Transcranial Magnetic Stimulation Trains at 1 Hz Frequency of the Right Posterior Parietal Cortex Facilitate Recognition Memory

Neuroimaging, neuropsychological, and brain stimulation studies have led to contrasting findings regarding the potential roles of the lateral parietal lobe in episodic memory. Studies using brain stimulation methods reported in the literature do not offer unequivocal findings on the interactions with stimulation location (left vs. right hemisphere) or timing of the stimulation (encoding vs. retrieval). To address these issues, active and sham 1 Hz repetitive transcranial magnetic stimulation (rTMS) trains of 600 stimuli were applied over the right or left posterior parietal cortex (PPC) before the encoding or before the retrieval phase of a recognition memory task of unknown faces in a group of 40 healthy subjects. Active rTMS over the right but not the left PPC significantly improved non-verbal recognition memory performance without any significant modulation of speed of response when applied before the retrieval phase. In contrast, rTMS over the right or the left PPC before the encoding phase did not modulate memory performance. Our results support the hypothesis that the PPC plays a role in episodic memory retrieval that appears to be dependent on both the hemispheric lateralization and the timing of the stimulation (encoding vs. retrieval).

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Hemispheric Asymmetry in Memory-Guided Pointing During Single-Pulse Transcranial Magnetic Stimulation of Human Parietal Cortex

Journal of Neurophysiology ◽

10.1152/jn.00411.2006 ◽

2006 ◽

Vol 96 (6) ◽

pp. 3016-3027 ◽

Cited By ~ 24

Author(s):

Michael Vesia ◽

Jachin A. Monteon ◽

Lauren E. Sergio ◽

J. D. Crawford

Keyword(s):

Transcranial Magnetic Stimulation ◽

Parietal Cortex ◽

Magnetic Stimulation ◽

Hemispheric Asymmetry ◽

Posterior Parietal Cortex ◽

Single Pulse ◽

Pointing Movements ◽

Posterior Parietal ◽

The Right ◽

Stimulation Of

Dorsal posterior parietal cortex (PPC) has been implicated through single-unit recordings, neuroimaging data, and studies of brain-damaged humans in the spatial guidance of reaching and pointing movements. The present study examines the causal effect of single-pulse transcranial magnetic stimulation (TMS) over the left and right dorsal posterior parietal cortex during a memory-guided “reach-to-touch” movement task in six human subjects. Stimulation of the left parietal hemisphere significantly increased endpoint variability, independent of visual field, with no horizontal bias. In contrast, right parietal stimulation did not increase variability, but instead produced a significantly systematic leftward directional shift in pointing (contralateral to stimulation site) in both visual fields. Furthermore, the same lateralized pattern persisted with left-hand movement, suggesting that these aspects of parietal control of pointing movements are spatially fixed. To test whether the right parietal TMS shift occurs in visual or motor coordinates, we trained subjects to point correctly to optically reversed peripheral targets, viewed through a left–right Dove reversing prism. After prism adaptation, the horizontal pointing direction for a given visual target reversed, but the direction of shift during right parietal TMS did not reverse. Taken together, these data suggest that induction of a focal current reveals a hemispheric asymmetry in the early stages of the putative spatial processing in PPC. These results also suggest that a brief TMS pulse modifies the output of the right PPC in motor coordinates downstream from the adapted visuomotor reversal, rather than modifying the upstream visual coordinates of the memory representation.

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Neglect-like visual exploration behaviour after theta burst transcranial magnetic stimulation of the right posterior parietal cortex

European Journal of Neuroscience ◽

10.1111/j.1460-9568.2008.06154.x ◽

2008 ◽

Vol 27 (7) ◽

pp. 1809-1813 ◽

Cited By ~ 72

Author(s):

Thomas Nyffeler ◽

Dario Cazzoli ◽

Pascal Wurtz ◽

Mathias Lüthi ◽

Roman von Wartburg ◽

...

Keyword(s):

Transcranial Magnetic Stimulation ◽

Parietal Cortex ◽

Magnetic Stimulation ◽

Posterior Parietal Cortex ◽

Visual Exploration ◽

Posterior Parietal ◽

The Right ◽

Theta Burst ◽

Stimulation Of

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Transcranial Magnetic Stimulation Disrupts Eye-Hand Interactions in the Posterior Parietal Cortex

Journal of Neurophysiology ◽

10.1152/jn.2000.84.3.1677 ◽

2000 ◽

Vol 84 (3) ◽

pp. 1677-1680 ◽

Cited By ~ 48

Author(s):

Paul Van Donkelaar ◽

Ji-Hang Lee ◽

Anthony S. Drew

Keyword(s):

Transcranial Magnetic Stimulation ◽

Parietal Cortex ◽

Magnetic Stimulation ◽

Posterior Parietal Cortex ◽

Hand Movement ◽

Open Loop ◽

Neurophysiological Studies ◽

Posterior Parietal ◽

Hand Coordination

Recent neurophysiological studies have started to shed some light on the cortical areas that contribute to eye-hand coordination. In the present study we investigated the role of the posterior parietal cortex (PPC) in this process in normal, healthy subjects. This was accomplished by delivering single pulses of transcranial magnetic stimulation (TMS) over the PPC to transiently disrupt the putative contribution of this area to the processing of information related to eye-hand coordination. Subjects made open-loop pointing movements accompanied by saccades of the same required amplitude or by saccades that were substantially larger. Without TMS the hand movement amplitude was influenced by the amplitude of the corresponding saccade; hand movements accompanied by larger saccades were larger than those accompanied by smaller saccades. When TMS was applied over the left PPC just prior to the onset of the saccade, a marked reduction in the saccadic influence on manual motor output was observed. TMS delivered at earlier or later periods during the response had no effect. Taken together, these data suggest that the PPC integrates signals related to saccade amplitude with limb movement information just prior to the onset of the saccade.

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Transcranial Magnetic Stimulation Over the Human Medial Posterior Parietal Cortex Disrupts Depth Encoding During Reach Planning

Cerebral Cortex ◽

10.1093/cercor/bhaa224 ◽

2020 ◽

Vol 31 (1) ◽

pp. 267-280

Author(s):

Rossella Breveglieri ◽

Annalisa Bosco ◽

Sara Borgomaneri ◽

Alessia Tessari ◽

Claudio Galletti ◽

...

Keyword(s):

Transcranial Magnetic Stimulation ◽

Parietal Cortex ◽

Magnetic Stimulation ◽

Posterior Parietal Cortex ◽

Critical Role ◽

The Body ◽

Visually Guided ◽

Visually Guided Reaching ◽

Posterior Parietal

Abstract Accumulating evidence supports the view that the medial part of the posterior parietal cortex (mPPC) is involved in the planning of reaching, but while plenty of studies investigated reaching performed toward different directions, only a few studied different depths. Here, we investigated the causal role of mPPC (putatively, human area V6A–hV6A) in encoding depth and direction of reaching. Specifically, we applied single-pulse transcranial magnetic stimulation (TMS) over the left hV6A at different time points while 15 participants were planning immediate, visually guided reaching by using different eye-hand configurations. We found that TMS delivered over hV6A 200 ms after the Go signal affected the encoding of the depth of reaching by decreasing the accuracy of movements toward targets located farther with respect to the gazed position, but only when they were also far from the body. The effectiveness of both retinotopic (farther with respect to the gaze) and spatial position (far from the body) is in agreement with the presence in the monkey V6A of neurons employing either retinotopic, spatial, or mixed reference frames during reach plan. This work provides the first causal evidence of the critical role of hV6A in the planning of visually guided reaching movements in depth.

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