计算机虚拟技术训练辅助盲人构建空间表征之研究

摘要 由于视觉经验的缺乏,盲人的空间认知存在一定的缺陷,尤其表现在对现实环境的空间布局认识存在困难。本研究欲探究计算机虚拟技术手段辅助盲人建构表征的成效,并在此基础上探究盲人定向行走的效果。本研究是一个现场实验,采用随机分配的方式将全盲被试分为三组,之后让被试接受三种不同的实验处理,即计算机虚拟技术、触觉地图和人导处理,最后接受空间任务测试,测试不仅考察被试对环境空间布局的认识,而且还测量了被试在现实环境的行走探路效率。结果发现,虚拟技术组的被试不仅能够对整个实验环境形成清晰整体的认识,而且还能借助形成的空间表征在测验场地有效地实施定向行走。从研究结果得知,计算机虚拟技术这一手段对应用于改善盲人空间表征系统及提高盲人定向行走训练效率具有一定的积极意义。     

Human four-dimensional spatial intuition in virtual reality

It is a long-lasting question whether human beings, who evolved in a physical world of three dimensions, are capable of overcoming this fundamental limitation to develop an intuitive understanding of four-dimensional space. Techniques of analogy and graphical illustration have been developed with some subjective reports of success. However, there has been no objective evaluation of such achievements. Here, we show evidence that people with basic geometric knowledge can learn to make spatial judgments on the length of, and angle between, line segments embedded in four-dimensional space viewed in virtual reality with minimal exposure to the task and no feedback to their responses. Their judgments incorporated information from both the three-dimensional (3-D) projection and the fourth dimension, and the underlying representations were not algebraic in nature but based on visual imagery, although primitive and short lived. These results suggest that human spatial representations are not completely constrained by our evolution and development in a 3-D world. Illustration of the stimuli and experimental procedure (as video clips) and the instruction to participants (as a pdf file) may be downloaded from http://pbr.psychonomic-journals.org/content/supplemental.     

Introducing a new age-and-cognition-sensitive measurement for assessing spatial orientation using a landmark-less virtual reality navigational task

Age-related impairments during spatial navigation have been widely reported in egocentric and allocentric paradigms. However, the effect of age on more specific navigational components such as the ability to drive or update directional information has not received enough attention. In this study we investigated the effect of age on spatial updating of a visual target after a series of whole–body rotations and transitions using a novel landmark-less virtual reality (VR) environment. Moreover, a significant number of previous studies focused on measures susceptible to a general decline in motor skills such as the spent time navigating, the distance traversed. The current paper proposes a new compound spatial measure to assess navigational performance, examines its reliability and compares its power with those of the measures of duration and traversed distance in predicting participants' age and cognitive groups assessed by Montreal Cognitive Assessment (MoCA) scores. Using data from 319 adults (20–83 years), our results confirm the reliability, the age sensitivity, and the cognitive validity of the designed spatial measure as well as its superiority to the measures of duration and traversed distance in predicting age and MoCA score. In addition, the results show the significant effect of age cognitive status on spatial updating.     

Visual landmarks facilitate rodent spatial navigation in virtual reality environments

Because many different sensory modalities contribute to spatial learning in rodents, it has been difficult to determine whether spatial navigation can be guided solely by visual cues. Rodents moving within physical environments with visual cues engage a variety of nonvisual sensory systems that cannot be easily inhibited without lesioning brain areas. Virtual reality offers a unique approach to ask whether visual landmark cues alone are sufficient to improve performance in a spatial task. We found that mice could learn to navigate between two water reward locations along a virtual bidirectional linear track using a spherical treadmill. Mice exposed to a virtual environment with vivid visual cues rendered on a single monitor increased their performance over a 3-d training regimen. Training significantly increased the percentage of time avatars controlled by the mice spent near reward locations in probe trials without water rewards. Neither improvement during training or spatial learning for reward locations occurred with mice operating a virtual environment without vivid landmarks or with mice deprived of all visual feedback. Mice operating the vivid environment developed stereotyped avatar turning behaviors when alternating between reward zones that were positively correlated with their performance on the probe trial. These results suggest that mice are able to learn to navigate to specific locations using only visual cues presented within a virtual environment rendered on a single computer monitor.     

