title: K-Complexes: Interaction between the Central and Autonomic Nervous Systems during Sleep.
abstract: To investigate the relationship between K-complexes (KCs) and cardiac functioning.
  
  
  
  Forty healthy adolescents aged 16-22 y (19 females) participated in the study. Heart rate (HR) fluctuations associated with spontaneous and evoked KCs were investigated on two nights, one with (event-related potential night) and one without auditory tones presented across the night.
  
  
  
  There was a clear biphasic cardiac response to evoked and spontaneous KCs, with an initial acceleration in HR followed by a deceleration (P < 0.001). HR acceleration occurred immediately to KCs in response to tones presented in the first third of the interbeat interval, but was delayed a beat when the tone occurred later in the cardiac cycle (P < 0.05). Sex differences were also evident. Pretone baseline HR was higher, and the magnitude of the HR response was blunted and delayed, in female compared to male adolescents (P < 0.001). Also, pretone baseline HR was lower when a tone elicited a KC compared to when it did not (P < 0.001), suggesting that KCs are possibly more likely to be elicited by external stimuli in states of reduced cardiac activation.
  
  
  
  The strict dependency observed between KCs and cardiac control indicates a potential role of KCs in modulating the cardiovascular system during sleep. Sex differences in the KC-cardiac response indicate the sensitivity of this measure in capturing sex differences in cardiac regulatory physiology.
authors: Center for Health Sciences, SRI International, Menlo Park, CA.
authors: Massimiliano
authors: M
authors: de Zambotti
authors: Center for Health Sciences, SRI International, Menlo Park, CA.
authors: Adrian R
authors: AR
authors: Willoughby
authors: University of Pittsburgh School of Medicine, Pittsburgh, PA.
authors: Peter L
authors: PL
authors: Franzen
authors: University of Pittsburgh School of Medicine, Pittsburgh, PA.
authors: Duncan B
authors: DB
authors: Clark
authors: Center for Health Sciences, SRI International, Menlo Park, CA.|Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa.
authors: Fiona C
authors: FC
authors: Baker
authors: Center for Health Sciences, SRI International, Menlo Park, CA.|Melbourne School of Psychological Sciences, University of Melbourne, Parkville, Victoria, Australia.
authors: Ian M
authors: IM
authors: Colrain
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D001341:Autonomic Nervous System / Q000502:physiology*; D002490:Central Nervous System / Q000502:physiology*; D004569:Electroencephalography; D005071:Evoked Potentials; D005260:Female; D064368:Healthy Volunteers; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D012727:Sex Characteristics; D012890:Sleep / Q000502:physiology*; D012894:Sleep Stages / Q000502:physiology; D055815:Young Adult
keywords: K-complex; autonomic nervous system; cardiovascular; heart rate; sex differences; sleep