Slower Visuomotor Corrections with Unchanged Latency are Consistent with Optimal Adaptation to Increased Endogenous Noise in the Elderly

We analyzed age-related changes in motor response in a visuomotor compensatory tracking task. Subjects used a manipulandum to attempt to keep a displayed cursor at the center of a screen despite random perturbations to its location. Cross-correlation analysis of the perturbation and the subject response showed no age-related increase in latency until the onset of response to the perturbation, but substantial slowing of the response itself. Results are consistent with age-related deterioration in the ratio of signal to noise in visuomotor response. The task is such that it is tractable to use Bayesian and quadratic optimality assumptions to construct a model for behavior. This model assumes that behavior resembles an optimal controller subject to noise, and parametrizes response in terms of latency, willingness to expend effort, noise intensity, and noise bandwidth. The model is consistent with the data for all young (n = 12, age 20–30) and most elderly (n = 12, age 65–92) subjects. The model reproduces the latency result from the cross-correlation method. When presented with increased noise, the computational model reproduces the experimentally observed age-related slowing and the observed lack of increased latency. The model provides a precise way to quantitatively formulate the long-standing hypothesis that age-related slowing is an adaptation to increased noise

Executive Function in Very Preterm Children at Early School Age

We examined whether very preterm (≤30 weeks gestation) children at early school age have impairments in executive function (EF) independent of IQ and processing speed, and whether demographic and neonatal risk factors were associated with EF impairments. A consecutive sample of 50 children (27 boys and 23 girls) born very preterm (mean age = 5.9 years, SD = 0.4, mean gestational age = 28.0 weeks, SD = 1.4) was compared to a sample of 50 age-matched full-term controls (23 girls and 27 boys, mean age = 6.0 years, SD = 0.6) with respect to performance on a comprehensive EF battery, assessing the domains of inhibition, working memory, switching, verbal fluency, and concept generation. The very preterm group demonstrated poor performance compared to the controls on all EF domains, even after partialing out the effects of IQ. Processing speed was marginally related to EF. Analyses with demographic and neonatal risk factors showed maternal education and gestational age to be related to EF. This study adds to the emerging body of literature showing that very preterm birth is associated with EF impairments

Exploratory Study of Executive Function Abilities Across the Adult Lifespan in Individuals Receiving an ASD Diagnosis in Adulthood

The few studies of autism spectrum disorder (ASD) across adulthood suggest different age-related associations in different aspects of executive function (EF). In this exploratory study we examined EF abilities and self-report autism traits in 134 adults (aged 18-75 years; mean=31 years) with abilities in the normal range, receiving a first diagnosis of ASD. Results suggest that in some EF relying on speed and sequencing (Trails A and B; Digit Symbol), late-diagnosed ASD individuals may demonstrate better performance than typical age-norms. On other EF (Digit Span, Hayling, Brixton tests) age-related correlations were similar to typical age-norms. Different domains of EF may demonstrate different trajectories for ageing with ASD, with patterns of slower, accelerated or equivalent age-related change observed across different measures

Exploratory Study of Executive Function Abilities Across the Adult Lifespan in Individuals Receiving an ASD Diagnosis in Adulthood

The few studies of autism spectrum disorder (ASD) across adulthood suggest different age-related associations in different aspects of executive function (EF). In this exploratory study we examined EF abilities and self-report autism traits in 134 adults (aged 18-75 years; mean=31 years) with abilities in the normal range, receiving a first diagnosis of ASD. Results suggest that in some EF relying on speed and sequencing (Trails A and B; Digit Symbol), late-diagnosed ASD individuals may demonstrate better performance than typical age-norms. On other EF (Digit Span, Hayling, Brixton tests) age-related correlations were similar to typical age-norms. Different domains of EF may demonstrate different trajectories for ageing with ASD, with patterns of slower, accelerated or equivalent age-related change observed across different measures

The effects of age on well-being, psychopathology and repressive coping

Original article can be found at: http://www.informaworld.com/smpp/title~content=t713404778 Copyright Informa Taylor and Francis Group. DOI: 10.1080/13607860600963737The present study was conducted to test the hypothesis that the increased psychological well-being and positivity effect in old age can be related to a high prevalence of repressive coping in healthy older adults. Both older (mean age 73) and younger (mean age 20) adults completed a range of indices measuring psychopathology and repressive coping. Results showed that older adults scored lower than younger adults on almost all indices of psychopathology, and were more likely to be classed as repressive copers than younger adults (41% versus 11%, respectively). Furthermore, when the repressive copers and borderline repressors were removed from both samples, age effects on several, but not all, measures of psychopathology disappeared indicating that even older non-repressors showed better mental health than young non-repressors. Possible mechanisms of increased positivity, in terms of repressive coping and reductions in intrusive thoughts and rumination in old age, are discussed.Peer reviewe

What determines saccade timing in sequences of coordinated eye and hand movements?

In action sequences, the eyes are generally fixated ahead of the stimulus being responded to, overlapping the processing of adjacent stimuli. What determines when the saccade to the next item is initiated and what processing is overlapped remain controversial. Saccade initiation has been linked directly to the difficulty of the underlying processing on the fixated item or to a rhythmic timer whose period is adjusted to the difficulty of the context. We compared the effects of item and context difficulty when subjects made speeded choice responses to five visual stimuli arrayed linearly. Item difficulty was manipulated by varying stimulus-response compatibility, creating contexts (sequences) whose average item difficulty differed. Results showed that saccade initiation time reflected item difficulty, not context difficulty, with evidence that saccade initiation was delayed until central processing was completed. We discuss the implications of these results for the control of saccades and processing in action sequences