Contralateral neglect induced by right posterior parietal rTMS in healthy subjects

Fierro, Brigida; Brighina, Filippo; Oliveri, Massimiliano; Piazza, Aurelio; Bua, Vincenzo; Buffa, D; Bisiach, Edoardo

doi:10.1097/00001756-200005150-00031

Cited by 149 publications

(118 citation statements)

References 8 publications

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“…effects that last as long as 50 ms after the single pulse) at the cortical level induced by single-pulse TMS [27,28]. Our results are consistent with a previous TMS study [15] showing it is possible to interfere with visuo-spatial processing by stimulating the right PPC although repetitive TMS and different parietal zones of stimulation (P5 and P6 instead of P3 and P4 in the present study) were used in this earlier experiment.…”

Section: Discussionsupporting

confidence: 89%

“…Here we showed that single-pulse TMS applied over the right PPC mainly corresponding to BA7 is able to selectively interfere with visuo-spatial processing at an early stage (50 ms poststimulus). The use of the TMS±MRI co-registration algorithm indicated that stimulations in the right (P4) and left (P3) PPC do not overlap the post-central gyrus, as previously suggested by others [13,15].…”

Section: Discussionsupporting

confidence: 76%

“…The interference from TMS is manifested by a processing cost for ipsilateral targets, suggesting that the impairment produced by single pulse TMS applied over the right PPC is qualitatively different from the contralateral impairment produced by repetitive TMS applied over the same lobe (see [15] for a comparison). Our results are compatible with previous neuropsychological studies [29] showing that some patients with damage in the right parietal lobe show ipsilesional neglect on line bisection tasks.…”

Section: Resultsmentioning

confidence: 99%

“…Facilitatory effects of single-pulse TMS applied over the posterior parietal and frontal cortex have been demonstrated in brain-damaged patients [13,14] and con®rmed the involvement of the parietal cortex together with the frontal cortex in directing attention to spatial locations. Using repetitive TMS in normal subjects, Fierro and colleagues [15] recently demonstrated the possibility of inducing contralateral hemispatial neglect while stimulating the right parietal cortex, but did not provide information about the time-course of the transient interference in the parietal lobe. Previous electrophysiological studies [16] have demonstrated an early contribution (100 ms post-stimulus) of the parietal lobe for visuo-spatial processing.…”

Section: Introductionmentioning

confidence: 99%

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Event-related TMS over the right posterior parietal cortex induces ipsilateral visuo-spatial interference

Vandermeeren¹,

Olivier²,

Gelder³

2001

Neuroreport

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The right posterior parietal cortex (PPC) is implicated in visuo-spatial processing, as illustrated by patients with visuo-spatial neglect, but the precise time-course of its contribution is still an open question. In the present study we assessed whether single-pulse transcranial magnetic stimulation (TMS) can interfere with the performance of normal subjects in a standard visuo-spatial task. Participants had to perform a landmark task while TMS was applied over the right PPC, the homologue region in the left hemisphere or the right primary motor cortex. Stimulation was time-locked to the stimulus presentation with a stimulus onset asynchrony (SOA) varying between 50 and 200 ms. Our results indicate that TMS interfered mainly with the visuo-spatial task when applied over the right PPC at an early stage (50 ms post-stimulus). The interference effect of single-pulse TMS in the present visuo-spatial processing is revealed by a processing cost for ipsilateral targets. These results are ... The right posterior parietal cortex (PPC) is implicated in visuospatial processing, as illustrated by patients with visuo-spatial neglect, but the precise time-course of its contribution is still an open question. In the present study we assessed whether single-pulse transcranial magnetic stimulation (TMS) can interfere with the performance of normal subjects in a standard visuo-spatial task. Participants had to perform a landmark task while TMS was applied over the right PPC, the homologue region in the left hemisphere or the right primary motor cortex. Stimulation was time-locked to the stimulus presentation with a stimulus onset asynchrony (SOA) varying between 50 and 200 ms. Our results indicate that TMS interfered mainly with the visuo-spatial task when applied over the right PPC at an early stage (50 ms post-stimulus). The interference effect of single-pulse TMS in the present visuo-spatial processing is revealed by a processing cost for ipsilateral targets. These results are in agreement with neuropsychological and brain imaging studies showing a right hemispheric dominance in visuo-spatial processing but add crucial information about the time-course of visuo-spatial processing within the right PPC.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 76%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Event-related TMS over the right posterior parietal cortex induces ipsilateral visuo-spatial interference

