Individual variation in the location of the parietal eye fields: a TMS study

Ryan, Suzanne; Bonilha, Leonardo; Jackson, Stephen R.

doi:10.1007/s00221-006-0379-9

Cited by 20 publications

(15 citation statements)

References 33 publications

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“…Some studies have shown evidence that TMS stimulation of the parietal cortex can affect saccade amplitude and latency (Müri et al, 1996;van Donkelaar and Müri, 2002), although these findings remain controversial (Wessel and Kömpf, 1991;Ryan et al, 2006;Chang and Ro, 2007). Here, we show that the changes in saccade task performance cannot be attributed to changes in saccade metrics.…”

Section: Effects Of Tms On Saccade Metrics and Latencymentioning

confidence: 46%

“…Accordingly, these parietal stimulation sites could correspond to the putative human parietal eye fields (cf. Ryan et al, 2006), a region (or regions) thought to be homologous to macaque LIP, identified in previous human brain imaging studies (for review, see Culham and Valyear, 2006). Two additional control conditions were conducted to yield estimates of nonspecific effects of TMS.…”

Section: Methodsmentioning

confidence: 99%

“…The difference among these various studies could be the precise localization of stimulation. Recently, it was suggested that there is no specific parietal site where TMS has an effect on saccade metrics (Wessel and Kömpf, 1991;Ryan et al, 2006). Areas of the PPC related to visually guided saccades have been shown to vary greatly between subjects (Pierrot-Deseilligny, 1994; PierrotDeseilligny and Müri, 1997).…”

Section: Tms Effect Not Attributed To Changes In Saccade Metricsmentioning

confidence: 99%

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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: Effects Of Tms On Saccade Metrics and Latencymentioning

confidence: 46%

Section: Methodsmentioning

confidence: 99%

Section: Tms Effect Not Attributed To Changes In Saccade Metricsmentioning

confidence: 99%

See 1 more Smart Citation

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

“…Accordingly, these parietal stimulation sites could correspond to a region slightly more lateral to the putative human parietal eye fields (cf. Ryan et al 2006), a region (or regions) thought to be homologous to macaque LIP, identified in previous human brain imaging (for review, see Culham and Valyear 2006;for examples, see Astafiev et al 2003;Medendorp et al 2003;Schluppeck et al 2005;Sereno et al 2001). Two additional control experiments were conducted to yield estimates of nonspecific effects of TMS.…”

Section: Localization Of Brain Sites and Tms Protocolmentioning

confidence: 99%

Transcranial Magnetic Stimulation Over Human Dorsal–Lateral Posterior Parietal Cortex Disrupts Integration of Hand Position Signals Into the Reach Plan

Vesia

Yan

Henriques

et al. 2008

Journal of Neurophysiology

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Vesia M, Yan X, Henriques DY, Sergio LE, Crawford JD. Transcranial magnetic stimulation over human dorsal-lateral posterior parietal cortex disrupts integration of hand position signals into the reach plan. J Neurophysiol 100: -2014, 2008. First published August 6, 2008 doi:10.1152/jn.90519.2008. Posterior parietal cortex (PPC) has been implicated in the integration of visual and proprioceptive information for the planning of action. We previously reported that single-pulse transcranial magnetic stimulation (TMS) over dorsallateral PPC perturbs the early stages of spatial processing for memoryguided reaching. However, our data did not distinguish whether TMS disrupted the reach goal or the internal estimate of initial hand position needed to calculate the reach vector. To test between these hypotheses, we investigated reaching in six healthy humans during left and right parietal TMS while varying visual feedback of the movement. We reasoned that if TMS were disrupting the internal representation of hand position, visual feedback from the hand might still recalibrate this signal. We tested four viewing conditions: 1) final vision of hand position; 2) full vision of hand position; 3) initial and final vision of hand position; and 4) middle and final vision of hand position. During the final vision condition, left parietal stimulation significantly increased endpoint variability, whereas right parietal stimulation produced a significant leftward shift in both visual fields. However, these errors significantly decreased with visual feedback of the hand during both planning and control stages of the reach movement. These new findings demonstrate that 1) visual feedback of hand position during the planning and early execution of the reach can recalibrate the perturbed signal and, importantly, and 2) TMS over dorsal-lateral PPC does not disrupt the internal representation of the visual goal, but rather the reach vector, or more likely the sense of initial hand position that is used to calculate this vector.

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“…For example, we recently used TMS to implicate a site close to the posterior part of the adjoining IPS situated over the angular gyrus (AG) (see Fig. 1, triangle) in computing the reach vector from hand and target position signals (Vesia et al, 2006, and others have shown effects on saccade performance in PPC (Oyachi and Ohtsuka, 1995; Müri et al, 1996;Nyffeler et al, 2005;Ryan et al, 2006). To our knowledge, TMS has not yet been used systematically to determine effector specificity in human PPC.…”

Section: Introductionmentioning

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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Individual variation in the location of the parietal eye fields: a TMS study

Cited by 20 publications

References 33 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

Transcranial Magnetic Stimulation Over Human Dorsal–Lateral Posterior Parietal Cortex Disrupts Integration of Hand Position Signals Into the Reach Plan

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

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