Ultra-high field fMRI characterisation of cortical depth dependent BOLD responses in the primary visual cortex in neonates

Motivation: Despite the visual system's importance across life, development is slow in early infancy. The increased sensitivity and spatial specificity of ultra-high field fMRI provide new insights into this critical developmental phase. Goal(s): To characterise BOLD responses in the neonatal primary visual cortex. Approach: Cortical responses to an 8Hz flicker stimulus visual stimuli were characterized at 7T in a term-aged neonate and 4 adults using high resolution GRE-BOLD fMRI. Results: A robust positive BOLD response in V1 was observed in both the neonate and adults. However, the induced functional responses show distinct temporal differences with slower and longer responses in neonates compared to adults. Impact: We demonstrated the first robust positive BOLD response at 7T in the neonatal visual system comparable to adults. Characterising the differences in depth-dependent activation gives us an insight into the developing neurobiology of the visual system.