The Journal of Neurophysiology Vol. 83 No. 3 March 2000, pp. 1415-1425
Copyright ©2000 by the American Physiological Society
Synchronized Fast Rhythms in Inspiratory and Expiratory Nerve
Discharges During Fictive Vocalization
Ken
Nakazawa,
Antonio R.
Granata, and
Morton I.
Cohen
Department of Physiology and Biophysics, Albert Einstein College of
Medicine, Bronx, New York 10461
Nakazawa, Ken,
Antonio R. Granata, and
Morton I. Cohen.
Synchronized Fast Rhythms in Inspiratory and Expiratory Nerve
Discharges During Fictive Vocalization. J. Neurophysiol. 83: 1415-1425, 2000. In precollicular
decerebrate and paralyzed cats, respiratory nerve activities were
recorded during fictive vocalization (FV), which consisted of a
distinctive pattern of 1) decreased inspiratory (I) and
expiratory (E) phase durations, 2) marked increase of phrenic activity and moderate changes of recurrent laryngeal (RL) and
superior laryngeal (SL) I activities, and 3) massive
recruitment of laryngeal and abdominal (ABD; lumbar) E activities. FV
was produced by electrical stimulation (100 Hz) in the midbrain
periaqueductal gray (PAG) or its putative descending pathways in the
ventrolateral pons (VLP). Spectral and correlation analyses revealed
three types of effect on fast rhythms during FV. 1)
I activities: the coherent high-frequency oscillations
in I (I-HFO, 60-90 Hz) present in phrenic and RL discharges during the
control state did not change qualitatively, but there was an increase
of power and a moderate increase (4-10 Hz) of frequency. Sometimes a
distinct relatively weak stimulus-locked rhythm appeared.
2) RL and SL activities during E: in
recruited discharges, a prominent intrinsic rhythm (coherent E-HFOs at
50-70 Hz) appeared; sometimes a distinct relatively strong
stimulus-locked rhythm appeared. 3) ABD
activities during E: this recruited activity had no intrinsic
rhythm but had an evoked oscillation locked to the stimulus frequency.
Thus FV is characterized by 1) appearance of prominent
coherent intrinsic rhythms in RL and SL E discharges, which presumably
arise as a result of excitation and increased interactions in laryngeal
networks; 2) modification of intrinsic rhythmic
interactions in inspiratory networks; and 3) evoked
rhythms in augmenting-E neuron networks without occurrence of intrinsic rhythms.
