Spectral content of forced expiratory wheezes during air, He, and SF6 breathing in normal humans.

The effect of gas density on the spectral content of forced expiratory wheezes was studied in the search for additional information on the mechanism of generation of respiratory wheezes. Five normal adults performed forced vital capacity maneuvers through four or five orifice resistors (0.4-1.92 cm ID) after breathing air, 80% He-20% O2, or 80% SF6-20% O2. Tracheal lung sounds, flow, volume, and airway opening (Pao) and esophageal (Pes) pressures were measured during duplicate runs for each orifice and gas. Wheezes were detected in running spectra of lung sounds by use of a frequency domain peak detection algorithm. The wheeze spectrograms were presented along side expiratory flow rate and transpulmonary pressure (Ptp = Pao - Pes) as function of volume. The frequencies and patterns of wheeze spectrograms were evaluated for gas density effects. We found that air, He, and SF6 had similar wheeze spectrograms. Both wheeze frequency and patterns (as function of volume) did not exhibit consistent changes with gas density. Speech tone, however, was substantially affected in the usual pattern. These observations support the hypothesis that airway wall vibratory motion, rather than gas phase oscillations, is the source of acoustic energy of wheezes.     

A Minicomputer-aided Method for the Detection of Features from Vocalisations of the Cotton-top Tamarin

Lagging behind the methodological standard reached in human speech analysis, spectrograms from animal vocalisations must still be analysed at least partly “by hand”. The method described here uses minicomputer feature detection techniques to extract frequency modulation and amplitude modulation contours and the number of harmonics automatically from cotton-top tamarin vocalisations. This system thus offers a very workable tool for the detailed analysis of animal vocalisations, as demonstrated in an application where the stereotypy of an amplitude modulation pattern of cotton-top tamarin calls is shown.     

Communication of Stimulus Size and Shape in Alarm Calls of Gunnison's Prairie Dogs, Cynomys gunnisoni

Gunnison's prairie dogs ( Cynomys gunnisoni ) emit multiple-note alarm calls to terrestrial predators that vary in acoustic structure according to the eliciting stimulus. The characteristics of the predator that are salient with respect to alarm call variation, however, are poorly understood. Although the behavior of predators has been shown to influence alarm call production in other species of ground-dwelling sciurids, the degree to which sciurid alarm calls describe physical characteristics of predators has not been addressed independently of the effects of variation in predator behavior. The effect of variation in the size and shape of the eliciting stimulus was studied by presenting silhouette models to a colony of prairie dogs and recording the alarm calls that were elicited. Discriminant function analysis on 7 variables measured from spectrograms revealed that the alarm calls differed with respect to silhouette. These results suggest that information with respect to stimulus size and shape is encoded in prairie dog alarm calls.     

FT-IR,FT-Raman spectra and DFT vibrational analysis of 2-aminobiphenyl

In this work, the Fourier transform infrared (FT-IR) and Fourier transform Raman (FT-Raman) spectra of 2-aminobiphenyl (2ABP) were recorded in the solid phase. The optimised geometry, frequency and intensity of the vibrational bands of 2ABP were obtained by the density functional theory (BLYP and B3LYP) methods with complete relaxation in the potential energy surface using 6-31G(d) basis set. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FT-IR and FT-Raman spectra. The observed and the calculated frequencies are found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theoretically constructed spectrograms.     

Frequency following response to cochlear nuclei in cats to polycomponent sonic signals]

Under chloralose-urethane anaesthesia, by means of spectrograms and dynamic spectrograms studies have been made on frequency following response (FFR) in the cochlear nuclei of cats evoked by sonic stimulation. It was shown that FFR readily reproduces frequencies of the acoustic spectrum of separate tones and two-tonal harmonic complexes (the upper reproduced frequency in FFR - 6.0-6.5 kc/sec). The main deteils of the acoustic spectrum of the sounds of speech are also easily reproduced in FFR. Combination tones were observed in FFR during application of two-tonal harmonic complexes. The first harmonic is inhibited in FFR when combined with higher ones (the fifth or the sixth) or at certain phase angle between the first and the second harmonics ("doubling" phenomenon).     

