[Impact of very preterm birth on visuospatial processes at 5 years of age]. / Conséquences de la grande prématurité dans le domaine visuo-spatial, à l'âge de cinq ans.

OBJECTIVE: Very preterm children can experience cognitive and behavioral difficulties. The aim of this study was to assess the impact of very preterm birth on visuospatial processes at preschool age. DESIGN AND METHODS: Data come from the Epipage study. Participants underwent a follow-up evaluation at age 5 years. During the psychological evaluation, children took subtests of the K-ABC and the WPPSI-R. Six subtests are based on visuospatial information. RESULTS: The results concern 183 children assessed in the Lorraine region of France, who were born with birthweight appropriate for gestational age and had no neurological sequelae. Thirty-six children were born at term, 112 were born very prematurely (28-32 GW), and 35 were born extremely prematurely (<28 GW). Birth term was significantly correlated with performance on the six subtests. In all cases, the children born at term obtained higher scores compared to the children born very prematurely and extremely prematurely. On two subtests of the K-ABC, the children born extremely prematurely obtained lower scores than those of the children born very prematurely. The mother's level of education was correlated with performance on three subtests. CONCLUSION: The results suggest that a very preterm birth can exert a negative impact on visuospatial and visuomotor processes. These deficits may involve difficulties in some activities at school and in daily life.

[Cognitive development and attention performances at school age of "normal" prematurely born children]. / Développement cognitif et performances attentionnelles de l'ancien prématuré "normal" à l'âge scolaire.

OBJECTIVE: A preterm birth can exert an influence on cognitive development. The aim of this study was to determine whether preterm birth may impact on attention executive processes, at school age, in children without neurological sequelae. DESIGN AND METHODS: Prematurely born children admitted in the level III NICU of the Maternité régionale of Nancy between 1992 and 1994, underwent at 8 to 10 years 8 subtests of the mental processing scales of the K-ABC, which assess process categories involved in learning. The children were also submitted to 3 tests that evaluate attention mechanisms efficiency (category fluency task, backward digits span, Tower of London). The controls were children born at term recruted in schools of the same area. RESULTS: The 124 children were born with birth weight appropriate for gestational age, and were in the school grades expected for their ages, in 3rd, 4rth, and 5fth grades. Fifty-three children were born at term, 29 were prematurely born (33-36 w), and 42 were very prematurely born (28-32 w). Birth term was significantly correlated (P < 0.001) with scores at sequential processing scale, at simultaneous processing scale and at the mental processing composite scale. At this scale, the children born at term obtained a median score of 112, the children prematurely born of 101, and the children very prematurely born of 98.5. For 40 third grade children (18 born at term, 10 prematurely born, and 12 very prematurely born), birth term was significantly correlated with performances at the 3 tests of attention. In all cases, preterm was inversely correlated with performances. CONCLUSION: The results are consistent with a lower efficiency in attention executive processes which may be related to the higher frequency of learning disabilities associated with prematurity.

Long-term effects of early diazepam exposure on social differentiation in adult male rats subjected to the diving-for-food situation.

The present study was designed to investigate the consequences of a chronic diazepam (DZ) exposure (10 mg/kg/day) during the first 3 weeks of life on social behavior of adult male rats measured in a situation of restricted access to food, the diving-for-food model. The treatment had no long-term effects on the acquisition of social roles related to feeding. However, DZ-exposed rats were less efficient than controls in carrying food from the feeder to the cage during the 1st session but were able to adapt and improve their performances during the 2nd one. In the home cage, DZ-exposed rats were more aggressive toward conspecifics than controls and compensated for their deficit of food by stealing it from the others. These results suggest that an early DZ exposure has long-term consequences on social behavior of rats, possibly reflecting a reduction of the level of emotionality.

[Chronic prenatal exposure to diazepam, brain metabolism and behavior: long-term consequences in the adult rat]. / Exposition chronique précoce au diazépam, métabolisme cérébral et comportement: conséquences à long terme chez le rat adulte.

The long-term consequences of a neonatal exposure to diazepam (DZP) on behavioral abilities and local cerebral metabolic rates for glucose (LCMRglc) in selected brain regions involved in the control of memory and anxiety were studied in adult rats. Rat pups received a daily subcutaneous injection of 10 mg/kg DZP or of the dissolution vehicle from postnatal day (P) 2 to 21. Learning and memory were tested in P60-P70 rats on 5 consecutive days in a T maze and an eight arm maze while anxiety and reaction to novelty were tested in a 2 compartment box with a 2 step staircase on one side. Social behavior was evaluated in a condition of restricted access to food. LCMRglcs were measured at P60 by the quantitative autoradiographic [14C]deoxyglucose method. In the T maze, when performed without delay between the 2 trials, the rate of alternation was significantly lower in DZP than in vehicle-exposed rats on the first 2 days of testing and similar in both groups on days 3-5. In the procedure with a 30 s intertrial delay, the rate of alternation was similar in DZP and vehicle-treated rats on all days of testing. In the eight arm maze, DZP-treated rats were more active, i.e. entering more arms per min than control animals. The number of arms entered before the first error was lower on day 1 and higher on day 3 in DZP compared to vehicle-exposed rats. In the 2 compartment box, DZP-treated rats crossed more often the lower step of the staircase and spent more time than controls on the 2 steps of the staircase while control rats made more rearings than DZP-exposed rats in the well protected corner of the box. LCMRglcs were decreased by early DZP exposure in several cortical regions, mammillary body, septum and dorsomedian caudate nucleus. In conclusion, an early chronic DZP treatment induces an increase in activity, only a delay but no impairment in learning and leads to a decrease in the level of anxiety and emotionality leading to an active response to novelty. These quite subtle behavioral changes are accompanied by discrete metabolic changes and probably reflect the state of hyperactivity/hyperarousal of these animals which could result from a change in the distribution, the sensitivity and/or function of GABA-BZD receptors.

Potential stock differences in the social behavior of rats in a situation of restricted access to food.

The social behavior of outbred Long-Evans (LE) and Wistar (WI) rats was compared in a situation where access to food was particularly difficult (clearing an aquatic barrier, plus the necessity of carrying the food back to the home cage). In groups of either six WI or LE rats, only about 50% of individuals carried the food, and the others survived by attacking those that did. However, behavioral profiles associated with these acts were different in the two cases: LE carriers, contrary to WI carriers, restole some food, and LE noncarriers expressed more agonistic behavior and were more often attacked than were the WI noncarriers. Food flow and all associated, interactive behaviors were more complex in the LE than in the WI rats, indicating the likelihood of potential genetic differences in this testing situation.