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Richard A Andersen - One of the best experts on this subject based on the ideXlab platform.

  • Human Posterior Parietal Cortex Plans Where to Reach and What to Avoid
    The Journal of neuroscience : the official journal of the Society for Neuroscience, 2010
    Co-Authors: Axel Lindner, Asha Iyer, Igor Kagan, Richard A Andersen
    Abstract:

    In this time-resolved functional magnetic resonance imaging (fMRI) study, we aimed to trace the neuronal correlates of covert planning processes that precede visually guided motor behavior. Specifically, we asked whether human Posterior Parietal Cortex has prospective planning activity that can be distinguished from activity related to retrospective visual memory and attention. Although various electrophysiological studies in monkeys have demonstrated such motor planning at the level of Parietal neurons, comparatively little support is provided by recent human imaging experiments. Rather, a majority of experiments highlights a role of human Posterior Parietal Cortex in visual working memory and attention. We thus sought to establish a clear separation of visual memory and attention from processes related to the planning of goal-directed motor behaviors. To this end, we compared delayed-response tasks with identical mnemonic and attentional demands but varying degrees of motor planning. Subjects memorized multiple target locations, and in a random subset of trials targets additionally instructed (1) desired goals or (2) undesired goals for upcoming finger reaches. Compared with the memory/attention-only conditions, both latter situations led to a specific increase of preparatory fMRI activity in Posterior Parietal and dorsal premotor Cortex. Thus, Posterior Parietal Cortex has prospective plans for upcoming behaviors while considering both types of targets relevant for action: those to be acquired and those to be avoided.

  • Posterior Parietal Cortex encodes autonomously selected motor plans
    Neuron, 2007
    Co-Authors: He Cui, Richard A Andersen
    Abstract:

    The Posterior Parietal Cortex (PPC) of rhesus monkeys has been found to encode the behavioral meaning of categories of sensory stimuli. When animals are instructed with sensory cues to make either eye or hand movements to a target, PPC cells also show specificity depending on which effector (eye or hand) is instructed for the movement. To determine whether this selectivity retrospectively reflects the behavioral meaning of the cue or prospectively encodes the movement plan, we trained monkeys to autonomously choose to acquire a target in the absence of direct instructions specifying which effector to use. Activity in PPC showed strong specificity for effector choice, with cells in the lateral intraParietal area selective for saccades and cells in the Parietal reach region selective for reaches. Such differential activity associated with effector choice under identical stimulus conditions provides definitive evidence that the PPC is prospectively involved in action selection and movement preparation.

  • Movement intention is better predicted than attention in the Posterior Parietal Cortex
    The Journal of neuroscience : the official journal of the Society for Neuroscience, 2006
    Co-Authors: Rodrigo Quian Quiroga, Lawrence H. Snyder, Aaron P. Batista, He Cui, Richard A Andersen
    Abstract:

    We decoded on a trial-by-trial basis the location of visual targets, as a marker of the locus of attention, and intentions to reach and to saccade in different directions using the activity of neurons in the Posterior Parietal Cortex of two monkeys. Predictions of target locations were significantly worse than predictions of movement plans for the same target locations. Moreover, neural signals in the Parietal reach region (PRR) gave better predictions of reaches than saccades, whereas signals in the lateral intraParietal area (LIP) gave better predictions of saccades than reaches. Taking together the activity of both areas, the prediction of either movement in all directions became nearly perfect. These results cannot be explained in terms of an attention effect and support the idea of two segregated populations in the Posterior Parietal Cortex, PRR and LIP, that are involved in different movement plans.

  • Sensorimotor Transformations in the Posterior Parietal Cortex
    2004
    Co-Authors: Richard A Andersen, Daniella Meeker, Bijan Pesaran, Boris Breznen, Christopher A. Buneo, Hans Scherberger
    Abstract:

    The Posterior Parietal Cortex (PPC) sits at the interface between sensory and motor areas and performs sensorimotor transformations. Current research is beginning to unravel the details of this transformation process. The first part of this chapter focuses on planning signals found in the PPC. Experiments show that the thought to reach can be read out from the Parietal reach region of monkeys and used to control the position of a computer cursor without any reach movements being made by the monkeys. The second section reviews recent studies of coordinate tral15formations, which are an important aspect of sensorimotor transformations and involve the PPC.

  • Intentional maps in Posterior Parietal Cortex
    Annual review of neuroscience, 2002
    Co-Authors: Richard A Andersen, Christopher A. Buneo
    Abstract:

    The Posterior Parietal Cortex (PPC), historically believed to be a sensory structure, is now viewed as an area important for sensory-motor integration. Among its functions is the forming of intentions, that is, high-level cognitive plans for movement. There is a map of intentions within the PPC, with different subregions dedicated to the planning of eye movements, reaching movements, and grasping movements. These areas appear to be specialized for the multisensory integration and coordinate transformations required to convert sensory input to motor output. In several subregions of the PPC, these operations are facilitated by the use of a common distributed space representation that is independent of both sensory input and motor output. Attention and learning effects are also evident in the PPC. However, these effects may be general to Cortex and operate in the PPC in the context of sensory-motor transformations.

Mark Hallett - One of the best experts on this subject based on the ideXlab platform.

Anke Karabanov - One of the best experts on this subject based on the ideXlab platform.

Maurizio Corbetta - One of the best experts on this subject based on the ideXlab platform.

