Some aspects of mammalian hearing under water

1960 ◽  
Vol 152 (946) ◽  
pp. 54-62 ◽  
Keyword(s):  
Nervous System ◽  
Low Frequency ◽  
Pressure Waves ◽  
Sound Waves ◽  
Tactile Sense ◽  
Very Low Frequency ◽  
Lateral Line Organ ◽  
Hearing Organ ◽  
Line Organ ◽  
Remote Past

In all probability the first, most primitive life must have had its origin in the water. When one tries to form an idea of the development of ‘hearing under water’, it is understandable that the formation of an adequate sensory apparatus for hearing depends on the development of the tactile sense, and later on the coming into being of a nervous system, lateral line organ, and finally on the formation of the stato-acoustic end-organs of the labyrinth. This gives little cause for wonder, as the reaction to pressure waves must have been an early felt biological necessity. The step from pressure waves under water to sound waves of very low frequency is neither a great nor a fundamental step; it is merely the addition of sound modality to vibration. Before, in a remote past, dramatic geological changes had created the conditions for the development of life on land and therefore also for life in the air, the fishes were the most highly developed vertebrates. They probably possessed a hearing organ entirely adapted and adjusted to hearing under water. We assume that some of these animals possessed the potency to answer with success the tremendous demands made by the transition to land life. Under-water hearing was transmuted into air-hearing. Air-hearing finally reached its highest degree of development in the mammals.

scholarly journals The state of response of autonomic nervous system in children with mitral valve prolapse

2021 ◽  
Vol 26 (4) ◽  
pp. 74-80
Author(s):  
І.О.  Mitiuriaeva-Korniyko ◽  
O.V. Kuleshov ◽  
Ya.A. Medrazhevska ◽  
L.O. Fik ◽  
T.D. Klets
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Mitral Valve ◽  
Frequency Domain ◽  
Mitral Valve Prolapse ◽  
Low Frequency ◽  
Very Low Frequency ◽  
Autonomic Nervous ◽  
Significant Difference

The article presents summarized materials on connective tissue dysplasia of the heart, primary mitral valve prolapse, dysfunction of the autonomic system. Aim of research: to estimate the condition of autonomic nervous system in children with primary mitral valve prolapse. We examined 106 children with mitral valve prolapse aged from 13 to 17 years old on the clinical base of city hospital “Center of mother and child” in Vinnitsya. Research included time and frequency domain (evaluation with cardiointervalography. Final results were compared with the control group records. The results showed no statistical significance among time domain parameters in the main group of children. All these indices displayed tendency to sympathetic and parasympathetic autonomic nervous system tonus increase in boys. However, sympathicotonia tendency was noted in girls only. Frequency domain parameters showed similar results, compared with the previous. Nevertheless, very low frequency parameters had statistically significant difference in both subgroups of patience with mitral valve prolapse, including males (3205.8±190.9 against 1717±154, р<0.05) and females (3280±220.1 against 1433±811, р<0.05). There were no statistically significant difference among other frequency domain parameters. Conclusions: we estimated that children with mitral valve prolapse have imbalanced autonomic homeostasis manifested by tone disturbances of both autonomic vegetative system branches with sympathetic predominance. Patients with primary mitral valve prolapse generally have increased sympathetic tone - both boys and girls - according to spectral analysis of heart rate variability indices, heart rate oscillation power of a very low frequency in particular (p<0.05). In children with mitral valve prolapse, the tone of parasympathetic nervous system is generally normal; there is a tendency to its increase in boys and decrease in girls. These children should be under close medical supervision by pediatricians and cardiologists.

scholarly journals Heart Rate Variability of Children with Mitral Valve Prolapse in Orthostatic Test

2021 ◽  
Vol 6 (3) ◽  
pp. 293-299
Author(s):  
T. M. Krainyk ◽  
◽  
S. H. Starodubtsev ◽  
O. V. Petrenko ◽  
O. V. Dovgan ◽  
...  
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Mitral Valve ◽  
Mitral Valve Prolapse ◽  
Sinus Node ◽  
Low Frequency ◽  
Control Group ◽  
Orthostatic Test ◽  
Very Low Frequency ◽  
Mode Amplitude

The purpose of the research was to study the state of autonomic regulation in prepubertal children with mitral valve prolapse during an orthostatic test Materials and methods. The study involved 2 groups: the main – 26 children aged 10-11 years with mitral valve prolapse, and a control group – 22 relatively healthy children. The adaptive mechanisms were monitored by analyzing heart rate variability. All children participated in a cardiorhythmic examination at rest lying down and during an active orthostatic test. Results and discussion. Among the indicators that had significant differences, the indicators of regulatory process adequacy index and mode amplitude should be noted. In the group of children with mitral valve prolapse, an increase of the regulatory process adequacy index indicated the predominance of the functioning of the sinus node over the activity of the sympathetic division of the autonomic nervous system. An increase in the adequacy index and mode amplitude indicates the connection of the central structures of rhythm control (subcortical rhythms) during a change in body position. Stress index also increased. This index of tension of regulatory systems shows the activity of the mechanisms of sympathetic regulation, the state of central regulation. Children in the control group had a well-coordinated response of the sympathetic nervous system to the orthostatic test: the low frequency spectrum and very low frequency indicators increased. While in main group, the value of low frequency spectrum (the work of the sinus node) increased, the value of very low frequency (the reaction of the central structures of the nervous system) decreased. This indicates dysfunction of the most important reactions, which also affects the daily activities of children, increases the risk of mitral valve prolapse complications. Conclusion. In children with mitral valve prolapse, the absence of a pronounced typical reaction to an ortho test is a reflection of an adaptive-regulatory overstrain in conditions of morphological determinacy of connective tissue dysplasia, which are trying to ensure the adequacy of intracardiac hemodynamics. The data obtained will be useful for predicting the reaction of the body of children with mitral valve prolapse to physical activity of varying intensity

