Eye Movements and Visuo-spatial Perception

NCT ID: NCT03112408

Last Updated: 2025-09-03

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 24 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2018-09-26
• Study Completion Date: 2020-10-02

Brief Summary

This research aims to highlight the key roles of the cerebellar and cortical fronto-parietal networks in the coupling of eye movements with visual perception and visuo-spatial attention.

Detailed Description

The first axe of this research focuses on the role of the cerebellum which has a major contribution to sensorimotor adaptation and more precisely in saccadic adaptation but the nature of this contribution is still debated. A classical assumption stipulates cerebellum has an exclusive action on saccadic burst generator in the brainstem whereas recent data increasingly support the view that cerebellum could also modulates cerebral cortex through a cerebello-thalamo-cortical pathway. On the other hand, several studies have shown that modification of saccade amplitude by saccadic adaptation leads to a distortion of the visual localization of briefly flashed spatial probes but no study to date has tested, the contribution of the cerebellum in these adaptation-induced mislocalizations. The main objective of this axe is to define the role of the cerebellum not only in saccadic adaptation, but also in mislocalizations which occur after adaptation. Moreover, in testing this assumption, arguments in favour -or in disfavor- of the action of the cerebellum on cortical stages dedicated to visuo-spatial perceptual processing will be provided. Besides, variability of cerebellar lesion (or cerebellar dysfunction) location in patients can lead to different pattern in saccadic adaptation and localization task performances. Identification of dissociations between these two abilities in some patients will define more precisely the role of the cerebellum in the coupling between saccadic adaptation and visuo spatial perception as an oculomotor plasticity territory and / or as a territory underlying the error signal coding generating this type of plasticity.

This second axe of this research aims to apply basic findings in healthy subject on the coupling between oculomotor plasticity and spatial attention to patients with parietal lesion, in order to evaluate a rehabilitation procedure for neglect patients. Habchi and colleagues showed that the adaptation of reactive saccades in the left hemifield has a boosting effect on attentional performance in the same hemifield. The coupling between these two mechanisms highlighted in healthy subjects can be used as fundamentals in the elaboration of a rehabilitation procedure for attentional disorders in the neglect syndrome. This syndrome is mainly observed after cerebral lesions in the right hemisphere, and is characterized by very disabling cognitive disorders such as an alteration of the spatial representation of left hemi-space and/or left hemi-body. stimulation of sensorimotor plasticity thanks to prismatic adaptation could be used as a rehabilitation procedure for this syndrome. Being another efficient way to stimulate sensorimotor plasticity, the equip believe that saccadic adaptation can also be used as a rehabilitation procedure for neglect patients. Moreover, due to its tight coupling with visual attention, the benefits of saccadic adaptation could be even stronger and longer lasting than the visuo-manual plasticity induced by prismatic adaptation.

Conditions

Cerebellum Disease

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: FACTORIAL
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: SINGLE

Study Groups

FORWARD (Axe 1)

Group Type: EXPERIMENTAL

Forward adaptation of reactive saccades

Intervention Type: BEHAVIORAL

Protocol of reactive saccade where the target is displaced in the same direction as the saccade in order to induce an adaptive increase of saccade amplitude ('forward adaptation')

BACKWARD (Axe 1)

Group Type: EXPERIMENTAL

Backward adaptation of reactive saccades

Intervention Type: BEHAVIORAL

Protocol of reactive saccade where the target is displaced in a direction opposite to the saccade in order to induce an adaptive decrease of saccade amplitude ('backward adaptation')

CONTROL (Axe 1)

Group Type: EXPERIMENTAL

Execution of reactive saccades

Intervention Type: BEHAVIORAL

Control protocol of reactive saccade with no displacement of the saccadic target (controlling for non specific factors possibly involved in forward and backward adaptation conditions)

ADAPTATION (Axe 2)

Group Type: EXPERIMENTAL

Backward adaptation of reactive saccades

Intervention Type: BEHAVIORAL

Protocol of reactive saccade where the target is displaced in a direction opposite to the saccade in order to induce an adaptive decrease of saccade amplitude ('backward adaptation')

CONTROL (Axe 2)

Group Type: EXPERIMENTAL

Generation of reactive saccades

Intervention Type: BEHAVIORAL

Control protocol of reactive saccade with no displacement of the saccadic target (controlling for non specific factors possibly involved in adaptation condition)

Interventions

Forward adaptation of reactive saccades

Protocol of reactive saccade where the target is displaced in the same direction as the saccade in order to induce an adaptive increase of saccade amplitude ('forward adaptation')

Intervention Type: BEHAVIORAL

Backward adaptation of reactive saccades

Protocol of reactive saccade where the target is displaced in a direction opposite to the saccade in order to induce an adaptive decrease of saccade amplitude ('backward adaptation')

Intervention Type: BEHAVIORAL

Execution of reactive saccades

Control protocol of reactive saccade with no displacement of the saccadic target (controlling for non specific factors possibly involved in forward and backward adaptation conditions)

Intervention Type: BEHAVIORAL

Generation of reactive saccades

Control protocol of reactive saccade with no displacement of the saccadic target (controlling for non specific factors possibly involved in adaptation condition)

Intervention Type: BEHAVIORAL

Eligibility Criteria

Inclusion Criteria

• Age : from 18 to 80 ans included
• Visual acuity monocularly at distance and near corrected : > 5/10
• Possible understanding of experimental guidelines
• Possible respect for sustained seated position
• Subject covered by social security
• Agreement of the subject

• Cerebellar patients - Cerebellar degenerative disease (group A) or stroke (group B, délai depuis l'AVC : delay from the stroke : at least 1 month)

• Scanner or MRI showing diffuse atrophy (group A) or focal cerebellar lesion (group B)
• Healthy subjects

• Absence of known ophtalmological or neurological pathology

• Stroke patients - ischemic or hemorrhagic stroke

• Encephalic MRI or CT scan showing an unique lesion
• Minimal delay of one year after the stroke

Exclusion Criteria

• Visual acuity monocularly < 5/10
• Language disorder restricting oral and reading comprehension of the study
• Severe disability limiting the maintenance of sitting position and concentration capacities for a period of 30 minutes consecutive
• Poor French language skills
• Non-stabilized medical condition
• Psychotropic medication intake
• Pregnant and / or nursing women
• Subject under guardianship or curatorship
• Subject frequently in healthcare or social care for purposes other than research
• Subject deprived of liberty by a judicial or administrative decision

• Cerebellar patients

• Disorders prohibiting the correct performance of the task (tremor, ocular instability)

• Stroke patients

• Hemianopsia homonima lateral
• Neurological degenerative disease

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 80 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Hospices Civils de Lyon

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Caroline Tilikete, MD

Role: PRINCIPAL_INVESTIGATOR

Hospices Civils de Lyon

Locations

Hospices Civils de Lyon

Bron, , France

Countries

France

References

Cheviet A, Masselink J, Koun E, Salemme R, Lappe M, Froment-Tilikete C, Pelisson D. Cerebellar signals drive motor adjustments and visual perceptual changes during forward and backward adaptation of reactive saccades. Cereb Cortex. 2022 Sep 4;32(18):3896-3916. doi: 10.1093/cercor/bhab455.

Reference Type: BACKGROUND

PMID: 34979550 (View on PubMed)

Other Identifiers

2017-A00942-51

Identifier Type: OTHER

Identifier Source: secondary_id

69HCL17_0109

Identifier Type: -

Identifier Source: org_study_id