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Li T, Sakthivelpathi V, Qian Z, Soetedjo R, Chung JH. Primate eye tracking with carbon-nanotube-paper-composite based capacitive sensors and machine learning algorithms. J Neurosci Methods 2024; 410:110249. [PMID: 39151657 DOI: 10.1016/j.jneumeth.2024.110249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 07/20/2024] [Accepted: 08/13/2024] [Indexed: 08/19/2024]
Abstract
BACKGROUND Accurate real-time eye tracking is crucial in oculomotor system research. While the scleral search coil system is the gold standard, its implantation procedure and bulkiness pose challenges. Camera-based systems are affected by ambient lighting and require high computational and electric power. NEW METHOD This study presents a novel eye tracker using proximity capacitive sensors made of carbon-nanotube-paper-composite (CPC). These sensors detect femtofarad-level capacitance changes caused by primate corneal movement during horizontal and vertical eye rotations. Data processing and machine learning algorithms are evaluated to enhance the accuracy of gaze angle prediction. RESULTS The system performance is benchmarked against the scleral coil during smooth pursuits, saccades tracking, and fixations. The eye tracker demonstrates up to 0.97 correlation with the coil in eye tracking and is capable of estimating gaze angle with a median absolute error as low as 0.30°. COMPARISON The capacitive eye tracker demonstrates good consistency and accuracy in comparison to the gold-standard scleral search coil method. CONCLUSIONS This lightweight, non-invasive capacitive eye tracker offers potential as an alternative to traditional coil and camera-based systems in oculomotor research and vision science.
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Affiliation(s)
- Tianyi Li
- Mechanical Engineering, University of Washington, Seattle, WA 98195, USA
| | | | - Zhongjie Qian
- Mechanical Engineering, University of Washington, Seattle, WA 98195, USA
| | - Robijanto Soetedjo
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA; Washington National Primate Research Center, University of Washington, Seattle, WA 98195, USA
| | - Jae-Hyun Chung
- Mechanical Engineering, University of Washington, Seattle, WA 98195, USA.
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2
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Kojima Y, Yoshino H, Ling L, Phillips JO. Comparison of adaptation characteristics between visually and memory-guided saccades. J Neurophysiol 2024; 132:335-346. [PMID: 38865580 PMCID: PMC11302833 DOI: 10.1152/jn.00050.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 06/11/2024] [Accepted: 06/12/2024] [Indexed: 06/14/2024] Open
Abstract
Saccade adaptation plays a crucial role in maintaining saccade accuracy. The behavioral characteristics and neural mechanisms of saccade adaptation for an externally cued movement, such as visually guided saccades (VGS), are well studied in nonhuman primates. In contrast, little is known about the saccade adaptation of an internally driven movement, such as memory-guided saccades (MGS), which are guided by visuospatial working memory. As the oculomotor plant changes because of growth, aging, or skeletomuscular problems, both types of saccades need to be adapted. Do both saccade types engage a common adaptation mechanism? In this study, we compared the characteristics of amplitude decrease adaptation in MGS with VGS in nonhuman primates. We found that the adaptation speed was faster for MGS than for VGS. Saccade duration changed during MGS adaptation, whereas saccade peak velocity changed during VGS adaptation. We also compared the adaptation field, that is, the gain change for saccade amplitudes other than the adapted. The gain change for MGS declines on both smaller and larger sides of adapted amplitude, more rapidly for larger than smaller amplitudes, whereas the decline in VGS was reversed. Thus, the differences between VGS and MGS adaptation characteristics support the previously suggested hypothesis that the adaptation mechanisms of VGS and MGS are distinct. Furthermore, the result suggests that the MGS adaptation site is a brain structure that influences saccade duration, whereas the VGS adaptation site influences saccade peak velocity. These results should be beneficial for future neurophysiological experiments.NEW & NOTEWORTHY Plasticity helps to overcome persistent motor errors. Such motor plasticity or adaptation can be investigated with saccades. Thus far our knowledge is primarily about visually guided saccades, an externally cued movement, which we can make only when the object is visible at the time of saccade. However, as the world is complex, we can make saccades even when the object is not visible. Here, we investigate the adaptation of an internally driven movement: the memory-guided saccade.
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Affiliation(s)
- Yoshiko Kojima
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington, United States
- Washington National Primate Research Center, University of Washington, Seattle, Washington, United States
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington, United States
| | - Hidetaka Yoshino
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington, United States
- Washington National Primate Research Center, University of Washington, Seattle, Washington, United States
| | - Leo Ling
- Washington National Primate Research Center, University of Washington, Seattle, Washington, United States
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington, United States
| | - James O Phillips
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington, United States
- Washington National Primate Research Center, University of Washington, Seattle, Washington, United States
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington, United States
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3
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Tarrit K, Freedman EG, Francisco AA, Horsthuis DJ, Molholm S, Foxe JJ. No evidence for differential saccadic adaptation in children and adults with an autism spectrum diagnosis. Front Integr Neurosci 2023; 17:1232474. [PMID: 37869448 PMCID: PMC10587467 DOI: 10.3389/fnint.2023.1232474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 08/24/2023] [Indexed: 10/24/2023] Open
Abstract
Background Altered patterns of eye-movements during scene exploration, and atypical gaze preferences in social settings, have long been noted as features of the Autism phenotype. While these are typically attributed to differences in social engagement and interests (e.g., preferences for inanimate objects over face stimuli), there are also reports of differential saccade measures to non-social stimuli, raising the possibility that fundamental differences in visuo-sensorimotor processing may be at play. Here, we tested the plasticity of the eye-movement system using a classic saccade-adaptation paradigm to assess whether individuals with ASD make typical adjustments to their eye-movements in response to experimentally introduced errors. Saccade adaptation can be measured in infants as young as 10 months, raising the possibility that such measures could be useful as early neuro-markers of ASD risk. Methods Saccade amplitudes were measured while children and adults with ASD (N = 41) and age-matched typically developing (TD) individuals (N = 68) made rapid eye-movements to peripherally presented targets. During adaptation trials, the target was relocated from 20-degrees to 15-degrees from fixation once a saccade to the original target location was initiated, a manipulation that leads to systematic reduction in saccade amplitudes in typical observers. Results Neither children nor adults with ASD showed any differences relative to TD peers in their abilities to appropriately adapt saccades in the face of persistently introduced errors. Conclusion Of the three studies to date of saccade adaptation in ASD, none have shown deficits in saccade adaptation that are sufficient to generalize to the whole or a subgroup of the ASD population. Unlike prior studies, we found no evidence for a slower adaptation rate during the early adaptation phase, and no of evidence greater variance of saccade amplitudes in ASD. In post hoc analysis, there was evidence for larger primary saccades to non-adapted targets, a finding requiring replication in future work.
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Affiliation(s)
- Katy Tarrit
- Information and Computer Sciences Department, University of Hawai’i at Manoa, Honolulu, HI, United States
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Edward G. Freedman
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Ana A. Francisco
- The Cognitive Neurophysiology Laboratory, Department of Pediatrics and Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Douwe J. Horsthuis
- The Cognitive Neurophysiology Laboratory, Department of Pediatrics and Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Sophie Molholm
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
- The Cognitive Neurophysiology Laboratory, Department of Pediatrics and Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States
| | - John J. Foxe
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
- The Cognitive Neurophysiology Laboratory, Department of Pediatrics and Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States
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Kojima Y, Koketsu D, May PJ. Activity of the Substantia Nigra Pars Reticulata during Saccade Adaptation. eNeuro 2023; 10:ENEURO.0092-23.2023. [PMID: 37596048 PMCID: PMC10500979 DOI: 10.1523/eneuro.0092-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 08/14/2023] [Accepted: 08/15/2023] [Indexed: 08/20/2023] Open
Abstract
When movements become inaccurate, the resultant error induces motor adaptation to improve accuracy. This error-based motor learning is regarded as a cerebellar function. However, the influence of the other brain areas on adaptation is poorly understood. During saccade adaptation, a type of error-based motor learning, the superior colliculus (SC) sends a postsaccadic error signal to the cerebellum to drive adaptation. Since the SC is directly inhibited by the substantia nigra pars reticulata (SNr), we hypothesized that the SNr might influence saccade adaptation by affecting the SC error signal. In fact, previous studies indicated that the SNr encodes motivation and motivation influences saccade adaptation. In this study, we first established that the SNr projects to the rostral SC, where small error signals are generated, in nonhuman primates. Then, we examined SNr activity while the animal underwent adaptation. SNr neurons paused their activity in association with the error. This pause was shallower and delayed compared with those of no-error trial saccades. The pause at the end of the adaptation was shallower and delayed compared with that at the beginning of the adaptation. The change in the intertrial interval, an indicator of motivation, and adaptation speed had a positive correlation with the changes in the error-related pause. These results suggest that (1) the SNr exhibits a unique activity pattern during the error interval; (2) SNr activity increases during adaptation, consistent with the decrease in SC activity; and (3) motivational decay during the adaptation session might increase SNr activity and influence the adaptation speed.
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Affiliation(s)
- Yoshiko Kojima
- Department of Otolaryngology-Head and Neck Surgery, Washington National Primate Research Center, University of Washington, Seattle, WA 98195
| | - Daisuke Koketsu
- Division of System Neurophysiology, National Institute for Physiological Sciences, Okazaki 444-8585, Japan
| | - Paul J May
- Department of Advanced Biomedical Education, University of Mississippi Medical Center, Jackson, MS 39216
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5
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Pomè A, Tyralla S, Zimmermann E. Altered oculomotor flexibility is linked to high autistic traits. Sci Rep 2023; 13:13032. [PMID: 37563189 PMCID: PMC10415324 DOI: 10.1038/s41598-023-40044-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 08/03/2023] [Indexed: 08/12/2023] Open
Abstract
Autism is a multifaced disorder comprising sensory abnormalities and a general inflexibility in the motor domain. The sensorimotor system is continuously challenged to answer whether motion-contingent errors result from own movements or whether they are due to external motion. Disturbances in this decision could lead to the perception of motion when there is none and to an inflexibility with regard to motor learning. Here, we test the hypothesis that altered processing of gaze-contingent sensations are responsible for both the motor inflexibility and the sensory overload in autism. We measured motor flexibility by testing how strong participants adapted in a classical saccade adaptation task. We asked healthy participants, scored for autistic traits, to make saccades to a target that was displaced either in inward or in outward direction during saccade execution. The amount of saccade adaptation, that requires to shift the internal target representation, varied with the autistic symptom severity. The higher participants scored for autistic traits, the less they adapted. In order to test for visual stability, we asked participants to localize the position of the saccade target after they completed their saccade. We found the often-reported saccade-induced mis-localization in low Autistic Quotient (AQ) participants. However, we also found mislocalization in high AQ participants despite the absence of saccade adaptation. Our data suggest that high autistic traits are associated with an oculomotor inflexibility that might produce altered processing of trans-saccadic vision which might increase the perceptual overstimulation that is experienced in autism spectrum disorders (ASD).
