Robert D. Moore

Effects of the FITKids Randomized Controlled Trial on Executive Control and Brain Function

OBJECTIVE: To assess the effect of a physical activity (PA) intervention on brain and behavioral indices of executive control in preadolescent children. METHODS: Two hundred twenty-one children (7–9 years) were randomly assigned to a 9-month afterschool PA program or a wait-list control. In addition to changes in fitness (maximal oxygen consumption), electrical activity in the brain (P3-ERP) and behavioral measures (accuracy, reaction time) of executive control were collected by using tasks that modulated attentional inhibition and cognitive flexibility. RESULTS: Fitness improved more among intervention participants from pretest to posttest compared with the wait-list control (1.3 mL/kg per minute, 95% confidence interval [CI]: 0.3 to 2.4; d = 0.34 for group difference in pre-to-post change score). Intervention participants exhibited greater improvements from pretest to posttest in inhibition (3.2%, 95% CI: 0.0 to 6.5; d = 0.27) and cognitive flexibility (4.8%, 95% CI: 1.1 to 8.4; d = 0.35 for group difference in pre-to-post change score) compared with control. Only the intervention group increased attentional resources from pretest to posttest during tasks requiring increased inhibition (1.4 µV, 95% CI: 0.3 to 2.6; d = 0.34) and cognitive flexibility (1.5 µV, 95% CI: 0.6 to 2.5; d = 0.43). Finally, improvements in brain function on the inhibition task (r = 0.22) and performance on the flexibility task correlated with intervention attendance (r = 0.24). CONCLUSIONS: The intervention enhanced cognitive performance and brain function during tasks requiring greater executive control. These findings demonstrate a causal effect of a PA program on executive control, and provide support for PA for improving childhood cognition and brain health.

2K: A Reflective, Component-Based Operating System for Rapidly Changing Environments

Modern computing environments face both low-frequency infrastructural changes, such as software and hardware upgrades, and frequent changes, such as fluctuations in the network bandwidth and CPU load. However, existing operating systems are not designed to cope with rapidly changing environments. They provide no mechanism to permit the insertion of self-adapting components that can optimize system performance according to diversity, software and hardware changes, and variations in the environment. They are not designed to accommodate dynamic updates of software, or to deal with component interdependence.

A history of sport-related concussion on event-related brain potential correlates of cognition.

Over the past decade, a growing body of research has detailed persistent changes to neuroelectric indices of cognition in amateur and professional athletes with a concussion history. Here, we review the relevant neuroelectric findings on this relationship while considering the duration from the last concussive event. Collectively, the findings support a negative relation of concussive injury to neuroelectric indices of brain health and cognition in the presence of normal clinical findings. The results suggest that event-related brain potentials are especially well-suited for identifying aspects of cognition that remain dysfunctional for an extended period of time, which are otherwise unidentified using standard neuropsychological tests. Such findings also suggest the need for additional research to fully elucidate the extent to which concussive injuries negatively impact brain health and cognition.

The Persistent Influence of Concussive Injuries on Cognitive Control and Neuroelectric Function

CONTEXT Increasing attention is being paid to the deleterious effects of sport-related concussion on cognitive and brain health. OBJECTIVE To evaluate the influence of concussion incurred during early life on the cognitive control and neuroelectric function of young adults. DESIGN Cross-sectional study. SETTING Research laboratory. PATIENTS OR OTHER PARTICIPANTS Forty young adults were separated into groups according to concussive history (0 or 1+). Participants incurred all injuries during sport and recreation before the age of 18 years and were an average of 7.1 ± 4.0 years from injury at the time of the study. INTERVENTION(S) All participants completed a 3-stimulus oddball task, a numeric switch task, and a modified flanker task during which event-related potentials and behavioral measures were collected. MAIN OUTCOME MEASURE(S) Reaction time, response accuracy, and electroencephalographic activity. RESULTS Compared with control participants, the concussion group exhibited decreased P3 amplitude during target detection within the oddball task and during the heterogeneous condition of the switch task. The concussion group also displayed increased N2 amplitude during the heterogeneous version of the switch task. Concussion history was associated with response accuracy during the flanker task. CONCLUSIONS People with a history of concussion may demonstrate persistent decrements in neurocognitive function, as evidenced by decreased response accuracy, deficits in the allocation of attentional resources, and increased stimulus-response conflict during tasks requiring variable amounts of cognitive control. Neuroelectric measures of cognitive control may be uniquely sensitive to the persistent and selective decrements of concussion.

Aerobic fitness and intra-individual variability of neurocognition in preadolescent children

This study examined behavioral and neuroelectric intra-individual variability (IIV) in preadolescent children during a task requiring variable amounts of cognitive control. The current study further examined whether IIV was moderated by aerobic fitness level. Participants performed a modified flanker task, comprised of congruent and incongruent arrays, within compatible and incompatible stimulus-response conditions. Results revealed that congruent, relative to incongruent, conditions were associated with less IIV of RT. Further, less IIV of RT, P3 amplitude, and P3 latency was observed for the compatible relative to the incompatible condition. Higher fitness was associated with shorter and less variable RT only for the incompatible condition, with no fitness-related differences observed for P3 variability. The findings suggest that conditions requiring greater cognitive control are associated with increased IIV, and that higher fitness may be associated with greater integrity of cognitive control systems during development.

