Coupling between neuronal activity and microcirculation: implications for functional brain imaging.

Area of Science:

• Neuroscience
• Neuroimaging
• Systems Neuroscience

Background:

• Neurons with similar response properties cluster in the neocortex, forming functional architecture.
• Functional brain imaging techniques have revolutionized neuroscience by revealing the spatial organization of active neurons.
• Understanding functional architecture is closely tied to the development of imaging methodologies.

Purpose of the Study:

• To review the link between functional imaging methodologies and the understanding of functional architecture.
• To focus on indirect imaging techniques (metabolic/haemodynamic signals) versus direct electrical activity measurement.
• To discuss the spatio-temporal characteristics of neurovascular coupling and its implications for brain imaging.

Main Methods:

• Review of functional brain imaging techniques, including post-mortem and in-vivo methods.
• Emphasis on indirect imaging methods that measure metabolic or haemodynamic signals.
• Highlighting optical imaging of intrinsic signals for its high spatial resolution (~50 µm).

Main Results:

• Functional imaging has yielded crucial information about the spatial organization of active neurons.
• Optical imaging of intrinsic signals provides high-resolution characterization of metabolic and haemodynamic responses.
• These methods allow for the characterization of neurovascular coupling induced by sensory-evoked neuronal activity.

Conclusions:

• The development of functional imaging techniques has significantly advanced our understanding of neocortical functional architecture.
• Indirect imaging methods, particularly optical imaging, offer high spatial resolution for studying neuronal activity.
• Findings on neurovascular coupling have important implications for various functional brain imaging techniques, including PET and fMRI.