Donepezil Effect on Visual Attention and Training
Condition: Healthy
Study type: Interventional

Summary: 
      The present proposal investigates the role of the cholinergic system (the neurotransmitter
      acetylcholine) in improving vision and visual attention. Vision results from a complex
      processing of particular stimuli of the visual field. Attention enhances and prolongs the
      neural representations of visual input in the visual cortex. It has recently been shown that
      attention in the visual cortex depends on cholinergic mechanisms. The action of acetylcholine
      in the visual cortex consists in enhancement of the responsiveness to thalamocortical inputs,
      depression of local neuronal connections or extrastriate feedback projections and induction
      of gamma synchronisation. The investigators hypothesize that these effects are associated
      with long-term changes in functional connectivity in the visual cortex, visual attention and
      visual learning (improvement of the visual capacities).

      In the present proposal, the investigators will test whether the administration of donepezil
      (Aricept, 5mg), a drug that increases the level of acetylcholine in the brain, will enhances
      the perceptual-cognitive abilities of young adult subjects. Perceptual-cognitive performance
      will be assessed in a multiple object tracking (MOT) task in a 3D automatic virtual
      environment. MOT is a task where observers are asked to maintain attentional focus on a
      limited number of preselected subgroup of elements in a dynamic scene. Multifocal attentional
      mechanisms are necessary to process the information. The task will be tested five time at one
      week interval to test whether donepezil and training improved the task performance of the
      subject, i.e. lead to perceptual learning. This study could help establish an intervention
      procedure to improve visual performance of subjects that need it.
    

Detailed description: 
      Stages of a given perceptual-cognitive task (from Faubert and Sidebottom, Journal of Clinical
      Sport Psychology, 2012, 6, 85-102):

        1. a predetermined number of spheres (typically eight) are presented in a 3D dimensional
           virtual volumetric cube space. The spheres are typically all identical.

        2. a subset of spheres (typically four) is indexed via highlighting for a brief period of 1
           s.

        3. the spheres return to their original color and start moving within the restricted 3D
           virtual space. During this movement, the spheres can collide and consequently suddenly
           change direction, and they can cross over others, thus occluding their view.

        4. the spheres stop moving after a predetermined time, and the observer has to identify the
           spheres that were initially indexed with halos. The subject is then given feedback on
           the response by having the spheres identified by revealing the appropriate indexed
           stimuli.

      The main task starts at a given speed, and if all four spheres are not correctly identified,
      the next trial will be slower. If the four spheres are correctly identified, then the next
      trial will be faster. Trials are repeated like this following a staircase procedure, and
      ultimately, a speed threshold is established.
    

Intervention name(s): Donepezil administration; Placebo administration
Intervention type(s): Drug; Drug
Other intervention name(s): Aricept, Pfizer; Lactose pill
Intervention MeSH terms: Donepezil
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Basic Science
Keywords: acetylcholine; cholinergic system; visual perception; visual attention; multiple objects tracking; perceptual learning; vision training