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PubMed1990

Frequency variation in spontaneous sound emissions from guinea pig and human ears.

Spontaneous acoustic emissions were recorded from 7 of 15 human ears at frequencies between 900 and 4000 Hz and just above 1000 Hz in a guinea pig. The constancy or changes in the frequency composition of these emissions is of particular interest in the light of current models which implicate outer hair cell activity in their generation. In our present study, most emissions underwent continuous fluctuations in frequency over a bandwidth of 0.5-10 Hz in humans and more than 20 Hz in a young guinea pig. Jumps in frequency of emission by as much as 20 Hz occurred during test sessions in some of the human ears. Changes in emission frequency were also observed during suppression by an externally delivered tone. The frequency of the emissions at successive test sessions also varied in some human ears and in the guinea pig between the ages of 6 and 9 weeks. The guinea pig emission also underwent an increase of 50 Hz in frequency and a reduction of 25 dB in level during recovery from anaesthesia. Neely's model for the role of hair cells in the generation of spontaneous emissions suggests that changes in hair cell conductance could influence the frequency of spontaneous oscillation. The small, but continuous changes in spontaneous emission frequency seen in all ears may reflect changes in conductance at the hair cell level due to synaptic and transducer channel activity.

Aging↗
PubMed1985

Frequency composition of spontaneous cochlear emissions.

Spontaneous cochlear emissions consist of one or more sinus tones. Oscillations and frequency shifts clearly widen averaged traces. Multiple peaks, if present, are spaced at intervals of 2-3% of the frequency, and increase with frequency. A frequency jump by the same amount was seen in one case. This appears to represent the distance between hair cells, and suggests that individual hair cells play a leading role in these oscillations.

Adult↗
PubMed1983

Glutamate activated postsynaptic channels in crayfish muscle investigated by noise analysis.

Excitatory synaptic channels in crayfish muscle were investigated under various experimental conditions. Small muscle fibres of length l less than or equal to 0.6 mm were voltage clamped, spatial control of the voltage being sufficient up to at least 500 Hz. Excitatory synaptic current was induced by superfusion of glutamate. The power density spectra of this current could be fitted by single component Lorentz curves. The analysis revealed a mean open time tau noise = 0.93 ms and a conductance gamma = 32.3 pS of the glutamate operated ion channels (membrane potential E = -60 mV, temperature T = 8 degrees C). Both the conductance gamma and the channel closing rate alpha = tau -1 noise increased significantly with temperature (Q10 approximately 2). The temperature dependence of gamma and alpha could be described by Arrhenius equations with the temperature independent activation energies E gamma = 42.3 kJ/mol and E alpha = 50.2 kJ/mol. alpha also dependent on the membrane potential, increasing about e-fold when the membrane was hyperpolarized by 120 mV. The potential dependence varied considerably from fibre to fibre. The mean channel open time tau noise agreed with the time constant of decay tau (sEPSC) of spontaneous excitatory postsynaptic currents (sEPSCs).

Animals↗
PubMed1987

Topographic representation of vocal frequency demonstrated by microstimulation of anterior cingulate cortex in the echolocating bat, Pteronotus parnelli parnelli.

1. A midline region of brain dorsal and anterior to the corpus callosum, presumably anterior cingulate cortex, has been explored for its role in the production of vocalization in the mustached bat, Pteronotus p. parnelli. 2. Vocalizations elicited by microstimulation were virtually indistinguishable from natural biosonar sounds. The spectral content, relative intensity of harmonic components, and durations of emitted pulses are comparable to spontaneous emissions. 3. The frequencies of elicited vocalizations were within the range typically used by the mustached bat during Doppler-shift compensation. The frequency of the second-harmonic constant-frequency component (CF2) covered the range from 57-62 kHz, but was most commonly emitted at frequencies of 59-61 kHz. 4. An increase in the frequency of vocalizations over a number of consecutive pulses towards a steady-state plateau is evident in both spontaneous vocalizations and emissions elicited by microstimulation just above threshold. Increasing the stimulus intensity caused the frequency of emissions to approach the steady state more rapidly. 5. The anterior cingulate cortex appears to be organized topographically for increasing frequency of elicited biosonar sounds along a rostrocaudal axis. The area from which biosonar emissions were elicited was overrepresented for a 2 kHz band of frequencies just below the bats' CF2 resting frequency. Audible vocalizations with a complex spectrum resembling social cries can also be elicited by microstimulation, but only in an area that is adjacent and posterior to the biosonar region. 6. Some examples of both elicited and spontaneous vocalizations contained a relative intensity pattern of the harmonic components which deviated from the typical pattern. This suggests that mustached bats are capable of actively altering the spectrum of their pulses to subserve different tasks in echolocation.

