Abstract
In three experiments, startle responses to brief intense tone-bursts (30 msec, 110 dB, 6000 Hz) and single pulse (0.1 msec) stimulation of the cochlear nucleus and the nucleus reticularis pontis caudalis are studied under high pressures of heliox (from 0 bar to 50 bars) in the rat. For each rat (N=12), mean amplitude and latency changes in startle responses (nuchal electromyography and whole-body accelerometry) are compared at normobaric pressure and during compression, at a speed of 100 bar/H. The results indicate that high pressures decrease (50% of control size) tone evoked startle by acting on the peripheral auditory organ, probably through middle and/or inner ear barotrauma. The large increases in electrically-elicited startle (250% of control size) from the cochlear and reticular nuclei, under hyperbaric conditions, suggest that high pressures affect sensorimotor reactivity by excitatory action on synaptic transmission in the relays of the acoustic startle reflex arc at the lower brainstem and spinal levels. Startle latencies remain unaffected by the heliox high pressures studied here.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
