Frédéric Lévesque

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Laterality in paw use was investigated over a period of 6 years in 44 domestic cats trained to perform a reaching movement toward a moving spot of light. Both paw preference and paw performance were recorded. At a 50 percent criterion, no significant paw preference was found at the level of the group. When a 90 percent criterion was considered, 23 subjects(More)
Detailed in vivo and in vitro studies of glucose and insulin metabolism in Friedreich's ataxia patients and unaffected family members have further defined the extent of the abnormalities in carbohydrate metabolism. The high incidence of glucose intolerance and a hyperinsulinemic response to a glucose challenge in a high percentage of Friedreich's ataxia(More)
OBJECTIVES Seasonal affective disorder (SAD) is characterized by a mood lowering in autumn and/or winter followed by spontaneous remission in spring or summer. Bright light (BL) is recognized as the treatment of choice for individuals affected with this disease. It was speculated that BL acts on photosensitive retinal ganglion cells, particularly sensitive(More)
The motor deficits induced by red nucleus lesions have been well documented but so far based upon approaches destroying both cells and fibres of passage. In the present study we used kaïnic lesions, which are known to spare, at least partially, the fibres of passage in order to re-investigate the motor deficit induced by rubral lesion. Five cats were fully(More)
The role of the ventrolateral thalamic nucleus (VL) has been analyzed in the phase of motor recovery that takes place when the execution of a previously learned movement has been perturbed by damage to another brain area. Cats were trained to perform a reaching movement toward a moving target-spot; they underwent bilateral brain lesions after performance(More)
Impairments in reaching toward stationary and moving targets were studied in cats after restricted or extensive removal of visual cortical areas (areas 17, 18 and 19 and lateral suprasylvian visual areas). Regardless of the extent of the cortical lesion, cats were at first unable to localise and reach for a stationary target whereas they were soon able to(More)
In order to test the hypothesis that visual information reaching the cerebellum through the pontine nuclei is involved in the control of visually guided movements, the effects of bilateral kainic acid pontine lesions have been analysed in cats performing a reaching movement towards a spot of light that was either stationary or moving. In 4 cats, the lesion(More)
The existence of long-term effects of dark-rearing on visuo-motor coordination is still controversial. In this study 2 dark-reared (DR) cats were trained, after 5-6 years of recovery, to perform a reaching movement towards a stationary or a moving target. The accuracy, and the reaction and movement times were evaluated. The scores obtained by the DR cats(More)
Bilateral lesions of the substantia nigra were carried out in cats previously overtrained at performing a visually guided forepaw movement towards a moving target. Both their reaction time (RT) and movement time (MT) were impaired postoperatively. On the other hand, their pointing precision was unimpaired after lesion and even improved relative to the(More)
The pontocerebellar pathway in the brachium pontis (BP), is known to convey signals from various cortical and subcortical visual structures to the cerebellum. Recently, a cortico-pontocerebellar pathway involving the BP has been implicated in the control of visually guided movements, on the basis of anatomical and physiological data. To further test this(More)
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