1,721,152 research outputs found
Parietal versus temporal lobe components in spatial cognition: Setting the mid-point of a horizontal line.
No full textRecent anatomo-clinical correlation studies have extended to the superior temporal gyrus, the right hemisphere lesion sites associated with the left unilateral spatial neglect, in addition to the traditional posterior-inferior-parietal localization of the responsible lesion (supramarginal gyrus, at the temporo-parietal junction). The study aimed at teasing apart, by means of repetitive transcranial magnetic stimulation (rTMS), the contribution of the inferior parietal lobule (angular gyrus versus supramarginal gyrus) and of the superior temporal gyrus of the right hemisphere, in making judgments about the mid-point of a horizontal line, a widely used task for detecting and investigating spatial neglect. rTMS trains at 25 Hz frequency were delivered over the inferior parietal lobule (angular gyrus and supramarginal gyrus), the superior temporal gyrus and the anterior parietal lobe of the right hemisphere, in 10 neurologically unimpaired participants, performing a line bisection judgment task. rTMS of the inferior parietal lobule at the level of the supramarginal gyrus brought about a rightward error in the bisection judgment, ipsilateral to the side of the rTMS, with stimulation over the other sites being ineffective. The neural correlates of computing the mid-point of a horizontal segment include the right supramarginal gyrus in the inferior parietal lobule and do not extend to the angular gyrus and the superior temporal gyrus. These rTMS data in unimpaired subjects constrain the evidence from lesion studies in brain-damaged patients, emphasizing the major role of a subset of relevant regions
The impairment of auditory-verbal short-term storage
No full textThis work summarizes the empirical and theoretical work on impairments of short-term memory (often caused by damage in the left cerebral hemisphere) and contains chapters from virtually every scientist in Europe and North America working on the problem. The chapters present evidence from both normal and brain-damaged patients. Two neuropsychological issues are discussed in detail: first, the specific patterns of immediate memory impairment resulting from brain damage with reference to both multistore and the interactive-activation theoretical frameworks. Also considered is the relation between verbal STM and sentence comprehension disorders in patients with a defective immediate auditory memory: an area of major controversy in more recent years
Directional hypokinesia in spatial hemineglect: A case study
No full textA patient with an ischaemic lesion involving the right frontal lobe and basal ganglia showed left spatial hemineglect in visuomotor exploratory tasks, requiring the use of the right unaffected hand. Her performance was, however, entirely preserved, with no evidence of neglect, when she was required to identify targets among distractors in both the left and right halves of space, and in the Wundt-Jastrow illusion test. The latter tasks do not require any arm movement in extrapersonal space. In this patient spatial hemineglect may be explained in terms of defective organisation of movements towards the left half-space (directional hypokinesia). The frontal lesion of the patient may be the neural correlate of this selective disorder. This pattern of impairment may be contrasted with the typical deficit found in patients with right brain damage with perceptual neglect. One case had a defective performance both in visuomotor and in purely perceptual tasks
Articulatory coding and phonological judgements on written words and pictures: The role of the phonological output buffer
No full textLexical decision in left neglect dyslexia: Word frequency and nonword orthographic neighborhood effects
No full text
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
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