Barking in domestic dogs: context specificity and individual identification

In this study we sought to determine whether dog barks could be divided into subtypes based on context. We recorded barking from 10 adult dogs, Canis familiaris, of six breeds in three different test situations: (1) a disturbance situation in which a stranger rang the doorbell, (2) an isolation situation in which the dog was locked outside or in a room isolated from its owner and (3) a play situation in which either two dogs or a human and a dog played together. We analysed spectrograms of 4672 barks using macros that took 60 sequential frequency measurements and 60 sequential amplitude measurements along the length of the call. Statistical analyses revealed that barks are graded vocalizations that range from harsh, low-frequency, unmodulated calls to harmonically rich, higher-frequency, modulated calls. The harsh, low-frequency, unmodulated barks were more commonly given in the disturbance situation, and the more tonal, higher-pitch, modulated barks were more commonly given in the isolation and play situations. Disturbance barks were also longer in duration with more rapid repetition than the barks given in other contexts. Discriminant analysis revealed that dog barks can be divided into different subtypes based on context even within individual dogs, and that dogs can be identified by their bark spectrograms despite the context of the bark.     

Catalogue of sounds of the Pigtailed macaque (Macaca nemestrina)

A catalogue of sounds from a laboratory population of Pigtailed macaques has been developed from spectograms. Sounds are divided into four general classes: clear, harsh and high-pitched calls, and miscellaneous sounds. It appears that all parameters of the vocal signal are independently manipulatable. A plot of selected spectral characteristics demonstrated the uniqueness of individual signals. In some instances, different sounds are developed by rearrangement of specific fragments, or by acoustical activities performed on similar sounds. This latter phenomenon, which will be termed mosaicism , parallels aspects of language design. Lastly, comparison of spectrograms for Pigtailed macaques with those published for Rhesus macaques ( Macaca mulatta ) reveals similarities in structure.     

Structural variability in primate vocalizations and its functional significance: an analysis of squirrel monkey chuck calls

Sound spectrograms of vocalizations recorded from 'Gothic arch' squirrel monkeys were examined for shared structural characteristics. A rapidly descending element, the 'mast', was found to be diagnostic for a group of variable but structurally similar vocalizations called chucks. In addition to the mast, a variable FM element ('flag') and a terminal noisy element ('cackle') formed a basic 3-element structural unit. A review of functional studies suggests that this flag-mast-cackle structure is used by the squirrel monkey and a variety of other New World primates in circumstances involving close social contact.     

黑头噪鸦的鸣声分析及其繁殖行为联系

黑头噪鸦(Perisoreusinternigrans)是我国青藏高原高山针叶林的特有鸟类,由于分布海拔高、数量稀少,因此对于黑头噪鸦的研究非常少。本文对2 0 0 0年3月～2 0 0 3年6月在甘肃和四川录制的黑头噪鸦的8种叫声进行了描述及声谱分析。结合野外观察,分析了黑头噪鸦的叫声及其行为联系。黑头噪鸦的乞食叫声可能在整个繁殖生活史中具有重要意义。研究中未发现黑头噪鸦对录音回放产生回应。     

中国43种蛙类鸣声特征数据集

无尾两栖动物的鸣声通常具有物种特异性,了解其鸣声特征信息,是利用生物声学进行物种多样性调查及物种监测的前提。本文汇总、整理了2012–2020年间利用高保真录音设备在野外记录的43种(隶属于7科26属)无尾两栖动物的鸣声数据,以及相应的鸣声采集信息。对音频文件进行降噪处理后,提供了由61个鸣声的波形图及语图组成的鸣声特征数据集。本数据集展示了鸣声的多种时域和频域信息,如单音节或多音节、音节数、音节时长、音节间隔、鸣声时长、主频、基频、谐波等,为我国无尾两栖类的声学研究、物种多样性调查及鸣声监测提供了数据支持。     

