Alcohol increases hypnotic susceptibility

One approach to hypnosis suggests that for hypnotic experience to occur frontal lobe activity must be attenuated. For example, cold control theory posits that a lack of awareness of intentions is responsible for the experience of involuntariness and/or the subjective reality of hypnotic suggestions. The mid-dorso-lateral prefrontal cortex and the ACC are candidate regions for such awareness. Alcohol impairs frontal lobe executive function. This study examined whether alcohol affects hypnotisability. We administered 0.8 mg/kg of alcohol or a placebo to 32 medium susceptible participants. They were subsequently hypnotised and given hypnotic suggestions. All participants believed they had received some alcohol. Participants in the alcohol condition were more susceptible to hypnotic suggestions than participants in the placebo condition. Impaired frontal lobe activity facilitates hypnotic responding, which supports theories postulating that attenuation of executive function facilitates hypnotic response, and contradicts theories postulating that hypnotic response involves enhanced inhibitory, attentional or other executive function.     

Adapting to an initial self-regulatory task cancels the ego depletion effect

The resource-based model of self-regulation provides a pessimistic view of self-regulation that people are destined to lose their self-control after having engaged in any act of self-regulation because these acts deplete the limited resource that people need for successful self-regulation. The cognitive control theory, however, offers an alternative explanation and suggests that the depletion effect reflects switch costs between different cognitive control processes recruited to deal with demanding tasks. This account implies that the depletion effect will not occur once people have had the opportunity to adapt to the self-regulatory task initially engaged in. Consistent with this idea, the present study showed that engaging in a demanding task led to performance deficits on a subsequent self-regulatory task (i.e. the depletion effect) only when the initial demanding task was relatively short but not when it was long enough for participants to adapt. Our results were unrelated to self-efficacy, mood, and motivation.     

Event-related potentials as brain correlates of item specific proportion congruent effects

The item-specific proportion congruency (ISPC) effect is consistent with the idea that control processes can be applied rapidly in accord with previously experienced conflict for a particular category. An alternative account of this effect is that it reflects item-specific learning processes unrelated to control at the level of the category. The accounts predict the same behaviour but differ in terms of electrophysiological predictions. Two experiments examined the ISPC effect with a particular focus on neural correlates that might reveal whether, and how early in processing, high and low proportion congruent items are treated as distinct classes of stimuli. For both tasks, the proportion congruency category was distinguished prior to the congruence of the specific stimulus, as early as 100 ms post-stimulus onset for the global/local identification task (Experiment 1) and 150 ms for the Stroop task (Experiment 2). The results support an on-line control account of ISPC effects.     

Effects of Backpack Carriage on Dual-Task Performance in Children During Standing and Walking

Primary school children perform parts of their everyday activities while carrying school supplies and being involved in attention-demanding situations. Twenty-eight children (8–10 years old) performed a 1-legged stance and a 10 m walking test under single- and dual-task situations in unloaded (i.e., no backpack) and loaded conditions (i.e., backpack with 20% of body mass). Results showed that load carriage did not significantly influence children's standing and walking performance (all p > .05), while divided attention affected all proxies of walking (all p < .001). Last, no significant load by attention interactions was detected. The single application of attentional but not load demand negatively affects children's walking performance. A combined application of both did not further deteriorate their gait behavior.     

The Impact of Strategic Trajectory Optimization on Illusory Target Biases During Goal-Directed Aiming

During rapid aiming, movements are planned and executed to avoid worst-case outcomes that require time and energy to correct. As such, downward movements initially undershoot the target to avoid corrections against gravity. Illusory target context can also impact aiming bias. Here, the authors sought to determine how strategic biases mediate illusory biases. Participants aimed to Müller-Lyer figures in different directions (forward, backward, up, down). Downward biases emerged late in the movement and illusory biases emerged from peak velocity. The illusory effects were greater for downward movements at terminal endpoint. These results indicate that strategic biases interact with the limb-target control processes associated with illusory biases. Thus, multiple control processes during rapid aiming may combine and later affect endpoint accuracy (D. Elliott et al., 2010 Elliott, D., Hansen, S., Grierson, L. E. M., Lyons, J., Bennett, S. J., &; Hayes, S. J. (2010). Goal-directed aiming: two components but multiple processes. Psychological Bulletin, 136, 1023–1044.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]).     