  • The contribution of the human Posterior Parietal Cortex to episodic memory
    Nature Reviews Neuroscience, 2017
    Co-Authors: Carlo Sestieri, Gordon L. Shulman, Maurizio Corbetta
    Abstract:

    Recent human neuroimaging studies suggest that, in addition to its role in visuospatial and sensorimotor processes, the Posterior Parietal Cortex (PPC) also plays an important part in episodic memory retrieval. Here, Sestieri, Shulman and Corbetta present a functional–anatomical model of the involvement of the PPC in memory retrieval. The Posterior Parietal Cortex (PPC) is traditionally associated with attention, perceptual decision making and sensorimotor transformations, but more recent human neuroimaging studies support an additional role in episodic memory retrieval. In this Opinion article, we present a functional–anatomical model of the involvement of the PPC in memory retrieval. Parietal regions involved in perceptual attention and episodic memory are largely segregated and often show a push–pull relationship, potentially mediated by prefrontal regions. Moreover, different PPC regions carry out specific functions during retrieval — for example, representing retrieved information, recoding this information based on task demands, or accumulating evidence for memory decisions.

  • the contribution of the human Posterior Parietal Cortex to episodic memory
    Nature Reviews Neuroscience, 2017
    Co-Authors: Carlo Sestieri, Gordon L. Shulman, Maurizio Corbetta
    Abstract:

    The Posterior Parietal Cortex (PPC) is traditionally associated with attention, perceptual decision making and sensorimotor transformations, but more recent human neuroimaging studies support an additional role in episodic memory retrieval. In this Opinion article, we present a functional-anatomical model of the involvement of the PPC in memory retrieval. Parietal regions involved in perceptual attention and episodic memory are largely segregated and often show a push-pull relationship, potentially mediated by prefrontal regions. Moreover, different PPC regions carry out specific functions during retrieval - for example, representing retrieved information, recoding this information based on task demands, or accumulating evidence for memory decisions.

  • attention to memory and the environment functional specialization and dynamic competition in human Posterior Parietal Cortex
    The Journal of Neuroscience, 2010
    Co-Authors: Carlo Sestieri, Gordon L. Shulman, Maurizio Corbetta
    Abstract:

    Posterior Parietal Cortex has been traditionally associated with perceptual attention and sensory-motor processing, but recent studies also indicate a potential role in episodic memory retrieval. Here, we developed a new paradigm to isolate top-down attention-related activity directed to either memory or perceptual information. We demonstrated a robust topographic separation in human Posterior Parietal Cortex associated with searching for task-relevant information in episodic memory or in the environment. Control analyses confirmed that this difference was not dependent on differences in sensory stimulation or eye movements across tasks. Notably, we observed in memory- and perception-related regions a mechanism of reciprocal dynamic competition that was related to behavioral performance. These results provide the first evidence for a double dissociation between Parietal networks involved in top-down attention to memory and the environment and support the idea of neural competition between perception and memory.

Keiji Iramina - One of the best experts on this subject based on the ideXlab platform.

  • Measurements of evoked electroencephalograph by transcranial magnetic stimulation applied to motor Cortex and Posterior Parietal Cortex
    Journal of Applied Physics, 2009
    Co-Authors: M. Iwahashi, Shoogo Ueno, Yohei Koyama, Akira Hyodo, Takehito Hayami, Keiji Iramina
    Abstract:

    To investigate the functional connectivity, the evoked potentials by stimulating at the motor Cortex, the Posterior Parietal Cortex, and the cerebellum by transcranial magnetic stimulation (TMS) were measured. It is difficult to measure the evoked electroencephalograph (EEG) by the magnetic stimulation because of the large artifact induced by the magnetic pulse. We used an EEG measurement system with sample-and-hold circuit and an independent component analysis to eliminate the electromagnetic interaction emitted from TMS. It was possible to measure EEG signals from all electrodes over the head within 10 ms after applying the TMS. When the motor area was stimulated by TMS, the spread of evoked electrical activity to the contralateral hemisphere was observed at 20 ms after stimulation. However, when the Posterior Parietal Cortex was stimulated, the evoked electrical activity to the contralateral hemisphere was not observed. When the cerebellum was stimulated, the cortical activity propagated from the stimu...

  • a study of temporal aspect of Posterior Parietal Cortex in visual search using transcranial magnetic stimulation
    Ieej Transactions on Electronics Information and Systems, 2007
    Co-Authors: Akira Matsuoka, Shoogo Ueno, Keiji Iramina
    Abstract:

    It is known that the Posterior Parietal Cortex (PPC) plays a dominant role in spatial processing during visual search. However, the temporal aspect of the PPC is unclear. In the present study, to investigate the temporal aspects of the PPC in feature search, we applied Transcranial Magnetic Stimulation (TMS) over the right PPC with the TMS stimulus onset asynchronies (SOAs) set at 100, 150, 200 and 250 ms after visual search stimulation. We found that when SOA was set at 150 ms, compared to the sham TMS condition, there was a significant elevation in response time when TMS pulses were applied. However, there was no significant difference between the TMS and sham TMS conditions for the other SOA settings. Therefore, we suggest that the spatial processing of feature search is probably processed in the Posterior Parietal Cortex at about 150-170 ms after visual search stimuli presentation.

  • Transcranial magnetic stimulation study of temporal aspect of Posterior Parietal Cortex in visual search
    International Congress Series, 2007
    Co-Authors: Akira Matsuoka, Shoogo Ueno, Keiji Iramina
    Abstract:

    Abstract In this study, we examined the temporal aspects of the right Posterior Parietal Cortex in easy feature visual search using transcranial magnetic stimulation (TMS). The transcranial magnetic stimulations were applied over the right Posterior Parietal Cortex of the subjects with the TMS onset times were set at 100, 150, 200 and 250 ms after visual stimulus presentation. We found that when TMS stimulus onset asynchronies SOA = 150 ms, compared to the no-TMS condition, there was a significant elevation in response time when TMS pulses were applied. However for the other SOA cases, there was no significant difference between the TMS and no-TMS conditions. Therefore, we considered that the feature search was processed in the right Posterior Parietal Cortex at about 150 ms after stimulation.