Biomedical subjects

J Blanc-Garin

Publications and source records attributed to J Blanc-Garin.

10 recordsLinked to original sources

PubMed1989

Spatial performance and perceptual asymmetries in beginning readers: shift of hand advantage in dichhaptic tasks.

The stability of perceptual asymmetries was studied in two groups of 6-year-old, right-handed children (normal, NL, and poor, PL) learning reading, by means of two experiments occurring at a year's interval (Experiment I and Experiment II). A dichhaptic procedure derived from S. F. Witelson's method (1974, Cortex, 10, 3-17) was used. With group data, perceptual asymmetries were stable over time, whereas with individual data, perceptual asymmetries were highly variable. NL children demonstrated a left-hand advantage at the group level in both Experiment I and Experiment II, with relatively little individual evolution over time. No significant hand advantage was found in PL children in Experiment I, but dramatic alterations occurred in Experiment II where all PL children shifted to a left-hand advantage. This shift was accompanied by an improvement in spatial performance. Such changes in perceptual asymmetry might be of an adaptive nature. Individual changes across time may be related to developmental plasticity (cerebral maturation) and/or neurocognitive flexibility (differential activation of cerebral subsystems).

Attention↗

PubMed1987

Tactual laterality effects and the processing of spatial characteristics: dichaptic exploration of forms by first and second grade children.

Tactual laterality effects (T.L.E.) were examined in first- and second-grade children when performing a dichaptic task. Our procedure, a modified version of Witelson's standard dichaptic task, emphasized the type of errors made, so that we could construct a weighted index (W.I.) for scoring rather than a strictly dichotomous one. The same data were compared using the two types of scoring indexes stated above. T.L.E. occurred consistently with the W.I. scores only, both in two independent groups or in the same group at a year's interval, suggesting (1) that a strictly dichotomous index might lead to loss of information, (2) that the results are reliable at least at the group level. Results are discussed in terms of possible applications of such a procedure to investigating the relationship between performance (spatial processing) and brain organization (hemispheric balance).

Child↗

PubMed1980

Visual evoked potentials and sensory dimensions.

Concomitant variations of physical stimulus characteristics and variations of responses elicited in the human adult subject were studied under conditions of adaptation to darkness or light in order to stimulate the B or the D sub-system described by Jung. Temporal processing in these two systems was compared by analysing output variables (VEPs and sensory ratings) in response to a range of electrophysiological and perceptual responses run in parallel: the temporal summation law, which is a basic code in the nervous system, is found to be obeyed in both B and D subsystems. But asymmetries are also observed, indicating specific characteristics of B and D functioning.

Adult↗

PubMed1976