The physiology of developmental changes in BOLD functional imaging signals

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Cognitive Neuroscience

Background:

• Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) is widely used to study human brain development.
• BOLD signals reflect the relationship between neuronal activity, cerebral blood flow, and oxygen consumption.
• Developmental changes in BOLD signals may be confounded by alterations in neurovascular coupling or energy metabolism.

Purpose of the Study:

• To review the generation of BOLD signals and the pathways linking neuronal activity to blood flow.
• To summarize neural circuitry development from childhood to adulthood.
• To present changes in neurovascular coupling and energy use during human development.

Main Methods:

• Literature review of BOLD signal generation mechanisms.
• Synthesis of research on neural circuitry maturation.
• Review of studies on developmental changes in neurovascular coupling and energy metabolism.

Main Results:

• BOLD signal generation involves neuronal activity increasing cerebral blood flow, modulated by oxygen consumption.
• Human brain circuitry undergoes significant maturation from childhood through adolescence to adulthood.
• Neurovascular coupling and neural energy use also change substantially during development.

Conclusions:

• Developmental BOLD fMRI findings must consider concurrent changes in neurovascular coupling and energy metabolism.
• A framework is provided to differentiate BOLD signal changes due to cognitive processing versus physiological alterations.
• Accurate interpretation of developmental BOLD fMRI requires understanding these underlying physiological changes.