Nigel Foreman

Object exploration and reactions to spatial and nonspatial changes in hooded rats following damage to parietal cortex or hippocampal formation.

Hooded rats with bilateral lesions of the anterior part of the hippocampal formation (HIP), anterior region of the posterior parietal cortex (APC), or posterior region of the posterior parietal cortex (PPC) were compared with controls for their exploration of 5 objects in an open field, habituation of locomotion and object investigation, and response to spatial and nonspatial change. First, all groups displayed habituation of both locomotor and exploratory activity. Second, controls selectively reexplored displaced objects, and APC-lesioned rats reexplored all objects, whereas PPC- and HIP-lesioned rats failed to react to the spatial change. Third, a novel object induced reexploration in all groups. The results are consistent with the roles of the HIP and PPC in spatial information processing. Moreover, the APC and PPC are involved in attentional effortful processing and visuospatial information processing necessary for spatial representation, respectively.

Virtual reality, disability and rehabilitation

Virtual reality, or virtual environment computer technology, generates simulated objects and events with which people can interact. Existing and potential applications for this technology in the field of disability and rehabilitation are discussed. The main benefits identified for disabled people are that they can engage in a range of activities in a simulator relatively free from the limitations imposed by their disability, and they can do so in safety. Evidence that the knowledge and skills acquired by disabled individuals in simulated environments can transfer to the real world is presented. In particular, spatial information and life skills learned in a virtual environment have been shown to transfer to the real world. Applications for visually impaired people are discussed, and the potential for medical interventions and the assessment and treatment of neurological damage are considered. Finally some current limitations of the technology, and ethical concerns in relation to disability, are discussed.

Transfer of Spatial Information from a Virtual to a Real Environment

A group 10 severely physically disabled children explored a to-scale computer simulation of a real multi-storey building. Following exploration, their knowledge of the spatial properties of the real environment was assessed by asking them to point to fire apparatus that was not visible from the test site. Subjects in a control group were asked to complete the same assessment tasks, but without the opportunity to explore either the real building or the computer simulation. The estimates of the disabled children were superior to the control group indicating good transfer of spatial knowledge. Route finding and recognition reports provided support for the pointing data in indicating good transfer of spatial information.

Transfer of spatial information from a virtual to a real environment in physically disabled children

A group of 10 severely physically disabled children explored a to-scale computer simulation of a real multi-storey building. Following exploration, their knowledge of the spatial properties of the real environment was assessed by asking them to point to fire apparatus that was not visible from the test site. Subjects in a control group were asked to complete the same assessment tasks, but without the opportunity to explore either the real building or the computer simulation. The estimates of the disabled children were superior to the control group indicating good transfer of spatial knowledge. Route finding and recognition reports provided support for the pointing data in indicating good transfer of spatial information.

Relationships between the superior colliculus and hippocampus: Neural and behavioral considerations

Theories of superior collicular and hippocampal function have remarkable similarities. Both structures have been repeatedly implicated in spatial and attentional behaviour and in inhibitory control of locomotion. Moreover, they share certain electrophysiological properties in their single unit responses and in the synchronous appearance and disappearance of slow wave activity. Both are phylogenetically old and the colliculus projects strongly to brainstem nuclei instrumental in the generation of theta rhythm in the hippocampal EEC On the other hand, close inspection of behavioural and electrophysiological data reveals disparities. In particular, hippocampal processing mainly concerns stimulus ambiguity, contextual significance, and spatial relations or other subtle, higher order characteristics. This requires the use of largely preprocessed sensory information and mediation of poststimulus investigation. Although collicular activity must also be integrated with that of “higher” centres (probably to a varying degree, depending on the nature of stimuli being processed and the task requirements), its primary role in attention is more “peripheral” and specific in controlling orienting/localisation via eye and body movements toward egocentrically labelled spatial positions. In addition, the colliculus may exert a nonspecific influence in alerting higher centres to the imminence of information potentially worthy of focal attention. Nevertheless, it is noteworthy that collicular and hippocampal lesions produce deficits on similar tasks, although the type of deficit is usually different (often opposite) in each case. Functional overlap between hippocampus and colliculus (i.e., strategically synchronised or mutually interdependent activity) is virtually certain vis-a-vis stimulus sampling, for example in the acquisition of information via vibrissal movements and visual scanning. In addition, insofar as stimulus significance is a factor in collicular orienting mechanisms, the hippocampus — cingulate – cortex — colliculus pathway may play a significant role, modulating collicular responsiveness and thus ensuring an attentional strategy appropriate to current requirements (stimulus familiarity, stage of learning). A tentative “reciprocal loop” model is proposed which bridges physiological and behavioural levels of analysis and which would account for the observed degree and nature of functional overlap between the superior colliculus and hippocampus.

Improving spatial functioning in children with cerebral palsy using computerized and traditional game tasks.

