Modular organization of internal models of tools in the human cerebellum

Imamizu, Hiroshi; Kuroda, Tomoe; Miyauchi, Satoru; Yoshioka, Toshinori; Kawato, Mitsuo

doi:10.1073/pnas.0835746100

Cited by 289 publications

(216 citation statements)

References 36 publications

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“…Previous functional imaging studies (Imamizu et al 2003(Imamizu et al , 2004 also supported the MOSAIC model and suggested that a prefrontal region (Brodmann area 46) contributes to the predictor while loops between the parietal regions (Pisella et al 2000) and the cerebellum contribute to the estimator. The current behavioral study in the context of previous computational (Wolpert et al 1995;Wolpert and Kawato 1998;Kawato 1999) and imaging studies (Imamizu et al 2004) suggests that, to achieve adaptation to multiple environments, a predictive mechanism, possibly located in the frontal cortex, needs to switch multiple internal models residing in the cerebellum.…”

Section: Discussionmentioning

confidence: 66%

Explicit contextual information selectively contributes to predictive switching of internal models

Imamizu¹,

Sugimoto²,

Osu

et al. 2007

Exp Brain Res

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Many evidences suggest that the central nervous system (CNS) acquires and switches internal models for adaptive control in various environments. However, little is known about the neural mechanisms responsible for the switching. A recent computational model for simultaneous learning and switching of internal models proposes two separate switching mechanisms: a predictive mechanism purely based on contextual information and a postdictive mechanism based on the difference between actual and predicted sensorimotor feedbacks. This model can switch internal models solely based on contextual information in a predictive fashion immediately after alteration of the environment. Here we show that when subjects simultaneously adapted to alternating blocks of opposing visuomotor rotations, explicit contextual information about the rotations improved the initial performance at block alternations and asymptotic levels of performance within each block but not readaptation speeds. Our simulations using separate switching mechanisms duplicated these effects of contextual information on subject performance and suggest that improvement of initial performance was caused by improved accuracy of the predictive switch while adaptation speed corresponds to a switch dependent on sensorimotor feedback. Simulations also suggested that a slow change in output signals from the switching mechanisms causes contamination of motor commands from an internal model used in the previous context (anterograde interference) and partial destruction of internal models (retrograde interference). Explicit contextual information prevents destruction and assists memory retention by improving the changes in output signals. Thus, the asymptotic levels of performance improved.

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Section: Discussionmentioning

confidence: 66%

Explicit contextual information selectively contributes to predictive switching of internal models

Imamizu¹,

Sugimoto²,

Osu

et al. 2007

Exp Brain Res

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“…Recent investigations by Hutchinson et al (76) suggest that frequency and intensity of complex cognitive behaviors, such as music practice, correlate with increases in cerebellar volume. Additionally, cerebellar representational topography changes with exposure to new tools and related motor routines (77,78). As with skeletal morphology, it appears that variation in cerebellar morphology is partitioned between genetic factors and developmental and functional plasticity.…”

Section: Discussionmentioning

confidence: 99%

Reciprocal evolution of the cerebellum and neocortex in fossil humans

Weaver

2005

Proc. Natl. Acad. Sci. U.S.A.