A model of hippocampal neurogenesis in memory and mood disorders

The mounting evidence for neurogenesis in the adult hippocampus has fundamentally challenged the traditional view of brain development. The intense search for clues as to the functional significance of the new neurons has uncovered a surprising connection between neurogenesis and depression. In animal models of depression, neurogenesis is reduced, whereas many treatments for depression promote neurogenesis. We speculate on why the hippocampus, traditionally viewed as a memory structure, might be involved in mood disorders, and what specific role the new neurons might have in the pathogenesis of and recovery from depression. The proposed role of neurogenesis in contextual-memory formation predicts a specific pattern of cognitive deficits in depression and has important implications for treatment of this highly prevalent and debilitating disorder.     

Development of allocentric spatial recall from new viewpoints in virtual reality

Using landmarks and other scene features to recall locations from new viewpoints is a critical skill in spatial cognition. In an immersive virtual reality task, we asked children 3.5–4.5 years old to remember the location of a target using various cues. On some trials they could use information from their own self‐motion. On some trials they could use a view match. In the very hardest kind of trial, they were ‘teleported’ to a new viewpoint and could only use an allocentric spatial representation. This approach provides a strict test for allocentric coding (without either a matching viewpoint or self‐motion information) while avoiding additional task demands in previous studies (it does not require them to deal with a small table‐top environment or to manage stronger cue conflicts). Both the younger and older groups were able to point back at the target location better than chance when they could use view matching and/or self‐motion, but allocentric recall was only seen in the older group (4.0–4.5). In addition, we only obtained evidence for a specific kind of allocentric recall in the older group: they tracked one major axis of the space significantly above chance, r(158) = .28, but not the other, r(158) = ?.01. We conclude that there is a major qualitative change in coding for spatial recall around the fourth birthday, potentially followed by further development towards fully flexible recall from new viewpoints.     

虚拟现实技术在执行功能评估中的应用

执行功能反映了个体对自身的认知过程进行调节和控制的能力,其评估在儿童认知能力发展水平和特殊人群认知功能损伤程度的评定中起着重要作用。虽然执行功能的评估自20世纪初就开始被实施和应用,但传统评估方法仍存在着生态效度不高、不易操纵实验环境的复杂性、不易操纵被试觉醒水平等缺陷。近年来,虚拟现实技术以其有限的成本和快速的发展被越来越多地应用于执行功能评估,并被证实具有生态效度高、实验条件高度可控等显著优点。     

A slow wave investigation of working memory biases in mood disorders

Mood-congruent working memory biases were examined in a delayed matching to sample paradigm using the slow wave (SW) event-related brain potential (ERP) component. Mood-congruent working memory biases, indexed by SW amplitudes, were demonstrated among individuals experiencing a major depressive episode (MDE) and nondepressed controls but not individuals with dysthymia. However, analyses of symptom severity demonstrated that those with dysthymia exhibited significantly less negative SW amplitudes with increasing depressive mood severity, whereas individuals with major depression demonstrated more negative SW amplitudes with increasing depressive mood severity. These results are discussed in the context of diagnostic specificity for cognitive biases associated with working memory of mood-disordered individuals.     

The influence of action on episodic memory: A virtual reality study

A range of empirical findings suggest that active learning is important for memory. However, few studies have focused on the mechanisms underlying this enactment effect in episodic memory using complex environments. Research using virtual reality has yielded inconsistent results. We postulated that the effect of action depends on the degree of interaction with the environment and freedom in the planning of an itinerary. To test these hypotheses, we disentangled the interaction and planning components of action to investigate whether each enhances factual and spatial memory. Seventy-two participants (36 male and 36 female) explored a virtual town in one of three experimental conditions: (a) a passive condition where participants were immersed as passenger of the car (no interaction, no planning); (b) a planning-only condition (the subject chose the itinerary but did not drive the car); (c) an interaction-only condition (the subject drove the car but the itinerary was fixed). We found that itinerary choice and motor control both enhanced spatial memory, while factual memory was impaired by online motor control. The role of action in memory is discussed.     

