Cerebral haemodynamic response to somatosensory stimulation in neonatal lambs.

Key points Cerebral haemodynamic response to neural stimulation has been extensively studied in adults, but little is known about cerebral haemodynamic response in the fetal and neonatal brain., The present study describes the cerebral haemodynamic response measured by near infrared spectroscopy to somatosensory stimulation in newborn lambs, in comparison to recent findings in fetal sheep., The cerebral haemodynamic responses in the newborn lamb brain can involve an increase in oxyhaemoglobin (oxyHb), or a decrease of oxyHb suggestive of reduced perfusion and oxygenation., Positive correlations between changes in oxyHb and mean arterial blood pressure were found in newborn but not fetal sheep, which suggests the result is unlikely to be due to immature autoregulation alone., In contrast to adult studies, hypercapnia increased the changes in cerebral blood flow and oxyHb in most of the lambs in response to somatosensory stimulation., Abstract The neurovascular coupling response has been defined for the adult brain, but in the neonate non-invasive measurement of local cerebral perfusion using near infrared spectroscopy or blood oxygen level-dependent functional magnetic resonance imaging have yielded variable and inconsistent results, including negative responses suggesting decreased perfusion and localized tissue tissue hypoxia. Also, the impact of permissive hypercapnia ( [ABSTRACT FROM AUTHOR]