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Affiliation(s)
- Antonella Pomè
- Institute for Experimental Psychology, Heinrich Heine University Duesseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany.
| | - Sandra Tyralla
- Institute for Experimental Psychology, Heinrich Heine University Duesseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Eckart Zimmermann
- Institute for Experimental Psychology, Heinrich Heine University Duesseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
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6
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Masselink J, Cheviet A, Froment-Tilikete C, Pélisson D, Lappe M. A triple distinction of cerebellar function for oculomotor learning and fatigue compensation. PLoS Comput Biol 2023; 19:e1011322. [PMID: 37540726 PMCID: PMC10456158 DOI: 10.1371/journal.pcbi.1011322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 08/25/2023] [Accepted: 07/02/2023] [Indexed: 08/06/2023] Open
Abstract
The cerebellum implements error-based motor learning via synaptic gain adaptation of an inverse model, i.e. the mapping of a spatial movement goal onto a motor command. Recently, we modeled the motor and perceptual changes during learning of saccadic eye movements, showing that learning is actually a threefold process. Besides motor recalibration of (1) the inverse model, learning also comprises perceptual recalibration of (2) the visuospatial target map and (3) of a forward dynamics model that estimates the saccade size from corollary discharge. Yet, the site of perceptual recalibration remains unclear. Here we dissociate cerebellar contributions to the three stages of learning by modeling the learning data of eight cerebellar patients and eight healthy controls. Results showed that cerebellar pathology restrains short-term recalibration of the inverse model while the forward dynamics model is well informed about the reduced saccade change. Adaptation of the visuospatial target map trended in learning direction only in control subjects, yet without reaching significance. Moreover, some patients showed a tendency for uncompensated oculomotor fatigue caused by insufficient upregulation of saccade duration. According to our model, this could induce long-term perceptual compensation, consistent with the overestimation of target eccentricity found in the patients' baseline data. We conclude that the cerebellum mediates short-term adaptation of the inverse model, especially by control of saccade duration, while the forward dynamics model was not affected by cerebellar pathology.
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Affiliation(s)
- Jana Masselink
- Institute for Psychology & Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Münster, Münster, Germany
| | - Alexis Cheviet
- IMPACT Team, Lyon Neuroscience Research Center, University Claude Bernard Lyon 1, Bron cedex, France
- Department of Psychology, Durham University, South Road, Durham, United Kingdom
| | - Caroline Froment-Tilikete
- IMPACT Team, Lyon Neuroscience Research Center, University Claude Bernard Lyon 1, Bron cedex, France
- Hospices Civils de Lyon—Pierre-Wertheimer Hospital, Neuro-Ophtalmology Unit, Bron cedex, France
| | - Denis Pélisson
- IMPACT Team, Lyon Neuroscience Research Center, University Claude Bernard Lyon 1, Bron cedex, France
| | - Markus Lappe
- Institute for Psychology & Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Münster, Münster, Germany
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7
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Markanday A, Hong S, Inoue J, De Schutter E, Thier P. Multidimensional cerebellar computations for flexible kinematic control of movements. Nat Commun 2023; 14:2548. [PMID: 37137897 PMCID: PMC10156706 DOI: 10.1038/s41467-023-37981-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/07/2023] [Indexed: 05/05/2023] Open
Abstract
Both the environment and our body keep changing dynamically. Hence, ensuring movement precision requires adaptation to multiple demands occurring simultaneously. Here we show that the cerebellum performs the necessary multi-dimensional computations for the flexible control of different movement parameters depending on the prevailing context. This conclusion is based on the identification of a manifold-like activity in both mossy fibers (MFs, network input) and Purkinje cells (PCs, output), recorded from monkeys performing a saccade task. Unlike MFs, the PC manifolds developed selective representations of individual movement parameters. Error feedback-driven climbing fiber input modulated the PC manifolds to predict specific, error type-dependent changes in subsequent actions. Furthermore, a feed-forward network model that simulated MF-to-PC transformations revealed that amplification and restructuring of the lesser variability in the MF activity is a pivotal circuit mechanism. Therefore, the flexible control of movements by the cerebellum crucially depends on its capacity for multi-dimensional computations.
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Affiliation(s)
- Akshay Markanday
- Hertie Institute for Clinical Brain Research, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Sungho Hong
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Junya Inoue
- Hertie Institute for Clinical Brain Research, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Erik De Schutter
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Peter Thier
- Hertie Institute for Clinical Brain Research, Eberhard Karls University Tübingen, Tübingen, Germany.
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8
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Bosco A, Sanz Diez P, Filippini M, Fattori P. The influence of action on perception spans different effectors. Front Syst Neurosci 2023; 17:1145643. [PMID: 37205054 PMCID: PMC10185787 DOI: 10.3389/fnsys.2023.1145643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 04/10/2023] [Indexed: 05/21/2023] Open
Abstract
Perception and action are fundamental processes that characterize our life and our possibility to modify the world around us. Several pieces of evidence have shown an intimate and reciprocal interaction between perception and action, leading us to believe that these processes rely on a common set of representations. The present review focuses on one particular aspect of this interaction: the influence of action on perception from a motor effector perspective during two phases, action planning and the phase following execution of the action. The movements performed by eyes, hands, and legs have a different impact on object and space perception; studies that use different approaches and paradigms have formed an interesting general picture that demonstrates the existence of an action effect on perception, before as well as after its execution. Although the mechanisms of this effect are still being debated, different studies have demonstrated that most of the time this effect pragmatically shapes and primes perception of relevant features of the object or environment which calls for action; at other times it improves our perception through motor experience and learning. Finally, a future perspective is provided, in which we suggest that these mechanisms can be exploited to increase trust in artificial intelligence systems that are able to interact with humans.
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Affiliation(s)
- Annalisa Bosco
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
- Alma Mater Research Institute for Human-Centered Artificial Intelligence (Alma Human AI), University of Bologna, Bologna, Italy
- *Correspondence: Annalisa Bosco
| | - Pablo Sanz Diez
- Carl Zeiss Vision International GmbH, Aalen, Germany
- Institute for Ophthalmic Research, Eberhard Karls University Tüebingen, Tüebingen, Germany
| | - Matteo Filippini
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Patrizia Fattori
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
- Alma Mater Research Institute for Human-Centered Artificial Intelligence (Alma Human AI), University of Bologna, Bologna, Italy
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Agaoglu MN, Fung W, Chung STL. Oculomotor responses of the visual system to an artificial central scotoma may not represent genuine visuomotor adaptation. J Vis 2022; 22:17. [PMID: 36136045 PMCID: PMC9513737 DOI: 10.1167/jov.22.10.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Patients with central vision loss often adopt a location outside their scotoma as the new reference for vision, the preferred retinal locus (PRL). The development of a PRL is important not only for the rehabilitation of patients with central vision loss, but also helps us better understand how the brain adapts to the lack of visual input. Many investigators studied this question using a gaze-contingent display paradigm by imposing an artificial scotoma to simulate central vision loss for normally sighted subjects, with an important assumption that the “PRL” thus developed is the result of visuomotor adaptation, as is the case for people with a real scotoma. In this study, we tested the validity of this assumption. We used a gaze-contingent display combined with an artificial scotoma to first train normally sighted subjects to develop a “PRL” for saccade eye movements. Then, we compared the properties of saccades when the artificial scotoma was randomly turned off or on. When the artificial scotoma was absent, subjects automatically reverted to using their fovea, with a shorter saccade latency. Our findings suggest that the development of a “PRL” in response to an artificial scotoma may represent a strategy, instead of a genuine visuomotor adaptation.
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Affiliation(s)
- Mehmet N Agaoglu
- School of Optometry, University of California Berkeley, Berkeley, CA, USA.,
| | - Wai Fung
- School of Optometry, University of California Berkeley, Berkeley, CA, USA.,
| | - Susana T L Chung
- School of Optometry, University of California Berkeley, Berkeley, CA, USA.,
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Duménieu M, Marquèze-Pouey B, Russier M, Debanne D. Mechanisms of Plasticity in Subcortical Visual Areas. Cells 2021; 10:3162. [PMID: 34831385 PMCID: PMC8621502 DOI: 10.3390/cells10113162] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/10/2021] [Accepted: 11/11/2021] [Indexed: 01/10/2023] Open
Abstract
Visual plasticity is classically considered to occur essentially in the primary and secondary cortical areas. Subcortical visual areas such as the dorsal lateral geniculate nucleus (dLGN) or the superior colliculus (SC) have long been held as basic structures responsible for a stable and defined function. In this model, the dLGN was considered as a relay of visual information travelling from the retina to cortical areas and the SC as a sensory integrator orienting body movements towards visual targets. However, recent findings suggest that both dLGN and SC neurons express functional plasticity, adding unexplored layers of complexity to their previously attributed functions. The existence of neuronal plasticity at the level of visual subcortical areas redefines our approach of the visual system. The aim of this paper is therefore to review the cellular and molecular mechanisms for activity-dependent plasticity of both synaptic transmission and cellular properties in subcortical visual areas.
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Affiliation(s)
| | | | | | - Dominique Debanne
- INSERM, Aix-Marseille Université, UNIS, 13015 Marseille, France; (M.D.); (B.M.-P.); (M.R.)
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11
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Van der Stigchel S, Schut MJ, Fabius J, Van der Stoep N. Transsaccadic perception is affected by saccade landing point deviations after saccadic adaptation. J Vis 2021; 20:8. [PMID: 32915955 PMCID: PMC7488614 DOI: 10.1167/jov.20.9.8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Whenever we move our eyes, some visual information obtained before a saccade is combined with the visual information obtained after a saccade. Interestingly, saccades rarely land exactly on the saccade target, which may pose a problem for transsaccadic perception as it could affect the quality of postsaccadic input. Recently, however, we showed that transsaccadic feature integration is actually unaffected by deviations of saccade landing points. Possibly, transsaccadic integration remains unaffected because the presaccadic shift of attention follows the intended saccade target and not the actual saccade landing point during regular saccades. Here, we investigated whether saccade landing point errors can in fact alter transsaccadic perception when the presaccadic shift of attention follows the saccade landing point deviation. Given that saccadic adaptation not only changes the saccade vector, but also the presaccadic shift of attention, we combined a feature report paradigm with saccadic adaptation. Observers reported the color of the saccade target, which occasionally changed slightly during a saccade to the target. This task was performed before and after saccadic adaptation. The results showed that, after adaptation, presaccadic color information became less precise and transsaccadic perception had a stronger reliance on the postsaccadic color estimate. Therefore, although previous studies have shown that transsaccadic perception is generally unaffected by saccade landing point deviations, our results reveal that this cannot be considered a general property of the visual system. When presaccadic shifts of attention follow altered saccade landing points, transsaccadic perception is affected, suggesting that transsaccadic feature perception might be dependent on visual spatial attention.