Disturbances of spontaneous empathic processing relate with the severity of the negative symptoms in patients with schizophrenia: A behavioural pilot-study using virtual reality technology

Behavioural and neuroimaging data have recently pointed out that empathy (feeling into someone else) is associated with mental imagery and transformation related to one’s and other’s visuo-spatial perspectives. Impairments of both empathic and visuo-spatial abilities have been observed in patients with schizophrenia. Especially, it has been suggested that schizophrenics are altered in spontaneously simulating another individual’s first-person experience. However, there is so far only little evidence regarding the relationship between deficits in empathy and disturbances in spontaneous heterocentered coding in schizophrenia. In the present pilot-study, we tested with schizophrenic patients our behavioural paradigm that enables to measure from the bodily postures and movements whether individuals in ecologically more valid conditions are interacting with another individual by using egocentered – as in sympathy (feeling with someone else) – or heterocentered – as in empathy – visuo-spatial mechanisms. For that, ten patients and ten controls, standing and moving, interacted with a virtual tightrope walker, displayed life-sized, standing and moving as well. We show that patients with higher negative symptoms had, in most cases, deficits in spontaneously using heterocentered visuo-spatial mechanisms and employed preferentially an egocentered referencing to interact with the avatar. In contrast, preserved spontaneous heterocentered visuo-spatial strategies were not linked to a prevailing negative or positive symptomatology. Our data suggest that the severity of the negative symptoms in schizophrenia relates with disturbances of spontaneous (“on-line”) empathic processing in association with lower scoring self-reported trait cognitive empathy.     

The use of virtual reality for episodic memory assessment: effects of active navigation

Episodic memory was assessed using Virtual Reality (VR). Forty-four (44) subjects visualized a target virtual apartment containing specific objects in each room. Then they visualized a second virtual apartment comprised of specific objects and objects shared by the two apartments. Subjects navigated in the virtual apartments in one of the following two conditions: active and passive. Four main episodic memory components were scored from the VR exposures: (1) learning effect; (2) active forgetting effect; (3) strategies at encoding and at retrieval; and (4) false recognitions (FRs). The effect of navigation mode (active vs. passive) on each memory component was examined. Active subjects had better learning and retrieval (recognition hits) performances compared to passive subjects. A beneficial effect of active navigation was also observed on the source-based FR rates. Active subjects made fewer source-based FRs compared to passive subjects. These overall results for the effect of active navigation are discussed in terms of the distinction between item-specific and relational processing.     

Initial validation of a virtual environment for assessment of memory functioning: virtual reality cognitive performance assessment test.

The current project is an initial attempt at validating the Virtual Reality Cognitive Performance Assessment Test (VRCPAT), a virtual environment-based measure of learning and memory. To examine convergent and discriminant validity, a multitrait-multimethod matrix was used in which we hypothesized that the VRCPAT's total learning and memory scores would correlate with other neuropsychological measures involving learning and memory but not with measures involving potential confounds (i.e., executive functions; attention; processing speed; and verbal fluency). Using a sequential hierarchical strategy, each stage of test development did not proceed until specified criteria were met. The 15-minute VRCPAT battery and a 1.5-hour in-person neuropsychological assessment were conducted with a sample of 30 healthy adults, between the ages of 21 and 36, that included equivalent distributions of men and women from ethnically diverse populations. Results supported both convergent and discriminant validity. That is, findings suggest that the VRCPAT measures a capacity that is (a) consistent with that assessed by traditional paper-and-pencil measures involving learning and memory and (b) inconsistent with that assessed by traditional paper-and-pencil measures assessing neurocognitive domains traditionally assumed to be other than learning and memory. We conclude that the VRCPAT is a valid test that provides a unique opportunity to reliably and efficiently study memory function within an ecologically valid environment.     

