title: Measure of synchrony in the activity of intrinsic cardiac neurons.
abstract: Recent multielectrode array recordings in ganglionated plexi of canine atria have opened the way to the study of population dynamics of intrinsic cardiac neurons. These data provide critical insights into the role of local processing that these ganglia play in the regulation of cardiac function. Low firing rates, marked non-stationarity, interplay with the cardiovascular and pulmonary systems and artifacts generated by myocardial activity create new constraints not present in brain recordings for which almost all neuronal analysis techniques have been developed. We adapted and extended the jitter-based synchrony index (SI) to (1) provide a robust and computationally efficient tool for assessing the level and statistical significance of SI between cardiac neurons, (2) estimate the bias on SI resulting from neuronal activity possibly hidden in myocardial artifacts, (3) quantify the synchrony or anti-synchrony between neuronal activity and the phase in the cardiac and respiratory cycles. The method was validated on firing time series from a total of 98 individual neurons identified in 8 dog experiments. SI ranged from -0.14 to 0.66, with 23 pairs of neurons with SI > 0.1. The estimated bias due to artifacts was typically <1%. Strongly cardiovascular- and pulmonary-related neurons (SI > 0.5) were found. Results support the use of jitter-based SI in the context of intrinsic cardiac neurons.
authors.affiliation: Centre de Recherche, Hôpital du Sacré-Coeur de Montréal, 5400 boulevard Gouin Ouest, Montréal (Québec) H4J 1C5, Canada. Department of Physiology, Université de Montréal, Canada.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Longpré
authors.forename: Siamak
authors.initials: S
authors.lastname: Salavatian
authors.forename: Eric
authors.initials: E
authors.lastname: Beaumont
authors.forename: J Andrew
authors.initials: JA
authors.lastname: Armour
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Ardell
authors.forename: Vincent
authors.initials: V
authors.lastname: Jacquemet
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D004285:Dogs; D006321:Heart / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D012119:Respiration; D016276:Ventricular Function / Q000502:physiology