Grant: Operating Grant

Because vision is not only a matter of eyes, the proposed research studies how the neurons in the brain could improve vision. The final objective is to find new pharmacological agents to alleviate visual deficits. The research particularly focuses on acetylcholine (ACh), a chemical substance secreted by certain neurons in the brain to communicate with each other. It is hypothesized that ACh could enhance the functioning of the region of the brain where visual information is first analyzed (named primary visual cortex or V1). The role of ACh in vision was examined because this neurochemical plays an active role in attention, learning and memory. The involvement of ACh in visual learning implies that this neurochemical facilitates the recognition of visual elements in a scene by increasing the rapidity and the efficiency of V1 to analyze these particular elements. We have already shown that ACh enhances the responses of the V1 neurons in rats to visual stimulation in a very persistent manner. Now the proposed experiments will examine the capacity of a repetitive exposition (during 2 weeks) of the rats to a visual pattern in combination to ACh circuit activation to improve permanently vision, electrical activity and neuronal circuits in V1. This is tested in normal animals as well as in animals with a retinal lesion to investigate whether a treatment with ACh contributes to the recovery of vision. First, these groups of rats will be tested in a maze in order to recognize the pattern to which they have been exposed regularly. Electrical activity in V1 will be measured by a technique similar to electroencephalography and the neuronal circuits will be analyzed on brain slices by microscopy. Finally, cerebral imaging will be used to observe the changes induced by the training on the representation of the pattern in V1. This study should provide new findings in order to potentiate the rehabilitation therapy to recover visual capacities by low vision people.