1,721,012 research outputs found
Development of the hemispheric dominance in children from 5 to 10 years of age and their relations with the development of cognitive processes.
No full text[No abstract available
Effects of field-dependency, social class and sex of children between ages 5 and 10
No full textDevelopment of field-independency has been studied as a function of age (5 to 10), social class, and sex utilizing two groups of 96 subjects each of high and low social class. On the Children's Embedded-figures Test a critical developmental period appears between ages 5 and 8 yr. for all Ss; on the Draw-a-Person such a period appears between ages 5 and 6 for high social class and between ages 6 and 8 for lower social class; scores on both tests were statistically significant as a function of social class at every age beginning at age 6. Sex did not seem to play any significant role. Three main masking factors have been singled out on the Children's Embedded-figures Test. Their differential effects on scores of Ss in the two classes are examined
Somatosensory stimulation improves imagery disorders in neglect
No full textA group of 9 right brain damaged patients with unilateral neglect performed a set of tasks involving mental imagery with and without a transcutaneous electrical neural stimulation (TENS) to both sides of the neck. Results showed that TENS on the left side of the neck produced significant improvements of performances on the left side of mental representations of objects (drawing, shape comparison) as well as on left side of mental images of space (description of squares). The results suggest that the modification induced by TENS may affect the imagery systems involved in objects as well as in space representatio
Gravitational inputs modulate visuospatial neglect
No full textRight brain-damaged patients with left visuospatial
neglect were required to bisect a line placed in
front of them in two different body positions (upright
and supine) and two different light conditions (light and
dark). The neglect patients, unlike right brain-damaged
patients without neglect, strongly reduced their rightward
directional error in the supine compared with the upright
position. No systematic changes were produced by the
light-dark manipulation. The present result cannot be explained
with an attentional interpretation of hemispatial
neglect. We suggest that the present data provide futher
evidence that hemineglect is the consequence of a mismatch
between different afferent information integrated
into an egocentric space representation. According to this
model, the presence of a lateralized brain lesion produces
asymmetries in some intermediate spatial representations
(eye-head, head-trunk, body-environment) but not in the
retinotopic one. Any experimental manipulation that reduces
the asymmetry of the intermediate representation
such as the reduction of gravitational inputs may improve
the dynamic integration of the egocentric coordinates
Gravity and hemineglect
No full textSpatial cognition requires the integration of visual inputs with proprioceptive and vestibular information about the position of the eye, the head and the body. All these sources are used by the brain to produce multiple higher-order (e.g. egocentric) representations of space, subserving accurate spatial behaviour. Such spatial representations are disrupted by unilateral cerebral damage producing neglect in the contralateral side of space. In eight brain-damaged patients with left unilateral neglect the manipulation of gravitational-otolithic information, obtained by placing patients in a supine position, produced a significant reduction of the rightward directional error in the line bisection task in all cases. This finding suggests that, in patients with neglect, gravitational information is processed in a non-symmetrical fashion, with a rightward bias towards the side of the lesion. This is the first study showing that manipulation of gravitational input affects neuropsychological disorders of visuo-spatial processing
Evidence for separate allocentric and egocentric space processing in neglect patients
No full textSpatial orientation was investigated in two different conditions: (a) when the shape of the enclosure was the only available information; (b) when a clearly perceivable visual cue was added. Three groups of subjects were investigated: normal controls, right brain-damaged patients without and with hemispatial neglect. The performance of the first two groups clearly demonstrated the capacity to use the geometric properties of the environment and to integrate this information with an additional visual cue. Considered as a group, patients with hemispatial neglect were able to use the shape of the environment and, to a lesser extent, the additional visual cue. However, individual differences suggest two opposite performance patterns: two patients responded randomly when the shape of the environment was the only available information, and they improved considerably when the cue was offered; two other patients showed normal competence in dealing with the geometrical properties of the environment, but were unable to take advantage of the cue. The different lesion site in these two types of patients suggests a possible dissociation of processing based upon allocentric or egocentric coding of space in humans as well as in animals
When space merges into language
No full textWe present data from right brain-damaged patients, with and without spatial heminattention, which show the influence of hemispatial deficits on spoken language processing. We explored the findings of a previous study, which used an emphatic stress detection task and suggested spatial transcoding of a spoken active sentence in a 'language line'. This transcoding was impaired in its initial portion (the subject-word) when the neglect syndrome was present. By expanding the original methodology, the present study provides a deeper understanding of the level of spoken language processing involved in the heminattentional bias. To ascertain the role played by syntactic structure, active and passive sentences were compared. Sentences comprised of musical notes and of a sequence of unrelated nouns were also compared to determine whether the bias was manifest with any sequence of events (not only linguistic ones) deployed over time, and with a sequence of linguistic events not embedded in a structured syntactic frame. Results showed that heminattention exerted an influence only when a syntactically structured linguistic input (=sentence with agent of action, action and recipient of action) was processed, and that it did not interfere when a sequence of non-linguistic sounds or unrelated words was presented. Furthermore, when passing from active to passive sentences, the heminattentional bias was inverted, suggesting that heminattention primarily involves the logical subject of the sentence, which has an inverted position in passive sentences. These results strongly suggest that heminattention acts on the spatial transcoding of the deep structure of spoken language. (c) 2005 Elsevier Ltd. All rights reserved
Disturbances of the rapid eye movements (REMs) of REM sleep in patients with unilateral attentional neglect: clue for the understanding of the functional meaning of REMs.
No full textHorizontal saccades during wakefulness and horizontal rapid eye movements (REMs) during REM sleep were recorded in 6 unilateral brain damaged patients suffering from attentional neglect and 6 unilateral brain damaged control patients. During REM sleep, patients with neglect showed a nearly total suppression of REMs directed away from the side of the lesion; controls had a significantly milder frequency reduction of the same movements. In all patients the frequency reduction of REMs contralateral to the lesion equally affected isolated REMs (i.e., REMs preceded by intervals of oculomotor quiescence longer than 2 sec) and REM bursts (i.e., REMs preceded by intervals shorter than 2 sec). During voluntary inspection in waking, saccades directed ipsilaterally and contralaterally to the lesion were present in both groups of patients, although patients with neglect confined their inspection to the hemispace ipsilateral to the lesion. Results are discussed in terms of their implications for the understanding of the neurophysiological basis of REM sleep oculomotor activity and dream production, as well as for the neurophysiopathological basis of the neglect syndrome. It is proposed that REMs are functionally equivalent to waking reflex orienting saccades generated by a neural network including the relevant modulatory action of the parietal lobes and the superior collicul
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