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    Abstract The current study used a high frequency TMS protocol known as continuous theta burst stimulation (cTBS) to test a model of hand choice that relies on competing interactions between the hemispheres of the posterior parietal cortex. Based on the assumption that cTBS reduces cortical excitability, the model predicts a significant decrease in the likelihood of selecting the hand contralateral to stimulation. An established behavioural paradigm was used to estimate hand choice in each individual, and these measures were compared across three stimulation conditions: cTBS to the left posterior parietal cortex, cTBS to the right posterior parietal cortex, or sham cTBS. Our results provide no supporting evidence for the interhemispheric competition model. We find no effects of cTBS on hand choice, independent of whether the left or right posterior parietal cortex was stimulated. Our results are nonetheless of value as a point of comparison against prior brain stimulation findings that, in contrast, provide evidence for a causal role for the posterior parietal cortex in hand choice. Highlights High-frequency TMS applied to the left and right posterior parietal cortex, separately, did not produce reliable aftereffects on hand choice. Response times to initiate actions were significantly increased when reaching near the point in space where hand choice was equally probable.
    CTBS
    Citations (0)
    We investigated the involvement of the posterior parietal cortex in time perception by temporarily disrupting normal functioning in this region, in subjects making prospective judgements of time or pitch. Disruption of the right posterior parietal cortex significantly slowed reaction times when making time, but not pitch, judgements. Similar interference with the left parietal cortex and control stimulation over the vertex did not significantly change performance on either pitch or time tasks. The results show that the information processing necessary for temporal judgements involves the parietal cortex, probably to optimise spatiotemporal accuracy in voluntary action. The results are in agreement with a recent neuroimaging study and are discussed with regard to a psychological model of temporal processing and a recent proposal that time is part of a parietal cortex system for encoding magnitude information relevant for action.
    Temporal cortex
    Parietal lobe
    Time perception
    Citations (80)
    Abstract The parietal cortex is divided into two major functional regions: the anterior parietal cortex that includes primary somatosensory cortex, and the posterior parietal cortex (PPC) that includes the rest of the parietal lobe. The PPC contains multiple representations of space. In Dijkerman & de Haan's (D&dH's) model, higher spatial representations are separate from PPC functions. This model should be developed further so that the functions of the somatosensory system are integrated with specific functions within the PPC and higher spatial representations. Through this further specification of the model, one can make better predictions regarding functional interactions between somatosensory and visual systems.
    Parietal lobe
    Citations (0)
    Rodent posterior parietal cortex, similar to its homologue in primates, has been shown to be critically involved in spatial navigation. We summarize here selected neurophysiological data and their relevance to recent lesion-behavioral studies. The findings indicate that the rat posterior parietal cortex contains a significant proportion of neurons that code for head-centered (or body-centered) space by making use of the vestibular and proprioceptive inputs. Some posterior parietal neurons may store a working representation of space, which appears to be allocentric.
    Proprioception
    Representation
    Citations (27)