Visual Feedback of Target Position Affects Accuracy of Sequential Movements at Even Spaces

The role of visual feedback during movement is attributed to its accuracy, but findings regarding the utilization of this information are inconsistent. We developed a novel dot-placing task to investigate the role of vision in arm movements. Participants conducted pointing-like movements between two target stimuli at even spaces. In Experiment 1, visual feedback of targets and response positions was manipulated. Although visual loss of target stimuli hindered accuracy of movements, the absence of the position of previously placed dots had little effect. In Experiment 2, the effect of movement time on accuracy was assessed, as the relationship between these has been traditionally understood as a speed/accuracy trade-off. Results revealed that duration of movement did not impact movement accuracy.     

The effect of persistent posttraumatic stress disorder symptoms on executive functions in preadolescent children witnessing a single incident of death

We compared executive functions (EFs) of traumatized preadolescent children with and without marked posttraumatic stress disorder (PTSD) symptoms to the performance of a nontraumatized control group, and examined the relationships between EF deficits and functional status in traumatized preadolescent children. Fifty-one preadolescent children who had witnessed a death at school 30 months prior (26 with marked PTSD symptoms and 25 without) and 30 healthy controls who had not been traumatized participated. EFs were examined using the Comprehensive Attention Test (CAT). The functional state of traumatized children was measured by the Parent Report Form-Children's Health and Illness Profile-Children's Edition (PRF-CHIP-CE). The traumatized children, regardless of status of PTSD symptomatology, showed poorer working memory performance than nontraumatized healthy controls. The traumatized children with marked PTSD symptoms performed more poorly on measures of interference control compared to those children without marked PTSD symptoms. Lower levels of EFs were associated with lower risk avoidance and diminished academic achievement in traumatized children. These results indicate that an inhibitory control deficit is specifically associated with the current PTSD symptoms but not with trauma exposure per se.     

Scaling movement amplitude: adaptation of timing and amplitude control in a bimanual task

Participants traced two circles simultaneously and the diameter of one circle was scaled as the diameter of the other circle remained constant. When the scaled circle was larger, amplitude error shifted from overshooting to undershooting, while shifting from undershooting to overshooting when this circle was smaller. Asymmetric coordination was unstable when the left arm traced a circle larger than the right arm, yet stable when the left arm traced a smaller circle. When producing symmetric coordination and the left arm traced the larger circle, relative phase shifted by 30°, but a right arm lead predominated. When the left arm traced the smaller circle and symmetric coordination was required, a 30° shift in relative phase occurred, but hand lead changed from left to right. The modulation of movement amplitude and relative phase emerged simultaneously as a result of neural crosstalk effects linked to initial amplitude conditions and possibly visual feedback of the hands' motion.     

A Body Image Resilience Model for First-Year College Women

The purpose of this study was to investigate Choate’s (2005) theoretical model of body image resilience by examining the association among protective factors and body image. First-year college women (N?=?301) from two universities in the United States (one in the South and one in the Northeast) completed questionnaires assessing five protective factors. The hypothesized model fit the data well. As predicted, high family support; low levels of perceived sociocultural pressure from family, friends, and media regarding the importance of achieving a thin-and beautiful ideal; rejection of the superwoman ideal; positive physical self-concept; and active coping skills contributed to a woman’s overall wellness, which was associated with a more positive body image. Results can inform prevention for young women at risk for eating disorders and suggest specific counseling interventions to improve body dissatisfaction and initial maladaptive eating practices.     

GSK-3β activity in the hippocampus is required for memory retrieval

Several molecules were recently found to be important for the memory retrieval process in the hippocampus; however, the mechanisms underlying the memory retrieval remain poorly understood. GSK-3β has been implicated in the control of synaptic plasticity and memory formation. Here, we investigated the relationship between hippocampal GSK-3β activity and memory retrieval using behavioral and Western blotting methods. We found that GSK-3β was activated in the hippocampus after a retention session in the passive avoidance task. An intrahippocampal injection of the GSK-3β inhibitor, SB 216763, before the retention session blocked memory retrieval (but not reconsolidation) without affecting locomotor activity. These results suggest that GSK-3β activation would be essential for memory retrieval in the hippocampus.     

The interaction of tactile information and movement amplitude in a multijoint bimanual circle-tracing task: Phase transitions and loss of stability

Adaptive behaviour in bimanual coordination was examined with the use of a bimanual circle-tracing task. Circle diameter and tactile information were manipulated to form four tracing conditions: tracing a pair of 3-cm diameter circles with the tips of the index fingers (3F) or hand-held styli (3S) and tracing a pair of 10-cm diameter circles with the tips of the index fingers (10F) or hand-held styli (10S). Movement frequency was increased in all conditions. In the 3F, 3S, and 10S tracing conditions, an abrupt transition from asymmetric to symmetric coordination was the main adaptive response, while in the 10F tracing condition, phase wandering was the main adaptive response. Enhancement of fluctuations in relative phase, a signature of loss of stability, occurred before the transition from asymmetric to symmetric coordination. Movement frequency and movement amplitude interact as control parameters in this task. The results are discussed with reference to tactile surface contact and joint motion as sources of sensory information that can be used to stabilize bimanual coordination patterns. The presence or absence of tactile information is directly linked to the specific form of adaptive behaviour (phase transition or phase wandering) that emerges as a function of required movement amplitude and required pacing frequency.