Gaston Chevalier

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During the past decade, electrophysiological approaches have greatly improved understanding of the involvement of the basal ganglia in motor behaviour. This review reports that the basal ganglia contribute to the initiation of movement by arousing executive motor centres via a disinhibitory mechanism. We propose that the basal ganglia output is used as a(More)
As a major output station of the basal ganglia, the pars reticulata of the substantia nigra has stimulated much interest. In the past two decades there has been a growing body of evidence for a partition of this structure into separate channels to express the striatal processing. To further our knowledge on the functional partitioning of the rodent(More)
The physiological processes by which basal ganglia participate in the elaboration of movement are still poorly understood. In particular, lack of information about the synaptic organization of the output pathways of the basal ganglia impedes functional analysis of this system. To bridge this gap electroanatomical studies have been undertaken of one of the(More)
The aim of the present study was to identify in the rat the diencephalic nuclei addressed by ascending collaterals of tecto-spinal neurons. For this purpose we made use of anterograde axonal transport method to determine the pattern of diencephalic projections arising from the lateral portion of the superior colliculus where most of tecto-spinal neurons are(More)
The neurons located in the ventromedial tegmentum (VMT) and projecting either to the frontal cortex, to the septum or to the nucleus accumbens were identified by the antidromic activation method in normal rats and in animals whose dopaminergic (DA) systems had been previously lesioned by microinjections of 6-hydroxydopamine (6-OHDA). Two groups of VMT(More)
The susceptibility to lipid peroxidation (LPO) of liver, kidneys, brains, lungs, heart, and testes was assessed in rats administered intraperitoneally with various doses of cadmium (Cd). Dose-response studies were carried out with male Long Evans rats (12-week-old; 300 +/- 33 g) injected with 25, 125, 500, and 1250 micrograms Cd/kg as CdCl2 and sacrificed(More)
The nigro-collicular pathway that links the basal ganglia to the sensorimotor layers of superior colliculus plays a crucial role in promoting orienting behaviors. This connection originating in the pars reticulata and lateralis of the substantia nigra has been shown in rat and cat to be topographically organized. In rat, a functional compartmentalization of(More)
The aim of the present study was to test the GABAergic nature of the inhibitory projection from substantia nigra, pars reticulata (SNr) to superior colliculus (SC) in the rat, through the use of extracellular recordings and microiontophoresis. The effect of SN stimulation on the spontaneous or glutamate-evoked firing of SC units was analyzed. Among 28 SC(More)