[Spatial effects of movement: their role and their processing].
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Discrimination Learning↗
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Results for “Space Perception”
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[Visual perception disorders in depressive syndromes].
A wide range of psychopathological visual phenomena, part of which are traditionally considered as derealizational disturbances, are described in the structure of depressive states. Five main types of disordered visual perception are singled out, which differ by their structure and degree of correlation with the depressive affect and symptoms of depersonalization in a wide sense. The results point to certain dynamics in the described phenomena, their sensory basis. Electrooculographic studies of eye movements indicating a peculiar formation of a visual image in different forms of depressions are demonstrated.
Adolescent↗
Developmental vs. difference theories of mental retardation: a new look.
Performance of three groups of children (retarded, nonretarded, and language-impaired) on nonlinguistic symbolic and conceptual cognitive tasks was measured. The performance of the retarded and nonretarded groups was essentially similar, while both of these groups generally performed at higher stage levels than did the language-impaired group. Several testable implications were suggested.
Child↗
[Lateral homonymous hemianopsia with anosognosia and spatial disorientation following coronariography].
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Angiography↗
Infant perception of numerosity.
A multiple habituation paradigm was used to determine whether 10--12-month-old infants were able to discriminate between visual arrays which differed only in their numerosity (2 vs. 3, 3, vs. 4, or 4 vs. 5 items). 96 infants were tested in one of two conditions. In the heterogeneous condition, infants were habituated to a series of slides in which only the number of items remained invariant, while the item type (e.g., dogs, houses, etc.), size, and position varied on each slide. In the homogeneous condition, both the item type (chicks) and number remained invariant, while the size and position of the stimuli varied. Infants in both conditions were then tested with slides which contained either N + 1 or N - 1 items. The results demonstrated that, regardless of condition (homogeneous/heterogeneous), infants were able to discriminate between 2 and 3 items and unable to discriminate between 4 and 5 items. For the 3 versus 4 discrimination, a condition x sex interaction indicated that females discriminated between the items in the homogeneous condition while males were able to make the discrimination in the heterogeneous condition. Since the subjects in this study were preverbal infants, the results suggest that early counting skills are preceded by a more perceptual awareness of numerosity.
Concept Formation↗
Scaling spatial extent, velocity and duration of motion.
Experiments on magnitude estimation of spatial extent, velocity and duration of 11 moving stimuli which had low correlations between the stimulus attributes revealed psychophysical curves of different slopes and shapes for the three attributes of motion. A psychophysical power function with an exponent almost equal to 1.0 described the magnitude estimation of distance. Deviations in velocity judgments were observed with shortening the spatial extent of motion. Duration estimation determined by moving stimuli was found to differ significantly from the estimation of time intervals of the same range presented with stationary light stimuli (Marinova, Mitrani, Yakimoff, 1980). The results indicate that velocity cannot be regarded as a directly perceived attribute of motion. Distance only seems to be directly perceived.
Distance Perception↗
[Effects of subjective contours in stroboscopic motion (author's transl)].
It was tested whether "subjective" contours have functional effects similar to real contours on stroboscopic motion. The probability of seeing motion between a pair of subjective contour stimuli was compared with that between a pair of the corresponding real contour stimuli. The results were as follows: (1) For both identical shapes and disparate shapes, subjective contours had functional effects similar to real contours, but this equivalence was not enhanced increasing duration. (2) Three types of stroboscopic motion were observed when between two disparate shapes was used as stimuli (two-dimensional rotation of rigid shapes, rotation in depth and plastic deformation), dependent on geometrical transformations between stimulus pairs rather than on ISI and duration.
Adult↗
Effects of auditory feedback on velocity extrapolation by mentally retarded and nonretarded groups during rotary pursuit tracking.
Retarded adolescents, CA-matched nonretarded adolescents, and MA-matched nonretarded children stylus-tracked an intermittently disappearing rotary pursuit target with and without auditory feedback. Under the no-feedback condition, all groups demonstrated an almost linear increase in deviation errors over five successive 2-second intervals following disappearance of the target, with the retarded group showing a greater increase than did the CA-matched and MA-matched groups. Under the feedback condition, the CA-matched group reached an asymptote of target proximity 4 seconds after the target disappeared, whereas errors for the retarded and MA-matched groups continued to increase throughout the 10-second sample period. Performance of the retarded group with no feedback was interpreted as evidence for deficient velocity extrapolation, and failure of the retarded and MA-matched groups to stabilize proximity under the feedback condition was attributed to delayed response of the feedback.
