| Technologies |
Underlying physical activity |
Electrode placement |
Measurement frequency range |
Typical amplitude |
Spatial resolution |
Temporal resolution |
Key advantage |
Key disadvantage |
| EEG |
Synchronous neuronal activities (potential) |
Scalp contact (usually cap) |
0.1 Hz to 100 Hz |
Less than 100 µV |
1 cm |
1- 5 ms |
Non-invasive, portability |
Spatial resolution |
| MEG |
Synchronous neuronal activities (current) |
Remote (eg. helmet) |
2 Hz to 100 Hz |
Less than 10−14 Tesla |
2 – 3 mm |
~1 ms |
Non-invasive |
Non-portability |
| MRI |
Increased blood flow at cortical lobes |
Remote (bed inside a tubular equipment) |
- |
- |
1 – 10 mm |
1 – 2 s |
Non-invasive, non-contact |
Non-portability, temporal resolution |
| ECoG (or iEEG) |
Local field potential |
Intracranial, cortical surface |
1 Hz to 100 Hz |
Several hundred µV |
0.5 – 3 mm |
~1 ms |
Signal quality, spatial and temporal resolution |
Surgery requirement, highly invasive |
| Microelectrode (or Microwire) |
Extracellular action potential |
Intracranial, intracortical |
0.5 – 5 kHz |
A few mV |
~100 µm2 |
0.1 ms |
Signal quality, spatial and temporal resolution |
High risk surgery requirement, gliosis and other medical complication |
| MEA |
Extracellular neuronal activities from multiple sites |
Intracranial, intracortical |
0.5 – 5 kHz |
A few mV |
~100 µm2 at each site |
0.1 ms |
Signal quality, simultaneous monitoring of multiple sites |
High risk surgery requirement, gliosis and other medical complications |