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Affiliation(s)
| | - Martijn J Schut
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, The Netherlands
| | - Jasper Fabius
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, The Netherlands
| | - Nathan Van der Stoep
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, The Netherlands
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12
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Abstract
Since most gaze shifts are to targets that lie at a different distance from the viewer than the current target, gaze changes commonly require a change in the angle between the eyes. As part of this response, lens curvature must also be adjusted with respect to target distance by the ciliary muscle. It has been suggested that projections by the cerebellar fastigial and posterior interposed nuclei to the supraoculomotor area (SOA), which lies immediately dorsal to the oculomotor nucleus and contains near response neurons, support this behavior. However, the SOA also contains motoneurons that supply multiply innervated muscle fibers (MIFs) and the dendrites of levator palpebrae superioris motoneurons. To better determine the targets of the fastigial nucleus in the SOA, we placed an anterograde tracer into this cerebellar nucleus in Macaca fascicularis monkeys and a retrograde tracer into their contralateral medial rectus, superior rectus, and levator palpebrae muscles. We only observed close associations between anterogradely labeled boutons and the dendrites of medial rectus MIF and levator palpebrae motoneurons. However, relatively few of these associations were present, suggesting these are not the main cerebellar targets. In contrast, labeled boutons in SOA, and in the adjacent central mesencephalic reticular formation (cMRF), densely innervated a subpopulation of neurons. Based on their location, these cells may represent premotor near response neurons that supply medial rectus and preganglionic Edinger-Westphal motoneurons. We also identified lens accommodation-related cerebellar afferent neurons via retrograde trans-synaptic transport of the N2c rabies virus from the ciliary muscle. They were found bilaterally in the fastigial and posterior interposed nuclei, in a distribution which mirrored that of neurons retrogradely labeled from the SOA and cMRF. Our results suggest these cerebellar neurons coordinate elements of the near response during symmetric vergence and disjunctive saccades by targeting cMRF and SOA premotor neurons.
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The Substantia Nigra Pars Reticulata Modulates Error-Based Saccadic Learning in Monkeys. eNeuro 2021; 8:ENEURO.0519-20.2021. [PMID: 33707204 PMCID: PMC8114898 DOI: 10.1523/eneuro.0519-20.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/24/2021] [Accepted: 03/01/2021] [Indexed: 11/21/2022] Open
Abstract
The basal ganglia have long been considered crucial for associative learning, but whether they also are involved in another type of learning, error-based motor learning, is not clear. Error-based learning has been considered the province of the cerebellum. However, learning to use a robotic arm and saccade adaptation, which use error-based learning, are facilitated by motivation, which is a function of the basal ganglia. Additionally, patients with Parkinson’s disease, a basal ganglia deficit, show slower saccade adaptation than age matched controls. To further investigate whether the basal ganglia actually influence error-based learning, we reversibly inactivated the oculomotor portion of the substantia nigra pars reticulata (SNr) in two monkeys and tested saccade adaptation. Here, we show that nigral inactivation affected saccade adaptation. In particular, the inactivation facilitated the amplitude decrease adaptation of ipsiversive saccades. Consistent with previous studies, no effect was seen on the amplitude of the ipsiversive saccades when we did not induce adaptation. Therefore, the facilitated adaptation was not caused by inactivation directly modulating ipsiversive saccades. On the other hand, the kinematics of corrective saccades, which represent error processing, were changed after the inactivation. Thus, our data suggest that the oculomotor SNr assists saccade adaptation by strengthening the error signal. This effect indicates the basal ganglia influence error-based motor learning, a previously unrecognized function.
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Masselink J, Lappe M. Visuomotor learning from postdictive motor error. eLife 2021; 10:64278. [PMID: 33687328 PMCID: PMC8057815 DOI: 10.7554/elife.64278] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 03/04/2021] [Indexed: 01/02/2023] Open
Abstract
Sensorimotor learning adapts motor output to maintain movement accuracy. For saccadic eye movements, learning also alters space perception, suggesting a dissociation between the performed saccade and its internal representation derived from corollary discharge (CD). This is critical since learning is commonly believed to be driven by CD-based visual prediction error. We estimate the internal saccade representation through pre- and trans-saccadic target localization, showing that it decouples from the actual saccade during learning. We present a model that explains motor and perceptual changes by collective plasticity of spatial target percept, motor command, and a forward dynamics model that transforms CD from motor into visuospatial coordinates. We show that learning does not follow visual prediction error but instead a postdictive update of space after saccade landing. We conclude that trans-saccadic space perception guides motor learning via CD-based postdiction of motor error under the assumption of a stable world.
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Affiliation(s)
- Jana Masselink
- Institute for Psychology and Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Muenster, Münster, Germany
| | - Markus Lappe
- Institute for Psychology and Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Muenster, Münster, Germany
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Neugebauer A, Stingl K, Ivanov I, Wahl S. Influence of Systematic Gaze Patterns in Navigation and Search Tasks with Simulated Retinitis Pigmentosa. Brain Sci 2021; 11:brainsci11020223. [PMID: 33673036 PMCID: PMC7917782 DOI: 10.3390/brainsci11020223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 12/29/2022] Open
Abstract
People living with a degenerative retinal disease such as retinitis pigmentosa are oftentimes faced with difficulties navigating in crowded places and avoiding obstacles due to their severely limited field of view. The study aimed to assess the potential of different patterns of eye movement (scanning patterns) to (i) increase the effective area of perception of participants with simulated retinitis pigmentosa scotoma and (ii) maintain or improve performance in visual tasks. Using a virtual reality headset with eye tracking, we simulated tunnel vision of 20° in diameter in visually healthy participants (n = 9). Employing this setup, we investigated how different scanning patterns influence the dynamic field of view—the average area over time covered by the field of view—of the participants in an obstacle avoidance task and in a search task. One of the two tested scanning patterns showed a significant improvement in both dynamic field of view (navigation 11%, search 7%) and collision avoidance (33%) when compared to trials without the suggested scanning pattern. However, participants took significantly longer (31%) to finish the navigation task when applying this scanning pattern. No significant improvements in search task performance were found when applying scanning patterns.
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Affiliation(s)
- Alexander Neugebauer
- ZEISS Vision Science Lab., Institute for Ophthalmic Research, Eberhard-Karls-University Tuebingen, 72076 Tuebingen, Germany;
- Correspondence:
| | - Katarina Stingl
- Center for Ophthalmology, University Eye Hospital, Eberhard Karls University Tuebingen, 72076 Tuebingen, Germany;
- Center for Rare Eye Diseases, Eberhard Karls University Tuebingen, 72076 Tuebingen, Germany
| | - Iliya Ivanov
- Carl Zeiss Vision International GmbH, 73430 Aalen, Germany;
| | - Siegfried Wahl
- ZEISS Vision Science Lab., Institute for Ophthalmic Research, Eberhard-Karls-University Tuebingen, 72076 Tuebingen, Germany;
- Carl Zeiss Vision International GmbH, 73430 Aalen, Germany;
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16
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Gheorghe DA, Panouillères MTN, Walsh ND. Investigating the effects of cerebellar transcranial direct current stimulation on saccadic adaptation and cortisol response. CEREBELLUM & ATAXIAS 2021; 8:1. [PMID: 33397502 PMCID: PMC7784285 DOI: 10.1186/s40673-020-00124-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 11/30/2020] [Indexed: 12/17/2022]
Abstract
BACKGROUND Transcranial Direct Current Stimulation (tDCS) over the prefrontal cortex has been shown to modulate subjective, neuronal and neuroendocrine responses, particularly in the context of stress processing. However, it is currently unknown whether tDCS stimulation over other brain regions, such as the cerebellum, can similarly affect the stress response. Despite increasing evidence linking the cerebellum to stress-related processing, no studies have investigated the hormonal and behavioural effects of cerebellar tDCS. METHODS This study tested the hypothesis of a cerebellar tDCS effect on mood, behaviour and cortisol. To do this we employed a single-blind, sham-controlled design to measure performance on a cerebellar-dependent saccadic adaptation task, together with changes in cortisol output and mood, during online anodal and cathodal stimulation. Forty-five participants were included in the analysis. Stimulation groups were matched on demographic variables, potential confounding factors known to affect cortisol levels, mood and a number of personality characteristics. RESULTS Results showed that tDCS polarity did not affect cortisol levels or subjective mood, but did affect behaviour. Participants receiving anodal stimulation showed an 8.4% increase in saccadic adaptation, which was significantly larger compared to the cathodal group (1.6%). CONCLUSION The stimulation effect on saccadic adaptation contributes to the current body of literature examining the mechanisms of cerebellar stimulation on associated function. We conclude that further studies are needed to understand whether and how cerebellar tDCS may module stress reactivity under challenge conditions.
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Affiliation(s)
- Delia A. Gheorghe
- School of Psychology, University of East Anglia, Norwich, UK
- Department of Psychiatry, University of Oxford, Oxford, UK
| | - Muriel T. N. Panouillères
- Department of Experimental Psychology, University of Oxford, Oxford, UK
- CIAMS, Université Paris-Saclay, 91405 Orsay Cedex, France
- CIAMS, Université d’Orléans, 45067 Orléans, France
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Bey K, Lippold JV, Aslan B, Hurlemann R, Ettinger U. Effects of lorazepam on prosaccades and saccadic adaptation. J Psychopharmacol 2021; 35:91-99. [PMID: 33274663 DOI: 10.1177/0269881120972424] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Benzodiazepines have reliable adverse effects on saccadic eye movements, but the impact of sex as a potential modulator of these effects is less clear. A recent study reported stronger adverse effects on the spatial consistency of saccades in females, which may reflect sex differences in cerebellar mechanisms. AIMS We aimed to further examine the role of sex as a potential modulator of benzodiazepine effects by employing the saccadic adaptation paradigm, which is known to be sensitive to cerebellar functioning. METHODS A total of n=50 healthy adults performed a horizontal step prosaccade task and a saccadic adaptation task under 0.5 mg lorazepam, 1 mg lorazepam and placebo in a double-blind, within-subjects design. RESULTS In the prosaccade task, lorazepam had adverse effects on measures of peak velocity, latency and spatial consistency. The administration of 0.5 mg lorazepam led to significant reductions in gain-decrease adaptation, while a dose of 1 mg did not impair adaptation learning. Gain-increase adaptation was generally less pronounced, and unaffected by the drug. There were no significant drug×sex interactions in either task. CONCLUSIONS We conclude that a low dose of lorazepam impairs gain-decrease adaptation independent of sex. At higher doses, however, increasing fatigue may facilitate adaptation and thus counteract the adverse effects observed at lower doses. With regards to prosaccades, our findings confirm peak velocity as well as latency and spatial measures as sensitive biomarkers of GABAergic effects.
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Affiliation(s)
- Katharina Bey
- Department of Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany
| | | | - Behrem Aslan
- Department of Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany
| | - René Hurlemann
- Department of Psychiatry, University of Oldenburg, Bad Zwischenahn, Germany.,Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
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Valsecchi M, Cassanello C, Herwig A, Rolfs M, Gegenfurtner KR. A comparison of the temporal and spatial properties of trans-saccadic perceptual recalibration and saccadic adaptation. J Vis 2020; 20:2. [PMID: 32271892 PMCID: PMC7409593 DOI: 10.1167/jov.20.4.2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Repeated exposure to a consistent trans-saccadic step in the position of the saccadic target reliably produces a change of saccadic gain, a well-established trans-saccadic motor learning phenomenon known as saccadic adaptation. Trans-saccadic changes can also produce perceptual effects. Specifically, a systematic increase or decrease in the size of the object that is being foveated changes the perceptually equivalent size between fovea and periphery. Previous studies have shown that this recalibration of perceived size can be established within a few dozen trials, persists overnight, and generalizes across hemifields. In the current study, we use a novel adjustment paradigm to characterize both temporally and spatially the learning process that subtends this form of recalibration, and directly compare its properties to those of saccadic adaptation. We observed that sinusoidal oscillations in the amplitude of the trans-saccadic change produce sinusoidal oscillations in the reported peripheral size, with a lag of under 10 trials. This is qualitatively similar to what has been observed in the case of saccadic adaptation. We also tested whether learning is generalized to the mirror location on the opposite hemifield for both size recalibration and saccade adaptation. Here the results were markedly different, showing almost complete generalization for recalibration and no generalization for saccadic adaptation. We conclude that perceptual and visuomotor consequences of trans-saccadic changes rely on learning mechanisms that are distinct but develop on similar time scales.