Sex differences in brain plasticity: a new hypothesis for sex ratio bias in autism

Several observations support the hypothesis that differences in synaptic and regional cerebral plasticity between the sexes account for the high ratio of males to females in autism. First, males are more susceptible than females to perturbations in genes involved in synaptic plasticity. Second, sex-related differences in non-autistic brain structure and function are observed in highly variable regions, namely, the heteromodal associative cortices, and overlap with structural particularities and enhanced activity of perceptual associative regions in autistic individuals. Finally, functional cortical reallocations following brain lesions in non-autistic adults (for example, traumatic brain injury, multiple sclerosis) are sex-dependent. Interactions between genetic sex and hormones may therefore result in higher synaptic and consecutively regional plasticity in perceptual brain areas in males than in females. The onset of autism may largely involve mutations altering synaptic plasticity that create a plastic reaction affecting the most variable and sexually dimorphic brain regions. The sex ratio bias in autism may arise because males have a lower threshold than females for the development of this plastic reaction following a genetic or environmental event.

The persistent influence of pediatric concussion on attention and cognitive control during flanker performance.

This study investigated the influence of concussion history on childrens neurocognitive processing. Thirty-two children ages 8-10 years (16 with a concussion history, 16 controls) completed compatible and incompatible conditions of a flanker task while behavioral and neuroelectric data were collected. Relative to controls, children with a concussion history exhibited alterations in the sequential congruency effect, committed more omission errors, and exhibited decreased post-error accuracy. Children with a concussion history exhibited longer N2 latency across task conditions, increased N2 amplitude during the incompatible condition of the task, and decreased P3b amplitude across task conditions. Children with a history of concussion also exhibited decreased ERN and Pe amplitudes, with group difference increasing for the incompatible condition of the task. The current results indicate that pediatric concussion may lead to subtle, but pervasive deficits in attention and cognitive control. These results serve to inform a poorly understood but significant public health concern.

Sport-Related Concussion and Sensory Function in Young Adults

CONTEXT The long-term implications of concussive injuries for brain and cognitive health represent a growing concern in the public consciousness. As such, identifying measures sensitive to the subtle yet persistent effects of concussive injuries is warranted. OBJECTIVE To investigate how concussion sustained early in life influences visual processing in young adults. We predicted that young adults with a history of concussion would show decreased sensory processing, as noted by a reduction in P1 event-related potential component amplitude. DESIGN Cross-sectional study. SETTING Research laboratory. PATIENTS OR OTHER PARTICIPANTS Thirty-six adults (18 with a history of concussion, 18 controls) between the ages of 20 and 28 years completed a pattern-reversal visual evoked potential task while event-related potentials were recorded. MAIN OUTCOME MEASURE(S) The groups did not differ in any demographic variables (all P values > .05), yet those with a concussive history exhibited reduced P1 amplitude compared with the control participants (P = .05). CONCLUSIONS These results suggest that concussion history has a negative effect on visual processing in young adults. Further, upper-level neurocognitive deficits associated with concussion may, in part, result from less efficient downstream sensory capture.

The association between a history of concussion and variability in behavioral and neuroelectric indices of cognition

Associations between a history of concussion and variability in behavioral and neuroelectric indices of cognition were assessed in college-aged adults with a history of concussion and a healthy control group, in response to a stimulus discrimination task and a more attentionally demanding flanker task. Greater intra-individual variability was observed only for behavioral indices of reaction time in response to the flanker task for those with a history of concussion. An association was also observed between the number of concussions resulting in a loss of consciousness and greater variability of reaction time regardless of the type of task. Relative to neuroelectric measures, a concussive history was associated with smaller P3 amplitude only in response to the flanker task; with no differences between groups observed in response to the oddball task or for intra-individual variability measures. Thus, increased variability associated with a history of concussion appears to be behavior and process specific. The behavioral metrics and functions assessed are important considerations for identifying subtle, yet persistent influences of concussion on cognitive performance. Further, factors such as loss of consciousness associated with a concussive injury may moderate the extent to which these increases in behavioral variability manifest. Thus, the identification of persistent cognitive impairment following concussive injuries necessitates the utilization of appropriate tasks and may be facilitated by going beyond behavioral measures of central tendency.

The Selective Effect of Acute Aerobic Exercise on Neuroelectric Indices of Attention during Development

Background: A growing literature demonstrates the beneficial effects of aerobic exercise on higher-cognition during development. This study sought to investigate the specificity of the effects of acute aerobic exercise on attentional processing during development. This study also investigated whether maturation would interact with the effect of acute exercise on attentional processing. Methods: Event-related potentials (ERPs) evoked by a 3-stimulus visual oddball task, were recorded in 8-9 (n=16) and 11-12 year-old (n=16) children. Two ERP components, each reflecting different attentional processes were studied (i.e., P3a and P3b). The P3b reflects attentional resource allocation during stimulus engagement, and the P3a reflects the orienting of focal attention to novel or distracting information. On separate days, and in a counter balance manner, the children completed the oddball task two times, once at following rest and once following 30 minutes of moderate aerobic (cycling) exercise. Results: Relative to rest, the amplitude of the P3b was significantly greater following exercise for both age groups. No significant differences were observed for the amplitude or the latency of the P3a. Conclusion: The present findings suggest that, regardless of age, acute aerobic exercise in children selectively benefits the neural resources underlying attentional resource allocation during stimulus engagement, with no influence on attentional orienting.