Regulate to facilitate: A scoping review of prefrontal asymmetry in sport and exercise

BackgroundPrefrontal asymmetry (PFA) describes the relative activity of the right PFC compared to the left PFC. It has been shown that PFA is associated with affective and motivational variables in several contexts, including sport and exercise. Considering the significant roles of affect and motivation in different performance settings, PFA might also be an important indicator of athletic performance. However, the relevance of PFA in the sport and exercise setting has not yet been addressed in its entirety. Instead, previous systematic reviews have solely focused on affective variables. Mapping out the complex interactions between PFA and affective, motivational as well as performance variables could help to understand what determines successful athletic performance as well as the positive psychological effects associated with exercise.ApproachScientific databases were searched for quantitative studies in English language published in international peer-reviewed journals. All 27 selected studies assessed physical activity and measured PFA in the brain locations F4-F3 and/or F8-F7 using electroencephalography.FindingsThe majority of the studies used a non-athlete sample (78%) and exercise types were diverse. While all studies focused on affective or motivational processes, 19% also reported associations with performance. Even though findings are inconsistent, they support the assumption that PFA plays a role in self-regulation.ConclusionThere is evidence for an involvement of PFA in affective, motivational and performance processes in the sport and exercise setting that can be interpreted as regulatory mechanisms. Future research on the underlying mechanisms is warranted, in particular, associations with motivational processes and performance need to be investigated more explicitly.     

On optimal smoothing and derivative estimation from noisy displacement data in biomechanics

Estimating derivatives from noisy displacement data is a notoriously ill-posed problem in signal processing and biomechanics. Following the work of Wood and Jennings (1978) and Hatze (1979, 1981), the present paper describes the use of optimally regularized, natural quintic splines for estimating smoothed positions, velocities, and accelerations from equidistantly sampled, noisy position measurements. It appears that the nature of the boundary conditions of the data is of some importance, since various algorithms used hitherto result in artefacts throughout the data if the true derivatives at the record ends differ significantly from zero. Natural quintic splines do not suffer from this disadvantage below the third derivative.The ill-posed character of movement analysis has some interesting implications for movement synthesis and optimization, similar to the indeterminacy of muscular co-contraction from merely external, biomechanical measurements.     

Personality correlates of retrieval processes in intentional and unintentional forgetting

Early accounts of intentional forgetting relied exclusively on mechanisms that operate at encoding. The results of more recent experiments indicate that memory-retrieval inhibition also is involved, thus linking waking intentional forgetting with hypnotic amnesia. The present Experiment 1 was designed to provide further support for the retrieval-inhibition hypothesis by testing four alternative explanations for some of the recent results. Experiment 2 examined the role of word affect in both intentional forgetting and unintentional forgetting to evaluate theoretical interpretations of the retrieval mechanisms thought to be involved. Unintentional forgetting of negative words was consistent with a repression-like interpretation, whereas intentional forgetting of negative words appeared to be limited by sensitization. Personality correlates of the recall results were identified and were found to be in support of these interpretations.     

Stimulus generalization following extradimensional and intradimensional training in educable retarded children

Five related experiments investigating stimulus generalization following go/no-go discrimination training of educable retarded children are reported. Experiment 1 employed an Extradimensional paradigm in which generalization testing was on the hue dimension following training on an independent (orientation) dimension. Following True discrimination training only 25% of children showed a decremental stimulus generalization gradient on the hue dimension, though all children exhibited flat gradients in Pseudodiscrimination and S+ only control groups. An increase in difficulty of the orientation discrimination in Experiment 2 did not increase the number of decremental gradients. In Experiment 3, children who exhibited decremental gradients in Experiments 1 and 2 underwent further generalization testing with modified stimuli to establish a symmetrical gradient peaked at a hue S+ to be employed in Experiments 4 and 5. In these experiments an Intradimensional paradigm was employed with S+ and S? stimuli drawn from the hue dimension. Excitatory control by S+ and inhibitory control by S? were demonstrated, as were inhibitory consequences of S? such as peak and area shift.