Animals↗
PubMed1986

The squirrel monkey as an experimental model in the study of cerebral organization of emotional vocal utterances.

The different human nonverbal emotional vocal utterances (e.g., laughing, shrieking, moaning) and emotional intonation patterns (e.g., scolding, lamenting, caressing) can be shown to have their acoustic and emotional counterparts in the vocal repertoire of the squirrel monkey. This makes the latter an attractive model for investigations on the neural control of human emotional vocal utterances. Neurophysiological investigations in the squirrel monkey suggest that the cerebral control of emotional vocal utterances is organized hierarchically (Fig. 3). The lowest level - above that of the motor neurons - is represented by the reticular formation of the lateral pons and medulla; here, the motor coordination of laryngeal, respiratory and articulatory movements takes place. The next level is represented by the periaqueductal grey and laterally bordering tegmentum of the caudal midbrain. This area serves to couple specific motivational states to their corresponding vocal expressions. It is a necessary relay station for all vocalization-inducing stimuli. The periaqueductal area receives its input partly from limbic motivation-controlling regions (amygdala, hypothalamus, midline thalamus), partly from sensory pathways (collaterals of spinothalamic tract, fibers from superior and inferior colliculus), and partly from the anterior cingulate cortex. The latter represents the highest level within the system and seems to be responsible for the volitional control of emotional vocal utterances.

Amygdala↗
PubMed1992

Surgical voice rehabilitation after laryngopharyngectomy. Functional results of tracheo-hypopharyngeal shunts by jejunal transplantation.

For surgical voice rehabilitation after pharyngolaryngectomy we use the technique of placing a siphonlike jejunal interposition in order to create a tracheohypopharyngeal shunt. In this paper we present the functional benefits of this method of voice rehabilitation. The best results achieved are compared with a normal voice using the following test parameters: electroacoustic sound analyses and voice status. The findings show that the siphon voice is adequate for everyday purposes and can achieve useful social verbal communication.

Anastomosis, Surgical↗
PubMed1990

Inheritance of male courtship sound characteristics in Drosophila littoralis.

Males of Drosophila littoralis vibrate their wings during courtship to deliver a "love song." This consists of 25- to 50-ms-long pulses with a basic frequency of about 250-400 Hz, separated by 250- to 500-ms pauses. When recording the sounds of flies from several localities in Europe, we found that males of one strain from northern Finland displayed courtship sounds with an unusually low wing beat frequency (below 250 Hz). In a genetic analysis utilizing marker stocks, the anomalous frequency was found to be caused by genes on all major autosomes, the strongest factors being on the second chromosome. Interaction between genes on chromosome 2 and on the fused chromosome 3-4 was non-additive. In low-frequency sounds, the number of cycles in the pulse (CN) was decreased, so that the length of the sound pulse (PL) remained more or less unchanged. We suggest that the genetically and physiologically most thoroughly controlled trait in the sound of Drosophila littoralis is the length of the pulse.

Animals↗
PubMed1990

Drosophila courtship song cycles in normal and period mutant males revisited.

Courtship songs of normal males and those expressing short-period, long-period, and arrhythmic mutations at the period (per) locus of Drosophila melanogaster have been reanalyzed for rhythmic components, using spectral treatments of the fluctuating rates of tone pulse production that occur during courtship. It was concluded, as in previous studies, that such songs are strongly rhythmic, except for courtships performed by per01 males. Songs produced by males expressing this and other per alleles were compared to computer-generated "random" ones. Interpulse interval variations influenced by per01 and songs stimulated to be arrhythmic both were found to be associated with cryptic rhythmicities; several such period values, extracted by the spectral analyses, defined very short cycle durations. We discuss the implications of these findings and of some recently reported results that have challenged the existence of rhythmicity in Drosophila songs.

Animal Communication↗
PubMed1989

Spectral analysis of courtship songs in behavioral mutants of Drosophila melanogaster.

Spectral analyses were applied to the courtship songs of the mutants cacophony (cac), dissonance (diss), fruitless (fru), and period (per), as well as to the double mutant cac diss. Aberrant intervals between song pulses were observed in diss, cac, cac diss, and fru songs. diss males displayed a defect in song hums manifested by an irregular sine wave, although the fundamental frequencies were normal. Sine song frequencies and intrapulse frequencies were aberrant in cac diss males. Two per mutant alleles (pero1 and pers) were associated with normal song [corrected] pulses and hums. These findings are discussed with regard to the mechanisms of song production and the role of these sounds in Drosophila reproduction.

Animals↗
PubMed1992

Behavioral coupling in tettigoniid hybrids (Orthoptera).

