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Intermittent coupling between cardiorespiratory oscillations and neuronal discharge in the medulla of freely moving rats.
Author(s) -
Kocsis Bernat,
Topchiy Irina
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a472-c
Subject(s) - medulla , cardiorespiratory fitness , premovement neuronal activity , respiratory system , medulla oblongata , neuroscience , bursting , coupling (piping) , neuron , chemistry , medicine , physics , biology , central nervous system , materials science , metallurgy
Simultaneous recordings of multiple single neurons were obtained using tetrode electrodes aimed at central autonomic structures in the medulla, including the nucleus tractus solitarii and the rostral ventrolateral medulla. Periodic modulations of neuronal discharges were assessed by calculating the firing probability relative to the ECG R‐waves using spike triggered averages. Respiratory rhythm was also derived from the ECG by identifying periodically occurring bradycardic episodes (respiratory sinus arrhythmia). Three tetrodes (12 microwires) were used which allowed simultaneous recording of 4 to 35 neurons for 10 to 50 min. Neurons located in close vicinity to each other usually exhibited different levels of coupling with cardiorespiratory oscillations. Several discharge patterns were found in simultaneous recordings of different neurons, including cardiac rhythmicity, respiratory rhythmicity, or patterns in which cardiac‐related modulation was periodically enhanced at specific phases of the respiratory cycle. The coupling between R‐waves and neuronal discharge was in most cases intermittent and showed slipping of the relative phase indicating relative coordination and was frequently modulated by the level of vigilance. Sleep‐related slowing of neuronal discharge was often associated with shifts in the R‐wave – neuron frequency ratio.