Visual awareness, emotion, and gamma band synchronization.
What makes us become aware? A popular hypothesis is that if cortical neurons fire in synchrony at a certain frequency band (gamma), we become aware of what they are representing. We tested this hypothesis adopting brain-imaging techniques with good spatiotemporal resolution and frequency-specific information. Specifically, we examined the degree to which increases in event-related synchronization (ERS) in the gamma band were associated with awareness of a stimulus (its detectability) and/or the emotional content of the stimulus. We observed increases in gamma band ERS within prefrontal-anterior cingulate, visual, parietal, posterior cingulate, and superior temporal cortices to stimuli available to conscious awareness. However, we also observed increases in gamma band ERS within the amygdala, visual, prefrontal, parietal, and posterior cingulate cortices to emotional relative to neutral stimuli, irrespective of their availability to conscious access. This suggests that increased gamma band ERS is related to, but not sufficient for, consciousness.
Luo
Qian
Q
Mood and Anxiety Disorders Program, MEG Core Facility, National Institute of Mental Health, 15K North Drive, MSC 2670, Bethesda, MD 20892, USA. luoj@mail.nih.gov
Mitchell
Derek
D
Cheng
Xi
X
Mondillo
Krystal
K
Mccaffrey
Daniel
D
Holroyd
Tom
T
Carver
Frederick
F
Coppola
Richard
R
Blair
James
J
D000328:Adult; D001288:Attention / Q000502:physiology; D001364:Awareness / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D003243:Consciousness / Q000502:physiology; D004644:Emotions / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D010775:Photic Stimulation; D011597:Psychomotor Performance; D014796:Visual Perception / Q000502:physiology