Neural Correlates of Internal-Model Loading

Bursztyn, Lulu L.C.D.; Ganesh, Gowrishankar; Imamizu, Hiroshi; Kawato, Mitsuo; Flanagan, J. Randall

doi:10.1016/j.cub.2006.10.051

Cited by 63 publications

(48 citation statements)

References 32 publications

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“…This is highly consistent with an implication of this region in visually directed movements (Stein, 1986;Bursztyn et al, 2006) and eye-hand coordination (Miall et al, 2000). A similar activation was found in the late stage of a visual rotation tracking task , and attributed to the acquisition of a new internal model after visual perturbation.…”

Section: Cerebellumsupporting

confidence: 87%

Dynamic Changes in Brain Activity during Prism Adaptation

Luauté

Schwartz²,

Rossetti³

et al. 2009

J. Neurosci.

215

184

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Prism adaptation does not only induce short-term sensorimotor plasticity, but also longer-term reorganization in the neural representation of space. We used event-related fMRI to study dynamic changes in brain activity during both early and prolonged exposure to visual prisms. Participants performed a pointing task before, during, and after prism exposure. Measures of trial-by-trial pointing errors and corrections allowed parametric analyses of brain activity as a function of performance. We show that during the earliest phase of prism exposure, anterior intraparietal sulcus was primarily implicated in error detection, whereas parieto-occipital sulcus was implicated in error correction. Cerebellum activity showed progressive increases during prism exposure, in accordance with a key role for spatial realignment. This time course further suggests that the cerebellum might promote neural changes in superior temporal cortex, which was selectively activated during the later phase of prism exposure and could mediate the effects of prism adaptation on cognitive spatial representations.

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Section: Cerebellumsupporting

confidence: 87%

Dynamic Changes in Brain Activity during Prism Adaptation

Luauté

Schwartz²,

Rossetti³

et al. 2009

J. Neurosci.

215

184

View full text Add to dashboard Cite

show abstract

“…Even though our data are in good agreement with the current mirror neuron theory, an alternative, not mutually exclusive interpretation can be that the experimental context activated movement representations in terms of stored internal models (Bursztyn, Ganesh, Imamizu, Kawato, & Flanagan, 2006;Jenmalm, Schmitz, Forssberg, & Ehrsson, 2006). More specifically, experiment 2 showed that the presentation of tension/pressure cues on grip force was sufficient to mediate force-related activity within the observer's M1.…”

Section: Functional Significance and Potential Mechanisms Underlying supporting

confidence: 81%

“…More specifically, similar to the way that the sight of an object can recruit internal models for scaling the forces needed to handle the object ) the sight of different levels of hand contraction may have induced the activation of stored internal motor representations for scaling the observed isometric forces. In this respect, the elicited M1 responses might have been driven by other pathways than those predicted by the mirror neuron theory, potentially involving the cerebellum (Bursztyn et al, 2006;Jenmalm et al, 2006).…”

Section: Functional Significance and Potential Mechanisms Underlying mentioning

confidence: 93%

Observing how others lift light or heavy objects: Which visual cues mediate the encoding of muscular force in the primary motor cortex?

2010

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a b s t r a c tObservers are able to judge quite accurately the weights lifted by others. Only recently, neuroscience has focused on the role of the motor system to accomplish this task. In this respect, a previous transcranial magnetic stimulation (TMS) study showed that the muscular force requirements of an observed action are encoded by the primary motor cortex (M1).Overall, three distinct visual sources may provide information on the applied force of an observed lifting action, namely, (i) the perceived kinematics, (ii) the hand contraction state and finally (iii) intrinsic object properties. The principal aim of the present study was to disentangle these three visual sources and to explore their importance in mediating the encoding of muscular force requirements in the observer's motor system. A series of experiments are reported in which TMS was used to measure 'force-related' responses from the hand representation in left M1 while subjects observed distinct action-stimuli.Overall, results indicated that observation-induced activity in M1 reflects the level of observed force when kinematic cues of the lift (exp. 1) or cues on the hand contraction state (exp. 2) are available. Moreover, when kinematic cues and intrinsic object properties provide distinct information on the force requirements of an observed lifting action, results from experiment 3 indicated a strong preference for the use of kinematic features in mapping the force requirements of the observed action. In general, these findings support the hypothesis that the primary motor cortex contributes to action observation by mapping the muscle-related features of observed actions.

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“…Consistent with the inverse dynamics hypothesis, cerebellar patients have difficulty adapting to external force fields [23,40]. Changes in the activation of the cerebellum following motor learning in normal subjects also implicate this structure in the acquisition and storage of inverse models [8,10,16,37]. …”

mentioning

confidence: 63%

Cerebellum Predicts the Future Motor State

2008

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Feed forward control and estimates of the future state of the motor system are critical for fast and coordinated movements. One framework for generating these predictive signals is based on the central nervous system implementing internal models. Internal models provide for representations of the input-output properties of the motor apparatus or their inverses. It has been widely hypothesized that the cerebellum acquires and stores internal models of the motor apparatus. The results of psychophysical, functional imaging and transcranial magnetic stimulation studies in normal subjects support this hypothesis. Also, the deficits in patients with cerebellar dysfunction can be attributed to a failure of predictive feed forward control and/or to accurately estimate the consequences of motor commands. Furthermore, the computation performed by the cerebellar-like electrosensory lobes in several groups of fishes is to predict the sensory consequences of motor commands. However, only a few electrophysiological investigations have directly tested whether neurons in the cerebellar cortex have the requisite signals compatible with either an inverse or forward internal model. Our studies in the monkey performing manual pursuit tracking demonstrate that the simple spike discharge of Purkinje cells does not have the dynamics-related signals required to be the output of an inverse dynamics model. However, Purkinje cell firing has several of the characteristics of a forward internal model of the arm. A synthesis of the evidence suggests that the cerebellum is involved in integrating the current state of the motor system with internally generated motor commands to predict the future state. KeywordsPrimate; Cerebellum; Purkinje cell; Simple spike; Internal models ReviewInternal models are widely discussed as a mechanism by which the central nervous system (CNS) generates feed forward commands and/or makes predictions about the upcoming states. Forward internal models predict the state of the system, either the motor variables or the sensory output, as a consequence of the current state of the system and the motor commands. Inverse dynamics models, in response to the desired trajectory, generate the signals required to produce the joint torques/forces used to control a movement. Numerous psychophysical findings support the hypothesis that the CNS uses internal models. Prominent examples include the anticipatory changes in grip forces during predictable manipulations of object load [11,17] and our ability to adapt and generalize reaching movements in novel dynamic environments [38,42]. Furthermore, sensory feedback loops have delays that are too long and gains too low to control fast and coordinated movements.Correspondence to: Timothy J. Ebner. Many investigators postulate that the cerebellum acquires and stores internal models of the motor system [16,18,26,37,44]. Support for these hypotheses is largely based on deficits in patients with cerebellar dysfunction or on functional imaging studies. Consistent with the inverse d...

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Neural Correlates of Internal-Model Loading

Cited by 63 publications

References 32 publications

Dynamic Changes in Brain Activity during Prism Adaptation

Dynamic Changes in Brain Activity during Prism Adaptation

Observing how others lift light or heavy objects: Which visual cues mediate the encoding of muscular force in the primary motor cortex?

Cerebellum Predicts the Future Motor State

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