Cerebral haemodynamic response to somatosensory stimulation in preterm lambs and 7–10-day old lambs born at term: Direct synchrotron microangiography assessment

Ishmael M. Inocencio, Nhi T. Tran, Shinji Nakamura, Song J. Khor, Manon Wiersma, Katja Stoecker, Anton Maksimenko, Graeme R. Polglase, David W. Walker, James T. Pearson, Flora Y. Wong

Research output: Contribution to journalArticleResearchpeer-review

1 Citation (Scopus)


Neurovascular coupling has been well-defined in the adult brain, but variable and inconsistent responses have been observed in the neonatal brain. The mechanisms that underlie functional haemodynamic responses in the developing brain are unknown. Synchrotron radiation (SR) microangiography enables in vivo high-resolution imaging of the cerebral vasculature. We exploited SR microangiography to investigate the microvascular changes underlying the cerebral haemodynamic response in preterm (n = 7) and 7–10-day old term lambs (n = 4), following median nerve stimulation of 1.8, 4.8 and 7.8 sec durations. Increasing durations of somatosensory stimulation significantly increased the number of cortical microvessels of ≤200 µm diameter in 7–10-day old term lambs (p < 0.05) but not preterm lambs where, in contrast, stimulation increased the diameter of cerebral microvessels with a baseline diameter of ≤200 µm. Preterm lambs demonstrated positive functional responses with increased oxyhaemoglobin measured by near infrared spectroscopy, while 7–10-day old term lambs demonstrated both positive and negative responses. Our findings suggest the vascular mechanisms underlying the functional haemodynamic response differ between the preterm and 7–10-day old term brain. The preterm brain depends on vasodilatation of microvessels without recruitment of additional vessels, suggesting a limited capacity to mount higher cerebral haemodynamic responses when faced with prolonged or stronger neural stimulation.

Original languageEnglish
Pages (from-to)315-328
Number of pages14
JournalJournal of Cerebral Blood Flow and Metabolism
Issue number2
Publication statusPublished - Feb 2022


  • Cerebral haemodynamic response
  • neurovascular coupling
  • newborn
  • preterm
  • synchrotron microangiography

Cite this