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Nault DR, Munhall KG. Individual variability in auditory feedback processing: Responses to real-time formant perturbations and their relation to perceptual acuity. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 148:3709. [PMID: 33379900 DOI: 10.1121/10.0002923] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 11/25/2020] [Indexed: 06/12/2023]
Abstract
In this study, both between-subject and within-subject variability in speech perception and speech production were examined in the same set of speakers. Perceptual acuity was determined using an ABX auditory discrimination task, whereby speakers made judgments between pairs of syllables on a /ɛ/ to /æ/ acoustic continuum. Auditory feedback perturbations of the first two formants were implemented in a production task to obtain measures of compensation, normal speech production variability, and vowel spacing. Speakers repeated the word "head" 120 times under varying feedback conditions, with the final Hold phase involving the strongest perturbations of +240 Hz in F1 and -300 Hz in F2. Multiple regression analyses were conducted to determine whether individual differences in compensatory behavior in the Hold phase could be predicted by perceptual acuity, speech production variability, and vowel spacing. Perceptual acuity significantly predicted formant changes in F1, but not in F2. These results are discussed in consideration of the importance of using larger sample sizes in the field and developing new methods to explore feedback processing at the individual participant level. The potential positive role of variability in speech motor control is also considered.
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Affiliation(s)
- Daniel R Nault
- Department of Psychology, Queen's University, Humphrey Hall, 62 Arch Street, Kingston, Ontario, K7L 3N6, Canada
| | - Kevin G Munhall
- Department of Psychology, Queen's University, Humphrey Hall, 62 Arch Street, Kingston, Ontario, K7L 3N6, Canada
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Kalidindi HT, Vannucci L, Laschi C, Falotico E. Cerebellar adaptive mechanisms explain the optimal control of saccadic eye movements. BIOINSPIRATION & BIOMIMETICS 2020; 16:016004. [PMID: 33150874 DOI: 10.1088/1748-3190/abae7f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Cerebellar synaptic plasticity is vital for adaptability and fine tuning of goal-directed movements. The perceived sensory errors between desired and actual movement outcomes are commonly considered to induce plasticity in the cerebellar synapses, with an objective to improve desirability of the executed movements. In rapid goal-directed eye movements called saccades, the only available sensory feedback is the direction of reaching error information received only at end of the movement. Moreover, this sensory error dependent plasticity can only improve the accuracy of the movements, while ignoring other essential characteristics such as reaching in minimum-time. In this work we propose a rate based, cerebellum inspired adaptive filter model to address refinement of both accuracy and movement-time of saccades. We use optimal control approach in conjunction with information constraints posed by the cerebellum to derive bio-plausible supervised plasticity rules. We implement and validate this bio-inspired scheme on a humanoid robot. We found out that, separate plasticity mechanisms in the model cerebellum separately control accuracy and movement-time. These plasticity mechanisms ensure that optimal saccades are produced by just receiving the direction of end reaching error as an evaluative signal. Furthermore, the model emulates encoding in the cerebellum of movement kinematics as observed in biological experiments.
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Affiliation(s)
- Hari Teja Kalidindi
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, Pontedera, 56025, Italy
| | - Lorenzo Vannucci
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, Pontedera, 56025, Italy
| | - Cecilia Laschi
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, Pontedera, 56025, Italy
| | - Egidio Falotico
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, Pontedera, 56025, Italy
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21
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van Leeuwen J, Belopolsky AV. Rapid spatial oculomotor updating across saccades is malleable. Vision Res 2020; 178:60-69. [PMID: 33115692 DOI: 10.1016/j.visres.2020.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 07/18/2020] [Accepted: 09/16/2020] [Indexed: 11/19/2022]
Abstract
The oculomotor system uses a sophisticated updating mechanism to adjust for large retinal displacements which occur with every saccade. Previous studies have shown that updating operates rapidly and starts before saccade is initiated. Here we used saccade adaptation to alter life-long expectations about how a saccade changes the location of an object on the retina. Participants made a sequence of one horizontal and one vertical saccade and ignored an irrelevant distractor. The time-course of oculomotor updating was estimated using saccade curvature of the vertical saccade, relative to the distractor. During the first saccade both saccade targets were shifted on 80% of trials, which induced saccade adaptation (Experiment 1). Critically, since the distractor was left stationary, successful saccade adaptation (e.g., saccade becoming shorter) meant that after the first saccade the distractor appeared in a different hemifield than without adaptation. After adaptation, second saccades curved away only from the newly learned distractor location starting at 80 ms after the first saccade. When on the minority of trials (20%) the targets were not shifted, saccades again first curved away from the newly learned (now empty) location, but then quickly switched to curving away from the life-long learned, visible location. When on some trials the distractor was removed during the first saccade, saccades curved away only from the newly learned (but empty) location (Experiment 2). The results show that updating of locations across saccades is not only fast, but is highly malleable, relying on recently learned sensorimotor contingencies.
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Affiliation(s)
- Jonathan van Leeuwen
- Department of Experimental and Applied Psychology, Vrije Universiteit, Amsterdam, The Netherlands.
| | - Artem V Belopolsky
- Department of Experimental and Applied Psychology, Vrije Universiteit, Amsterdam, The Netherlands
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22
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Vencato V, Madelain L. Perception of saccadic reaction time. Sci Rep 2020; 10:17192. [PMID: 33057041 PMCID: PMC7560701 DOI: 10.1038/s41598-020-72659-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 08/07/2020] [Indexed: 12/02/2022] Open
Abstract
That saccadic reaction times (SRTs) may depend on reinforcement contingencies has been repeatedly demonstrated. It follows that one must be able to discriminate one's latencies to adequately assign credit to one's actions, which is to connect behaviour to its consequence. To quantify the ability to perceive one's SRT, we used an adaptive procedure to train sixteen participants in a stepping visual target saccade paradigm. Subsequently, we measured their RTs perceptual threshold at 75% in a conventional constant stimuli procedure. For each trial, observers had to saccade to a stepping target. Then, in a 2-AFC task, they had to choose one value representing the actual SRT, while the other value proportionally differed from the actual SRT. The relative difference between the two alternatives was computed by either adding or subtracting from the actual SRT a percent-difference value randomly chosen among a fixed set. Feedback signalling the correct choice was provided after each response. Overall, our results showed that the 75% SRT perceptual threshold averaged 23% (about 40 ms). The ability to discriminate small SRT differences provides support for the possibility that the credit assignment problem may be solved even for short reaction times.
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Affiliation(s)
- Valentina Vencato
- UMR 9193-SCALab, CNRS, Univ. Lille, 59000, Lille, France.
- Institut de Neurosciences de la Timone, UMR 7289, CNRS, Faculté de Médecine de la Timone, Aix Marseille Université, 27 Bd Jean Moulin, Marseille, 13005, France.
| | - Laurent Madelain
- UMR 9193-SCALab, CNRS, Univ. Lille, 59000, Lille, France
- Institut de Neurosciences de la Timone, UMR 7289, CNRS, Faculté de Médecine de la Timone, Aix Marseille Université, 27 Bd Jean Moulin, Marseille, 13005, France
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Saccadic adaptation shapes perceived size: Common codes for action and perception. Atten Percept Psychophys 2020; 82:3676-3685. [PMID: 32725486 DOI: 10.3758/s13414-020-02102-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recent findings suggest that perceptual and motor systems share common codes; for instance, perceived object location is known to correlate with motor changes in the oculomotor system. Here, we investigate whether modifying saccade amplitude affects object size perception. Participants saw in peripheral vision a test disk that could vary in size across trials. This disk was then replaced by a small target cross, which was the signal to make a saccade. After the saccade, the target cross was extinguished and replaced by a reference disk (thus seen in foveal vision). Participants had to compare the post- to the pre-saccade disk sizes. Psychometric functions were obtained before and after one session of 142 saccades made toward the cross that either stepped toward the fixation point during the saccade (backward adaptation group) or remained stationary (control group). In the experimental group, stepping the target cross toward fixation during saccades decreased movement amplitude, a phenomenon called saccadic adaptation. We observed a concurrent shift in the psychometric functions reflecting a decrease in perceived object size. Such a perceptual modification did not occur in the control group. Our results reveal that motor changes co-occur with changes in perceived object size. Unlike previous studies evaluating the impact of saccadic adaptation on perceived location, we measured here the perception of another spatial feature (the object size) that is not relevant for the sensorimotor transformation. Theoretical implications of the strong links between oculomotor parameters and object perception are discussed.
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Xie XY, Liu L, Yu C. A new perceptual training strategy to improve vision impaired by central vision loss. Vision Res 2020; 174:69-76. [PMID: 32615458 DOI: 10.1016/j.visres.2020.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 10/24/2022]
Abstract
Patients with central vision loss depend on peripheral vision for everyday functions. A preferred retinal locus (PRL) on the intact retina is commonly trained as a new "fovea" to help. However, reprogramming the fovea-centered oculomotor control is difficult, so saccades often bring the defunct fovea to block the target. Aligning PRL with distant targets also requires multiple saccades and sometimes head movements. To overcome these problems, we attempted to train normal-sighted observers to form a preferred retinal annulus (PRA) around a simulated scotoma, so that they could rely on the same fovea-centered oculomotor system and make short saccades to align PRA with the target. Observers with an invisible simulated central scotoma (5° radius) practiced making saccades to see a tumbling-E target at 10° eccentricity. The otherwise blurred E target became clear when saccades brought a scotoma-abutting clear window (2° radius) to it. The location of the clear window was either fixed for PRL training, or changing among 12 locations for PRA training. Various cues aided the saccades through training. Practice quickly established a PRL or PRA. Comparing to PRL-trained observers whose first saccade persistently blocked the target with scotoma, PRA-trained observers produced more accurate first saccade. The benefits of more accurate PRA-based saccades also outweighed the costs of slower latency. PRA training may provide an efficient strategy to cope with central vision loss, especially for aging patients who have major difficulties adapting to a PRL.
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Affiliation(s)
- Xin-Yu Xie
- School of Psychology, IDG/McGovern Institute of Brain Research, and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Lei Liu
- School of Optometry, University of Alabama at Birmingham, Birmingham, AL, United States.
| | - Cong Yu
- School of Psychology, IDG/McGovern Institute of Brain Research, and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China.
