Alpha EEG coherence in different brain states: an electrophysiological index of the arousal level in human subjects

• Published in: Neuroscience letters Vol. 271; no. 3; pp. 167 - 170
• Main Authors: Cantero, José L., Atienza, Mercedes, Salas, Rosa M., Gómez, Carlos M.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 27.08.1999; Elsevier
• Subjects: Adult; Alert index; Alpha activity; Alpha Rhythm; Arousal - physiology; Biological and medical sciences; Drowsiness; EEG coherence; Fourier Analysis; Frontal Lobe - physiology; Fundamental and applied biological sciences. Psychology; Humans; Occipital Lobe - physiology; Rapid eye movement sleep; Sleep Stages - physiology; Sleep, REM - physiology; Sleep. Vigilance; Vertebrates: nervous system and sense organs; Wakefulness; EEG coherence; Alpha activity; Wakefulness; Alert index; Humans; Drowsiness; Rapid eye movement sleep; Human; Alpha rhythm; Central nervous system; Electrophysiology; Electroencephalography; Brain (vertebrata)
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/S0304-3940(99)00565-0

The functional relationships between the brain areas supposedly involved in the generation of the alpha activity were quantified by means of INTRA- and INTER-hemispheric coherences during different arousal states (relaxed wakefulness, drowsiness at sleep onset, and rapid eye movement sleep) where such an activity can be clearly detectable in the human EEG. A significant decrease in the fronto-occipital as well as in the inter-frontal coherence values in the alpha range was observed with the falling of the vigilance level, which suggests that the brain mechanisms underlying these coherences are state dependent. Making fronto-frontal coherence values in the alpha frequency band useful indexes to discern between brain functional states characterized by a different arousal level.