Interhemispheric imbalance during visuospatial attention investigated by unilateral and bilateral TMS over human parietal cortices

Dambeck, Nina; Sparing, Roland; Meister, Ingo G.; Wienemann, M.; Weidemann, Juergen; Töpper, Rudolf; Boroojerdi, Babak

doi:10.1016/j.brainres.2005.05.075

Cited by 109 publications

(81 citation statements)

References 30 publications

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“…Accordingly, the intensity of magnetic stimulation was fixed to 60% of the stimulator output (Beckers and Zeki, 1995;Corthout et al, 1999;Lewald et al, 2002;Dambeck et al, 2006;Vesia et al, 2006). All stimulation parameters were in accordance with the safety guidelines for magnetic stimulation (Wassermann, 1998).…”

Section: Methodsmentioning

confidence: 99%

Transcranial Magnetic Stimulation over Posterior Parietal Cortex Disrupts Transsaccadic Memory of Multiple Objects

Prime¹,

Vesia²,

Crawford³

2008

Journal of Neuroscience

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The posterior parietal cortex (PPC) plays a role in spatial updating of goals for eye and arm movements across saccades, but less is known about its role in updating perceptual memory. We reported previously that transsaccadic memory has a capacity for storing the orientations of three to four Gabor patches either within a single fixation (fixation task) or between separate fixations (saccade task). Here, we tested the role of the PPC in transsaccadic memory in eight subjects by simultaneously applying single-pulse transcranial magnetic stimulation (TMS) over the right and left PPC, over several control sites, and comparing these to behavioral controls with no TMS. In TMS trials, we randomly delivered pulses at one of three different time intervals around the time of the saccade, or at an equivalent time in the fixation task. Controls confirmed that subjects could normally retain at least three visual features. TMS over the left PPC and a control site had no significant effect on this performance. However, TMS over the right PPC disrupted memory performance in both tasks. This TMS-induced effect was most disruptive in the saccade task, in particular when stimulation coincided more closely with saccade timing. Here, the capacity to compare presaccadic and postsaccadic features was reduced to one object, as expected if the spatial aspect of memory was disrupted. This finding suggests that right PPC plays a role in the spatial processing involved in transsaccadic memory of visual features. We propose that this process uses saccade-related feedback signals similar to those observed in spatial updating.

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Section: Methodsmentioning

confidence: 99%

Transcranial Magnetic Stimulation over Posterior Parietal Cortex Disrupts Transsaccadic Memory of Multiple Objects

Prime¹,

Vesia²,

Crawford³

2008

Journal of Neuroscience

View full text Add to dashboard Cite

show abstract

“…Stokes et al, 2005;Oliver et al, 2009). Accordingly, the intensity of magnetic stimulation was fixed to 60% of the stimulator output, similar to a number of previous TMS studies of PPC (Lewald et al, 2002;Dambeck et al, 2006;Vesia et al, 2006Vesia et al, , 2008Buelte et al, 2008;Prime et al, 2008). This protocol yielded an individual mean resting motor threshold (rMT) of 104% (SD, 2.08%; range, 101-108%) across the sessions and subjects.…”

Section: Figurementioning

confidence: 99%

Specificity of Human Parietal Saccade and Reach Regions during Transcranial Magnetic Stimulation

Vesia

Prime²,

Yan³

et al. 2010

J. Neurosci.

144

159

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Single-unit recordings in macaque monkeys have identified effector-specific regions in posterior parietal cortex (PPC), but functional neuroimaging in the human has yielded controversial results. Here we used on-line repetitive transcranial magnetic stimulation (rTMS) to determine saccade and reach specificity in human PPC. A short train of three TMS pulses (separated by an interval of 100 ms) was delivered to superior parieto-occipital cortex (SPOC), a region over the midposterior intraparietal sulcus (mIPS), and a site close to caudal IPS situated over the angular gyrus (AG) during a brief memory interval while subjects planned either a saccade or reach with the left or right hand. Behavioral measures then were compared to controls without rTMS. Stimulation of mIPS and AG produced similar patterns: increased end-point variability for reaches and decreased saccade accuracy for contralateral targets. In contrast, stimulation of SPOC deviated reach end points toward visual fixation and had no effect on saccades. Contralateral-limb specificity was highest for AG and lowest for SPOC. Visual feedback of the hand negated rTMS-induced disruptions of the reach plan for mIPS and AG, but not SPOC. These results suggest that human SPOC is specialized for encoding retinally peripheral reach goals, whereas more anterior-lateral regions (mIPS and AG) along the IPS possess overlapping maps for saccade and reach planning and are more closely involved in motor details (i.e., planning the reach vector for a specific hand). This work provides the first causal evidence for functional specificity of these parietal regions in healthy humans.

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“…The technique of transcranial magnetic stimulation (TMS) is a well-established tool for inducing transient disruptions of neural activity (''virtual lesions'') noninvasively in human volunteers (Hallett 2000;Pascual-Leone et al 2000;Walsh and Cowey 2000;George et al 2002;Sack 2006). Accordingly, TMS studies have established the relevance of parietal cortices in visuospatial processing (Cohen et al 1996;Topper et al 1998;Rushworth et al 2003;Vannini et al 2004;Kim et al 2005;Koch et al 2005;Go¨bel et al 2006), visuospatial attention (Hilgetag et al 2001;Stewart, Ellison, et al 2001;Mu¨ri et al 2002;Chambers et al 2004;Hung et al 2005;Mevorach et al 2005;Thut et al 2005;Dambeck et al 2006), visuomotor mental rotation (Bestmann et al 2002), and visuomotor integration (Rushworth et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Imaging the Brain Activity Changes Underlying Impaired Visuospatial Judgments: Simultaneous fMRI, TMS, and Behavioral Studies

et al. 2007

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Damage to parietal cortex impairs visuospatial judgments. However, it is currently unknown how this damage may affect or indeed be caused by functional changes in remote but interconnected brain regions. Here, we applied transcranial magnetic stimulation (TMS) to the parietal cortices during functional magnetic resonance imaging (fMRI) while participants were solving visuospatial tasks. This allowed us to observe both the behavioral and the neural effects of transient parietal activity disruption in the active healthy human brain. Our results show that right, but not left, parietal TMS impairs visuospatial judgment, induces neural activity changes in a specific right-hemispheric network of frontoparietal regions, and shows significant correlations between the induced behavioral impairment and neural activity changes in both the directly stimulated parietal and remote ipsilateral frontal brain regions. The revealed righthemispheric neural network effect of parietal TMS represents the same brain areas that are functionally connected during the execution of visuospatial judgments. This corroborates the notion that visuospatial deficits following parietal damage are brought about by a perturbation of activity across a specific frontoparietal network, rather than the lesioned parietal site alone. Our experiments furthermore show how concurrent fMRI and magnetic brain stimulation during active task execution hold the potential to identify and visualize networks of brain areas that are functionally related to specific cognitive processes.

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Interhemispheric imbalance during visuospatial attention investigated by unilateral and bilateral TMS over human parietal cortices

Cited by 109 publications

References 30 publications

Transcranial Magnetic Stimulation over Posterior Parietal Cortex Disrupts Transsaccadic Memory of Multiple Objects

Transcranial Magnetic Stimulation over Posterior Parietal Cortex Disrupts Transsaccadic Memory of Multiple Objects

Specificity of Human Parietal Saccade and Reach Regions during Transcranial Magnetic Stimulation

Imaging the Brain Activity Changes Underlying Impaired Visuospatial Judgments: Simultaneous fMRI, TMS, and Behavioral Studies

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