Changes in Saccadic and Manual Motor Control After Ocular Smooth Pursuit Adaptive Modifications

The gain of ocular smooth pursuit responses can be adaptively modified under certain circumstances. Evidence that these modifications are caused, at least partly, by changes at a sensory level comes from the fact that subsequent manual tracking movements generated during visual fixation are also modified in a similar manner. The question addressed in the present experiment was whether the modifications are constrained specifically to responses such as these, which are driven by retinal image motion, or whether they can also influence movements that make use of retinal image position. This was accomplished by comparing manual and oculomotor responses to step changes in target position before and after smooth pursuit adaptation. The results showed that, as with manual tracking movements, these responses were also modified by the adaptive procedure, although to a lesser extent. In particular, following a 20-min period in which subjects (N = 4) were submitted to a procedure designed to increase the gain of the smooth pursuit system, manual step tracking movements and ocular saccades displayed larger amplitudes than those shown prior to the adaptation. In addition, these gain changes were accompanied by appropriate alterations in response kinematics. Taken together, these results suggest that the mechanisms responsible for adaptive modifications in the smooth pursuit system are also able to more generally influence the processing of visuospatial information. The possible neurophysiological substrate underlying these mechanisms is discussed.     

Adaptation to a Nonlinear Visuomotor Amplitude Transformation With Continuous and Terminal Visual Feedback

The control of a cursor on a computer monitor offers a simple means of exploring the limits of the plasticity of human visuomotor coordination. The authors explored the boundary conditions for adaptation to nonlinear visuomotor amplitude transformations. The authors hypothesized that only with terminal visual feedback during practice, but not with continuous visual feedback, humans might develop an internal model of the nonlinear visuomotor amplitude transformation. Thus, 2 groups were engaged in a sensorimotor adaptation task receiving either continuous or terminal visual feedback during the practice phase. In contrast to expectations, adaptive shifts and aftereffects observed in visual open-loop tests were linearly related to target amplitudes for both groups. Although the 2 feedback groups did not differ with respect to adaptive shifts and aftereffects, terminal visual feedback resulted in stable visual open-loop performance for an extended period, whereas movement errors increased after continuous visual feedback during practice. The benefit of continuous visual feedback, on the other hand, was faster closed-loop performance, indicating an optimization of visual closed-loop control.     

Discordance in Recovery Between Altered Locomotion and Muscle Atrophy Induced by Simulated Microgravity in Rats

Exposure to a microgravity environment leads to adverse effects in motion and musculoskeletal properties. However, few studies have investigated the recovery of altered locomotion and muscle atrophy simultaneously. The authors investigated altered locomotion in rats submitted to simulated microgravity by hindlimb unloading for 2 weeks. Motion deficits were characterized by hyperextension of the knees and ankle joints and forward-shifted limb motion. Furthermore, these locomotor deficits did not revert to their original form after a 2-week recovery period, although muscle atrophy in the hindlimbs had recovered, implying discordance in recovery between altered locomotion and muscle atrophy, and that other factors such as neural drives might control behavioral adaptations to microgravity.     

Visual and Proprioceptive Adaptation of Arm Position in a Virtual Environment

The authors examined the resolution of a discrepancy between visual and proprioceptive estimates of arm position in 10 participants. The participants fixed their right shoulder at 0°, 30°, or 60° of transverse adduction while they viewed a video on a head-mounted display that showed their right arm extended in front of the trunk for 30 min. The perceived arm position more closely approached the seen arm position on the display as the difference between the actual and visually displayed arm positions increased. In the extreme case of a 90° discrepancy, the seen arm position on the display was very gradually perceived as approaching the actual arm position. The magnitude of changes in sensory estimates was larger for proprioception (20%) than for vision (< 10%).     

Adaptation in Visuomanual Tracking Depends on Intact Proprioception

The role of arm proprioception in motor learning was investigated in experiments in which, by moving the arm, subjects followed the motion of a target displayed on a monitor screen. Adaptive capabilities were tested in visuomanual tracking tasks following alterations in the relationship between the observer's actual arm movement and visual feedback of the arm movement given by a cursor motion on the screen. Tracking performance and adaptive changes, measured in terms of spatiotemporal error, tracking trajectory curvature, and spatial gain, were compared in 7 control subjects (CSs) and in 1 deafferented subject (DS). CSs adapted appropriately to altered visuomanual relationships; those changes were present in trials immediately after restoration of normal scaling. In contrast, although the DS modified his tracking strategy from trial to trial according to the altered conditions, he did not show plastic changes in internal visuomanual scaling. Like the results of prismatic adaptation experiments, the present results suggest that arm proprioception contributes to the plastic changes that follow alterations in the scaling of visuomanual gain.     

