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

  • Systems/Circuits Inactivation of Parietal Reach Region Affects Reaching But Not Saccade Choices in Internally Guided Decisions
    2016
    Co-Authors: Xvassilios N. Christopoulos, James Bonaiuto, Igor Kagan, Richard A. Andersen
    Abstract:

    The posterior Parietal cortex (PPC) has traditionally been considered important for awareness, spatial perception, and attention. How-ever, recent findings provide evidence that the PPC also encodes information important for making decisions. These findings have initiated a running argument ofwhether thePPC is critically involved indecisionmaking. To examine this issue,we reversibly inactivated the Parietal Reach Region (PRR), the area of the PPC that is specialized for Reaching movements, while two monkeys performed a memory-guided Reaching or saccade task. The task included choices between two equally rewarded targets presented simultaneously in opposite visual fields. Free-choice trials were interleaved with instructed trials, in which a single cue presented in the peripheral visual field defined the Reach and saccade target unequivocally. We found that PRR inactivation led to a strong reduction of contralesional choices, but only for Reaches. On the other hand, saccade choices were not affected by PRR inactivation. Importantly, Reaching and saccade movements to single instructed targets remained largely intact. These results cannot be explained as an effector-nonspecific deficit in spatial attention or awareness, since the temporary “lesion ” had an impact only on Reach choices. Hence, the PPR is a part of a network for Reach decisions and not just Reach planning. Key words: internally guided decisions; Parietal Reach Region; posterior Parietal cortex; Reaching; saccades; spatial extinctio

  • Systems/Circuits Spatial and Temporal Eye–Hand Coordination Relies on the Parietal Reach Region
    2015
    Co-Authors: Eun Jung Hwang, Markus Hauschild, Melanie Wilke, Richard A. Andersen
    Abstract:

    Coordinated eye movements are crucial for precision control of our hands. A commonly believed neural mechanism underlying eye– hand coordination is interaction between the neural networks controlling each effector, exchanging, andmatching information, such as movement target location and onset time. Alternatively, eye–hand coordinationmay result simply from common inputs to independent eye and hand control pathways. Thus far, it remains unknown whether and where either of these two possible mechanisms exists. A candidate location for the formermechanism, interpathway communication, includes the posterior Parietal cortex (PPC) where distinct effector-specific areas reside. If thePPCwerewithin thenetwork for eye–handcoordination, perturbing itwould affect both eye andhand movements that are concurrently planned. In contrast, if eye–hand coordination arises solely from common inputs, perturbing one effector pathway, e.g., the Parietal Reach Region (PRR), would not affect the other effector. To test these hypotheses, we inactivated part of PRR in themacaque, located in themedial bankof the intraParietal sulcus encompassing themedial intraParietal area and area 5V.When each effector moved alone, PRR inactivation shortened Reach but not saccade amplitudes, compatible with the known Reach-selective activity of PRR. However, when both effectorsmoved concurrently, PRR inactivation shortened both Reach and saccade amplitudes, and decoupled their reaction times. Therefore, consistent with the interpathway communication hypothesis, we propose that the planning of concurrent eye andhandmovements causes the spatial information inPRR to influence the otherwise independent eye control pathways, and that their temporal coupling requires an intact PRR. Key words: inactivation; movement endpoints; PPC; Reaches; reaction time; saccade

  • Behavioral/Systems/Cognitive Neural Dynamics in Monkey Parietal Reach Region Reflect Context-Specific Sensorimotor Transformations
    2015
    Co-Authors: Er Gail, Richard A. Andersen
    Abstract:

    We investigated the neural dynamics of sensorimotor transformations in the Parietal Reach Region (PRR) of monkeys. To dissociate sensory from motor goal representations, we used a memory-guided anti-Reach task. The monkeys had to Reach either to a visually instructed, memorized peripheral target position (pro-Reach) or to a diametrically opposed position (anti) while keeping central ocular fixation. Pro- and anti-Reaches were randomly interleaved and indicated by a color instruction from the beginning of each trial. We analyzed spatiotemporal single-cell tuning and performed time-resolved population decoding to quantify the dynamic representation of the spatial visual cue, the Reach goal, and the currently valid task rule (pro/anti mapping). Sensory information regarding the visual cue positionwas representedweaklyduringa short periodof cuevisibility. PRRpredominantly encoded the Reachgoal fromthe endof the cue period on. The representation of the Reach goal in thememory task evolves later for the anti- comparedwith pro-Reaches, consistent with a 40–50msdifference in reaction timebetween the two task rules. The task rule couldbedecodedbefore the appearance of the spatial cue, which indicates that abstract rule information is present in PRR that is independent of spatial cue or motor goal representations. Our findings support the hypothesis that PRR immediately translates current sensory information into Reach movement plans, rather than storing the memorized cue location in the instructed-delay task. This finding indicates that PRR represents integrated knowledge on spatial sensory information combined with abstract behavioral rules to encode the desired movement goal. Key words: sensorimotor transformation; posterior Parietal cortex; motor intention; goal-directed behavior; anti-Reach; S–R compatibilit

  • Behavioral/Systems/Cognitive The Posterior Parietal Cortex Encodes in Parallel Both Goals for Double-Reach Sequences
    2015
    Co-Authors: Daniel Baldauf, He Cui, Richard A. Andersen
    Abstract:

    The Parietal Reach Region (PRR) is known to be involved in the preparation of visually guided arm movements to single targets. We exploredwhether PRR encodes only the target of the nextmovement or, alternatively, also a subsequent goal in a double-Reach sequence. Twomonkeys were trained tomemorize the locations of two peripheral cues and to prepare for a memory-guided delayed double-Reach sequence. On aGO-signal they had to Reach in a predefined order to both remembered target locationswithout breaking eye fixation. The movement goals were arranged such that either the first or the second target was inside the response field of an isolated neuron. We analyzed the neural activity of single cells in PRR during the late memory period between cue offset and the GO-signal. During this memory period,most PRRcells encoded the first aswell as the second goal of the planned Reaching sequence. The results indicate that the posterior Parietal cortex is involved in the spatial planning of more complex action patterns and represents immediate and subsequent movement goals. Key words: double-Reach; motor planning; Parietal Reach Region; movement sequences; sensorimotor; hand; attentio

  • Behavioral/Systems/Cognitive Movement Intention Is Better Predicted than Attention in the Posterior Parietal Cortex
    2015
    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 indifferent directionsusing the activity of neurons in theposterior Parietal cortexof twomonkeys. Predictionsof target locations were significantly worse than predictions ofmovement 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 predic-tions 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. Key words: attention; motor intention; single-trial analysis; population coding; vision; parieta

Lawrence H. Snyder - One of the best experts on this subject based on the ideXlab platform.

  • local field potentials in the Parietal Reach Region reveal mechanisms of bimanual coordination
    Nature Communications, 2021
    Co-Authors: Eric Mooshagian, Charles D Holmes, Lawrence H. Snyder
    Abstract:

    Primates use their arms in complex ways that frequently require coordination between the two arms. Yet the planning of bimanual movements has not been well-studied. We recorded spikes and local field potentials (LFP) from the Parietal Reach Region (PRR) in both hemispheres simultaneously while monkeys planned and executed unimanual and bimanual Reaches. From analyses of interhemispheric LFP-LFP and spike-LFP coherence, we found that task-specific information is shared across hemispheres in a frequency-specific manner. This shared information could arise from common input or from direct communication. The population average unit activity in PRR, representing PRR output, encodes only planned contralateral arm movements while beta-band LFP power, a putative PRR input, reflects the pattern of planned bimanual movement. A parsimonious interpretation of these data is that PRR integrates information about the movement of the left and right limbs, perhaps in service of bimanual coordination.