Purpose: To examine the effectiveness of combining virtual environment (VE) instruction with additional desk-top tasks, based on the Luria-Vygotsky methodology, for spatial remediation in children having complex motor disabilities restricting movement. Method: In Experiment 1, from among children attending for residential rehabilitation, an experimental subgroup had additional spatial training using a VE and corresponding desk-top models. All children were tested at the start and end of training, using four spatial tests. In Experiment 2, larger groups of children (pair-matched for initial performance) were given the same training as in Experiment 1, but experimentals received both VE-based training and supporting tasks designed to improve executive functions and verbal regulation of spatial functioning. Assessment involved a wider range of tests than in Experiment 1. Results: In Experiment 1, both groups showed improvement at retest, but experimentals showed greater improvement. Children beginning with the lowest level of cognitive performance failed to benefit from the additional training. In Experiment 2 the experimental group made significantly greater improvement than controls, irrespective of initial performance level. Conclusions: VE-based spatial training is effective for children with complex disabilities, particularly when combined with training that remediates cognitive weaknesses.

Algorithmic responding on the radial maze in rats does not always imply absence of spatial encoding

Two experiments were conducted to determine whether consistent algorithmic response patterning on 8- and 10-arm versions of the radial maze is independent of spatial encoding. On the 8-arm version well-trained hooded rats were tested in darkness, after maze rotation that rendered room cues ambiguous with respect to arm positions, or with room cues unsystematically relocated. Ambiguous maze rotation was also used with well-trained subjects on the 10-arm version. If algorithmic patterning is a learned, non-spatial strategy, animals using it consistently ought not to have been affected by changes in the spatial layout of the test environment, and the type of pattern used by each subject would have remained constant. On the 8-arm radial maze, responses were most often made to arms 2 or 3 from that just visited. In many animals patterns were interchangeable, switching occurring between preferred angles of turn from day to day. Performance fell when animals were tested in darkness and upon ambiguous maze rotation early (but not later) in training. Testing in darkness increased the angle through which animals turned when responding, perhaps due to the disturbance of intramaze cue use. On the 10-arm maze the “consecutive arm” pattern was used persistently by several animals and appeared to protect their performance from disruption by ambiguous maze rotation. Animals not using rigid patterning were adversely affected. However, on both mazes animals using patterning correctly identified maze arms that had been omitted from otherwise patterned choice sequences. Animals adopted continuous patterning only when spatial encoding had been established. Response patterning appears to serve a mnemonic function and in rats complements rather than replaces the use of a spatial representation of the environment. It was concluded that a complex, flexible relationship exists between spatial functioning and its expression via motor responses.

High doses of caffeine impair performance of a numerical version of the Stroop task in men.

The effects of caffeine ingestion on mid-morning cognitive performance were investigated in thirty-two male subjects. These were given drinks containing either no caffeine, 125 mg caffeine (mean dose: 1.38 mg/kg), or 250 mg caffeine (mean dose: 3.45 mg/kg) and were tested on three tasks: 1) free recall of supraspan word lists, 2) a response time (pointing) task and 3) a numerical Stroop task. There were no significant group differences on the recall task or in response times, but subjects having the higher caffeine dose were seriously impaired on the Stroop test, making particularly slow responses. Caffeine may have a deleterious effect on the rapid processing of ambiguous or confusing stimuli, and this may account for its clear effect on the Stroop test than on other cognitive tests used hitherto.

Transfer of spatial knowledge to a two-level shopping mall in older people, following virtual exploration

Groups of older and younger participants explored a virtual shopping mall composed of more than 60 retail outlets on 2 levels. They were then compared with guessing controls for their understanding of the spatial layout of the real equivalent building. Experimental groups showed greater accuracy in making pointing judgments toward targets not visible from the pointing site, took shorter times to perform route tasks on foot, made better left-right directional judgments, and sketched better maps of the mall. Of the older participants, 2 out of 8 performed at chance throughout. Younger experimental participants remembered better than did older ones on which level targets were located. The study shows that many older people remain spatially competent and that age is not a barrier to the effective use of virtual environment technology, which may be used in the future to increase inclusion of older populations by encouraging their confident use of public buildings.

Locomotion, Active Choice, and Spatial Memory in Children

In two studies, children between 4 and 6 years old were tested on a radial search task requiring nonredundant sampling of eight identically labeled positions in a room. In the training phase (5 days), children made free choices by walking between positions, were passively transported in a pushchair, actively directed their own route from a pushchair, or were led on foot to positions selected by the experimenter. When tested (whether walking or directing while seated in a pushchair), children who had either walked independently or directed the experimenter while being pushed performed competently; those led on foot without spatial choice performed almost as well. Only the children who had neither independent locomotor experience nor autonomous choice performed very poorly. The results are related to neurobiological models of spatial cognition and may have implications for the transportation of children with mobility problems.