Superior Colliculus Activity in Parkinson Disease: a Potential Marker?

Summary

The ultimate goal of this project is to evaluate a possible new strategy to diagnose earlier Parkinson's disease, using the superior colliculus as a biomarker.

Preliminary data from the investigator's group in a rat model of Parkinson's disease suggest that the superior colliculus, a sensory structure, show an early deficit in visual processing. The investigator's data also suggests that with the evolution of the disease, this structure presents a neuronal re-organisation leading which causes a sensory rebound after the introduction of the treatment. The light responses in the superior colliculus were faster, bigger in amplitude and lasted longer (Rolland et al., 2012). Those results raise an important question about the superior colliculus functional state in Parkinson's patients. If this structure have a similar neuroplasticity, the investigators could hypothesize that the superior colliculus may also present a sensory rebound when introducing the treatment. If this hypothesis is true, the accelerated and amplified light responses of this structure may explain the difficulties felt by the patients to inhibit reflexive saccades induced by the appearance of unexpected visual stimuli. Indeed, the superior colliculus is involved in the orientation of the head and eye toward any sudden changes in our environment (Wurtz and Albano, 1980) and the light responses of this structure are strongly correlated with the speed of the saccade (Marino et al., 2012).

Therefore, the investigators want to test if a similar deficit could be observed in the superior colliculus of newly diagnosed PD patients. Data will be compared to matching controls.

Conditions

• Parkinson's Disease

Interventions

OTHER

fMRI

The investigators will use a non invasive fMRI technique centred on the superior colliculus during the presentation of flickered check-boards with varying contrast (1, 3, 5 and 9 %).

OTHER

Ophthalmologic evaluation

The aim of this experiment is the evaluate the functional state of a visual structure. Therefore, with this ophthalmologic test, the investigators will control if the participant does not present major visual deficits. This examination will evaluate the visual acuity and the visual field. A funduscopic examination will also be performed to check the retina.

OTHER

visual psychophysics test

This test will allow to control the sensitivity of the participant to our contrast. The participant will be asked to look at screen on which three static check-boards will be presented. The participant will have to choose the two check-boards with the closest contrast.

Sponsors & Collaborators

• Institut National de la Santé Et de la Recherche Médicale, France

  lead OTHER_GOV

Principal Investigators

• Elena Moro, MD/PhD · Institut National de la Santé Et de la Recherche Médicale, France

• Michel Dojat, PhD · Institut National de la Santé Et de la Recherche Médicale, France

Eligibility

Min Age

35 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2015-10-07

Primary Completion

2018-01-31

Completion

2018-01-19

Countries

• France

Study Locations