Neurobehavioural profile following cumulative mild traumatic brain injury in adolescent rugby players in South Africa

The study investigated the neurobehavioural components of executive dysfunction following sport-related Mild Traumatic Brain Injury (MTBI) in Grade 12 adolescent rugby players over a rugby season. In a non-equivalent quasi-experimental design, a rugby group (n?=?90) were compared with demographically equivalent noncontact sport controls (n?=?59). The Behaviour Rating Inventory of Executive Functions – Self Report (BRIEF-SR) was employed to assess the neurobehavioural component of executive functions. Independent and dependent t-test analyses were conducted to compare the groups at baseline and end-of-season intervals. The overall findings suggest more pronounced deleterious effects on executive functioning from exposure to the concussive and sub-concussive events among the rugby group. High school rugby players experience adverse neurobehavioural effects in executive dysfunction from contact rugby sport injuries.     

基于事件的前瞻记忆与认知控制

前瞻记忆和认知控制是人类认知能力的重要组成部分。Bugg等人(2013)发现前瞻记忆多重加工模型和双重认知控制理论具有共性。此后,越来越多的研究者关注认知控制在意图执行中和执行完成后的作用。本文对近年来关于前瞻记忆与认知控制的研究进行了梳理,发现认知控制对前瞻记忆的完成起支持作用,但二者也在脑机制层面存在差异。本研究能为未来更深入地探讨前瞻记忆的加工机制及生理基础提供新的视角。     

Radial bisection of words and lines in right‐brain‐damaged patients with spatial neglect

The bisection of lines positioned radially (with the two ends of the line close and far, with respect to the participant's body) has been less investigated than that of lines placed horizontally (with their two ends left and right, with respect to the body's midsagittal plane). In horizontal bisection, patients with left neglect typically show a rightward bias for both lines and words, greater with longer stimuli. As for radial bisection, available data indicate that neurologically unimpaired participants make a distal error, while results from right‐brain‐damaged patients with left spatial neglect are contradictory. We investigated the bisection of radially oriented words, with the prediction that, during bisection, linguistic material would be recoded to its canonical left‐to‐right format in reading, with the performance of neglect patients being similar to that for horizontal words. Thirteen right‐brain‐damaged patients (seven with left spatial neglect) and fourteen healthy controls were asked to manually bisect 40 radial and 40 horizontal words (5–10 letters), and 80 lines, 40 radial and 40 horizontal, of comparable length. Right‐brain‐damaged patients with spatial neglect exhibited a proximal bias in the bisection of short radial words, with the proximal part corresponding to the final right part of horizontally oriented words. This proximal error was not found in patients without neglect and healthy controls. For bisection, short radial words may be recoded to the canonical orthographic horizontal format, unveiling the impact of left neglect on radially oriented stimuli.     

Cerebellar neurophysiology in Gilles de la Tourette syndrome and its role as a target for therapeutic intervention

Therapy resistance of approximately one‐third of patients with Gilles de la Tourette syndrome (GTS) requires consideration of alternative therapeutic interventions. The article demonstrates the role of the cerebellum in neuropsychiatric disorders and GTS in particular, specifically its role in functions relating to motor and cognitive symptoms. Certain circuits in the cerebellum have been shown to undergo learning‐induced changes during conditioning, with cells in the cortex of the cerebellum appearing to decrease their activity whilst those in deep nuclei seem to do the inverse. Evidence exists showing that abnormal excitability of the motor cortex via the cerebellum could be expected to participate in motor tics in GTS possibly due to aberrations in certain structures of involved circuits. The role of the cerebellum in learning and plasticity processes renders it a strategic and valuable structure to consider for brain stimulation when investigating potential treatment options for neuropsychiatric disorders such as GTS. This article puts forth the concept of using non‐invasive and invasive brain stimulation techniques as a novel platform for non‐pharmacological neuromodulation of GTS symptoms.     