177

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Human brain evolution involved both neurological reorganization and an increase in overall brain volume relative to body mass. It is generally difficult to draw functional inferences about the timing and nature of brain reorganization, given that superficial brain morphology recorded on fossil endocasts is functionally ambiguous. However, the cerebellum, housed in the clearly delineated posterior cranial fossa, is functionally and ontologically discrete. The cerebellum is reciprocally connected to each of 14 neocortical regions important to human cognitive evolution. Cerebellar volume varies significantly relative to overall brain volume among mammalian orders, as well as within the primate order. There is also significant diachronic variation among fossil human taxa. In the australopithecines and early members of the genus Homo, the cerebral hemispheres were large in proportion to the cerebellum, compared with other hominoids. This trend continued in Middle and Late Pleistocene humans, including Neandertals and CroMagnon 1, who have the largest cerebral hemispheres relative to cerebellum volume of any primates, including earlier and Holocene humans. In recent humans, however, the pattern is reversed; the cerebellum is larger with respect to the rest of the brain (and, conversely, the cerebral hemispheres are smaller with respect to the cerebellum) than in Late Pleistocene humans. The cerebellum and cerebral hemispheres appear to have evolved reciprocally. Cerebellar development in Holocene humans may have provided greater computational efficiency for coping with an increasingly complex cultural and conceptual environment.human evolution ͉ Plio-Pleistocene hominins ͉ Upper Paleolithic transition P aleoneurologists agree that increased encephalization is an important dynamic of human brain evolution. However, brain evolution involved more than brain expansion. It also involved reorganization to support specific, uniquely human cognitive tasks, including those involved in linguistic processing and a highly developed facility for manufacturing and manipulating tools. Nevertheless, despite more than a century of effort, there is little consensus about how and when such reorganization occurred.One approach to exploring functional reorganization of the brain in humans has been the analysis of impressions of the brain's surface convolutions (sulci and gyri) on the inner table of the endocranium. However, endocranial markings are notoriously difficult to identify reliably (1, 2). Even where the impressions are fairly clear, taphonomic processes may distort the evidence. In addition, the functional correlates of the brain's surface convolutions, especially in fossils, are literally superficial. Cognitive functions occur through internal connections among brain regions, as well as through the distribution of neuroreceptors that cannot be detected by examining the surface of the brain, let alone from endocranial markings. Therefore, functional inferences based on sulcal patterns are problematic.Another approach to endocran...

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“…Cerebellum plays also a significant role in the early phases of acquisition and planning of motor sequences [Doyon et al, 2002], and is known to participate in a wide variety of cognitive and emotional processes [e.g., see Marien et al, 2001;Middleton and Strick, 1998;Rapoport et al, 2000;Salman, 2002]. Moreover, a modular organization of internal models of tool manipulation has been recently reported in the cerebellum using fMRI [Imamizu et al, 2003], extending the predictions of the MOSAIC computational model [Haruno et al, 2001;Wolpert and Kawato, 1998] from to the "motor" to the "cognitive" cerebellum. In the present study, we suggest that the vermian cerebellar activation associated with the innervatory pattern stage merely reflects its contribution to movement regulation [Deiber et al, 1996;Jueptner et al, 1996;Kitazawa, 2002] and integration of simple movements into more complex ones [Ramnani et al, 2001;Thach, 1998] during actual movement production.…”

Section: Innervatory Patternsmentioning

confidence: 96%

Imaging a cognitive model of apraxia: The neural substrate of gesture‐specific cognitive processes

Peigneux

Linden

Garraux

et al. 2004

Human Brain Mapping

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Abstract:The present study aimed to ascertain the neuroanatomical basis of an influential neuropsychological model for upper limb apraxia [Rothi LJ, et al. The Neuropsychology of Action. 1997. Hove, UK: Psychology Press]. Regional cerebral blood flow was measured in healthy volunteers using H 2 15O PET during performance of four tasks commonly used for testing upper limb apraxia, i.e., pantomime of familiar gestures on verbal command, imitation of familiar gestures, imitation of novel gestures, and an action-semantic task that consisted in matching objects for functional use. We also re-analysed data from a previous PET study in which we investigated the neural basis of the visual analysis of gestures. First, we found that two sets of discrete brain areas are predominantly engaged in the imitation of familiar and novel gestures, respectively. Segregated brain activation for novel gesture imitation concur with neuropsychological reports to support the hypothesis that knowledge about the organization of the human body mediates the transition from visual perception to motor execution when imitating novel gestures [Goldenberg Neuropsychologia 1995;33:63-72]. Second, conjunction analyses revealed distinctive neural bases for most of the gesture-specific cognitive processes proposed in this cognitive model of upper limb apraxia. However, a functional analysis of brain imaging data suggested that one single memory store may be used for "to-be-perceived" and "to-be-produced" gestural representations, departing from Rothi et al.'s proposal. Based on the above considerations, we suggest and discuss a revised model for upper limb apraxia that might best account for both brain imaging findings and neuropsychological dissociations reported in the apraxia literature.

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Modular organization of internal models of tools in the human cerebellum

Cited by 289 publications

References 36 publications

Explicit contextual information selectively contributes to predictive switching of internal models

Explicit contextual information selectively contributes to predictive switching of internal models

Reciprocal evolution of the cerebellum and neocortex in fossil humans

Imaging a cognitive model of apraxia: The neural substrate of gesture‐specific cognitive processes

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