Language in dreaming and regional EEG alpha power

In an intensive single-subject design, electroencephalographic (EEG) alpha power and receptive and expressive language in dreaming were studied in 12 dreams during rapid eye movement (REM) sleep on 12 separate nights. Bilateral EEG was recorded continuously from 21 sites and digitized. We used the Fast Fourier transformation (FFT) for power spectral analysis to measure EEG power in the alpha frequency range (8-12 Hz) at each of the EEG sites. The subject was awakened after about 14 minutes into the second REM period, and dream reports were collected. We scored the dream reports for expressive and receptive language. The lower the alpha power on the left sides of those homologous pairs that roughly correspond to Broca's (C3) or Wernicke's area (P3), the more expressive or receptive language in dream reports. The largest difference between the correlation of the left and that of the right homologous pair of regions was found in the central (C3, C4) area for expressive language and in the parietal (P3, P4) area for receptive language. Our finding suggests lateralized and localized cortical activation in relation to language in dreaming.