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Results for “Acoustic Stimulation”

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At least 19 recordsLinked to original sources
PubMed2026

Transient acoustic stimulation induces time-dependent synaptic remodeling and enhancement of auditory nerve output after threshold recovery.

BACKGROUND: Acoustic stress can alter cochlear function even in the absence of permanent threshold elevation; however, synaptic consequences of transient acoustic stimulation remain incompletely understood. OBJECTIVE: This study aimed to investigate whether transient acoustic stimulation induces changes in the auditory nerve output and cochlear ribbon synapse morphology following hearing threshold recovery. METHODS: Young adult CBA/CaJ mice were exposed to band-limited acoustic stimulation (45-2,000 Hz, 95 dB SPL, 2 h). Auditory brainstem responses (ABRs), hair cell and spiral ganglion neuron survival, and synaptic morphology were evaluated before exposure and up to 2 weeks post-exposure. RESULTS: ABR thresholds were transiently elevated immediately after exposure but largely recovered by 1 day post-exposure. In contrast, ABR wave I amplitudes significantly increased after threshold recovery across multiple test frequencies. Ribbon-associated puncta in both inner and outer hair cell regions exhibited biphasic temporal changes, with an initial decrease immediately after exposure followed by an increase at 1 day post-exposure. The ribbon-associated punctal area also increased after exposure and remained elevated at later post-exposure time points. No significant loss of hair cells or spiral ganglion neurons was observed. Exploratory genomic analysis suggested enrichment of pathways related to metabolic defense and cellular stress responses. CONCLUSIONS: Transient acoustic stimulation induces time-dependent synaptic remodeling and enhancement of peripheral auditory nerve output without overt cellular degeneration. These findings support a model in which early cochlear responses to acoustic perturbation include adaptive synaptic plasticity and gain regulation, extending current concepts of noise-induced cochlear change beyond irreversible synaptic loss.

Animals↗
PubMedDate not supplied

[Electrical activity of the cerebral ganglion of the mollusk Helix vulgaris upon acoustic stimulation of the statocyst].

Responses in the cerebral ganglia to acoustical stimulation were studied at the frequencies 30, 60, 150, 300, 500, 1000 Hz. The lowest threshold of response was at the frequency 30 Hz 60 dB spl. The reaction was in the form of evoked response or different patterns of spike activity. Responses could take place at one frequency of stimulation or in the wide range of frequencies. The reaction lasted sometimes even after the stimulation had ceased. After 3-4 stimulations by one frequency the reaction disappeared as a rule. But if the stimulation continued, but with another frequency, the response restored. The acoustic stimulation of the statocyst evokes various types of response in the cerebral ganglia.

Acoustic Stimulation↗
PubMed1976

Electrical responses of the auditory area of the cerebellar cortex to acoustic stimulation.

Single unit activity from the VI and VII lobuli of the cerebellar vermis cortex was studied following acoustical stimulation with sound signals of different parameters. Cerebellar neurons, as compared to those from the auditory system, showed low selectivity to sound frequency, intensity and duration. However, about 2/3 of the neurons were selectively sensitive to interaural time and intensity differences; about 1/3 of neurons showed a specific response to signals simulating sound motion in a definite direction. Thus, cerebellar neurons seem to be mainly responsive to those sound parameters which are essential for sound localization.

Acoustic Stimulation↗
PubMed1976

[Effect of noise on the physiological functions in fowl. 3. Effects of primary and repetitive acoustic stimulation on glucose and free-fatty-acid plasma levels in broilers of different age groups].

The effects of first and repetitive noise applications to broilers, aged 14, 28, and 56 days, were tested by the responses of the energetic substrates plasma glucose concentration and free fatty acids. The plasma concentrations of glucose and free fatty acids in broilers at slaughter age with no exposure to noise were higher than those in younger animals. Regular daily noise application of 100 dB, 60 to 8,000 Hz, for 30 minutes, which began on the first day of age, led to rises in the plasma glucose levels of animals aged 56 and 28 days even prior to renewed acoustic stimulation, which obviously was a conditioned reflex. Such rises were accompanied by decline in plasma concentrations of free fatty acids, which phenomenon was attributed to higher initial values of plasma glucose. First as well as repetitive noise application led to changes in the plasma content of energetic substrates. Both the direction and magnitude of the reaction appeared to depend on the given initial value. The plasma level responses of glucose and free fatty acids were opposite to one another in all animals, 56 days of age, which were exposed to repeated noise.

Acoustic Stimulation↗
PubMed1978

Effects of level of acoustic stimulation on locomotor activity in the gerbil.

Two experiments dealt with the behavioral responsiveness of the Mongolian gerbil to the onset, offset, and intensity of auditory stimulation. In Experiment I, the presence of background noise, relative to a condition of silence, was found to facilitate rate of shuttle activity in the gerbil. Also, both incremental and decremental shifts in noise intensity produced immediate increases and decreases, respectively, in activity level. Experiment II revealed that the relationship between shuttle-activity level and background noise intensity was nonmonotonic over the 60-90 dB range, with optimal facilitation manifested at 80 dB SPL. A similar trend was observed with running-wheel activity. Finally, in both experiments substantial habituation of general activity was obtained. The results were discussed in terms of theoretical conceptions of the energizing properties of environmental stimulation (e.g. , arousal theory, stimulus intensity dynamism) and psycho-physiological reactions of the gerbil to auditory stimulation.

Acoustic Stimulation↗
PubMed1979

Temporal integration of acoustic stimulation obtained in reflex inhibition in rats and humans.

An acoustic stimulus (S1) presented just before reflex elicitation inhibits reflex expression. The present studies questioned whether inhibition provided by initial stimuli of various durations conforms to established temporal integration functions. Initial stimuli were noise bursts varying in duration (2, 20, or 200 msec) and intensity (55 or 85 dB). Eliciting stimuli (S2) for rats were intense tone bursts, which elicited the acoustic startle reflex, and for humans electrotactile stimuli to the forehead, which elicited the eye blink. Findings revealed that inhibition was greater with the 85-dB S1 stimulus and increased linearly with log increases in duration. These latter data suggest that the acoustic substrate for reflex inhibition has a long-time constant. There was one exception to this general finding. For seven (of nine) human subjects, inhibition declined when the duration of the 85-dB S1 was increased from 20 to 200 msec. Postexperimental questioning and video monitoring suggest that this anomaly resulted from a reflex enhancing arousal process.

Acoustic Stimulation↗