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Kosovicheva A, Bex PJ. Perceptual effects of unequal saccadic adaptation produced by a dichoptic step. J Vis 2020; 20:7. [PMID: 32428198 PMCID: PMC7409615 DOI: 10.1167/jov.20.5.7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 03/02/2020] [Indexed: 11/24/2022] Open
Abstract
The binocular coordination of eye movements in a three-dimensional environment involves a combination of saccade and vergence movements. To maintain binocular accuracy and control in the face of sensory and motor changes (that occur with e.g., normal aging, surgery, corrective lenses), the oculomotor system must adapt in response to manifest visual errors. This may be achieved through a combination of binocular and monocular mechanisms, including the recalibration of saccade and vergence amplitudes in response to different visual errors induced in each eye (Maiello, Harrison, & Bex, 2016). This work has used a double-step paradigm to recalibrate eye movements in response to visual errors produced by dichoptic target steps (e.g., leftward in the left eye and rightward in the right eye). Here, we evaluated the immediate perceptual effects of this adaptation. Experiment 1 measured localization errors following adaptation by comparing the apparent locations of pre- and postsaccadic probes. Consistent with previous work showing localization errors following saccadic adaptation, our results demonstrated that adaptation to a dichoptic step produces different localization errors in the two eyes. Furthermore, in Experiment 2, this effect was reduced for a vergence shift in the absence of a saccade, indicating that saccade programming is responsible for a large component of this illusory shift. Experiment 3 measured postsaccadic stereopsis thresholds and indicated that, unlike localization judgments, adaptation did not influence stereoacuity. Together, these results demonstrate novel dichoptic visual errors following oculomotor adaptation and point to monocular and binocular mechanisms involved in the maintenance of binocular coordination.
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Affiliation(s)
- Anna Kosovicheva
- Department of Psychology, Northeastern University, Boston, MA, USA
| | - Peter J. Bex
- Department of Psychology, Northeastern University, Boston, MA, USA
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Souto D, Schütz AC. Task-relevance is causal in eye movement learning and adaptation. PSYCHOLOGY OF LEARNING AND MOTIVATION 2020. [DOI: 10.1016/bs.plm.2020.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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27
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The influence of bistable auditory feedback on speech motor control. Exp Brain Res 2019; 237:3155-3163. [DOI: 10.1007/s00221-019-05657-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 09/18/2019] [Indexed: 10/25/2022]
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Nicolas J, Bidet-Caulet A, Pélisson D. Inducing oculomotor plasticity to disclose the functional link between voluntary saccades and endogenous attention deployed perifoveally. Sci Rep 2019; 9:17770. [PMID: 31780727 PMCID: PMC6882914 DOI: 10.1038/s41598-019-54256-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 11/04/2019] [Indexed: 11/26/2022] Open
Abstract
To what extent oculomotor and attention systems are linked remains strongly debated. Previous studies suggested that saccadic adaptation, a well-studied model of oculomotor plasticity, and orienting of attention rely on overlapping networks in the parietal cortex and can functionally interact. Using a Posner-like paradigm in healthy human subjects, we demonstrate for the first time that saccadic adaptation boosts endogenous attention orienting. Indeed, the discrimination of perifoveal targets benefits more from central cues after backward adaptation of leftward voluntary saccades than after a control saccade task. We propose that the overlap of underlying neural networks actually consists of neuronal populations co-activated by oculomotor plasticity and endogenous attention deployed perifoveally. The functional coupling demonstrated here plaids for conceptual models not belonging to the framework of the premotor theory of attention as the latter has been rejected precisely for this voluntary/endogenous modality. These results also open new perspective for rehabilitation of visuo-attentional deficits.
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Affiliation(s)
- Judith Nicolas
- Integrative Multisensory Perception Action & Cognition Team (ImpAct), Lyon Neuroscience Research Center (CRNL), INSERM U1028, CNRS UMR5292, 69500, Bron, France. .,Brain Dynamics and Cognition (Dycog Team), Lyon Neuroscience Research Center (CRNL), INSERM U1028, CNRS UMR5292, 69500, Bron, France. .,University Claude Bernard Lyon 1, Université de Lyon, 69000, Lyon, France.
| | - Aurélie Bidet-Caulet
- Brain Dynamics and Cognition (Dycog Team), Lyon Neuroscience Research Center (CRNL), INSERM U1028, CNRS UMR5292, 69500, Bron, France.,University Claude Bernard Lyon 1, Université de Lyon, 69000, Lyon, France
| | - Denis Pélisson
- Integrative Multisensory Perception Action & Cognition Team (ImpAct), Lyon Neuroscience Research Center (CRNL), INSERM U1028, CNRS UMR5292, 69500, Bron, France.,University Claude Bernard Lyon 1, Université de Lyon, 69000, Lyon, France
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Gremmler S, Lappe M. Postsaccadic eye position contributes to oculomotor error estimation in saccadic adaptation. J Neurophysiol 2019; 122:1909-1917. [PMID: 31533010 DOI: 10.1152/jn.00095.2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated whether the proprioceptive eye position signal after the execution of a saccadic eye movement is used to estimate the accuracy of the movement. If so, saccadic adaptation, the mechanism that maintains saccade accuracy, could use this signal in a similar way as it uses visual feedback after the saccade. To manipulate the availability of the proprioceptive eye position signal we utilized the finding that proprioceptive eye position information builds up gradually after a saccade over a time interval comparable to typical saccade latencies. We confined the retention time of gaze at the saccade landing point by asking participants to make fast return saccades to the fixation point that preempt the usability of proprioceptive eye position signals. In five experimental conditions we measured the influence of the visual and proprioceptive feedback, together and separately, on the development of adaptation. We found that the adaptation of the previously shortened saccades in the case of visual feedback being unavailable after the saccade was significantly weaker when the use of proprioceptive eye position information was impaired by fast return saccades. We conclude that adaptation can be driven by proprioceptive eye position feedback.NEW & NOTEWORTHY We show that proprioceptive eye position information is used after a saccade to estimate motor error and adapt saccade control. Previous studies on saccadic adaptation focused on visual feedback about saccade accuracy. A multimodal error signal combining visual and proprioceptive information is likely more robust. Moreover, combining proprioceptive and visual measures of saccade performance can be helpful to keep vision, proprioception, and motor control in alignment and produce a coherent representation of space.
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Affiliation(s)
- Svenja Gremmler
- Institute of Psychology, University of Münster, Münster, Germany.,Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Münster, Münster, Germany
| | - Markus Lappe
- Institute of Psychology, University of Münster, Münster, Germany.,Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Münster, Münster, Germany
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30
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A differential role for the posterior cerebellum in the adaptive control of convergence eye movements. Brain Stimul 2019; 13:215-228. [PMID: 31427273 DOI: 10.1016/j.brs.2019.07.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 06/15/2019] [Accepted: 07/26/2019] [Indexed: 11/21/2022] Open
Abstract
INTRODUCTION The vergence oculomotor system possesses two robust adaptive mechanisms; a fast "dynamic" and a slow "tonic" system that are both vital for single, clear and comfortable binocular vision. The neural substrates underlying these vergence adaptive mechanisms in humans is unclear. METHODS We investigated the role of the posterior cerebellum in convergence adaptation using inhibitory continuous theta-burst repetitive transcranial magnetic stimulation (cTBS) within a double-blind, sham controlled design while eye movements were recorded at 250hz via infrared oculography. RESULTS In a preliminary experiment we validated our stimulation protocols by reproducing results from previous work on saccadic adaptation during the classic double-step adaptive shortening paradigm. Following this, across a series of three separate experiments we observed a clear dissociation in the effect of cTBS on convergence adaptation. Dynamic adaptation was substantially reduced while tonic adaptation was unaffected. Baseline dynamic fusional vergence response were also unaffected by stimulation. CONCLUSIONS These results indicate a differential role for the posterior cerebellum in the adaptive control of convergence eye movements and provide initial evidence that repetitive transcranial magnetic stimulation is a viable tool to investigate the neurophysiology of vergence control. The results are discussed in the context of the current models of implicit motor adaptation of vergence and their application to clinical populations and technology design in virtual and augmented head mounted display architectures. SIGNIFICANCE STATEMENT The cerebellum plays a critical role in the adaptive control of motor systems. Vergence eye movements shift our gaze in depth allowing us to see in 3D and exhibit two distinct adaptive mechanisms that are engaged under a range of conditions including reading, wearing head-mounted displays and using a new spectacle prescription. It is unclear what role the cerebellum plays in these adaptive mechanisms. To answer this, we temporarily disrupted the function of the posterior cerebellum using non-invasive brain stimulation and report impairment of only one adaptive mechanism, providing evidence for neural compartmentalization. The results have implications for vergence control models and applications to comfort and experience studies in head-mounted displays and the rehabilitation of clinical populations exhibiting vergence dysfunctions.
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Nicolas J, Bompas A, Bouet R, Sillan O, Koun E, Urquizar C, Bidet-Caulet A, Pélisson D. Saccadic Adaptation Boosts Ongoing Gamma Activity in a Subsequent Visuoattentional Task. Cereb Cortex 2019; 29:3606-3617. [PMID: 30295717 DOI: 10.1093/cercor/bhy241] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 08/04/2018] [Indexed: 01/15/2023] Open
Abstract
Attention and saccadic adaptation (SA) are critical components of visual perception, the former enhancing sensory processing of selected objects, the latter maintaining the eye movements accuracy toward them. Recent studies propelled the hypothesis of a tight functional coupling between these mechanisms, possibly due to shared neural substrates. Here, we used magnetoencephalography to investigate for the first time the neurophysiological bases of this coupling and of SA per se. We compared visual discrimination performance of 12 healthy subjects before and after SA. Eye movements and magnetic signals were recorded continuously. Analyses focused on gamma band activity (GBA) during the pretarget period of the discrimination and the saccadic tasks. We found that GBA increases after SA. This increase was found in the right hemisphere for both postadaptation saccadic and discrimination tasks. For the latter, GBA also increased in the left hemisphere. We conclude that oculomotor plasticity involves GBA modulation within an extended neural network which persists after SA, suggesting a possible role of gamma oscillations in the coupling between SA and attention.
