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A Desautels

Publications and source records attributed to A Desautels.

10 recordsLinked to original sources
PubMed2006

A novel autosomal dominant restless legs syndrome locus maps to chromosome 20p13.

The authors investigated genetic factors contributing to restless legs syndrome (RLS) by performing a 10-cM genome-wide scan in a large French-Canadian pedigree. They detected an autosomal-dominant locus mapping to chromosome 20p13, with a maximum multipoint lod score of 3.86 at marker D20S849. This is the third reported autosomal-dominant locus for RLS and the first autosomal-dominant RLS locus in the French-Canadian population.

Chromosome Mapping↗
PubMed2006

Long-term treatment with pramipexole in restless legs syndrome.

The aim of the present study was to look at the long-term efficacy and side effects profiles of pramipexole in a large cohort of drug naïve patients with regard to dopaminergic medications. In all, 195 consecutive restless legs syndrome (RLS) patients who were prescribed pramipexole more than 1 year previously, agreed to undergo a telephone interview to assess both the efficacy and side effects of pramipexole. Forty-three patients had discontinued pramipexole: 20 because of side effects, six because of a lack of efficacy, six for both and 11 for other reasons. Patients who continued pramipexole for more than 1 year (n = 152) reported a mean decrease in RLS symptoms severity of 80.9% (SD = 19.6%). At the onset of treatment, the most common side effects were nausea (30%), tiredness (9%), dizziness (8%), headache (4%), insomnia (3%), dry mouth (2%), difficulty to concentrate (1.3%) and sleepiness (0.7%), At 30 months, most patients (n = 124/152; 81.6%) reported an absence of side effects of pramipexole. None of the adverse effects occurred in more than 5% of patients at follow-up. The present study confirms, in a large cohort of unselected patients, that pramipexole is effective and safe in the long-term treatment of RLS.

Adult↗
PubMed2002

Evidence for a genetic association between monoamine oxidase A and restless legs syndrome.

BACKGROUND: Impairment in the central dopaminergic system has been consistently suggested as an etiologic factor in restless legs syndrome (RLS). OBJECTIVE: To investigate a possible role for the MAOA and MAOB genes in RLS using a population-based association study. METHODS: In addition to a dinucleotide repeat located within the second intron of the MAOB gene, a functional variable number of tandem repeat (VNTR) polymorphism recently identified in the MAOA gene promoter region was examined, using 96 extensively characterized patients and 200 control subjects matched for ethnic background. The relationship between variation at these loci and several clinical features was also considered. RESULTS: Pertaining to the MAOA gene, females with the high activity allele had a greater risk (OR: 2.0; 95% CI: 1.06 to 3.77) of being affected with RLS than females carrying the low activity alleles. The authors did not observe this association among the male subjects (OR: 0.98; 95% CI: 0.31 to 3.14). Interestingly, females carrying the high transcription alleles showed a longer sleep onset latency (U = 163.5; p = 0.015) and exhibited a higher movement index during the Suggested Immobilization Test (Student's t-test = -2.02; p = 0.048). No differences were observed regarding the MAOB gene in our sample. CONCLUSIONS: The high activity allele of the MAOA gene may represent a modifying factor involved in the severity of RLS manifestations in females.

Adult↗
PubMed2001

Identification of a major susceptibility locus for restless legs syndrome on chromosome 12q.

Restless legs syndrome (RLS) is a neurological disorder characterized by leg paresthesia associated with an irresistible urge to move that often interferes with nocturnal sleep, leading to chronic sleep deprivation. To map genes that may play a role in the vulnerability to RLS, a genomewide scan was conducted in a large French-Canadian family. Significant linkage was established on chromosome 12q, for a series of adjacent microsatellite markers with a maximum two-point LOD score of 3.42 (recombination fraction.05; P=6x10(-4); autosomal recessive mode of inheritance), whereas multipoint linkage calculations yielded a LOD score of 3.59. Haplotype analysis refined the genetic interval, positioning the RLS-predisposing gene in a 14.71-cM region between D12S1044 and D12S78. These findings represent the first mapping of a locus conferring susceptibility to RLS.

