Peer-Reviewed Journal Details
Mandatory Fields
Becker, C., Gramann, K., Müller, H.J., Elliott, M.A.
2009
March
Consciousness And Cognition
Electrophysiological correlates with the perception of subjective colors
Published
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Optional Fields
EEG Alpha band Gamma band Hallucinatory color Flicker EEG-ALPHA SELECTIVE ATTENTION SUBJECTIVE COLORS VISUAL ILLUSIONS GAMMA-ACTIVITY HUMANS OSCILLATIONS PERFORMANCE SYNCHRONIZATION PERCEPTION
18
266
276
In a recent study, Becker and Elliott [Becker, C., & Elliott, M. A. (2006). Flicker induced color and form: Interdependencies and relation to stimulation frequency and phase. Consciousness & Cognition, 15(1), 175-196] described the appearance of subjective experiences of color and form induced by stimulation with intermittent light. While there have been electroencephalographic studies of similar hallucinatory forms, brain activity accompanying the appearance of hallucinatory colors was never measured. Using a priming procedure where observers were required to indicate the presence of one of eight target colors we compared electrophysiological correlates of hallucinatory color with brain states associated with other visual phenomena. Different target colors were accompanied by different patterns of EEG activation. However. in general, we found that the appearance of hallucinatory colors is preceded by a power decrease in the lower alpha band alongside an increase in gamma band frequencies. We argue that decreasing activity in the lower alpha band acts as a gating mechanism, inducing a switch in perception between different colors. The increasing gamma activation may correlate with the formation of a coherent conscious percept. (C) 2008 Elsevier Inc. All rights reserved.
DOI 10.1016/j.concog.2008.05.001
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