Adolescent↗
Some mechanisms of visual recognition.
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Figural Aftereffect↗
A developmental study of interhemispheric transfer in children aged five to ten.
In light of anatomical evidence that the corpus callosum does not become fully mature until about age 10, the present study attempted to find evidence of a developmental increase in the efficiency with which information is transferred between the 2 hands (hemispheres). Children were tested at ages 5, 7, and 9 on a battery of 4 tasks which measured the interhemispheric transfer of information necessary to (1) perform a simple size discrimination, (2) reproduce a temporal pattern, (3) reproduce a linear motor movement, and (4) reconstruct a 2-dimensional spatial pattern. All tasks were performed without visual guidance and utilized unilateral tactual and/or kinesthetic input and a 1-handed response. 2 tasks--the motor movement task and the spatial pattern task--showed evidence of a developmental increase in interhemispheric transfer, but the developmental pattern seen on these 2 tasks differed. Possible reasons for the between-task differences are discussed as well as their possible developmental implications.
Cerebral Cortex↗
Sex differences in pattern copying: spatial cues or motor skills?
Accuracy of pattern copying was studied in male and female 10-year-olds. It was hypothesized that previous research reporting male superiority on this measure may have actually reflected the gross-motor skills requirements of the task. The use of smaller stimuli was predicted to eliminate or reverse this sex difference. In addition, visual reference cues were included on some trials to examine their potential facilitation effects. Contrary to expectations, males benefited from spatial reference cues whereas females did not, independent of stimulus size.
Child↗
[Standardized analysis of visuospatial perception. Studies of objectivity, reliability and validity].
Retest reliability and validity of a computational method (VS, [19]) for the analysis of visual spatial perception in brain damaged patients was investigated. Retest reliability was tested in 20 patients (retest interval: 1 week; range: 1-3) and varied from r = 0.65-0.95 for the different subtests for the "point of subjective equality" and r = 0.39-0.89 for the "interval of uncertainty". In the several investigations concerning the validity of VS. 234 patients and 10 normal subjects participated. In the first place, we found significant relationships of some of the subtests of VS to similar visual-spatial tests, but no relationship to tests of visual object perception. Secondly, we found significant relationships to certain tasks which approximated daily functioning. In summary, the present results demonstrate the objectivity, retest-reliability and validity of VS in brain damaged patients.
Adolescent↗
[Hepatic minimal encephalopathy. The most frequently overlooked, clinically occult "metabolic syndrome" on the cirrhosis patient].
The syndrome of minimal hepatic encephalopathy is used to describe discrete psychomental and neuro-psychological abnormalities in patients with chronic liver disease (cirrhosis) or portosystemic shunt, in whom classical clinical investigations reveal no evidence of mental or cerebro-neurological disorders, and who cannot be assigned to any of the usual stages of hepatic encephalopathy. Disorders of cerebral function, such as lack of concentration, impaired ability to think logically, loss of comprehension, impairment of space perception and the recognition of numbers and letters can be very reliably detected by simple psychometric tests (number-connection test, line-tracing test, handwriting), and are present in as many as 70% of cirrhotics. This may be expressed in everyday life by an impairment of driving ability, and at work by impaired ability to operate a machine. The use of established means of lowering blood ammonia levels (lactulose, ornithine-aspartate) results in a rapid improvement in the symptoms of encephalopathy.
Ammonia↗
Visual localization within single geometric planes of a space habitat.
BACKGROUND: The present study investigated how human subjects capture and restore visual information within a line representation drawing the three-dimensional configuration of a space module. METHODS: Nine subjects were asked to perform a visual localization task within this geometric model. The task consisted of localizing a light point appearing during 3 s in 40 different spatial positions and for 8 tilt angles of the model in the following random order: 0 degree, 45 degrees, 180 degrees, 225 degrees, 90 degrees, 315 degrees, 135 degrees, and 270 degrees. RESULTS: Results showed symmetric variations of the point-localizing errors about 180 degrees of tilt angle (vertical orientation) and a decrease of the errors when the points occurred in the distal, then in the median and in the proximal planes (virtual depth). The performance also varied according to the virtual ceiling, floor, right, left and back planes. The results have been discussed using a three-dimensional space representation based on a conservative mode of spatial information up to 90 degrees of tilt (horizontal orientation), and on a transformation mode beyond 90 degrees of tilt. CONCLUSION: We conclude that the visual localization in single geometric planes is orientation-dependent.
Computer Graphics↗
Memory for spatial location: role of the hippocampus in mediating spatial pattern separation.