Canada↗
PubMed2001

Dopaminergic neurotransmission and restless legs syndrome: a genetic association analysis.

In order to examine the genetic substrate of the dopamine hypothesis in restless legs syndrome, we analyzed eight genes coding for receptors and enzymes related to dopaminergic transmission, using a population of 92 patients with restless legs syndrome and 182 controls matched for ethnic background. No significant differences were found in the genotypic or allelic distributions between groups. Furthermore, no effect of the loci examined was observed with stratification using clinical parameters such as age at onset or periodic leg movements during sleep index.

Adult↗
PubMed2001

Higher-order motion processing in the pulvinar.

Thalamic nuclei have long been considered as passive relay stations for sensory signals en route to the cerebral cortex, where higher level processing occurs. In recent years, it has been proposed that thalamic nuclei may actively participate in the processing of specific information in conjunction with cortical areas. In support of this hypothesis, we recently discovered that neurons in the main extrageniculate visual nucleus, the pulvinar, exhibit higher-order visual properties that were, until now, only associated with higher-order cortical areas. Pulvinar neurons can indeed code the veridical direction of a moving plaid pattern, indicating that these cells can integrate ambiguous signals into a coherent percept. This finding as well as our demonstration that there are cortico-thalamo-cortical loops involved in complex motion analysis open promising avenues in unraveling the function of the pulvinar complex in normal vision.

Animals↗
PubMed2001

Response properties in the pulvinar complex after neonatal ablation of the primary visual cortex.

Injuries to specific areas of the brain (such as cerebrovascular accidents or surgical procedures) and particularly to the primary visual cortex, yield profound visual defects. The level of spared visual functions or residual vision depends on the extent and location of the lesion as well as the age at which the trauma occurs. For instance, in primate as well as non-primate species, it is well established that lesions in adulthood have a more profound effect than those occurring in young animals. The recovery of visually guided behavior observed after massive destruction of the occipital cortex in young animals across many species has been generally associated with the reorganization of the pathways from the extrageniculate thalamus to the spared visual cortex, i.e. the extrastriate areas. In this chapter, we present some evidence that the lateral posterior-pulvinar (LP-pulvinar) complex may contribute to maintaining visual capacities in brain-damaged cats. Our data indicate that the overall visual responsiveness of the lateral part of the LP (LPl) cells is not altered by the early removal of the visual cortex. However, some specific properties differ from those of intact animals: on average, LPl neurons in brain-damaged animals are more broadly tuned for orientation than that in intact cats. Spatial frequency tuning functions are also affected since most units in lesioned animals are of the low-pass type. Moreover, most LPl cells of lesioned cats responded to drifting gratings with modulated discharges and a linear spatial summation within their receptive field, a characteristic that is infrequently observed in intact animals. The change in LPl response properties observed in the present study is likely to come from the reorganization of cortical and retinal fibers reaching this extrageniculate nucleus.

Animals↗
PubMed1998

Motion integration in a thalamic visual nucleus.

Thalamic nuclei have long been regarded as passive relay stations for sensory information en route to higher level processing in the cerebral cortex. Recently, physiological and theoretical studies have reassessed the role of the thalamus and it has been proposed that thalamic nuclei may actively participate with cortical areas in processing specific information. In support of this idea, we now show that a subset of neurons in an extrageniculate visual nucleus, the lateral-posterior pulvinar complex, can signal the true direction of motion of a plaid pattern, indicating that thalamic cells can integrate different motion signals into a coherent moving percept. This is the first time that these computations have been found to occur outside the higher-order cortical areas. Our findings implicate extrageniculate cortico-thalamo-cortical loops in the dynamic processing of image motion, and, more generally, as basic computational modules involved in analysing specific features of complex visual scenes.

Animals↗