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Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Behavioral indices and ERP parameters were analyzed in 5-6 years old children who were shown a previously unseen set of fragmented drawings of familiar objects. Within this set, each object was represented by a series of drawings of different degree of fragmentation. It is found that children of 5-6, when compared to 7-8 years old children, are capable to recognize less fragmented drawings. In these children, no increase was found in N350-400 prefrontal negativity and late positive complex, otherwise a typical feature of mature recognition involving executive control. A comparison of ERP for recognized vs. unrecognized stimuli showed a significant increase in P300 and N400 amplitude over the right occipital area. A key feature of children of this age is a lack of significant difference between ERP to recognized vs. unrecognized stimuli over extrastriatal cortex (T5/T6) which is the crucial structure for recognition of fragmented objects via integration of their sensory features. The data we obtained suggest that both executive control immaturity and insufficient involvement of the ventral visual system constitute a specifics of recognition in children of 5-6.
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PMID:[Neurophysiological mechanisms of recognition fragmented images in 5 to 6-year-old children]. 2233 23

The present study investigated the development of visuospatial working memory (VSWM) capacity and the efficiency of filtering in VSWM in adolescence. To this end, a group of IQ-matched adults and adolescents performed a VSWM change detection task with manipulations of WM-load and distraction, while performance and electrophysiological contralateral delay activity (CDA) were measured. The CDA is a lateralized ERP marker of the number of targets and distracters that are selectively encoded/maintained in WM from one hemifield of the memory display. Significantly lower VSWM-capacity (Cowan's K) was found in adolescents than adults, and adolescents' WM performance (in terms of accuracy and speed) also suffered more from the presence of distracters. Distracter-related CDA responses were partly indicative of higher distracter encoding/maintenance in WM in adolescents and were positively correlated with performance measures of distracter interference. This correlation suggests that the higher interference of distracters on WM performance in adolescents was caused by an inability to block distracters from processing and maintenance in WM. The lower visuospatial WM-capacity (K) in adolescents in the high load (3 items) condition was accompanied by a trend (p<.10) towards higher CDA amplitudes in adolescents than adults, whereas CDA amplitudes in the low load (1 item) condition were comparable between adolescents and adults. These findings point to immaturity of frontal-parietal WM-attention networks that support visuospatial WM processing in adolescence.
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PMID:Electrophysiological evidence for immature processing capacity and filtering in visuospatial working memory in adolescents. 2292 23

Psychophysical and electrophysiological indices of recognition of incomplete objects with progressive increasing of fragments, were studied in children of three age groups: 5-6, 7-8 and 9-10 years old. It is shown that most pronounced change in the effectiveness of recognition takes place between 5-6 and 7-8 years of age. In the group of children of 5-6, neither significant influence of the recognition process on ERP was found in the prefrontal cortex nor any significant growth of the Nd component was observed over extrastriate cortex. However, in the extrastriate cortex, the amplitude N170-200 component that reflects sensory analysis and encoding extracted features did increase. In the majority of children of this age, the immaturity of the prefrontal cortex manifest itself in the deficit of inhibitory control that results in the tendency to give the impulsive responses and make numerous errors. In children of 7-8, successful recognition is accompanied by the growth of the amplitude of N100 and N250 components over the prefrontal cortex and the growth of NcI component over the extrastriate cortex. In these children, when compared to the children of 5-6, a significant reduction, is observed in the error rate and the recognition threshold. By the age of 9-10 years, the growing role of the prefrontal cortex shows in greater gain in the Nd amplitude and the later ERP component that correspond to cognitive operations related to the recognition process. The results of the study point to the qualitative difference in the mechanisms of recognition between pre-school children and the younger school-children. At the age of 5-6, recognition is carried out on the basis of integration of sensory signs of objects. Since the 7-8 age, in recognition of fragmented images major role belongs to the prefrontal cortex, with its participation search of possible analogs of object in memory and the object identification is carried out.
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PMID:[Development of mechanisms of recognition fragmented images at the preschool and early school ages]. 2310 Dec 35