  • spatial eye hand coordination during bimanual Reaching is not systematically coded in either lip or prr
    Proceedings of the National Academy of Sciences of the United States of America, 2018
    Co-Authors: Eric Mooshagian, Lawrence H. Snyder
    Abstract:

    We often orient to where we are about to Reach. Spatial and temporal correlations in eye and arm movements may depend on the posterior Parietal cortex (PPC). Spatial representations of saccade and Reach goals preferentially activate cells in the lateral intraParietal area (LIP) and the Parietal Reach Region (PRR), respectively. With unimanual Reaches, eye and arm movement patterns are highly stereotyped. This makes it difficult to study the neural circuits involved in coordination. Here, we employ bimanual Reaching to two different targets. Animals naturally make a saccade first to one target and then the other, resulting in different patterns of limb–gaze coordination on different trials. Remarkably, neither LIP nor PRR cells code which target the eyes will move to first. These results suggest that the Parietal cortex plays at best only a permissive role in some aspects of eye–hand coordination and makes the role of LIP in saccade generation unclear.

  • Region specific summation patterns inform the role of cortical areas in selecting motor plans
    Cerebral Cortex, 2016
    Co-Authors: Steve W C Chang, Anthony R Dickinson, Jeffrey L Calton, Bonnie M Lawrence, Lawrence H. Snyder
    Abstract:

    : Given an instruction regarding which effector to move and what location to move to, simply adding the effector and spatial signals together will not lead to movement selection. For this, a nonlinearity is required. Thresholds, for example, can be used to select a particular response and reject others. Here we consider another useful nonlinearity, a supralinear multiplicative interaction. To help select a motor plan, spatial and effector signals could multiply and thereby amplify each other. Such an amplification could constitute one step within a distributed network involved in response selection, effectively boosting one response while suppressing others. We therefore asked whether effector and spatial signals sum supralinearly for planning eye versus arm movements from the Parietal Reach Region (PRR), the lateral intraParietal area (LIP), the frontal eye field (FEF), and a portion of area 5 (A5) lying just anterior to PRR. Unlike LIP neurons, PRR, FEF, and, to a lesser extent, A5 neurons show a supralinear interaction. Our results suggest that selecting visually guided eye versus arm movements is likely to be mediated by PRR and FEF but not LIP.

  • Behavioral/Systems/Cognitive Movement Intention Is Better Predicted than Attention in the Posterior Parietal Cortex
    2015
    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 indifferent directionsusing the activity of neurons in theposterior Parietal cortexof twomonkeys. Predictionsof target locations were significantly worse than predictions ofmovement 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 predic-tions 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. Key words: attention; motor intention; single-trial analysis; population coding; vision; parieta

  • 2000).Saccade-related activity in the Parietal Reach Region
    2014
    Co-Authors: Lawrence H. Snyder, Aaron P. Batista, A. Andersen, Lawrence H, Richard A
    Abstract:

    Andersen. Saccade-related activity in the Parietal Reach Region. J

Douglas J Crawford - One of the best experts on this subject based on the ideXlab platform.

  • human Parietal Reach Region primarily encodes intrinsic visual direction not extrinsic movement direction in a visual motor dissociation task
    Cerebral Cortex, 2007
    Co-Authors: Juan Fernandezruiz, Herbert C Goltz, Joseph F X Desouza, Tutis Vilis, Douglas J Crawford
    Abstract:

    Posterior Parietal cortex (PPC) participates in the planning of visuospatial behaviors, including Reach movements, in gaze-centered coordinates. It is not known if these representations encode the visual goal in retinal coordinates, or the movement direction relative to gaze. Here, by dissociating the intrinsic retinal stimulus from the extrinsic direction of movement, we show that PPC employs a visual code. Using delayed pointing and event-related functional magnetic resonance imaging, we identified a cluster of PPC Regions whose activity was topographically (contralaterally) related to the direction of the planned movement. We then switched the normal visual-motor spatial relationship by adapting subjects to optical left/right reversing prisms. With prisms, movement-related PPC topography reversed, remaining tied to the retinal image. Thus, remarkably, the PPC Region in each hemisphere now responded more for planned ipsilateral pointing movements. Other non-PPC Regions showed the opposite world- or motor-fixed pattern. These findings suggest that PPC primarily encodes not motor commands but movement goals in visual coordinates.