Cognitive-behavioral treatment and antidepressants combined with virtual reality exposure for patients with chronic agoraphobia

In this study we compared the efficacy of virtual reality exposure combined with cognitive-behavioral therapy (VRET) to that of traditional cognitive-behavioral therapy (CBT) alone in reducing phobic symptoms in a sample of patients with long-term agoraphobia. The study was a between-subject design with three experimental conditions (VRET group, N = 30; CBT group, N = 30; and medication only group, N = 20) and repeated measures (pre-treatment, post-treatment, and six-month follow-up). All patients were receiving antidepressant medication. Results showed that all therapies were statistically effective both at post-treatment and six-month follow-up. The VRET group showed clinical improvement in most variables measured at follow-up. The CBT group showed the highest dropout rates. These results are discussed pointing out that VRET probably serves as an intermediate procedure for an efficient exposure to phobic stimuli. Besides describing the advantages of VRET for the treatment of agoraphobia symptoms in cost-benefit terms, the study also considered issues related to higher treatment adherence and motivation.     

The association of perimenopausal mood disorders with other reproductive-related disorders

Data regarding the increased incidence of psychiatric illness during midlife in women are still conflicting. However, there is a growing consensus that certain groups of women may in fact be at higher risk for mood symptoms and psychiatric disorders during the perimenopausal transition. Mood symptoms during the perimenopause may be related to mood disorders during other periods of hormonal fluctuation throughout a woman's reproductive lifecycle. Elucidating these associations may advance the understanding of mood disorders during the perimenopausal transition. The epidemiology and treatment of perimenopausal mood symptoms compared with the epidemiology and treatment of mood disorders during the late luteal phase of the menstrual cycle, pregnancy, and postpartum. Common risk factors associated with mood disorders during these periods of hormonal changes or instability include poor lifestyle habits, a history of hormonally related mood disorders, stress and negative life events, ethnicity, and comorbidity. Reproductive-related mood disorders also are subject to an improvement in symptoms in response to treatment with selective serotonin reuptake inhibitors. As the morbidity associated with mood disorders during midlife may be quite significant, and as life expectancy continues to increase, recognition, prevention, and treatment of perimenopausal affective illness is becoming increasingly essential.     

Spatial working memory for clustered and linear configurations of sites in a virtual reality foraging task

Two experiments using an immersive virtual reality foraging environment determined the spatial strategies spontaneously deployed by people in a foraging task and the effects on immediate serial recall of trajectories though the foraging space, which could conform or violate specific organisational constraints. People benefitted from the use of organised search patterns when attempting to monitor their travel though either a clustered "patchy" space or a matrix of locations. The results are discussed within a comparative framework.     

The impact of state and dispositional mindfulness on prospective memory: A virtual reality study

Prospective memory (PM) consists of remembering to perform an action that was previously planned. The recovery and execution of these actions require attentional resources. Mindfulness, as a state or a dispositional trait, has been associated with better attentional abilities while mind wandering is linked with attentional failures. In this study, we investigated the impact of mindfulness on PM. Eighty participants learned 15 cue-action associations. They were, then, asked to recall the actions at certain moments (time-based items) or places (event-based items) during a walk in a virtual town. Before the PM task, participants were randomly assigned to a mindfulness or mind wandering (control condition) session. Dispositional mindfulness was measured via the Five Facets Mindfulness Questionnaire (FFMQ). Although considered as two opposite states, we did not report any difference between the two groups on PM abilities. Nevertheless, the natural tendency to describe one's own sensations (the Describing facet of the FFMQ) predicted time-based performance in both groups. We discuss different hypotheses to explain this finding in light of recent findings on the impact of mind wandering on future oriented cognition. Our main observation is a positive link between the Describing facet and time-based PM performances. We propose that this link could be due to the common association of this mindfulness facets and PM with attentional and interoceptive abilities. Additional studies are needed to explore this hypothesis.