Biomedical subjects

Scania de Schonen

Publications and source records attributed to Scania de Schonen.

4 recordsLinked to original sources

PubMed2005

Early brain lesions and face-processing development.

Studies of functional plasticity after pre- or perinatal brain damage can tell us whether the neural substrate normally involved in the development of a given ability is specific and, if so, when it becomes functionally specified and unique. Development of face processing was investigated in 5- to 17-year-old children who had a unilateral brain injury in the pre-, peri-, or postnatal period. In Studies 1 and 2, patients with a posterior injury involving the temporal regions exhibited a face-processing deficit that was independent of their age at test time. Even though differences were observed between the two hemispheres in face processing during infancy as well as in adults in cases of normal development, no clear differences between right and left injury were observed here in face-processing deficit. Poor postlesional face-processing plasticity seems to contrast with results of several studies on speech development after early unilateral injury. If the difference in the time window for postlesional plasticity between these two areas of competency is confirmed, it would suggest that the two kinds of abilities rely on neural cells which are sensitive to different plasticity factors.

Adolescent↗

PubMed2004

Effect of visual experience on face processing: a developmental study of inversion and non-native effects.

In adults, three phenomena are taken to demonstrate an experience effect on face recognition: an inversion effect, a non-native face effect (so-called 'other-race' effect) and their interaction. It is crucial for our understanding of the developmental perception mechanisms of object processing to discover when these effects are present in childhood. Three- to 5-year-old Caucasian children (N = 64) were asked to recognize upright and inverted Caucasian and Asian faces. Recognition was tested with a forced-choice procedure. Overall performance improved with age. However, there was an interaction between the inversion and non-native effects that did not change with age between ages 3 and 5: (a) the inversion effect with native (Caucasian) faces was larger than with non-native (Asian) faces, and (b) upright native faces were recognized better than upright non-native faces. These results show that face orientation and morphology constrain face processing in 3- to 5-year-olds. The first 3 years of life during which the brain and the environment interact are sufficient to build a face-processing system that constrains recognition.

Adult↗

PubMed2003

Developmental changes in the processing of hierarchical shapes continue into adolescence.

The present study was designed to trace the normal development of local and global processing of hierarchical visual forms. We presented pairs of hierarchical shapes to children and adults and asked them to indicate whether the two shapes were the same or different at either the global or the local level. In Experiments 1 (6-year-olds, 10-year-olds, adults) and 2 (10-year-olds, 14-year-olds, adults), we presented stimuli centrally. All age groups responded faster on global trials than local trials (global precedence effect), but the bias was stronger in children and diminished to the adult level between 10 and 14 years of age. In Experiment 3 (10-year-olds, 14-year-olds, adults), we presented stimuli in the left or right visual field so that they were transmitted first to the contralateral hemisphere. All age groups responded faster on local trials when stimuli were presented in the right visual field (left hemisphere); reaction times on global trials were independent of visual field. The results of Experiment 3 suggest that by 10 years of age the hemispheres have adult-like specialization for the processing of hierarchical shapes, at least when attention is directed to the global versus local level. Nevertheless, their greater bias in Experiments 1 and 2 suggests that 10-year-olds are less able than adults to modulate attention to the output from local versus global channels-perhaps because they are less able to ignore distractors and perhaps because the cerebral hemispheres are less able to engage in parallel processing.

Adolescent↗

PubMed2002

Picture naming in young children: a developmental study on interhemispheric collaboration.

The aim of the present study was to determine how interhemispheric collaboration and visual attention in basic lexical tasks develop during early childhood. Two- to 6-year-old children were asked to name two different pictures presented simultaneously either one in each visual hemifield (bilateral condition) or both in a single hemifield (either right or left, unilateral condition). In the bilateral condition, children were overall more accurate in naming right visual field than left visual field pictures. This difference was significant for 2- and 3- to 4-year-old children, but not for 5- to 6-year-old children. These results show that the right and left cerebral hemispheres do not develop naming competencies equally well in early childhood. A second analysis, based on the order of report, showed that when 2- and 3- to 4-year-old children named both the left and the right visual field pictures, they named the right visual field picture first. In contrast, at the age of 5-6 years, children named the left visual field picture first and overall naming performance reached a ceiling level. Several interpretations are proposed to explain this shift of visual attention at the age of 5-6 years. In the unilateral condition, no difference was found between naming accuracy in the right and left visual fields, presumably because interhemispheric pathways are functional: visual stimuli presented to the right hemisphere can be processed by the most competent left hemisphere without degradation of information. This result confirms previous findings on the development of interhemispheric collaboration.

Child↗