Vandermeeren¹,

Olivier²,

Gelder³

2001

Neuroreport

View full text Add to dashboard Cite

show abstract

“…Right parietal repetitive (r)TMS induces a rightward bias in judgments about the symmetry of prebisected lines, which mimics the rightward error in line bisection, committed by right-brain-damaged patients with left neglect; left parietal rTMS, by contrast, has no detectable effects on this task [43,44]. rTMS of the left or of the right parietal lobe produces visual extinction of contralateral stimuli during double simultaneous stimulation [45].…”

Section: Trends In Cognitive Sciencesmentioning

confidence: 99%

Spatial cognition: evidence from visual neglect

Halligan

Fink

Marshall

et al. 2003

Trends in Cognitive Sciences

503

274

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Recent work on human attention and representational systems has benefited from a growing interplay between research on normal attention and neuropsychological disorders such as visual neglect. Research over the past 30 years has convincingly shown that, far from being a unitary condition, neglect is a protean disorder whose symptoms can selectively affect different sensory modalities, cognitive processes, spatial domains and coordinate systems. These clinical findings, together with those of functional neuroimaging, have increased knowledge about the anatomical and functional architecture of normal subsystems involved in spatial cognition. We provide a selective overview of how recent investigations of visual neglect are beginning to elucidate the underlying structure of spatial processes and mental representations.Once considered a unitary syndrome, it is now accepted that visuospatial neglect results from the interplay of damage to several different cognitive processes [1,2]. Even within such relatively simple tasks as copying or spontaneous drawing, patients show many qualitatively distinct patterns of omission and distortion in 'left' space [3].Deficits of attention, intention, global-local processing, spatial memory and mental representation can all contribute to the clinical picture of neglect, which accordingly cannot be traced back to the disruption of a single supramodal process [1,4]. Many of the symptoms traditionally ascribed to left neglect share little in common other than a contra-lesional gradient of increasing impairment, with comparatively well -preserved performance on the ipsilesional (right) side of space [1,5].Although characterising and remediating the clinical condition [1,2,5] are clearly crucial, the primary interest for cognitive neuroscience is how conditions such as visual neglect can inform existing cognitive theory and functional anatomy. That an abnormal bias towards one side of space can exist in the absence of contralateral peripheral sensory or motor loss (e.g. visual field losses or hemi-paralysis) suggests that impairment to higher level processes must be involved. The standard approach taken by cognitive neuropsychology characterises complex mental processes as information-processing systems with separate but interconnected components. Some of the informationprocessing stages involved in visual object recognition (see Fig. 1) illustrate the potential levels and links where lateralised deficits can arise after brain damage.This model charts the processing routes from preattentive assignment of simple structural features (i.e. without the need for focused attention and conscious awareness) to post-attentional integration of local and global processing (involving selective attention and conscious awareness) and the assignment of relevant spatial frames of reference prior to recognition and naming.

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Common and specific contributions of the intraparietal sulci to numerosity and length processing

Dormal

Pesenti

2009

Human Brain Mapping

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Numerical and spatial magnitude processing have long been intimately associated, leading to the suggestion that they share a common system of magnitude representation. Although separate investigations on the cerebral areas involved in numerosity and spatial estimation point toward the parietal cortex, the precise anatomical overlap, if any, has not yet been directly established. Here, functional magnetic resonance imaging was used to localize the cerebral network involved in processing both numerosity and length. Blood oxygenation level-dependent signal changes were measured while healthy volunteers were making numerosity comparisons on linear arrays of dots, and length comparisons on discrete linear arrays of dots and continuous rectangles. The results show the bilateral involvement of parietal regions around the intraparietal sulci in explicit and implicit processing of numerosity, and a right lateralized occipitoparietal network activation in length processing; numerosity and length processing both activate the right IPS and the precentral gyrus. By excluding the mandatory intrinsic spatial processing of arrays, we demonstrate that the left IPS is involved in numerosity processing only, whereas the right IPS underlies a common processing mechanism or representation of spatial and numerical magnitude.

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Contralateral neglect induced by right posterior parietal rTMS in healthy subjects

Cited by 149 publications

References 8 publications

Event-related TMS over the right posterior parietal cortex induces ipsilateral visuo-spatial interference

Event-related TMS over the right posterior parietal cortex induces ipsilateral visuo-spatial interference

Spatial cognition: evidence from visual neglect

Common and specific contributions of the intraparietal sulci to numerosity and length processing

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