A paradigm based on measuring short-term memory for spatial location information as a function of spatial similarity between distal cues was developed to examine the role of pattern separation in the modulation of short-term memory for spatial information. A delayed-match-to-sample for spatial location task using a dryland version of the Morris water maze was used to assess spatial pattern separation in male Long-Evans rats. In the sample phase, animals were trained to displace an object that covered a baited food well in one of 15 spatial locations along a row of food wells perpendicular to a start box. In the ensuing choice phase, the animal was allowed to choose between two objects identical to the sample phase object. One covered the same baited food well as did the object in the study phase (correct choice), and another foil object (incorrect choice) covered a different unbaited food well along the row of wells. Five spatial separations were randomly used to separate the correct object from the foil object. After reaching a criterion before the operation, animals were given either hippocampal or cortical control lesions. In trials after the operation, control animals matched their performance before the operation across all spatial separations. In contrast, hippocampal-lesioned animals displayed impairments across all spatial separations with the exception of the longest (105 cm) spatial separation. The results suggest that the hippocampus may serve to separate incoming spatial information by temporarily storing one place separate from another. It is proposed that hippocampal lesions decrease efficiency in pattern separation, resulting in impairments in trials with increased spatial similarity among working-memory representations.
Animals↗
Eye movements and conservation acceleration in mildly retarded children.
Thirty mildly retarded elementary-school children, 15 of whom had received perceptual/attentional training, were tested on four Piagetian conservation tasks (number, length, and continuous quantity solid/liquid) presented on 16 mm movie film with taped instructions. Eye movements were recorded during the response period for each task. Subsequent analyses of eye-movement patterns showed clear differences between the training and control groups. Trained conservers showed more visual exploratory activity and less perceptual centration than control group subjects. Moreover the eye-movement patterns of trained conservers closely approximated those shown by natural (i.e., untrained) retarded conservers in a previous study. The findings were discussed in terms of possible cognitive structural changes resulting from training and possible cognitive structural differences between mildly retarded and nonretarded children.
Child↗
Dissociation of mnemonic and perceptual processes during spatial and nonspatial working memory using fMRI.
Neuroimaging studies in humans have consistently found robust activation of frontal, parietal, and temporal regions during working memory tasks. Whether these activations represent functional networks segregated by perceptual domain is still at issue. Two functional magnetic resonance imaging experiments were conducted, both of which used multiple-cycle, alternating task designs. Experiment 1 compared spatial and object working memory tasks to identify cortical regions differentially activated by these perceptual domains. Experiment 2 compared working memory and perceptual control tasks within each of the spatial and object domains to determine whether the regions identified in experiment 1 were driven primarily by the perceptual or mnemonic demands of the tasks, and to identify common brain regions activated by working memory in both perceptual domains. Domain-specific activation occurred in the inferior parietal cortex for spatial tasks, and in the inferior occipitotemporal cortex for object tasks, particularly in the left hemisphere. However, neither area was strongly influenced by task demands, being nearly equally activated by the working memory and perceptual control tasks. In contrast, activation of the dorsolateral prefrontal cortex and the intraparietal sulcus (IPS) was strongly task-related. Spatial working memory primarily activated the right middle frontal gyrus (MFG) and the IPS. Object working memory activated the MFG bilaterally, the left inferior frontal gyrus, and the IPS, particularly in the left hemisphere. Finally, activation of midline posterior regions, including the cingulate gyrus, occurred at the offset of the working memory tasks, particularly the shape task. These results support a prominent role of the prefrontal and parietal cortices in working memory, and indicate that spatial and object working memory tasks recruit differential hemispheric networks. The results also affirm the distinction between spatial and object perceptual processing in dorsal and ventral visual pathways.
Adult↗
Distance perception within near visual space.
We investigated the perception of distance of visual targets with constant size and luminance presented between 20 and 120 cm from subjects' eyes. When retinal disparity cues were present, the subjects could reproduce very accurately the distance of a seen reference in this area. When only extraretinal information was available, distance perception was still correct for distances of 40 cm or less. However, distances beyond 60 cm were underestimated. When forced to evaluate the distance between a reference and themselves, e.g. when evaluating the absolute distance or half the distance or twice the distance of a reference, subjects used an egocentric plane of reference located on average 10.4 cm in front of their eyes. Measurements of binocular eye movements indicated a clear relationship between vergence angle and target distance. The egocentric plane of reference at 10.4 cm also corresponds to the maximum achievable vergence. These results suggest that ocular convergence can be used as a reliable cue for distance within the arm's reaching space.
Adult↗