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Affiliation(s)
- Judith Nicolas
- ImpAct Team, Lyon Neuroscience Research Center, INSERM U1028, CNRS-UMR5292, University Lyon1, 16, Ave. Doyen Lépine, France.,DyCog Team, Lyon Neuroscience Research Center, INSERM U1028, CNRS-UMR5292, University Lyon1, 95 bd. Pinel, France
| | - Aline Bompas
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff, UK
| | - Romain Bouet
- DyCog Team, Lyon Neuroscience Research Center, INSERM U1028, CNRS-UMR5292, University Lyon1, 95 bd. Pinel, France
| | - Olivier Sillan
- ImpAct Team, Lyon Neuroscience Research Center, INSERM U1028, CNRS-UMR5292, University Lyon1, 16, Ave. Doyen Lépine, France
| | - Eric Koun
- ImpAct Team, Lyon Neuroscience Research Center, INSERM U1028, CNRS-UMR5292, University Lyon1, 16, Ave. Doyen Lépine, France
| | - Christian Urquizar
- ImpAct Team, Lyon Neuroscience Research Center, INSERM U1028, CNRS-UMR5292, University Lyon1, 16, Ave. Doyen Lépine, France
| | - Aurélie Bidet-Caulet
- DyCog Team, Lyon Neuroscience Research Center, INSERM U1028, CNRS-UMR5292, University Lyon1, 95 bd. Pinel, France
| | - Denis Pélisson
- ImpAct Team, Lyon Neuroscience Research Center, INSERM U1028, CNRS-UMR5292, University Lyon1, 16, Ave. Doyen Lépine, France
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Cassanello CR, Ostendorf F, Rolfs M. A generative learning model for saccade adaptation. PLoS Comput Biol 2019; 15:e1006695. [PMID: 31398185 PMCID: PMC6703699 DOI: 10.1371/journal.pcbi.1006695] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 08/21/2019] [Accepted: 06/19/2019] [Indexed: 11/19/2022] Open
Abstract
Plasticity in the oculomotor system ensures that saccadic eye movements reliably meet their visual goals-to bring regions of interest into foveal, high-acuity vision. Here, we present a comprehensive description of sensorimotor learning in saccades. We induced continuous adaptation of saccade amplitudes using a double-step paradigm, in which participants saccade to a peripheral target stimulus, which then undergoes a surreptitious, intra-saccadic shift (ISS) as the eyes are in flight. In our experiments, the ISS followed a systematic variation, increasing or decreasing from one saccade to the next as a sinusoidal function of the trial number. Over a large range of frequencies, we confirm that adaptation gain shows (1) a periodic response, reflecting the frequency of the ISS with a delay of a number of trials, and (2) a simultaneous drift towards lower saccade gains. We then show that state-space-based linear time-invariant systems (LTIS) represent suitable generative models for this evolution of saccade gain over time. This state-equation algorithm computes the prediction of an internal (or hidden state-) variable by learning from recent feedback errors, and it can be compared to experimentally observed adaptation gain. The algorithm also includes a forgetting rate that quantifies per-trial leaks in the adaptation gain, as well as a systematic, non-error-based bias. Finally, we study how the parameters of the generative models depend on features of the ISS. Driven by a sinusoidal disturbance, the state-equation admits an exact analytical solution that expresses the parameters of the phenomenological description as functions of those of the generative model. Together with statistical model selection criteria, we use these correspondences to characterize and refine the structure of compatible state-equation models. We discuss the relation of these findings to established results and suggest that they may guide further design of experimental research across domains of sensorimotor adaptation.
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Affiliation(s)
- Carlos R. Cassanello
- Department of Psychology, Humboldt-Universität zu Berlin, Berlin, Germany
- Bernstein Center for Computational Neuroscience, Humboldt-Universität zu Berlin, Berlin, Germany
- * E-mail: (CRC); (MR)
| | - Florian Ostendorf
- Department of Neurology, Charité – University Medicine Berlin, Berlin, Germany
| | - Martin Rolfs
- Department of Psychology, Humboldt-Universität zu Berlin, Berlin, Germany
- Bernstein Center for Computational Neuroscience, Humboldt-Universität zu Berlin, Berlin, Germany
- * E-mail: (CRC); (MR)
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Sensorimotor maps can be dynamically calibrated using an adaptive-filter model of the cerebellum. PLoS Comput Biol 2019; 15:e1007187. [PMID: 31295248 PMCID: PMC6622474 DOI: 10.1371/journal.pcbi.1007187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 06/16/2019] [Indexed: 11/19/2022] Open
Abstract
Substantial experimental evidence suggests the cerebellum is involved in calibrating sensorimotor maps. Consistent with this involvement is the well-known, but little understood, massive cerebellar projection to maps in the superior colliculus. Map calibration would be a significant new role for the cerebellum given the ubiquity of map representations in the brain, but how it could perform such a task is unclear. Here we investigated a dynamic method for map calibration, based on electrophysiological recordings from the superior colliculus, that used a standard adaptive-filter cerebellar model. The method proved effective for complex distortions of both unimodal and bimodal maps, and also for predictive map-based tracking of moving targets. These results provide the first computational evidence for a novel role for the cerebellum in dynamic sensorimotor map calibration, of potential importance for coordinate alignment during ongoing motor control, and for map calibration in future biomimetic systems. This computational evidence also provides testable experimental predictions concerning the role of the connections between cerebellum and superior colliculus in previously observed dynamic coordinate transformations. The human brain contains a structure known as the cerebellum, which contains a vast number of neurons–around 80% of the total ~90 billion. We believe the cerebellum is involved in learning motor skills, and so is vitally important for accurately controlling the movements of our body, amongst other things. However, like most regions of the brain, we still do not fully understand the role of the cerebellum and evidence for new roles is appearing all the time. One such new role is in the calibration of sensorimotor maps in the brain that link our sensory perception to motor function, such as when a visual stimulus causes a redirect of our gaze. We investigated this problem by connecting a mathematical model of the cerebellar cortical microcircuit to simulated sensory maps in the superior colliculus that are used to control orienting movements. We found the error signal generated by inaccurate orienting movements could be used to accurately calibrate sensorimotor maps, and to allow predictive tracking of moving targets. This finding points to a potentially widespread role for the cerebellum in calibrating the sensorimotor maps that are ubiquitous in the brain and could prove useful in controlling the movements of multi-joint robots.
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Piu P, Pretegiani E, Rosini F, Serchi V, Zaino D, Chiantini T, Rufa A. The cerebellum improves the precision of antisaccades by a latency-duration trade-off. PROGRESS IN BRAIN RESEARCH 2019; 249:125-139. [PMID: 31325973 DOI: 10.1016/bs.pbr.2019.04.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The cerebellum adapts motor responses by controlling the gain of a movement, preserving its accuracy and by learning from endpoint errors. Adaptive behavior likely acts not only in the motor but also in the sensory, behavioral, and cognitive domains, thus supporting a role of cerebellum in monitoring complex brain performances. Here, we analyzed the relationship between saccade latency, duration and endpoint error of antisaccades in a group of 10 idiopathic cerebellar atrophy (ICA) patients compared to controls. The latency distribution was decomposed in a decision time and a residual time. Both groups showed a trade-off between duration and decision time, with a peak of entropy within the range of this trade-off where the information flow was maximized. In cerebellar patients, greater reductions of duration as the time of decision increased, were associated with a lower probability for a saccade to fall near the target, with a constant low entropy outside the optimal time window. We suggest a modulation of saccade duration, depending on the latency-related decision time (accumulation of sensory and motor evidences in favor of a goal-directed movement), normally adopted to perform efficient trajectories in goal-directed saccades. This process is impaired in cerebellar patients suggesting a role for the cerebellum in monitoring voluntary motor performance by controlling the movement onset until the ambiguity of planning is resolved.
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Affiliation(s)
- Pietro Piu
- Eye-tracking and Visual Application Lab (EVALab), Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Elena Pretegiani
- Eye-tracking and Visual Application Lab (EVALab), Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy; Laboratory of Sensorimotor Research-NEI, NIH, DHHS, Bethesda, MD, United States
| | - Francesca Rosini
- Eye-tracking and Visual Application Lab (EVALab), Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy; Neurological and Neurometabolic Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Valeria Serchi
- Eye-tracking and Visual Application Lab (EVALab), Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Domenica Zaino
- Eye-tracking and Visual Application Lab (EVALab), Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy; Neurological and Neurometabolic Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Tommaso Chiantini
- Eye-tracking and Visual Application Lab (EVALab), Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Alessandra Rufa
- Eye-tracking and Visual Application Lab (EVALab), Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy; Neurological and Neurometabolic Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy.
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Inter-individual variability and consistency of saccade adaptation in oblique saccades: Amplitude increase and decrease in the horizontal or vertical saccade component. Vision Res 2019; 160:82-98. [PMID: 31082404 DOI: 10.1016/j.visres.2019.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 04/10/2019] [Accepted: 05/03/2019] [Indexed: 11/21/2022]
Abstract
Despite changes in the physical structures controlling the eyes, saccades, the rapid eye movements used to explore the visual environment, remain accurate throughout the lifetime. The process underlying this sensorimotor adaptation is studied using a double step paradigm: an intra-saccadic target displacement introduces a systematic position error which triggers changes in saccadic amplitude or direction across trials. Numerous researches on this saccade adaptation have been conducted, but the level of inter-individual variability and consistency in saccade gain change and how it relates to increase- or decrease-amplitude paradigms is not fully described. We conducted experiments in four groups of 25 participants with 800 trials per participant, including 200 baseline trials and 200 recovery trials. We used four distinct double-step paradigms that differed by the intra-saccadic target-step leading to either a horizontal (Backward or Forward) or vertical (Upward or Downward) gain modulation. Across experiments 95% of the participants exhibited adaptation, revealing the consistency of this phenomenon. We observed strong inter-individual differences, both in the extent and rate of adaptation, which were not correlated with the individual baseline saccades characteristics. As previously reported, the rates of adaptation were higher for gain decrease than for gain increase experiments but the final extent of adaptation were similar. Our results also support the view that adaptation of oblique saccades occurs where the saccade command is represented as a vector. Finally, at the individual level, we did not observe systematic changes in the saccade metrics in relation to adaptation.
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36
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Soetedjo R, Kojima Y, Fuchs AF. How cerebellar motor learning keeps saccades accurate. J Neurophysiol 2019; 121:2153-2162. [PMID: 30995136 DOI: 10.1152/jn.00781.2018] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The neuronal substrate underlying the learning of a sophisticated task has been difficult to study. However, the advent of a behavioral paradigm that deceives the saccadic system into thinking it is making an error has allowed the mechanisms of the adaptation that corrects this error to be revealed in a primate. The neural elements that fashion the command signal for the generation of accurate saccades involve subcortical structures in the brain stem and cerebellum. In this review we show that sites in both those structures also are involved with the gradual adaptation of saccade size, a form of motor learning. Pharmacological manipulation of the oculomotor vermis (lobules VIc and VII) impairs mechanisms that either increase or decrease saccade size during adaptation. The net saccade-related simple spike (SS) activity of its Purkinje cells is correlated with the changes in saccade characteristics that occur during adaptation. These changes in SS activity are driven by an error signal delivered over climbing fibers, which create complex spikes whose probability of occurrence reflects the motor error between the actual and desired saccade size. These climbing fibers originate in the part of the inferior olive that receives projections from the superior colliculus (SC). Disabling the SC prevents adaptation and stimulation of the SC just after a normal saccade produces a surrogate error signal that drives adaptation without an actual visual error. Therefore, the SC provides not only the initial command that generates a saccade, as shown by others, but also the error signal that ensures that saccades remain accurate.
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Affiliation(s)
- Robijanto Soetedjo
- Department of Physiology and Biophysics, University of Washington , Seattle, Washington.,Washington National Primate Research Center, University of Washington , Seattle, Washington
| | - Yoshiko Kojima
- Washington National Primate Research Center, University of Washington , Seattle, Washington
| | - Albert F Fuchs
- Department of Physiology and Biophysics, University of Washington , Seattle, Washington
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A neuronal process for adaptive control of primate saccadic system. PROGRESS IN BRAIN RESEARCH 2019; 249:169-181. [PMID: 31325976 DOI: 10.1016/bs.pbr.2019.03.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
In 1980, Dr. Optican established the existence of an adaptive plasticity of saccades and its dependence on the cerebellum with Dr. Robinson. The advantage of saccades is that the neuronal mechanisms underlying their generation have been well established. This knowledge allows us to identify the neuronal elements that participate in saccade adaptation. Briefly, the superior colliculus (SC) produces a saccade command signal, which reaches motoneurons in the abducens nucleus via the brainstem burst generator. The SC saccade command also is sent to the oculomotor vermis (OMV), a saccade-related area of the cerebellar cortex, and finally converges on the same motoneurons via the caudal fastigial nucleus (cFN) and inhibitory burst neurons (IBN). During adaptation, the saccade-related burst of SC neurons does not change; however, the activity of the cerebellum and its downstream targets do. We demonstrate that the SC is the source of the error signal to the OMV, and the error signal increases the probability of complex spike occurrence and decreases simple spike activity in the OMV. This decrease, in turn, is delivered through the cFN and IBN neurons to decrease motoneuron activity and hence saccade amplitude.