An Analogue Study of the Psychological and Psychosocial Processes Associated With Post‐concussion Symptoms

This study used an analogue design to investigate post‐concussion syndrome and the psychological and psychosocial processes associated with post‐concussion symptom (PCSx) reporting. The study examined the role of expectation in reporting of PCSx, the nature of associated psychological and psychosocial difficulties, and the “good‐old‐days” phenomenon. Forty‐five healthy participants were randomly assigned to one of two groups: (1) a control group or (2) an expectation group who were asked to perform as if they had experienced a mild traumatic brain injury. Fourteen psychiatric patients comprised the clinical group. Self‐report questionnaires assessing PCSx and psychological and psychosocial variables were administered. It was hypothesised that PCSx would be non‐specific, that the expectation group would report greater dysfunction than controls, and that the “good‐old‐days” phenomenon would cause the expectation and clinical groups to underestimate pre‐morbid PCSx. All participants reported some degree of dysfunction, and the expectation and clinical groups underestimated past PCSx. The expectation group reported more PCSx and psychological and psychosocial dysfunction than controls, resembling the clinical group. The results demonstrate that expectation can cause otherwise healthy individuals to resemble a clinical group in terms of their level of endorsement of psychological and psychosocial dysfunction.     

Preference for fluent versus disfluent work schedules

Two studies were conducted that examined the preference of a student diagnosed with a brain injury. In Study 1, a preference assessment was followed by a three-choice concurrent-operants reinforcer assessment. Two choices resulted in access to preferred activities for completing work, and a third choice resulted in access to nothing (i.e., no activity). Unpredictably, the participant consistently chose the no-activity option. Study 2 examined why this student preferred work associated with no activity over preferred activities. Through a variety of concurrent-operants procedures, it was determined that she preferred fluent work followed by reinforcers rather than work that was broken up by access to preferred activities. Implications for research on preference are discussed.     

On the automaticity of emotion processing in words and faces: event-related brain potentials evidence from a superficial task

The degree to which emotional aspects of stimuli are processed automatically is controversial. Here, we assessed the automatic elicitation of emotion-related brain potentials (ERPs) to positive, negative, and neutral words and facial expressions in an easy and superficial face-word discrimination task, for which the emotional valence was irrelevant. Both emotional words and facial expressions impacted ERPs already between 50 and 100 ms after stimulus onset, possibly reflecting rapid relevance detection. Following this initial processing stage only emotionality in faces but not in words was associated with an early posterior negativity (EPN). Therefore, when emotion is irrelevant in a task which requires superficial stimulus analysis, automatically enhanced sensory encoding of emotional content appears to occur only for evolutionary prepared emotional stimuli, as reflected in larger EPN amplitudes to faces, but not to symbolic word stimuli.     

Delay discounting as impaired valuation: Delayed rewards in an animal obesity model

Obesity is a major public health problem, which, like many forms of addiction, is associated with an elevated tendency to choose smaller immediate rather than larger delayed rewards, a response pattern often referred to as excessive delay discounting. Although some accounts of delay discounting conceptualize this process as impulsivity (placing the emphasis on overvaluing the smaller immediate reward), others have conceptualized delay discounting as an executive function (placing the emphasis on delayed rewards failing to retain their value). The present experiments used a popular animal model of obesity that has been shown to discount delayed rewards at elevated rates (i.e., obese Zucker rats) to test two predictions that conceptualize delay discounting as executive function. In the first experiment, acquisition of lever pressing with delayed rewards was compared in obese versus lean Zucker rats. Contrary to predictions based on delay discounting as executive function, obese Zucker rats learned to press the lever more quickly than controls. In the second experiment, progressive ratio breakpoints (a measure of reward efficacy) with delayed rewards were compared in obese versus lean Zucker rats. Contrary to the notion that obese rats fail to value delayed rewards, the obese Zucker rats' breakpoints were (at least) as high as those of the lean Zucker rats.