Search results for "parietal cortex"
showing 10 items of 83 documents
The role of posterior parietal cortices on prismatic adaptation effects on the representation of time intervals
2013
Previous studies provided evidence of an ascending left-to-right spatial representation of time durations by using a technique affecting high levels of spatial cognition, i.e. prismatic adaptation (PA). Indeed, PA that induced a leftward aftereffect distorted time representation toward an underestimation, while PA that induced a rightward aftereffect distorted time representation toward an overestimation. The present study advances previous findings on the effects of PA on time by investigating the neural basis subtending these effects. We focused on the posterior parietal cortex (PPC) since it is involved in the PA procedure and also in the formulation of the spatial representation of time…
Neglect-like effects induced by tDCS modulation of posterior parietal cortices in healthy subjects
2011
Background Repetitive transcranial magnetic stimulation (rTMS) over right posterior parietal cortex was shown to induce interference on visuospatial perception in healthy subjects. Transcranial direct current stimulation (tDCS) is another noninvasive brain stimulation technique that works modulating cortical activity. It is applied through easy to use, noncostly, and portable devices. Objective/Hypothesis The aim of the current study was to investigate if the novel approach of “dual” stimulation over parietal cortices compared with the unilateral (right) cathodal one is able to induce greater and/or longer-lasting neglect-like effects in normal subjects performing a computerized visuospatia…
Inter-hemispheric remapping between arm proprioception and vision of the hand is disrupted by single pulse TMS on the left parietal cortex.
2013
International audience; Parietal cortical areas are involved in sensori-motor transformations for their respective contralateral hemifield/body. When arms of the subjects are crossed while their gaze is fixed straight ahead, vision of the hand is processed by the hemisphere ipsilateral to the arm position and proprioception of the arm by the contralateral hemisphere. It induces interhemispheric transfer and remapping. Our objective was to investigate whether a single pulse TMS applied to the left parietal cortical area would disturb interhemispheric remapping in a similar case, and would increase a simple reaction time (RT) with respect to a control single pulse TMS applied to the frontal c…
"…The times they aren't a-changin'…" rTMS does not affect basic mechanisms of temporal discrimination: a pilot study with ERPs.
2014
In time processing, the role of different cortical areas is still under investigation. Event-related potentials (ERPs) represent valuable indices of neural timing mechanisms in the millisecond-to-second domain. We used an interference approach by repetitive TMS (rTMS) on ERPs and behavioral performance to investigate the role of different cortical areas in processing basic temporal information. Ten healthy volunteers were requested to decide whether time intervals between two tones (S1-S2, probe interval) were shorter (800 ms), equal to, or longer (1200 ms) than a previously listened 1000-ms interval (target interval) and press different buttons accordingly. This task was performed at the b…
The role of Posterior Parietal Cortex in spatial representation of time: a TMS study.
2011
1. Introduction. The existence of a spatial representation of time, where temporal intervals are represented on a mental temporal line (MTL), oriented in ascending order from left to right, was demonstrated manipulating spatial attention by means of Prismatic Adaptation (PA). In young healthy subjects, prisms adaptation inducing a rightward shift of spatialattention produced an overestimation of time intervals, whereas prisms adaptation inducing a leftward shift of spatialattention produced an underestimation of time intervals [4]. The aimof the present study was to investigate the neural basis mediating the effects of PA on spatial time representation. PosteriorParietalCortex (PPC) is the …
Paired pulse TMS over the right posterior parietal cortex modulates visuospatial perception
2006
Abstract Objective We previously observed a relative contralateral neglect by right parietal single-pulse TMS given 150 ms after visual stimulus presentation. Here we investigated the effects of parietal paired TMS in normal subjects performing a visuospatial task. Methods Thirteen right-handed healthy subjects underwent a line-length judgement task during single-pulse and paired (1, 3, 5, 10 ms ISIs) TMS, delivered on the right parietal cortex 150 ms after visual stimulus. Results Single pulse TMS over the right parietal cortex induced a significant rightward bias compared to the baseline condition. At 1 and 3 ms ISIs, paired-pulse TMS did not show any effect in comparison with single puls…
Different neuronal contribution to N20 somatosensory evoked potential and to CO2 laser evoked potentials: an intracerebral recording study
2004
Abstract Objective : To investigate the possible contribution of the primary somatosensory area (SI) to pain sensation. Methods : Depth recordings of CO 2 laser evoked potentials (LEPs) and somatosensory evoked potentials (SEPs) were performed in an epileptic patient with a stereotactically implanted electrode (Talairach coordinates y =−23, z =40) that passed about 10 mm below the hand representation in her left SI area, as assessed by the source of the N20 SEP component. Results : The intracerebral electrode was able to record the N20 SEP component after non-painful electrical stimulation of her right median nerve. The N20 potential showed a phase reversal in the bipolar montage (at about …
Timing of right parietal and frontal cortex activity in visuo-spatial perception: A TMS study in normal individuals
2001
In a recent study we showed that repetitive transcranial magnetic stimulation (rTMS) with train duration of 400 ms over right frontal and right posterior parietal cortices gives rise to transitory contralateral visuo-spatial neglect in normal subjects. In the present experiment we investigated whether using single-pulse TMS it is possible to obtain information about the timing of cortical activity related to spatial cognition. Nine healthy subjects performed in baseline condition and during TMS a tachistoscopic task, requiring a forced-choice estimation of the length of the two segments of prebisected horizontal lines. Single-pulse TMS was triggered at various time intervals (150 ms, 225 ms…
Perceptual and response bias in visuospatial neglect due to frontal and parietal repetitive transcranial magnetic stimulation in normal subjects.
2002
Recently some authors have challenged the conventional association of directional motor neglect with damage of frontal structures, showing that pure sensory perceptual neglect (classically associated with parietal lesion) can follow damage of right frontal cortex. The aim of the present study was to assess the type of defect in visuo-spatial attention consequent upon a virtual frontal or parietal lesion induced by transcranial magnetic stimulation in normal subjects. To this purpose eleven subjects performed a visuo-spatial task requiring judgement about the length of the two segments of asymmetrically bisected horizontal lines, presented for 50 ms on a computer monitor. After each visual s…
On the Neurocognitive Co‐Evolution of Tool Behavior and Language: Insights from the Massive Redeployment Framework
2021
Understanding the link between brain evolution and the evolution of distinctive features of modern human cognition is a fundamental challenge. A still unresolved question concerns the co-evolution of tool behavior (i.e., tool use or tool making) and language. The shared neurocognitive processes hypothesis suggests that the emergence of the combinatorial component of language skills within the frontal lobe/Broca's area made possible the complexification of tool-making skills. The importance of the frontal lobe/Broca's area in tool behavior is somewhat surprising with regard to the literature on neuropsychology and cognitive neuroscience, which has instead stressed the critical role of the le…