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38
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Paraskevoudi N, Pezaris JS. Eye Movement Compensation and Spatial Updating in Visual Prosthetics: Mechanisms, Limitations and Future Directions. Front Syst Neurosci 2019; 12:73. [PMID: 30774585 PMCID: PMC6368147 DOI: 10.3389/fnsys.2018.00073] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 12/21/2018] [Indexed: 01/01/2023] Open
Abstract
Despite appearing automatic and effortless, perceiving the visual world is a highly complex process that depends on intact visual and oculomotor function. Understanding the mechanisms underlying spatial updating (i.e., gaze contingency) represents an important, yet unresolved issue in the fields of visual perception and cognitive neuroscience. Many questions regarding the processes involved in updating visual information as a function of the movements of the eyes are still open for research. Beyond its importance for basic research, gaze contingency represents a challenge for visual prosthetics as well. While most artificial vision studies acknowledge its importance in providing accurate visual percepts to the blind implanted patients, the majority of the current devices do not compensate for gaze position. To-date, artificial percepts to the blind population have been provided either by intraocular light-sensing circuitry or by using external cameras. While the former commonly accounts for gaze shifts, the latter requires the use of eye-tracking or similar technology in order to deliver percepts based on gaze position. Inspired by the need to overcome the hurdle of gaze contingency in artificial vision, we aim to provide a thorough overview of the research addressing the neural underpinnings of eye compensation, as well as its relevance in visual prosthetics. The present review outlines what is currently known about the mechanisms underlying spatial updating and reviews the attempts of current visual prosthetic devices to overcome the hurdle of gaze contingency. We discuss the limitations of the current devices and highlight the need to use eye-tracking methodology in order to introduce gaze-contingent information to visual prosthetics.
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Affiliation(s)
- Nadia Paraskevoudi
- Brainlab – Cognitive Neuroscience Research Group, Department of Clinical Psychology and Psychobiology, University of Barcelona, Barcelona, Spain
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - John S. Pezaris
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, United States
- Department of Neurosurgery, Harvard Medical School, Boston, MA, United States
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Kalidindi HT, George Thuruthel T, Laschi C, Falotico E. Modeling the Encoding of Saccade Kinematic Metrics in the Purkinje Cell Layer of the Cerebellar Vermis. Front Comput Neurosci 2019; 12:108. [PMID: 30687055 PMCID: PMC6335360 DOI: 10.3389/fncom.2018.00108] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 12/19/2018] [Indexed: 11/25/2022] Open
Abstract
Recent electrophysiological observations related to saccadic eye movements in rhesus monkeys, suggest a prediction of the sensory consequences of movement in the Purkinje cell layer of the cerebellar oculomotor vermis (OMV). A definite encoding of real-time motion of the eye has been observed in simple-spike responses of the combined burst-pause Purkinje cell populations, organized based upon their complex-spike directional tuning. However, the underlying control mechanisms that could lead to such action encoding are still unclear. We propose a saccade control model, with emphasis on the structure of the OMV and its interaction with the extra-cerebellar components. In the simulated bilateral organization of the OMV, each caudal fastigial nucleus is arranged to receive incoming projections from combined burst-pause Purkinje cell populations. The OMV, through the caudal fastigial nuclei, interacts with the brainstem to provide adaptive saccade gain corrections that minimize the visual error in reaching a given target location. The simulation results corroborate the experimental Purkinje cell population activity patterns and their relation with saccade kinematic metrics. The Purkinje layer activity that emerges from the proposed organization, precisely predicted the speed of the eye at different target eccentricities. Simulated granular layer activity suggests no separate dynamics with respect to shaping the bilateral Purkine layer activity. We further examine the validity of the simulated OMV in maintaining the accuracy of saccadic eye movements in the presence of signal dependent variabilities, that can occur in extra-cerebellar pathways.
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Affiliation(s)
| | | | - Cecilia Laschi
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Egidio Falotico
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
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van Es DM, Knapen T. Implicit and explicit learning in reactive and voluntary saccade adaptation. PLoS One 2019; 14:e0203248. [PMID: 30650083 PMCID: PMC6334942 DOI: 10.1371/journal.pone.0203248] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 12/18/2018] [Indexed: 11/18/2022] Open
Abstract
Saccades can either be elicited automatically by salient peripheral stimuli or can additionally depend on explicit cognitive goals. Similarly, it is thought that motor adaptation is driven by the combination of a more automatic, implicit process and a more explicit, cognitive process. However, the degree to which such implicit and explicit learning contribute to the adaptation of more reactive and voluntary saccades remains elusive. To study this question, we employed a global saccadic adaptation paradigm with both increasing and decreasing saccade amplitudes. We assessed the resulting adaptation using a dual state model of motor adaptation. This model decomposes learning into a fast and slow process, which are thought to constitute explicit and implicit learning, respectively. Our results show that adaptation of reactive saccades is equally driven by fast and slow learning, while fast learning is nearly absent when adapting voluntary (i.e. scanning) saccades. This pattern of results was present both when saccade gain was increased or decreased. Our results suggest that the increased cognitive demands associated with voluntary compared to reactive saccade planning interfere specifically with explicit learning.
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Affiliation(s)
- Daniel Marten van Es
- Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, Noord-Holland, the Netherlands
| | - Tomas Knapen
- Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, Noord-Holland, the Netherlands
- Spinoza Centre for Neuroimaging, Royal Academy of Sciences, Amsterdam, Noord-Holland, the Netherlands
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41
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Guidetti G, Guidetti R, Sgalla RA. The saccadic training for driving safety. HEARING, BALANCE AND COMMUNICATION 2019. [DOI: 10.1080/21695717.2018.1540233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Giorgio Guidetti
- Vertigo Center – Poliambulatorio Chirurgico Modenese, Modena, Italy
| | | | - Roberto Antonio Sgalla
- Director for Special Departments of the State Italian Police of Italian Ministry of the Interior, Italy
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Abstract
Several times per second, humans make rapid eye movements called saccades which redirect their gaze to sample new regions of external space. Saccades present unique challenges to both perceptual and motor systems. During the movement, the visual input is smeared across the retina and severely degraded. Once completed, the projection of the world onto the retina has undergone a large-scale spatial transformation. The vector of this transformation, and the new orientation of the eye in the external world, is uncertain. Memory for the pre-saccadic visual input is thought to play a central role in compensating for the disruption caused by saccades. Here, we review evidence that memory contributes to (1) detecting and identifying changes in the world that occur during a saccade, (2) bridging the gap in input so that visual processing does not have to start anew, and (3) correcting saccade errors and recalibrating the oculomotor system to ensure accuracy of future saccades. We argue that visual working memory (VWM) is the most likely candidate system to underlie these behaviours and assess the consequences of VWM's strict resource limitations for transsaccadic processing. We conclude that a full understanding of these processes will require progress on broader unsolved problems in psychology and neuroscience, in particular how the brain solves the object correspondence problem, to what extent prior beliefs influence visual perception, and how disparate signals arriving with different delays are integrated.
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Guillaume A, Fuller JR, Srimal R, Curtis CE. Cortico-cerebellar network involved in saccade adaptation. J Neurophysiol 2018; 120:2583-2594. [PMID: 30207858 PMCID: PMC6295533 DOI: 10.1152/jn.00392.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 09/07/2018] [Accepted: 09/08/2018] [Indexed: 01/10/2023] Open
Abstract
Saccade adaptation is the learning process that ensures that vision and saccades remain calibrated. The central nervous system network involved in these adaptive processes remains unclear because of difficulties in isolating the learning process from the correlated visual and motor processes. Here we imaged the human brain during a novel saccade adaptation paradigm that allowed us to isolate neural signals involved in learning independent of the changes in the amplitude of corrective saccades usually correlated with adaptation. We show that the changes in activation in the ipsiversive cerebellar vermis that track adaptation are not driven by the changes in corrective saccades and thus provide critical supporting evidence for previous findings. Similarly, we find that activation in the dorsomedial wall of the contraversive precuneus mirrors the pattern found in the cerebellum. Finally, we identify dorsolateral and dorsomedial cortical areas in the frontal and parietal lobes that encode the retinal errors following inaccurate saccades used to drive recalibration. Together, these data identify a distributed network of cerebellar and cortical areas and their specific roles in oculomotor learning. NEW & NOTEWORTHY The central nervous system constantly learns from errors and adapts to keep visual targets and saccades in registration. We imaged the human brain while the gain of saccades adapted to a visual target that was displaced while the eye was in motion, inducing retinal error. Activity in the cerebellum and precuneus tracked learning, whereas parts of the dorsolateral and dorsomedial frontal and parietal cortex encoded the retinal error used to drive learning.
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Affiliation(s)
- Alain Guillaume
- CNRS, Laboratoire de Neurosciences Cognitives, Aix Marseille Université , Marseille , France
- Department of Psychology, New York University , New York, New York
| | - Jason R Fuller
- Department of Psychology, New York University , New York, New York
| | - Riju Srimal
- Center for Neural Science, New York University , New York, New York
| | - Clayton E Curtis
- Department of Psychology, New York University , New York, New York
- Center for Neural Science, New York University , New York, New York
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Pélisson D, Habchi O, Panouillères MTN, Hernoux C, Farnè A. A cortical substrate for the long-term memory of saccadic eye movements calibration. Neuroimage 2018; 179:348-356. [PMID: 29933041 DOI: 10.1016/j.neuroimage.2018.06.051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 06/07/2018] [Accepted: 06/15/2018] [Indexed: 11/19/2022] Open
Abstract
How movements are continuously adapted to physiological and environmental changes is a fundamental question in systems neuroscience. While many studies have elucidated the mechanisms which underlie short-term sensorimotor adaptation (∼10-30 min), how these motor memories are maintained over longer-term (>3-5 days) -and thanks to which neural systems-is virtually unknown. Here, we examine in healthy human participants whether the temporo-parietal junction (TPJ) is causally involved in the induction and/or the retention of saccadic eye movements' adaptation. Single-pulse transcranial magnetic stimulation (spTMS) was applied while subjects performed a ∼15min size-decrease adaptation task of leftward reactive saccades. A TMS pulse was delivered over the TPJ in the right hemisphere (rTPJ) in each trial either 30, 60, 90 or 120 msec (in 4 separate adaptation sessions) after the saccade onset. In two control groups of subjects, the same adaptation procedure was achieved either alone (No-TMS) or combined with spTMS applied over the vertex (SHAM-TMS). While the timing of spTMS over the rTPJ did not significantly affect the speed and immediate after-effect of adaptation, we found that the amount of adaptation retention measured 10 days later was markedly larger (42%) than in both the No-TMS (21%) and the SHAM-TMS (11%) control groups. These results demonstrate for the first time that the cerebral cortex is causally involved in maintaining long-term oculomotor memories.
