Trends in Neurosciences
Research updateAbnormal cognition and behavior in preterm neonates linked to smaller brain volumes
Section snippets
Increased vulnerability of prenatal neurons
The neurological maturity of 6–10 day-old newborn rat pups corresponds to the crucial period for human brain development that occurs from the time just before birth to the time just after. This period is associated with peak rates of brain growth 6, synaptogenesis 7, and also with major changes in the expression, structure, and function of specific receptor populations, such as NMDA receptors that are a key component of excitotoxic cell death. Immature neurons have altered Ca 2+ signaling
Effect of adverse experiences
Animal models of hypoxia-ischemia, performed in neonatal rats have shown increased neuronal necrosis in the cerebral cortex, striatum, thalamus, and hippocampus 14. Similarly, infection of the neonatal mouse brain causes increased cortical and hippocampal apoptosis 15. In addition, models of sepsis and endotoxemia in neonatal pigs demonstrate increase susceptibility to neuronal and astrocytic injury in the frontal cortex associated with impaired integrity of the blood–brain barrier 16. Other
Concluding remarks
In spite of the improved survival of tiny preterm neonates, their neurodevelopmental outcomes remain a cause for grave concern. The two primary mechanisms leading to enhanced neuronal cell death in the immature brain are hypothesized to be: NMDA-mediated excitotoxicity (not discussed here); and enhanced naturally occurring neuronal apoptosis during early development as a result of multiple metabolic stresses.
The pattern and magnitude of abnormalities will depend on genetic variability as well
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Cited by (49)
Neurodevelopmental outcomes of the late preterm infant
2019, Seminars in Fetal and Neonatal MedicineCitation Excerpt :The late preterm brain is still immature and more likely to experience noxious stimuli from medical complications after birth such as respiratory distress syndrome, hypoglycemia, hyperbilirubinemia, and apnea. Evidence from animal models reveals that these factors can promote or precipitate neuronal cell death in the immature brain [52]. There is some evidence that it is unable to defend against such toxicities.
Sex differences in behavioral outcome following neonatal hypoxia ischemia: Insights from a clinical meta-analysis and a rodent model of induced hypoxic ischemic brain injury
2014, Experimental NeurologyCitation Excerpt :It was hypothesized that the protective behavioral effect expected in HI females would be concurrent to a lack (or reduction) of brain damage following induced HI injury. However, the current study revealed significant reduction in the volume of the right cortex and hippocampus, and a significant increase in the volume of the right ventricle, for both sexes (replicating neuropathology previously reported in male P7 HI rats; Alexander et al., 2013a; Bhutta, 2001; Hill et al., 2011a, 2011b; McClure et al., 2006; Towfighi, 1991). Thus, neuropathology indices did not show sex differences (Figs. 4a, b, & c).
Drug effects on endogenous brain activity in preterm babies
2014, Brain and DevelopmentCitation Excerpt :Increasing number of ELBW (extremely low birth weight) premature babies are surviving and the focus of attention in neonatal care is now shifting to their neurological outcome, because several studies on ex-preterm babies have reported later neurocognitive problems in NICU (neonatal intensive care unit) graduates [1,2]. It is now generally accepted that conditions associated with prematurity, or even treatment during NICU may account for the subsequent neurocognitive sequelae [3–10]. The time of NICU stay of ELBW babies corresponds to the early third trimester of pregnancy.
Neuroprotective approaches: Before and after delivery
2011, Clinics in PerinatologyCitation Excerpt :Imaging studies have recently shown that PVL is associated not only with reduced white matter volumes and ventricular enlargement but also reduced volume and complexity of cerebral cortical gray matter. This finding of reduced brain growth has been associated with poor neurodevelopmental outcomes in preterm neonates.46 This finding will further complicate the response to hypothermia or any other neuroprotective therapy in preterm infants.
Visual habituation and dishabituation in preterm infants: A review and meta-analysis
2010, Research in Developmental Disabilities