Development of BOLD signal hemodynamic responses in the human brain

Abstract

In the rodent brain the hemodynamic response to a brief external stimulus changes significantly during development. Analogous changes in human infants would complicate the determination and use of the hemodynamic response function (HRF) for functional magnetic resonance imaging (fMRI) in developing populations. We aimed to characterize HRF in human infants before and after the normal time of birth using rapid sampling of the Blood Oxygen Level Dependent (BOLD) signal. A somatosensory stimulus and an event related experimental design were used to collect data from 10 healthy adults, 15 sedated infants at term corrected post menstrual age (PMA) (median 41 + 1 weeks), and 10 preterm infants (median PMA 34 + 4 weeks). A positive amplitude HRF waveform was identified across all subject groups, with a systematic maturational trend in terms of decreasing time-to-peak and increasing positive peak amplitude associated with increasing age. Application of the age-appropriate HRF models to fMRI data significantly improved the precision of the fMRI analysis. These findings support the notion of a structured development in the brain's response to stimuli across the last trimester of gestation and beyond.

Hemodynamic response to burst-suppressed and discontinuous electroencephalography activity in infants with hypoxic ischemic encephalopathy

“…41 The nature of the healthy neonatal functional hemodynamic response is still an issue of some debate. While several studies suggest the neonatal (and even early preterm) hemodynamic response is consistent with that observed in the mature brain, 42,43 a recent study in the rat model suggests that the hemodynamic response to an external stimulus varies significantly with postnatal age. 44 In the infant rat, the hemodynamic response was found to consist of a small increase in HbO, followed by increase in HbR, while the response in the adult rat was consistent with the typical adult human response, i.e., an increase in HbO with a concomitant decrease in HbR.…”

Imaging structural and functional brain development in early childhood

“…For example, task-based fMRI and FNIRS studies using passive stimuli have revealed adult-like positive blood-oxygen-level-dependent (BOLD) signals in response to sensorimotor 74, 75 , visual 76 , and auditory stimuli 77, 78 in human newborns and infants. FNIRS studies have documented the emergence and gradual improvement of various other functional responses during spatiotemporal processing 79 , object recognition 80 , learning 81 and social processing 82 , among other processes, during the first year of life.…”

The emergence of functional architecture during early brain development

“…Much of our present-day knowledge about brain-behavior relationships shortly after birth comes from task-based fMRI studies (Allievi et al, 2016;Anderson et al, 2001;Arichi et al, 2013Arichi et al, , 2012Arichi et al, , 2010Born et al, 1996;Dehaene-Lambertz et al, 2010, 2002Erberich et al, 2006;Heep et al, 2009;Konishi et al, 2002;Morita et al, 2000). These studies have provided important background on the brain's responses to sensory input during the earliest phases of development of brain-behavior interactions.…”