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Affiliation(s)
- Denis Pélisson
- Lyon Neurosciences Research Center (CRNL), Inserm U1028 - CNRS UMR5292 - University Claude Bernard, Lyon, France.
| | - Ouazna Habchi
- Lyon Neurosciences Research Center (CRNL), Inserm U1028 - CNRS UMR5292 - University Claude Bernard, Lyon, France
| | | | - Charles Hernoux
- Lyon Neurosciences Research Center (CRNL), Inserm U1028 - CNRS UMR5292 - University Claude Bernard, Lyon, France
| | - Alessandro Farnè
- Lyon Neurosciences Research Center (CRNL), Inserm U1028 - CNRS UMR5292 - University Claude Bernard, Lyon, France
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Feil M, Abegg M, Abegg M. Timing of concurrent visual stimuli determines modulation of saccadic amplitude. J Vis 2018; 18:8. [PMID: 30347095 DOI: 10.1167/18.11.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The temporal relation of competing visual stimuli may determine the corresponding oculomotor response. In this study we systematically varied the temporal coincidence of two conflicting stimuli and investigated saccades that were elicited from such stimuli. We varied the time of presentation of two identical spatially separated stimuli between 0 and +165 ms and measured the amplitude of the saccade elicited by these stimuli using infrared eye tracking. In the first experiment, all stimuli were shown for 36 ms only. In the second experiment, stimuli remained on the screen until the subsequent stimulus appeared, whereas in the third experiment all stimuli were removed after saccade onset. Up to an interstimulus interval of 82 ms, we found a significant shift of the saccadic endpoint toward the location of the second stimulus as compared to saccades toward the first stimulus alone. The strongest saccadic bias was observed if a stimulus was shown 36 ms after or before another stimulus. In contrast, time intervals longer than 82 ms elicited saccade adaptation-that is, the saccadic landing point gradually moved toward the second location over time. In more than 99% of trials, the second stimulus appeared before the saccade reached its endpoint. The timing of a conflicting stimulus determines the associated saccadic response: Simultaneous presentation of two stimuli results in a saccadic endpoint at an averaged intermediate position, short interstimulus intervals result in a strong shift of the saccadic endpoint toward the location of the second of two consecutive stimuli, and longer interstimulus intervals elicit saccade adaptation. The timing of two stimuli thus is associated with distinct processes, which complement each other in order to provide an optimal oculomotor response.
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Affiliation(s)
- Moritz Feil
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Meinrad Abegg
- Forest Resources and Management, WSL Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Mathias Abegg
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Elimination of the error signal in the superior colliculus impairs saccade motor learning. Proc Natl Acad Sci U S A 2018; 115:E8987-E8995. [PMID: 30185563 PMCID: PMC6156644 DOI: 10.1073/pnas.1806215115] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Theories of cerebellar-dependent motor learning use the error between the desired and actual movement to correct the erroneous movement. To support this idea, several studies have tried to eliminate the error signal to the cerebellum and demonstrate an impairment of learning. However, such former approaches have not been successful because blocking the error signal also affected the movement to be learned. In this study, we selectively block an error signal for saccade adaptation, a type of cerebellar motor learning, by inactivating the source of the error signal in the superior colliculus without affecting the movement to be learned. Saccade adaptation was impaired. Thus, our study provides the first experimental evidence that an error signal is required for cerebellar motor learning. When movements become dysmetric, the resultant motor error induces a plastic change in the cerebellum to correct the movement, i.e., motor adaptation. Current evidence suggests that the error signal to the cerebellum is delivered by complex spikes originating in the inferior olive (IO). To prove a causal link between the IO error signal and motor adaptation, several studies blocked the IO, which, unfortunately, affected not only the adaptation but also the movement itself. We avoided this confound by inactivating the source of an error signal to the IO. Several studies implicate the superior colliculus (SC) as the source of the error signal to the IO for saccade adaptation. When we inactivated the SC, the metrics of the saccade to be adapted were unchanged, but saccade adaptation was impaired. Thus, an intact rostral SC is necessary for saccade adaptation. Our data provide experimental evidence for the cerebellar learning theory that requires an error signal to drive motor adaptation.
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Gaveau V, Priot AE, Pisella L, Havé L, Prablanc C, Rossetti Y. Paradoxical adaptation of successful movements: The crucial role of internal error signals. Conscious Cogn 2018; 64:135-145. [DOI: 10.1016/j.concog.2018.06.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 06/11/2018] [Accepted: 06/11/2018] [Indexed: 11/28/2022]
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Soetedjo R. Signals driving the adaptation of saccades that require spatial updating. J Neurophysiol 2018; 120:525-538. [PMID: 29694278 PMCID: PMC6139442 DOI: 10.1152/jn.00075.2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 04/10/2018] [Accepted: 04/22/2018] [Indexed: 11/22/2022] Open
Abstract
Saccades adapt to persistent natural or artificially imposed dysmetrias. The characteristics and circuitry of saccade adaptation have been revealed using a visually guided task (VGT) where the vectors of the target step and the intended saccade command are the same. However, in real life, another saccade occasionally intervenes before the saccade to the target occurs. This necessitates an updating of the intended saccade to account for the intervening saccadic displacement, which dissociates the visual target signal and the intended saccade command. We determined whether the adaptation process is similar for VGT and updated saccades by studying the transfer of adaptation between them. The ultimate visual target was dissociated from the intended saccade command with double-step saccade tasks (DSTs) in which two targets are flashed sequentially at different locations while the monkey maintains fixation. The resulting saccades toward the first and second targets occur in the dark. The transfer of visually guided saccade adaptation to the second saccades of a DST and vice versa depended on the eccentricity of the second visual target, and not the second saccade command. If a target with the same eccentricity as the adapted target appears briefly during the intersaccadic interval of a DST, more adaptation transfers. Because a brief appearance of the visual target either before the first saccade or during the intersaccadic interval influences how much adaptation transfer the second saccade will express, the processing of adaptation and DST updating may overlap. NEW & NOTEWORTHY Adaptation and the spatial updating of saccades are thought to be independent processes. When we dissociate the visual target and the intended saccade command, the transfer of visually guided saccade adaptation to the saccades of the double-step saccade tasks (DST) and vice versa is driven by a visual not motor error. The visual target has an effect until the second saccade of a DST occurs. Therefore, the processing of adaptation and the spatial updating of saccades may overlap.
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Affiliation(s)
- Robijanto Soetedjo
- Department of Physiology and Biophysics, University of Washington , Seattle, Washington
- Washington National Primate Research Center, University of Washington , Seattle, Washington
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Erkelens IM, Bobier WR. Adaptation of reflexive fusional vergence is directionally biased. Vision Res 2018; 149:66-76. [PMID: 29940192 DOI: 10.1016/j.visres.2018.06.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/22/2018] [Accepted: 06/08/2018] [Indexed: 11/27/2022]
Abstract
Divergence is known to differ from convergence across a wide range of clinical parameters. We have postulated that a limited neural substrate results in reduced fusional divergence velocities and subsequently a reduced capacity to adapt tonic vergence to uncrossed disparities. We further investigated this hypothesis by characterizing the degree of plasticity in reflexive fusional vergence to repetitive end-point errors using a disparity-based double-step paradigm. 10 adults completed 4 study visits where reflexive fusional convergence or divergence was measured (250 Hz infrared oculography) to a 2° disparity step and then lengthened or shortened via a repeated double-step (2° ± 1.5°). Stimuli were presented dichoptically at 40 cm. Adaptive modification of vergence responses was similar between directions for the shortening conditions, suggesting a common neural mechanism responds to overshooting errors. In comparison, adaptive lengthening of convergence was slower, but of equal magnitude, suggesting a second neural mechanism with a longer time constant for undershooting errors. Divergence response velocities were slower at baseline and did not increase after adaptive lengthening. Instead, increases in divergence response amplitudes were a result of increased response duration, implying saturation of the reflexive, preprogrammed response. Adaptive responses serving to increase or decrease reflexive fusional vergence recruitment were asymmetric. Adaptive lengthening of convergence and divergence identified further directional asymmetries. The results support the hypothesis that the neural substrate underlying divergence is attenuated, resulting in reduced reflexive plasticity when compared to convergence. The clinical and technological implications of these results are discussed.
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Affiliation(s)
- Ian M Erkelens
- University of Waterloo, School of Optometry & Vision Science, 200 Columbia St. West, Waterloo, ON, Canada.
| | - William R Bobier
- University of Waterloo, School of Optometry & Vision Science, 200 Columbia St. West, Waterloo, ON, Canada
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50
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Pretegiani E, Piu P, Rosini F, Federighi P, Serchi V, Tumminelli G, Dotti MT, Federico A, Rufa A. Anti-Saccades in Cerebellar Ataxias Reveal a Contribution of the Cerebellum in Executive Functions. Front Neurol 2018; 9:274. [PMID: 29740392 PMCID: PMC5926529 DOI: 10.3389/fneur.2018.00274] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 04/06/2018] [Indexed: 01/25/2023] Open
Abstract
OBJECTIVE Increasing evidence suggests a cerebellar contribution to modulate cognitive aspects of motor behavior and executive functions. Supporting findings come from studies on patients with neurodegenerative diseases, in which however, given the extent of the disease, the specific role of the cerebellum, could not be clearly isolated. Anti-saccades are considered a sensitive tool to test executive functions. The anti-saccade underlying neural network, consisting of different cortical areas and their downstream connections including the lateral cerebellum, has been largely clarified. To separate the role of the cerebellum with respect to other cortical structures in executive control, we compared the anti-saccade performances in two distinct cohorts of patients with cerebellar disorders (with and without cerebral cortical involvement). METHODS Eye movements during the execution of anti-saccades were recorded in 12 patients with spinocerebellar ataxia type 2 (a cortical-subcortical neurodegenerative disease), 10 patients with late onset cerebellar ataxia (an isolated cerebellar atrophy), and 34 matched controls. RESULTS In the anti-saccade task, besides dynamic changes already demonstrated in the pro-saccades of these patients, we found in both groups of cerebellar patients prolonged latency with larger variability than normal and increased directional error rate. Errors, however, were corrected by cerebellar patients as frequently as normal. No significant differences were found in patients with and without cortical involvement. CONCLUSION Our results indicate, in a large cohort of cerebellar patients, that the cerebellum plays a critical role in the regulation of executive motor control not only, as well known, by controlling the end of a movement, but also modulating its initiation and reducing reflexive responses that would perturb voluntary actions.
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Affiliation(s)
- Elena Pretegiani
- Eye-Tracking and Visual Application Laboratory (EVALab), Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Laboratory of Sensorimotor Research, National Eye Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, United States
| | - Pietro Piu
- Eye-Tracking and Visual Application Laboratory (EVALab), Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Francesca Rosini
- Eye-Tracking and Visual Application Laboratory (EVALab), Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Neurological and Neurometabolic Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Pamela Federighi
- Eye-Tracking and Visual Application Laboratory (EVALab), Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Department of Business and Law, University of Siena, Siena, Italy
| | - Valeria Serchi
- Eye-Tracking and Visual Application Laboratory (EVALab), Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Gemma Tumminelli
- Eye-Tracking and Visual Application Laboratory (EVALab), Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Neurological and Neurometabolic Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Maria Teresa Dotti
- Neurological and Neurometabolic Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Antonio Federico
- Neurological and Neurometabolic Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Alessandra Rufa
- Eye-Tracking and Visual Application Laboratory (EVALab), Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Neurological and Neurometabolic Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
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