Alexander Gail - One of the best experts on this subject based on the ideXlab platform.

  • planning movements in visual and physical space in monkey posterior Parietal cortex
    Cerebral Cortex, 2015
    Co-Authors: Alexander Gail, Shenbing Kuang, Pierre Morel
    Abstract:

    Neurons in the posterior Parietal cortex respond selectively for spatial parameters of planned goal-directed movements. Yet, it is still unclear which aspects of the movement the neurons encode: the spatial parameters of the upcoming physical movement (physical goal), or the upcoming visual limb movement (visual goal). To test this, we recorded neuronal activity from the Parietal Reach Region while monkeys planned Reaches under either normal or prism-reversed viewing conditions. We found predominant encoding of physical goals while fewer neurons were selective for visual goals during planning. In contrast, local field potentials recorded in the same brain Region exhibited predominant visual goal encoding, similar to previous imaging data from humans. The visual goal encoding in individual neurons was neither related to immediate visual input nor to visual memory, but to the future visual movement. Our finding suggests that action planning in Parietal cortex is not exclusively a precursor of impending physical movements, as reflected by the predominant physical goal encoding, but also contains spatial kinematic parameters of upcoming visual movement, as reflected by co-existing visual goal encoding in neuronal spiking. The co-existence of visual and physical goals adds a complementary perspective to the current understanding of Parietal spatial computations in primates.

  • synchronization patterns suggest different functional organization in Parietal Reach Region and dorsal premotor cortex
    Journal of Neurophysiology, 2014
    Co-Authors: Shubhodeep Chakrabarti, Pablo Martinezvazquez, Alexander Gail
    Abstract:

    The Parietal Reach Region (PRR) and dorsal premotor cortex (PMd) form part of the fronto-Parietal Reach network. While neural selectivity profiles of single-cell activity in these areas can be rema...

  • implementation of spatial transformation rules for goal directed Reaching via gain modulation in monkey Parietal and premotor cortex
    The Journal of Neuroscience, 2009
    Co-Authors: Alexander Gail, Christian Klaes, Stephanie Westendorff
    Abstract:

    Planning goal-directed movements requires the combination of visuospatial with abstract contextual information. Our sensory environment constrains possible movements to a certain extent. However, contextual information guides proper choice of action in a given situation and allows flexible mapping of sensory instruction cues onto different motor actions. We used anti-Reach tasks to test the hypothesis that spatial motor-goal representations in cortical sensorimotor areas are gain modulated by the behavioral context to achieve flexible remapping of spatial cue information onto arbitrary motor goals. We found that gain modulation of neuronal Reach goal representations is commonly induced by the behavioral context in individual neurons of both, the Parietal Reach Region (PRR) and the dorsal premotor cortex (PMd). In addition, PRR showed stronger directional selectivity during the planning of a Reach toward a directly cued goal (pro-Reach) compared with an inferred target (anti-Reach). PMd, however, showed stronger overall activity during Reaches toward inferred targets compared with directly cued targets. Based on our experimental evidence, we suggest that gain modulation is the computational mechanism underlying the integration of spatial and contextual information for flexible, rule-driven stimulus-response mapping, and thereby forms an important basis of goal-directed behavior. Complementary contextual effects in PRR versus PMd are consistent with the idea that posterior Parietal cortex preferentially represents sensory-driven, "automatic" motor goals, whereas frontal sensorimotor areas are stronger engaged in the representation of rule-based, "inferred" motor goals.