Roles of Visual Information for Control of Reaching Movements in Children

Poststroke hemiparetic individuals (n = 9) and a control group (n = 9) completed a frequency-scaled circle-drawing task in unimanual and bimanual conditions. Measures of intralimb spatial and temporal task accuracy and interlimb coordination parameters were analyzed. Significant reductions in task performance were seen in both limbs of the patients and controls with the introduction of bimanual movement. Spatial performance parameters suggested that the 2 groups focused on different hands during bimanual conditions. In the controls, interlimb coordination variables indicated predictable hand dominance effects, whereas in the patient group, dominance was influenced by the side of impairment and prior handedness of the individual. Therefore, in this particular bimanual task, performance improvements in the hemiplegic side could not be elicited. Intrinsic coupling asymmetries between the hands can be altered by unilateral motor deficits.     

Evidence Supporting the Importance of Peripheral Visual Information for the Directional Control of Aiming Movement

The focus of the present study was on determining whether the high level of directional accuracy found in aiming studies in which the subjects can see their hand in the visual periphery supports the existence of a kinetic visual channel or, rather, the advantage of binocular over monocular vision for movement directional control. The limits of this kinetic visual channel were also explored. The results of the 1st experiment indicated that seeing one's hand in the visual periphery is sufficient to ensure optimal directional aiming accuracy. Further, no differences in aiming accuracy were noted between monocular and binocular vision. These results supported the existence of a visual kinetic channel. In the 2nd experiment, whether this kinetic visual channel would operate with movements slower (55°/s) than those usually used in studies that had proved its existence (over 110°/s) was determined. The results indicated that this visual kinetic channel was operative even at relatively slow movement velocities. Central vision of the hand seemed to be used for on-line directional control of relatively slow movements.     

Biomechanical Study of Tandem Stance in Healthy Young Adults: Effects of Weight-Bearing and Limb Dominance

Postural strategies of healthy young adults to control tandem stance were investigated through the calculation of the relative contribution of the two loading-unloading (LU) and pressure-distribution (PD) mechanisms and the two legs for controlling the resultant center-of-pressure (CP_Res) displacements. Weight-bearing asymmetry and limb dominance were also studied. For antero-posterior and medio-lateral CP_Res displacements, LU and PD mechanisms mainly contribute, respectively. A significant LU contribution is nonetheless observed for medio-lateral control, due to a lateral gap between the CP positions under each foot despite a strict sagittal alignment for the two feet. Moreover, for medio-lateral control, the respective involvement of the two legs is related to the level of weight-bearing asymmetry, whereas the front leg mainly controls the antero-posterior sway. By specifying potential effects of body-weight asymmetry and limb dominance, to a better testing of patients with deficiencies in lateral sway control.     

The Effect of Posture on Early Reaching Movements

Infants of about 5 months of age who have just mastered the ability to reach succeed more frequently in contacting an object when they are seated upright than when they are supine or reclined. That effect of posture disappears in the subsequent months. Whether that effect can be attributed either to insufficient muscular strength or to insufficient control over the mechanically unstable arm was the subject of the present investigation. Kinematics and electromyography (EMG) of reaching movements of 8 sitting and supine infants at 12, 16, and 20 weeks of age were recorded. Maximum levels of shoulder torque as well as kinematic stability measures were similar in both postures. Coactivation levels and the frequency of on-off switching of muscles turned out to be higher in the sitting than in the supine posture. The authors suggest that the difference in reaching behavior resulted from the degree of error in the feedforward control signal that was allowed by the different postures rather than either insufficient muscular strength or insufficient control over the mechanically unstable arm.