Cerebellar contributions to the processing of saccadic errors

Department of Neuroscience, Erasmus MC, Rotterdam 3000 CA, The Netherlands.
The Cerebellum (Impact Factor: 2.86). 06/2009; 8(3):403-15. DOI: 10.1007/s12311-009-0116-6
Source: PubMed

ABSTRACT Saccades are fast eye movements that direct the point of regard to a target in the visual field. Repeated post-saccadic visual errors can induce modifications of the amplitude of these saccades, a process known as saccadic adaptation. Two experiments using the same paradigm were performed to study the involvement of the cerebrum and the cerebellum in the processing of saccadic errors using functional magnetic resonance imaging and in-scanner eye movement recordings. In the first active condition, saccadic adaptation was prevented using a condition in which the saccadic target was shifted to a variable position during the saccade towards it. This condition induced random saccadic errors as opposed to the second active condition in which the saccadic target was not shifted. In the baseline condition, subjects looked at a stationary dot. Both active conditions compared with baseline evoked activation in the expected saccade-related regions using a stringent statistical threshold [the frontal and parietal eye fields, primary visual area, MT/V5, and the precuneus (V6) in the cerebrum; vermis VI-VII; and lobule VI in the cerebellum, known as the oculomotor vermis). In the direct comparison between the two active conditions, significantly more cerebellar activation (vermis VIII, lobules VIII-X, left lobule VIIb) was observed with random saccadic errors (using a more relaxed statistical threshold). These results suggest a possible role for areas outside the oculomotor vermis of the cerebellum in the processing of saccadic errors. Future studies of these areas with, e.g., electrophysiological recordings, may reveal the nature of the error signals that drive the amplitude modification of saccadic eye movements.

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Available from: Aad van der Lugt, Aug 28, 2015
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    • "Several studies support that the parietal lobe modulates its activity for saccadic [25], [26], [27] and disparity (the input to vergence) [28], [29] stimulation. The cerebellum has also been implicated in error processing for motor learning for both saccadic [30], [31], [32] and vergence [33], [34], [35] movements. "
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    ABSTRACT: Eye movement research has traditionally studied solely saccade and/or vergence eye movements by isolating these systems within a laboratory setting. While the neural correlates of saccadic eye movements are established, few studies have quantified the functional activity of vergence eye movements using fMRI. This study mapped the neural substrates of vergence eye movements and compared them to saccades to elucidate the spatial commonality and differentiation between these systems. The stimulus was presented in a block design where the 'off' stimulus was a sustained fixation and the 'on' stimulus was random vergence or saccadic eye movements. Data were collected with a 3T scanner. A general linear model (GLM) was used in conjunction with cluster size to determine significantly active regions. A paired t-test of the GLM beta weight coefficients was computed between the saccade and vergence functional activities to test the hypothesis that vergence and saccadic stimulation would have spatial differentiation in addition to shared neural substrates. Segregated functional activation was observed within the frontal eye fields where a portion of the functional activity from the vergence task was located anterior to the saccadic functional activity (z>2.3; p<0.03). An area within the midbrain was significantly correlated with the experimental design for the vergence but not the saccade data set. Similar functional activation was observed within the following regions of interest: the supplementary eye field, dorsolateral prefrontal cortex, ventral lateral prefrontal cortex, lateral intraparietal area, cuneus, precuneus, anterior and posterior cingulates, and cerebellar vermis. The functional activity from these regions was not different between the vergence and saccade data sets assessed by analyzing the beta weights of the paired t-test (p>0.2). Functional MRI can elucidate the differences between the vergence and saccade neural substrates within the frontal eye fields and midbrain.
    PLoS ONE 11/2011; 6(11):e25866. DOI:10.1371/journal.pone.0025866 · 3.23 Impact Factor
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    • "Recent studies have also implicated the cerebellar hemispheres in ocular motor learning. For example, fMRI studies show that the hemispheric lobules VIII–X are active in processing of saccadic errors (van Broekhoven et al., 2009), and TMS over the hemispheric lobule Crus I has a dual effect on saccadic plasticity; potentiating adaptive lengthening and depressing adaptive shortening of saccade amplitudes (Panouilleres et al., 2011). There is also evidence for involvement of the cerebellar hemispheres in adaptation for more voluntary, internally generated saccades such as memory-guided saccades, as opposed to the OMV involvement in more reflexive, visually guided saccades (Nitschke et al., 2004; Alahyane et al., 2008; Kojima et al., 2010b). "
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    ABSTRACT: An intact cerebellum is a prerequisite for optimal ocular motor performance. The cerebellum fine-tunes each of the subtypes of eye movements so they work together to bring and maintain images of objects of interest on the fovea. Here we review the major aspects of the contribution of the cerebellum to ocular motor control. The approach will be based on structural-functional correlation, combining the effects of lesions and the results from physiologic studies, with the emphasis on the cerebellar regions known to be most closely related to ocular motor function: (1) the flocculus/paraflocculus for high-frequency (brief) vestibular responses, sustained pursuit eye movements, and gaze holding, (2) the nodulus/ventral uvula for low-frequency (sustained) vestibular responses, and (3) the dorsal oculomotor vermis and its target in the posterior portion of the fastigial nucleus (the fastigial oculomotor region) for saccades and pursuit initiation.
    Frontiers in Neurology 09/2011; 2:53. DOI:10.3389/fneur.2011.00053
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    • "They found activation in the oculomotor cerebellar vermis (lobules VI and VII) with an ipsilateral preponderance on the side to which the saccadic displacement was adapted. To separate the motor adaptation from the processes related to the visual error, Van Broekhoven et al. [166] employed a paradigm with a random intrasaccadic target step. Random intrasaccadic target steps do induce a postsaccadic visual error, but they do not lead to a gradual change in saccadic amplitudes. "
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    ABSTRACT: In this paper, we will review the anatomical components of the visuomotor cerebellum in human and, where possible, in non-human primates and discuss their function in relation to those of extracerebellar visuomotor regions with which they are connected. The floccular lobe, the dorsal paraflocculus, the oculomotor vermis, the uvula-nodulus, and the ansiform lobule are more or less independent components of the visuomotor cerebellum that are involved in different corticocerebellar and/or brain stem olivocerebellar loops. The floccular lobe and the oculomotor vermis share different mossy fiber inputs from the brain stem; the dorsal paraflocculus and the ansiform lobule receive corticopontine mossy fibers from postrolandic visual areas and the frontal eye fields, respectively. Of the visuomotor functions of the cerebellum, the vestibulo-ocular reflex is controlled by the floccular lobe; saccadic eye movements are controlled by the oculomotor vermis and ansiform lobule, while control of smooth pursuit involves all these cerebellar visuomotor regions. Functional imaging studies in humans further emphasize cerebellar involvement in visual reflexive eye movements and are discussed.
    The Cerebellum 08/2010; 11(2):392-410. DOI:10.1007/s12311-010-0204-7 · 2.86 Impact Factor
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