  • neural dynamics in monkey Parietal Reach Region reflect context specific sensorimotor transformations
    The Journal of Neuroscience, 2006
    Co-Authors: Alexander Gail, Richard A. Andersen
    Abstract:

    We investigated the neural dynamics of sensorimotor transformations in the Parietal Reach Region (PRR) of monkeys. To dissociate sensory from motor goal representations, we used a memory-guided anti-Reach task. The monkeys had to Reach either to a visually instructed, memorized peripheral target position (pro-Reach) or to a diametrically opposed position (anti) while keeping central ocular fixation. Pro- and anti-Reaches were randomly interleaved and indicated by a color instruction from the beginning of each trial. We analyzed spatiotemporal single-cell tuning and performed time-resolved population decoding to quantify the dynamic representation of the spatial visual cue, the Reach goal, and the currently valid task rule (pro/anti mapping). Sensory information regarding the visual cue position was represented weakly during a short period of cue visibility. PRR predominantly encoded the Reach goal from the end of the cue period on. The representation of the Reach goal in the memory task evolves later for the anti- compared with pro-Reaches, consistent with a 40-50 ms difference in reaction time between the two task rules. The task rule could be decoded before the appearance of the spatial cue, which indicates that abstract rule information is present in PRR that is independent of spatial cue or motor goal representations. Our findings support the hypothesis that PRR immediately translates current sensory information into Reach movement plans, rather than storing the memorized cue location in the instructed-delay task. This finding indicates that PRR represents integrated knowledge on spatial sensory information combined with abstract behavioral rules to encode the desired movement goal.

Herbert C Goltz - One of the best experts on this subject based on the ideXlab platform.

  • Human Parietal ‘‘Reach Region’ ’ Primarily Encodes Intrinsic Visual Direction, Not Extrinsic Movement Direction, in a Visual--Motor Dissociation Task
    2014
    Co-Authors: Juan Fern, Herbert C Goltz, Joseph F. X
    Abstract:

    Posterior Parietal cortex (PPC) participates in the planning of visuospatial behaviors, including Reach movements, in gaze-centered coordinates. It is not known if these representations encode the visual goal in retinal coordinates, or the movement direction relative to gaze. Here, by dissociating the intrinsic retinal stimulus from the extrinsic direction of movement, we show that PPC employs a visual code. Using delayed pointing and event-related functional magnetic resonance imaging, we identified a cluster of PPC Regions whose activity was topographically (con-tralaterally) related to the direction of the planned movement. We then switched the normal visual--motor spatial relationship by adapting subjects to optical left/right reversing prisms. With prisms, movement-related PPC topography reversed, remaining tied to the retinal image. Thus, remarkably, the PPC Region in each hemisphere now responded more for planned ipsilateral pointing movements. Other non-PPC Regions showed the opposite world- or motor-fixed pattern. These findings suggest that PPC primarily encodes not motor commands but movement goals in visual coordinates

  • human Parietal Reach Region primarily encodes intrinsic visual direction not extrinsic movement direction in a visual motor dissociation task
    Cerebral Cortex, 2007
    Co-Authors: Juan Fernandezruiz, Herbert C Goltz, Joseph F X Desouza, Tutis Vilis, Douglas J Crawford
    Abstract:

    Posterior Parietal cortex (PPC) participates in the planning of visuospatial behaviors, including Reach movements, in gaze-centered coordinates. It is not known if these representations encode the visual goal in retinal coordinates, or the movement direction relative to gaze. Here, by dissociating the intrinsic retinal stimulus from the extrinsic direction of movement, we show that PPC employs a visual code. Using delayed pointing and event-related functional magnetic resonance imaging, we identified a cluster of PPC Regions whose activity was topographically (contralaterally) related to the direction of the planned movement. We then switched the normal visual-motor spatial relationship by adapting subjects to optical left/right reversing prisms. With prisms, movement-related PPC topography reversed, remaining tied to the retinal image. Thus, remarkably, the PPC Region in each hemisphere now responded more for planned ipsilateral pointing movements. Other non-PPC Regions showed the opposite world- or motor-fixed pattern. These findings suggest that PPC primarily encodes not motor commands but movement goals in visual coordinates.