Nightmare sufferers show atypical emotional semantic associations and prolonged REM sleep-dependent emotional priming.
The objective of this study was to investigate whether nightmare (NM) sufferers exhibit an abnormal network of emotional semantic associations as measured by a recently developed, rapid eye movement (REM) sleep-sensitive, associational breadth (AB) task.



NM sufferers were compared to healthy controls (CTL) for their performance on an emotional AB task containing positive and negative cue words both before and after a nap with REM sleep. AB was assessed in both a priming condition, where cue words were explicitly memorized before sleep, and a non-priming condition, where cue words were not memorized. Performance was assessed again 1 week later.



The study was conducted in a sleep laboratory with polysomnographic recording at the Hôpital du Sacré-Coeur de Montréal



Twenty-eight participants between the ages of 18 and 35 years (Mage = 23.3 ± 3.4) were included in the study.



The NM group scored higher than the CTL group on both positive and negative AB, with group differences persisting at the 1-week retest. However, the two groups did not differ as expected in the AB priming effect following REM sleep. Both groups showed decreased REM sleep-related AB priming for negative cue words and increased AB priming for positive cue words. However, the NM group maintained these effects 1 week later, whereas the CTL group did not.



NM sufferers may access broader than normal emotional semantic networks in the wake state, a difference that may lead to this group being perceived as more creative. The fact that the AB priming effect is maintained at the 1-week retest for NM sufferers suggests that the presence of frequent NMs may alter REM sleep-dependent emotional processes over time.
Dream & Nightmare Laboratory, Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de Montréal, Montréal, Canada; Department of Biomedical Sciences, Université de Montréal, Montréal, Canada.
Michelle
M
Carr
Dream & Nightmare Laboratory, Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de Montréal, Montréal, Canada; Department of Biomedical Sciences, Université de Montréal, Montréal, Canada.
Cloé
C
Blanchette-Carrière
Dream & Nightmare Laboratory, Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de Montréal, Montréal, Canada; Department of Psychology, Université de Montréal, Montréal, Canada.
Louis-Philippe
LP
Marquis
Dream & Nightmare Laboratory, Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de Montréal, Montréal, Canada.
Cher Tieng
CT
Ting
Dream & Nightmare Laboratory, Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de Montréal, Montréal, Canada; Department of Psychiatry, Université de Montréal, Montréal, Canada. Electronic address: tore.nielsen@umontreal.ca.
Tore
T
Nielsen
D001143:Arousal / Q000502:physiology; D004325:Dreams; D004644:Emotions; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology; D017286:Polysomnography / Q000379:methods; D011792:Quebec; D012660:Semantics; D012890:Sleep / Q000502:physiology; D012894:Sleep Stages / Q000502:physiology; D012895:Sleep, REM / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult
Associative memory; Emotion; Nightmares; Psychopathology; REM sleep