Hippocampal theta waves as an electrocardiogram rhythm timer in paradoxical sleep.
Episodes of heart arrhythmia are present during paradoxical sleep, a known non-homeostatic--'open loop'--physiological state, while wakefulness and slow wave sleep exhibit 'closed-loop' control. A brain-stem autonomic oscillator, a hypothalamic and a corticofrontal center, entrained by baroreceptor input, has been proposed as the main heart rhythm control system. We are postulating another neural timer, i.e. the hippocampal theta rhythm. Cross-correlation between the R-wave of the electrocardiogram and the hippocampal theta revealed phase-locking during behavioral periods under 'open-loop' operations as paradoxical sleep indicative of a participation of such a rhythm in autonomic heart rate timing, in coordination with hypothalamic neuronal activities.
Pedemonte
M
M
Neurofisiología, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
Rodríguez
A
A
Velluti
R A
RA
D000818:Animals; D006224:Cricetinae; D004562:Electrocardiography; D006339:Heart Rate / Q000502:physiology; D006624:Hippocampus / Q000502:physiology*; D008297:Male; D008647:Mesocricetus; D010507:Periodicity; D051381:Rats; D012895:Sleep, REM / Q000502:physiology*; D013826:Theta Rhythm