Studies of the mating behavior of male and female F1 hybrids between closely related taxa can provide information concerning the genetic control of characters that play a major role in speciation. Orthoptera have been used previously for such studies. Hybrid crickets show behaviors which are broadly intermediate to the parentals but hybrid grasshoppers may retain parental behavior patterns. This study examines the behavior of hybrid Ephippiger ephippiger bushcrickets, the third major orthopteran group. The differences in male song and female preference are probably both mainly additive and male song differences not sex linked. Thus, given a choice, hybrid females would prefer to mate with hybrid males, an example of "behavioral coupling." The evolutionary inferences which can be drawn from studies of F1 hybrids between closely related taxa are discussed.

Animals↗
PubMed1992

The development of procedures for the measurement of vocal loudness behaviors.

Vocal loudness productions of five similar groups of speakers were analyzed. The groups differed significantly in "comfortable" loudness, in multiples (2x, 4x, and 0.5x) of comfortable loudness, and in ranges (4x -0.5x) of comfortable loudness. Interclass reliabilities for sets of measures were high and highly significant. Implications for the specification of vocal loudness behaviors are discussed.

Adult↗
PubMed1990

The inheritance of microstructure variation in the song of four generations of Roller canaries.

The microstructure of the calls and songs of four generations of Roller canaries was analyzed and compared. Many of the characteristics of the internal structure of the syllable show distributions in the progeny that suggest quantitative inheritance. The presence or absence of an underharmonic and the presence of a "block" underharmonic show a qualitative type of inheritance.

Animals↗
PubMed1990

Clinical application of spectral analysis of bowel sounds in intestinal obstruction.

The bowel sounds of 21 patients with mechanical obstruction of the intestine were studied. A computer analysis of bowel sounds was performed using a signal processor. Bowel sounds of patients were classified into 3 types (Types I, II, and III) based on the histograms, although these were not distinguishable on auscultation. The lower, peak, and upper frequencies were 173 +/- 25 Hz, 273 +/- 64 Hz, and 667 +/- 58 Hz, respectively, in Type I; 309 +/- 121 Hz, 632 +/- 94 Hz, and 878 +/- 116 Hz, respectively, in Type II; and 330 +/- 120 Hz, 612 +/- 86 Hz, and 766 +/- 82 Hz, respectively, in Type III. High frequency sounds above 900 Hz were recorded in Types I and II but not in Type III. The ratio of the operated patients was 0, 23, and 100 percent in Types I, II, and III, respectively. The intervals between the times of admission and operation were 4.3 days and 1.2 days in Types II and III, respectively. Thus, it appears that the methods described by the authors could provide a very objective assessment of the severity and help determine the treatment (conservative or operative) of each patient.

Adult↗
PubMed1992

Sounds of swallowing following total laryngectomy.

Accelerometer transduced sounds of swallowing in total laryngectomees did not show acoustical differences for liquid vs paste swallows, as are found in normals. Compared with normal swallows, tongue propulsion of the bolus in laryngectomee swallows occurred closer in time to a distinctive spectral change associated with bolus flow into the esophagus. Interpretation stressed the lack of mechanical traction from laryngeal elevation contributing to pharyngoesophageal sphincter opening, and the increased role of tongue propulsion in laryngectomee swallows.

Adult↗
PubMed1980

Acoustic analysis of the inflation sound in Eustachian catheterization.

To check the reliability of the Eustachian tube catheterization as a test of tubal dysfunction, a soundspectrographic analysis of inflation sound was carried out in 130 tubes. A close correlation between each tubal condition classified by objective tests and their soundspectrographic features indicated the reliability of the test. The origin of an inflation sound in obstructive tubes which displayed three sonagraphic types was examined by a tubal model. It was revealed that the stenotic sound mainly originated from turbulent air at the tubal orifice.

Catheterization↗
PubMed1982

Frequency analysis approach to the origin of the first and second heart sounds.

Catheter-tipped micromanometers were used to simultaneously record left ventricular and aortic pressures, and left ventricular and aortic internal phonocardiograms in order to determine if they had a common mode of origin and propagation. Spectrographic analysis showed that even with high-pass filtration the phonocardiogram obtained with a commonly used system (Millar) contained large amounts of energy in the subaudible frequency range (below 40 Hz). It was possible to derive close facsimiles of the phonocardiograms by double differentiation of the corresponding pressure pulse and conversely to derive the pressure pulse by double integration of the phonocardiograms. The propagation velocities of the first heart sound, second heart sound, and the foot of the aortic pressure pulse were found to be similar and were respectively, 4.3 +/- 0.2, 4.6 +/- 0.3, and 4.2 +/- 0.2 m/sec (+/- SE). These data support the concept that the low frequency pressure variations produced by the heart, which predominate in the left ventricular and aortic pressure pulse waveforms, are generated and propagated in the same manner as the high frequency pressure variations, which are the first and second heart sounds.

Animals↗
PubMed1992

Musical murmurs.

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Heart Murmurs↗