[Tachistoscopic study of hemispheric specialization in agenesis of the corpus callosum].
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Adolescent↗
Biomedical subjects
M Lassonde
Publications and source records attributed to M Lassonde.
Corpus callosotomy for control of intractable epilepsy in children.
Cerebral commissurotomy has often been reported to control seizures in patients suffering from intractable epilepsy. However, in adults, division of the corpus callosum alone has been shown to be equally effective while considerably reducing the surgical morbidity. The present study of nine epileptic callosotomized patients suggests that callosal section can also be performed successfully and safely in children. Neurologic and concomitant psychological improvements are described.
Adolescent↗
[The role of the corpus callosum and other commissures in the interhemispheric transfer of visual information].
In order to assess the contribution of the lateral suprasylvian area and subcortical pathways other than the corpus callosum in learning and interhemispheric transfer, a series of studies was undertaken in the cat. Groups of animals which received different types of cortical and subcortical lesions were tested for learning and interocular transfer of visual pattern discriminations. Results have shown that : 1. the lateral suprasylvian area is of equal importance in learning and transfer as areas 17, 18 and 19; 2. in the absence of the corpus callosum, other commissures could preserve interocular transfer of visual information. The results obtained on commissurotomized neonate kittens clearly support this assumption.
Animals↗
Spectral sensitivity in a female Cebus Griseus.
The photopic spectral sensitivity of one female Cebus Griseus was determined to complement published results showing that this monkey did not demonstrate the red deficiency typical of most New World monkeys. A modified method of limits was used to determine S's perceived brightness of different monochromatic stimuli. The results suggest that this monkey might be a normal trichromat.
Animals↗
Generalized lentigines associated with multiple congenital defects (leopard syndrome).
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Abnormalities, Multiple↗
Prosopagnosia: a case study involving problems in processing configural information.
An ongoing issue in face recognition research is whether holistic face processing relies on the segregation of local discrete facial parts. Evidence in favor of the holistic-plus-parts view stems from a recent study reported by Arguin and Saumier (1999), who show that the priming effects of individual facial parts (i.e., eyes, nose, mouth, orcontour) depends on the presence of configural information and that the magnitude of priming augments as the number of facial parts serving as primes increase. The present study demonstrates that these global processing effects are absent in a prosopagnosic patient (A.R.), who shows no priming from single face parts and a linear increase in the magnitude of priming as a function of the number of parts presented. These findings indicate that A.R. is incapable of integrating individual facial parts into a global facial configuration ant that this is likely at the root of her prosopagnosia.
Child↗
Development of noninvasive and quantitative methodologies for the assessment of chronic ulcers and scars in humans.
Chronic ulcers are a significant and common cause of morbidity and mortality worldwide. They disrupt the epidermis and dermis, resulting in a loss of barrier function. Keloids and hypertrophic scars (benign cutaneous tumors) represent an abnormal healing response. These fibroproliferative disorders are characterized by an overabundance of collagen and accumulation of extracellular matrix due to an imbalance between synthesis and degradation, culminating in excessive scarring. The objectives of this study were to evaluate and compare noninvasive biophysical methods for the measurement of outstanding quantitative parameters of scars and chronic ulcers, and to establish correlations between the parameters measured and the results of conventional subjective clinical evaluations. The development of new technologies, based on ultrasonography and laser Doppler, makes possible new dermatological evaluation methods. Fifteen patients (6 females and 9 males) with 15 chronic ulcers (4 diabetic ulcers, 10 venous ulcers and 1 pressure ulcer) and 30 patients (19 females and 11 males) with 30 scars (25 hypertrophic and 5 keloids) were included in this study. Clinical evaluation was performed by a dermatologist, an aesthetic surgeon and an endocrinologist. Biophysical measurements were used to assess local blood flow by laser Doppler flowmetry (Moor DRT4), thickness and echogenicity by high frequency ultrasonography (20 MHz, Dermascan C) and ulcer linear dimensions by image analysis. Our results show that blood flow within the ulcers and scars was higher than within normal skin. Also, skin thickness of chronic ulcers was decreased when compared to normal skin; the thickness of hypertrophic scars, but not of keloids, was increased in comparison to normal skin, and presented the possibility of measuring wound and scar surfaces with precision. In summary, this pilot study established the feasibility of measuring various biophysical parameters and adapted their potential utility to research on wounds.
Adult↗