Visual awareness, emotion, and gamma band synchronization.
Qian Luo, Derek Mitchell, Xi Cheng, Krystal Mondillo, Daniel Mccaffrey, Tom Holroyd, Frederick Carver, Richard Coppola, James Blair
Cerebral cortex (New York, N.Y. : 1991) August 1, 2009 DOI: 10.1093/cercor/bhn216 (opens in new tab) via PubMed
Summary
AI-generated from the abstractGamma-band synchronization in the brain is linked to conscious awareness but is not sufficient for it. Using brain-imaging, researchers observed increased gamma event-related synchronization (ERS) in prefrontal-anterior cingulate, visual, parietal, posterior cingulate, and superior temporal cortices when stimuli were consciously detected. However, gamma ERS also increased in the amygdala, visual, prefrontal, parietal, and posterior cingulate cortices for emotional versus neutral stimuli, regardless of whether participants were aware of them. This indicates that gamma-band activity is related to both conscious perception and emotional processing, but its presence does not guarantee consciousness.
Study at a glance
| Characteristics | Observational study Peer reviewed |
|---|---|
| Key finding | Increased gamma-band ERS is related to conscious awareness but also occurs for emotional stimuli without awareness, suggesting it is not sufficient for consciousness. |
Abstract
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.