Human brain mapping: hemodynamic response and electrophysiology.

Area of Science:

• Neuroscience
• Clinical Neurophysiology
• Medical Imaging

Background:

• Functional neuroimaging techniques are advancing rapidly.
• Non-invasive methods are crucial for human brain mapping.
• Understanding neurovascular coupling is key to interpreting brain activity.

Purpose of the Study:

• To review the current status of non-invasive functional neuroimaging techniques for human brain mapping.
• To integrate hemodynamic and electrophysiological principles in brain mapping.
• To discuss the application of these techniques in clinical neurophysiology.

Main Methods:

• Review of functional neuroimaging techniques based on hemodynamic principles: functional magnetic resonance imaging (fMRI), positron emission tomography (PET), single-photon emission computed tomography (SPECT), and near-infrared spectroscopy (NIRS).
• Review of electrophysiological techniques: electroencephalography (EEG), magnetoencephalography (MEG), and transcranial magnetic stimulation (TMS).
• Discussion of neurovascular coupling and the relationship between hemodynamic response and neuronal activity.

Main Results:

• Hemodynamic techniques (fMRI, PET, SPECT, NIRS) and electrophysiological techniques (EEG, MEG, TMS) offer distinct spatial and temporal resolutions.
• Hemodynamic response correlates with neuronal activity (local field potential) but is more widespread and longer-lasting.
• Multi-modal approaches, combining techniques like EEG and fMRI, improve brain mapping accuracy.
• Functional connectivity can be assessed using single techniques or combined stimulation and imaging methods.

Conclusions:

• Selecting the appropriate technique or combining methods is essential for specific research questions in brain mapping.
• Multi-modal neuroimaging approaches, including simultaneous and sequential combinations, enhance the study of brain function.
• Advances in technology and analysis will improve understanding of brain specialization and connectivity, aiding neurological and psychiatric disorder treatments.