Acculturation,Adaptation and Saudade Among Portuguese Migrants

Saudade is a psychological reaction to the absence of significant others and familiar places. This investigation examined differences in saudade in a sample of 227 Portuguese adults without migratory experience, and 202 Portuguese migrants living in Switzerland. Within the migrant group, the relation between saudade and acculturation and adaptation factors was also examined. Results indicate that migrants experienced higher levels of saudade than did non-migrants. Length of residence abroad influenced the level of saudade: the longer the time spent abroad the less saudade was felt. Acculturation and adaptation factors accounted for 44% of the explained variance in saudade. Among acculturation factors, higher Portuguese proficiency and separation, and lower assimilation predicted more saudade. Among the adaptation factors, higher sociocultural adaptation problems and lower migration satisfaction also predicted higher saudade. It is hoped that investigation on saudade continues, and suggestions are made for further research.     

Brief Sensation Seeking Scale for Chinese – Cultural adaptation and psychometric assessment

International behavioral research requires instruments that are not culturally-biased to assess sensation seeking. In this study we described a culturally adapted version of the Brief Sensation Seeking Scale for Chinese (BSSS-C) and its psychometric characteristics. The adapted scale was assessed using an adult sample (n = 238) with diverse educational and residential backgrounds. The BSSS-C (Cronbach alpha = 0.90) was correlated with the original Brief Sensation Seeking Scale (r = 0.85, p < 0.01) and fitted the four-factor model well (CFI = 0.98, SRMR = 0.03). The scale scores significantly predicted intention to and actual engagement in a number of health risk behaviors, including alcohol consumption, cigarette smoking, and sexual risk behaviors. In conclusion, the BSSS-C has adequate reliability and validity, supporting its utility in China and potential in other developing countries.     

Internet pornography and paedophilia

Various indices of use of Internet pornography have drawn attention to the extent of adult sexual interest in children; clinical experience and now research evidence are accumulating to suggest that the Internet is not simply drawing attention to those with existing paedophilic interests, but is contributing to the crystallisation of those interests in people with no explicit prior sexual interest in children. Drawing on clinical experience in a specialist NHS outpatient psychotherapy service, the author argues that a dichotomous notion of paedophilia is no longer tenable, and any model of paedophilia needs to take account of eruptions of a sexual interest in children in those who appear not to be consistently paedophilic and who have had adult-to-adult sexual relationships. This phenomenon is analysed in two ways: first, by considering how it is that the adult sexual adaptation might ‘unravel’ under the influence of Internet sex to reveal underlying paedophilic currents and second, by revisiting general and psychoanalytic theories of paedophilia and by considering how predisposing factors to paedophilia might be amplified through access to Internet pornography.     

Motivational and cognitive determinants of control during conflict processing

Previous studies suggest that both reward anticipation and expected or experienced conflicts activate cognitive control. The present study investigated how these factors interact during conflict processing. In two experiments, participants performed a variant of the Stroop task, receiving performance-dependent monetary rewards in some blocks. In addition, we manipulated the level of conflict-triggered reactive and expectancy-driven proactive control: In Experiment 1, we compared the Stroop effect after previously congruent and incongruent trials to examine the conflict adaptation effect (reactive control). We found that the level of motivation did not interact with conflict adaptation. In Experiment 2, we varied the proportion of congruent and incongruent trials to manipulate conflict expectancy (proactive control). The data suggest the effects of motivation to be less pronounced under conditions of high conflict expectancy. We conclude that the interaction of motivation with cognitive determinants of control depends on whether these activate proactive or reactive control processes.     

Setting Generalization during Self-Reinforcement with Educationally Handicapped Children

Eight educationally handicapped boys ranging in age form 10 to 11 years old and described as the worst behavior problems in their class participated in a series of single-subject studies carried out in their self-contained classrooms. Three served as target subjects, using self-reinforcement procedures to increase their sustained on-task behavior in a treatment setting; five served as generalization subjects. Data were collected in three settings within the self-contained classroom; an early morning treatment setting, a late morning generalization setting, and an afternoon generalization setting. The three target subjects averaged a 51% increase over their baseline median levels of sustained on-task behavior in the treatment setting. They averaged 84% and 96% generalization to the late morning and afternoon generalization settings, respectively. These results demonstrate that self-reinforcement can produce setting generalization of treatment effects in the absence of prior externally determined reinforcement. Evidence for subject and subject-setting generalization was also obtained.