Dynamics of heart rate response in sleeping infants exposed to tone stimuli |
| |
Authors: | V P Rozhkov I A Anurova |
| |
Institution: | (1) Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, pr. Morisa Toreza 44, 194223 St. Petersburg, Russia;(2) St. Petersburg State University, Universitetskaya nab. 7/9, 199034 St. Petersburg, Russia |
| |
Abstract: | Heart rate, EEG, and motor responses were recorded following presentation of a series of 6–10 sound stimuli (2.5-s tones of
1000, 4000, and 250 Hz, 70 dB, interstimulus intervals 18–25 s) in neonates aged 9 to 22 weeks during stage 2–3 sleep. The
infants (17 of 19) revealed heart rate (HR) changes in response to tone stimuli that consisted in an expanded form of three
phases: (1) short-latency (at 1 s after tone presentation) HR deceleration, (2) HR acceleration with a maximum at 3–5 s, and
(3) late HR deceleration at 6–9 s of the poststimulus interval. The occurrence rate of the first two phases of cardiac response
is relatively constant during a series of stimuli, whereas the likelihood of late HR deceleration is the highest following
the first tone presentation and decreases significantly when the stimulus is repeated. Differences in the dynamics and statistical
analysis allow a relative independence of all the three response phases to be suggested. The HR acceleration phase is dramatically
enhanced in association with the motor response elicited by the sound stimulus. The late HR deceleration phase occurs not
only after the first presentation of stimuli, but also when they are repeated if they evoke EEG reaction (vertex potentials)
in response to both the beginning and end of the tone sound. Possible mechanisms of the three phases of poststimulus HR changes
are: the vagal cardiac reflex associated with the acoustic (adaptive) reflex, activation of sympathetic efferents in combination
with the startle reflex, and secondary vagal deceleration of sinus rhythm likely to be associated with the processes of perception
(detection) of a “novel” stimulus and to serve as an indirect sign of an orienting reaction. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|