1. Past sounds

2015 ◽  
pp. 1-9
Author(s):  
Mike Goldsmith
Keyword(s):  
Low Frequency ◽  
Big Bang ◽  
Sound Waves ◽  
Very Low Frequency ◽  
Living Things ◽  
The World ◽  
Sonar Systems ◽  
History Of ◽  
Hearing Evolution ◽  
The Big Bang

‘Past sounds’ provides a history of sound from the origin of sound waves 300,000 years after the Big Bang to the modern day of ultrasound and electroacoustic technology. Primordial sound was of a very low frequency, but powerful and omnipresent, and the environment in which the first living things evolved was an acoustically rich one, profoundly affecting the forms, habits, and destinies of those creatures. Hearing evolution is described along with the human development of music and musical instruments. The Greeks built amphitheatres that dealt with the practicalities of sound and Pythagoras studied harmony on a monochord. The World Wars of the twentieth century accelerated electronics development and inspired underwater acoustic research and sonar systems.

scholarly journals Sleep-specific changes in physiological brain pulsations

2020 ◽  
Author(s):  
H Helakari ◽  
V Korhonen ◽  
SC Holst ◽  
J Piispala ◽  
M Kallio ◽  
...  
Keyword(s):  
Cardiac Cycle ◽  
Spectral Power ◽  
Low Frequency ◽  
Pressure Waves ◽  
List Type ◽  
Spectral Entropy ◽  
Long Distance ◽  
Very Low Frequency ◽  
Scalp Eeg ◽  
Power Increase

AbstractSleep is known to increase the convection of interstitial brain metabolites along with cerebrospinal fluid (CSF). We used ultrafast magnetic resonance encephalography (MREGBOLD) to quantify the effect of sleep on physiological (vasomotor, respiratory and cardiac) brain pulsations driving the CSF convection in humans. Transition to electroencephalography verified sleep occurred in conjunction with power increase and reduced spectral entropy (SE) of physiological brain pulsations. During sleep, the greatest increase in spectral power was in very-low frequency (VLF < 0.1 Hz) waves, followed by respiratory and cardiac brain pulsations. SE reduction coincided with decreased vigilance in awake state and could robustly (ROC 0.88, p < 0.001) differentiate between sleep vs. awake states, indicating the sensitivity of SE of the MREGBOLD signal as a marker for sleep level. In conclusion, the three physiological brain pulsation contribute to the sleep-associated increase in glymphatic CSF convective flow in an inverse frequency order.HighlightsBrain tissue contains almost no connective tissue, this enabling pressure waves to initiate long-distance brain pulsationsBrain pulsations are induced by vasomotion, respiration, and the cardiac cycleSleep strikingly increases spectral power and decreases spectral entropy of brain pulsations, especially for the very low frequency vasomotor wavesSpectral entropy of brain pulsations detected by MREG is a sensitive measure of vigilance, resembling the corresponding entropy changes detected by scalp EEG

The Attenuation of Very Low Frequency Brain Oscillations in Transitions from a Rest State to Active Attention

2009 ◽  
Vol 23 (4) ◽  
pp. 191-198 ◽  
Author(s):  
Suzannah K. Helps ◽  
Samantha J. Broyd ◽  
Christopher J. James ◽  
Anke Karl ◽  
Edmund J. S. Sonuga-Barke
Keyword(s):  
Brain Activity ◽  
Sampling Rate ◽  
Low Frequency ◽  
Future Research ◽  
Adhd Symptoms ◽  
Default Mode ◽  
Very Low Frequency ◽  
Wide Range ◽  
Interference Hypothesis ◽  
Mode Interference

Background: The default mode interference hypothesis ( Sonuga-Barke & Castellanos, 2007 ) predicts (1) the attenuation of very low frequency oscillations (VLFO; e.g., .05 Hz) in brain activity within the default mode network during the transition from rest to task, and (2) that failures to attenuate in this way will lead to an increased likelihood of periodic attention lapses that are synchronized to the VLFO pattern. Here, we tested these predictions using DC-EEG recordings within and outside of a previously identified network of electrode locations hypothesized to reflect DMN activity (i.e., S3 network; Helps et al., 2008 ). Method: 24 young adults (mean age 22.3 years; 8 male), sampled to include a wide range of ADHD symptoms, took part in a study of rest to task transitions. Two conditions were compared: 5 min of rest (eyes open) and a 10-min simple 2-choice RT task with a relatively high sampling rate (ISI 1 s). DC-EEG was recorded during both conditions, and the low-frequency spectrum was decomposed and measures of the power within specific bands extracted. Results: Shift from rest to task led to an attenuation of VLFO activity within the S3 network which was inversely associated with ADHD symptoms. RT during task also showed a VLFO signature. During task there was a small but significant degree of synchronization between EEG and RT in the VLFO band. Attenuators showed a lower degree of synchrony than nonattenuators. Discussion: The results provide some initial EEG-based support for the default mode interference hypothesis and suggest that failure to attenuate VLFO in the S3 network is associated with higher synchrony between low-frequency brain activity and RT fluctuations during a simple RT task. Although significant, the effects were small and future research should employ tasks with a higher sampling rate to increase the possibility of extracting robust and stable signals.

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