Table 1.
Overview of principle methods used to investigate neuroimaging signals and neurovascular coupling.
| Technique | Data streams | Main advantages | Relative disadvantages | Usable in humans? |
|---|---|---|---|---|
| High field fMRI | BOLD, CBV, CBF | Cross-species technique, whole brain imaging | High cost, difficult to combine with other techniques, limited spatial and temporal resolution | Yes |
| Near infrared spectroscopy | Oxy-, deoxy, and total hemoglobin | High temporal resolution, low cost human neuroimaging | Poor spatial resolution, limited depth penetration | Yes |
| Diffuse optical tomography | Oxy-, deoxy, and total hemoglobin | Cross-species technique | Poor spatial resolution, limited depth penetration | Yes |
| Optical imaging spectroscopy | Oxy-, deoxy, and total hemoglobin | Combination of good temporal and spatial resolution, easy to combine with other techniques | Limited depth penetration, cortical surface only | Intraoperative only |
| Photoacoustic tomography | Oxy-, deoxy, and total hemoglobin, microcirculation | Whole brain imaging, high spatial resolution | Relatively low temporal resolution | No |
| Optical coherence tomography | Blood flow (microcirculation) | Absolute measurement of flow, good depth penetration and spatial resolution | Only cortical (surface structure) imaging possible | No |
| Laser speckle contrast imaging | Blood flow (2D) | High sensitivity, can image through skull | Limited depth penetration, spatial resolution lower then optical techniques | No |
| Confocal microscopy | Blood flow, tissue oxygen, microcirculation, cellular activity | Excellent spatial and temporal resolution, can measure neuronal and vascular markers | Loss of spatial resolution at depth, higher risk of photobleaching | No |
| Two-photon microscopy | Blood flow, tissue oxygen, microcirculation, cellular activity | Highest spatial and temporal resolution, neuronal and vascular markers, good depth penetration | Relatively costly, not easy to combine with other techniques | No |
| Voltage sensitive dye imaging | Cellular activity | High spatial and temporal resolution measurement of cellular activity | Difficult to combine with other optical readouts, risk of toxicity from dyes | No |
| Laser doppler flowmetry | Blood flow (point mesaurement) | Easy to combine with other techniqies | Point measurement only | No |
| Tissue oxygen voltammetry | Tissue oxygen (point measurement) | High temporal resolution | Point measurement only, limited spatial precision | No |
| Tissue oxygen polarography | Tissue oxygen (point measurement) | Very high resolution recording | Point measurement only, fragile electrodes | No |
| Tissue oxygen luminescence | Tissue oxygen (point measurement) | Easy to use, good temporal resolution | Point measurement only, limited spatial precision | No |
| Invasive electrophysiology (Various) | Single or multi-unit activity, local field potentials | Highly localised recording, optimal temporal resolution | limited compatibility with fMRI, risk of damage to brain tissue from electrode | No |
| Non-invasive electrophysiology (EEG, MEG) | Event-related potentials, current sources and sinks | High temporal resolution, low cost human neuroimaging | Limited spatial resolution | Yes |