controls. In addition, the early negative contingent variation preceding motor execution was greater than those in the motor imagery conditions in both groups. Results of this study suggest impairments of attentional control and motor preparation in hazardous drinkers. Preparatory processes of motor execution and motor imagery mainly differ from each other in voluntary attention orientation, but not in motor preparation.

Special Issue - Therapeutic Benefits of Physical Activity for Mood: A Systematic Review on the Effects of Exercise Intensity, Duration, and Modality.

In contemporary society, people experience considerable stress in their daily lives. Therefore, developing effective approaches and convenient means to cope with their mood problems is important nowadays. Physical activity has been consistently reported as a cost-effective way to improve physical fitness, prevent mental illnesses, and alleviate mood problems. In this systematic review, the effects of exercise intensity, duration, and modality on mood change are discussed. Results show that moderate-intensity anaerobic exercise is associated with greater mood improvements. The relationship between exercise duration and mood change is non-linear; A regime of 10- to 30-minute exercise is sufficient for mood improvements. For exercise modality, anaerobic exercise improves mood, but the efficacy of aerobic and mindfulness-related exercises remains to be further examined. In addition to the systematic review of potential moderators, a narrative review of psychological and neurophysiological theories of exercise effects on mood is provided; we have highlighted the central role of neuroplasticity in integrating the two classes of theories. An adoption of neuroimaging techniques in future research is critical to reveal the mechanisms underpinning the therapeutic influence of physical activity on affective responses. Some future research directions are also raised.

Alzheimer's disease and mild cognitive impairment deteriorate fine movement control.

Sensory-motor dysfunctions are often associated with Alzheimer's disease (AD) or mild cognitive impairment (MCI). This study suggests that deterioration in fine motor control and coordination characterizes sensory-motor deficiencies of AD and MCI. Nine patients with a clinical diagnosis of probable AD, 9 amnestic MCI subjects and 10 cognitively normal controls performed four types of handwriting movement on a digitizer. Movement time and smoothness were analyzed between the groups and across the movement patterns. Kinematic profiles were also compared among the groups. AD and MCI patients demonstrated slower, less smooth, less coordinated, and less consistent handwriting movements than their healthy counterparts. The theoretical relevance and practical implications of fine motor tasks, such as these movements involved in handwriting, are discussed relative to the deteriorated sensory-motor system of AD and MCI patients.

Age-Related Changes in Field Dependence-Independence and Implications for Geriatric Rehabilitation: A Review.

Human aging is a dynamic life-long process and an inevitable experience. As the average age of the world's population rises, demands for effective geriatric rehabilitation dramatically increase. An important consideration for enhancing geriatric behavioral interventions is to better understand aging characteristics in perceptual, cognitive, and motor performances. A general shift in cognitive style from field independence to field dependence has been consistently observed during human aging, as older adults show a greater tendency to rely on environmental information, presumably reflecting a neuro-compensatory mechanism of reducing top-down control and relying instead on bottom-up processing. These changes in cognitive style can impact motor skill learning and relearning and, consequently, affect geriatric rehabilitation and behavioral treatments. In this article, we review research related to the cognitive style of field dependence and independence, and its dynamic associations with aging. We also identify implications of cognitive style for geriatric rehabilitation and explore future research.