Maturational Changes in Human Dorsal and Ventral Visual Networks.

Developmental neuroimaging studies report the emergence of increasingly diverse cognitive functions as closely entangled with a rise-fall modulation of cortical thickness (CTh), structural cortical and white-matter connectivity, and a time-course for the experience-dependent selective elimination of the overproduced synapses. We examine which of two visual processing networks, the dorsal (DVN; prefrontal, parietal nodes) or ventral (VVN; frontal-temporal, fusiform nodes) matures first, thus leading the neuro-cognitive developmental trajectory. Three age-dependent measures are reported: (i) the CTh at network nodes; (ii) the matrix of intra-network structural connectivity (edges); and (iii) the proficiency in network-related neuropsychological tests. Typically developing children (age ~6 years), adolescents (~11 years), and adults (~21 years) were tested using multiple-acquisition structural T1-weighted magnetic resonance imaging (MRI) and neuropsychology. MRI images reconstructed into a gray/white/pial matter boundary model were used for CTh evaluation. No significant group differences in CTh and in the matrix of edges were found for DVN (except for the left prefrontal), but a significantly thicker cortex in children for VVN with reduced prefrontal ventral-fusiform connectivity and with an abundance of connections in adolescents. The higher performance in children on tests related to DVN corroborates the age-dependent MRI structural connectivity findings. The current findings are consistent with an earlier maturational course of DVN.

Variation in individuals' semantic networks for common knowledge is associated with false memory.

Three experiments assessed the relationships between false memories of words and their degree of connectedness within individual semantic networks. In the first two experiments, participants studied associated word lists (e.g., hot, winter, ice), completed a recognition test that included related nonstudied words (e.g., cold, snow), and then rated the semantic relatedness of all word pairs including studied and nonstudied words. In the third experiment, the task order was reversed; participants completed pairwise ratings and then, two weeks later, completed the false memory task. The relatedness ratings were analysed using the Pathfinder scaling algorithm. In all experiments, items that an individual falsely recognized had higher semantic Pathfinder node densities than those items correctly rejected.

Medical students learn over distance using virtual reality simulation.

INTRODUCTION: This article presents the results of a demonstration project that was designed with the goal to determine the feasibility and acceptability of medical students in using distance technology and virtual reality (VR) simulation within a problem-based learning (PBL). METHODS: This pilot project involved students from the Universities of New Mexico and Hawaii and compared (1) control groups consisting of medical students in a tutor-guided PBL session using a text-based case, (2) distance groups using the same text-based case but interacting over distance from multiple sites, (3) groups using a VR simulation scenario integrated into the case without interaction over distance, and (4) combination groups interacting over distance from multiple sites with integration of a VR simulation scenario. RESULTS: The study results suggest that it is possible to successfully conduct a PBL tutorial with medical students from two institutions with the integration VR and distributed distance interaction in combination or independently. The addition of these modalities did not interfere with learning dynamics when compared with traditional tutorial sessions. CONCLUSIONS: These findings suggest the feasibility and acceptability by students in the use of VR simulation integrated into a PBL learning session, as well as multipoint distance technologies that allowed interaction between students and tutors in different locations. The authors believe that these modalities can be applied where students and tutors from different institutions are in separate locations and can be used to support interactive experiential learning in a distributed network or on site and suggest areas for additional research.

The effect of degree of immersion upon learning performance in virtual reality simulations for medical education.

Simulations are being used in education and training to enhance understanding, improve performance, and assess competence. However, it is important to measure the performance of these simulations as learning and training tools. This study examined and compared knowledge acquisition using a knowledge structure design. The subjects were first-year medical students at The University of New Mexico School of Medicine. One group used a fully immersed virtual reality (VR) environment using a head mounted display (HMD) and another group used a partially immersed (computer screen) VR environment. The study aims were to determine whether there were significant differences between the two groups as measured by changes in knowledge structure before and after the VR simulation experience. The results showed that both groups benefited from the VR simulation training as measured by the significant increased similarity to the expert knowledge network after the training experience. However, the immersed group showed a significantly higher gain than the partially immersed group. This study demonstrated a positive effect of VR simulation on learning as reflected by improvements in knowledge structure but an enhanced effect of full-immersion using a HMD vs. a screen-based VR system.

Dissociation between MEG alpha modulation and performance accuracy on visual working memory task in obsessive compulsive disorder.

Oscillatory brain activity in the alpha band (8-13 Hz) is modulated by cognitive events. Such modulation is reflected in a decrease of alpha (event-related desynchronization; ERD) with high cognitive load, or an increase (event-related synchronization) with low cognitive demand or with active inhibition of distractors. We used magnetoencephalography to investigate the pattern of prefrontal and parieto-occipital alpha modulation related to two variants of visual working memory task (delayed matching-to-sample) with and without a distractor. We tested nonmedicated, nondepressed patients suffering obsessive-compulsive disorder (OCD), and pair-matched healthy controls. The level of event-related alpha as a function of time was estimated using the temporal-spectral evolution technique. The results in OCD patients indicated: (1) a lower level of prestimulus (reference) alpha when compared to controls, (2) a task-phase specific reduction in event-related alpha ERD in particular for delayed matching-to-sample task with distractor, (3) no significant correlations between the pattern of modulation in prefrontal and parietal-occipital alpha oscillatory activity. Despite showing an abnormally low alpha modulation, the OCD patients' performance accuracy was normal. The results suggest a relationship of alpha oscillations and the underlying thalamocortical network to etiology of OCD and an involvement of a compensatory mechanism related to effortful inhibition of extrinsic and intrinsic interference.

Virtual reality training improves students' knowledge structures of medical concepts.

Virtual environments can provide training that is difficult to achieve under normal circumstances. Medical students can work on high-risk cases in a realistic, time-critical environment, where students practice skills in a cognitively demanding and emotionally compelling situation. Research from cognitive science has shown that as students acquire domain expertise, their semantic organization of core domain concepts become more similar to those of an expert's. In the current study, we hypothesized that students' knowledge structures would become more expert-like as a result of their diagnosing and treating a patient experiencing a hematoma within a virtual environment. Forty-eight medical students diagnosed and treated a hematoma case within a fully immersed virtual environment. Student's semantic organization of 25 case-related concepts was assessed prior to and after training. Students' knowledge structures became more integrated and similar to an expert knowledge structure of the concepts as a result of the learning experience. The methods used here for eliciting, representing, and evaluating knowledge structures offer a sensitive and objective means for evaluating student learning in virtual environments and medical simulations.

Goal specificity and knowledge acquisition in statistics problem solving: evidence for attentional focus.

Solving training problems with nonspecific goals (NG; i.e., solving for all possible unknown values) often results in better transfer than solving training problems with standard goals (SG; i.e., solving for one particular unknown value). In this study, we evaluated an attentional focus explanation of the goal specificity effect. According to the attentional focus view, solving NG problems causes attention to be directed to local relations among successive problem states, whereas solving SG problems causes attention to be directed to relations between the various problem states and the goal state. Attention to the former is thought to enhance structural knowledge about the problem domain and thus promote transfer. Results supported this view because structurally different transfer problems were solved faster following NG training than following SG training. Moreover, structural knowledge representations revealed more links depicting local relations following NG training and more links to the training goal following SG training. As predicted, these effects were obtained only by domain novices.