Physiological explanation of coherence:
Coherence measures how synchronously two brain areas operate at a specific frequency.
High coherence (close to 1):
- Synchronous activity between channels
- Functional connection between brain regions
- Possible synchronization of neural ensembles
- Possible common noise source (interference, muscle artifacts)
Low coherence (close to 0):
- Independent channel activity
- No functional connection
Frequency specificity:
- Coherence can be high in some frequency ranges and low in others.
- This reflects frequency-specific functional connections.
Frequency-specific relationships:
- Alpha coherence (8–13 Hz): associated with relaxation and resting synchrony
- Beta coherence (13–30 Hz): associated with active information processing and cognitive tasks
- Gamma coherence (30–100 Hz): associated with information binding and perception
Practical significance:
- Changes in coherence reflect changes in functional brain networks.
- High coherence in appropriate ranges is a sign of efficient brain functioning.