Some nights are filled with happy dreams while other nights may be all about angry dreams. Researchers have found certain clues in the brain waves that show the reason why angry dreams occur when a person sleeps. The results of the study titled, “EEG Frontal Alpha Asymmetry and Dream Affect: Alpha Oscillations Over the Right Frontal Cortex During REM Sleep and Pre-Sleep Wakefulness Predict Anger in REM Sleep Dreams,” were published in the Journal of Neuroscience.
Researchers noted that there is an imbalance between two regions of the brain on the left and right sides. This imbalance leads to disturbing dreams. They called it frontal alpha asymmetry which meant that brain activity was higher in one side of the brain compared to the other.
The team from the UK, Finland and Sweden recruited 17 healthy volunteers (7 men and 10 women) who had had their brains scanned before sleep, while sleeping and after they woke up from sleep in a sleep laboratory. They tried to ascertain the effects of various emotions such as anger and curiosity on the brains of the participants. Electroencephalographic (or EEG) recordings of their brain activity was taken at the three settings. The participants were made to sleep in the labs for two nights.
Results revealed that among persons who had less brain wave activity in the right frontal cortex compared to the left during awake period and during REM sleep, were more likely to experience angry dreams.
To detect the dream phase the participants were allowed to sleep and once they reached REM sleep (Rapid eye movement sleep phase where dreams occur), they were allowed to sleep for five minutes before they were woken up to describe their dreams and rate their emotions. REM sleep is characterized by fast pulse, rapid breathing, movements and dreams. The ratings were either “angry” or “interest”.
Lead researcher Pilleriin Sikka, from University of Turku in Finland said, “It has been shown that expressing anger is related to relatively greater left [frontal activity], whereas controlling anger is related to relatively greater right frontal activity. Anger was experienced in 41 per cent of dreams, interest in 88 per cent of dreams. Participants experienced more anger in dreams than during the evening wakefulness, whereas the evening and morning anger ratings did not differ.”
The team noted that the imbalance between the two frontal cortex was associated with either angry dreams or dreams associated with suspicion and distrust. Thus this type of brain wave finding can be used to detect the emotions and type of dreams experienced by the person explain the researchers. This may help patients with post-traumatic stress disorders (PTSD) and other forms of sleep disorders write the authors.
The study was funded and supported by the Academy of Finland, Finnish Cultural Foundation, Turku University Foundation and the International Association for the Study of Dreams and Dream Science Foundation.