Neural representation of the acoustic biotope

Cats were stimulated with tones and with natural sounds selected from the normal acoustic environment of the animal. Neural activity evoked by the natural sounds and tones was recorded in the cochlear nucleus and in the medial geniculate body. The set of biological sounds proved to be effective in influencing neural activity of single cells at both levels in the auditory system. At the level of the cochlear nucleus the response of a neuron evoked by a natural sound stimulus could be understood reasonably well on the basis of the structure of the spectrograms of the natural sounds and the unit's responses to tones. At the level of the medial geniculate body analysis with tones did not provide sufficient information to explain the responses to natural sounds. At this level the use of an ensemble of natural sound stimuli allows the investigation of neural properties, which are not seen by analysis with simple artificial stimuli. Guidelines for the construction of an ensemble of complex natural sound stimuli, based on the ecology and ethology of the animal under investigation are discussed. This stimulus ensemble is defined as the Acoustic Biotope.     

Encoding of Natural Sounds at Multiple Spectral and Temporal Resolutions in the Human Auditory Cortex

Functional neuroimaging research provides detailed observations of the response patterns that natural sounds (e.g. human voices and speech, animal cries, environmental sounds) evoke in the human brain. The computational and representational mechanisms underlying these observations, however, remain largely unknown. Here we combine high spatial resolution (3 and 7 Tesla) functional magnetic resonance imaging (fMRI) with computational modeling to reveal how natural sounds are represented in the human brain. We compare competing models of sound representations and select the model that most accurately predicts fMRI response patterns to natural sounds. Our results show that the cortical encoding of natural sounds entails the formation of multiple representations of sound spectrograms with different degrees of spectral and temporal resolution. The cortex derives these multi-resolution representations through frequency-specific neural processing channels and through the combined analysis of the spectral and temporal modulations in the spectrogram. Furthermore, our findings suggest that a spectral-temporal resolution trade-off may govern the modulation tuning of neuronal populations throughout the auditory cortex. Specifically, our fMRI results suggest that neuronal populations in posterior/dorsal auditory regions preferably encode coarse spectral information with high temporal precision. Vice-versa, neuronal populations in anterior/ventral auditory regions preferably encode fine-grained spectral information with low temporal precision. We propose that such a multi-resolution analysis may be crucially relevant for flexible and behaviorally-relevant sound processing and may constitute one of the computational underpinnings of functional specialization in auditory cortex.     

Frequency-domain analysis of biomolecular sequences

MOTIVATION: Frequency-domain analysis of biomolecular sequences is hindered by their representation as strings of characters. If numerical values are assigned to each of these characters, then the resulting numerical sequences are readily amenable to digital signal processing. RESULTS: We introduce new computational and visual tools for biomolecular sequences analysis. In particular, we provide an optimization procedure improving upon traditional Fourier analysis performance in distinguishing coding from noncoding regions in DNA sequences. We also show that the phase of a properly defined Fourier transform is a powerful predictor of the reading frame of protein coding regions. Resulting color maps help in visually identifying not only the existence of protein coding areas for both DNA strands, but also the coding direction and the reading frame for each of the exons. Furthermore, we demonstrate that color spectrograms can visually provide, in the form of local 'texture', significant information about biomolecular sequences, thus facilitating understanding of local nature, structure and function.     

Comparison of ultrasonic vocalizations emitted by rodent pups.

Ultrasonic vocalizations (USVs) emitted by rodent pups, mouse, rat, Syrian hamster, vole, and Mongolian gerbil, were compared as a basic study for a screening test of anti-panic drugs. USVs of rodent pups, separated from their mother under a low temperature condition, were collected by Real-Time Spectrogram (RTS) apparatus, and transformed into spectrograms and power spectra by SIGNAL software. Waveforms of USVs emitted by the rodent pups showed several characteristic features, and species specificity of USVs was shown. We think that the species specificity might be due to differences of the anatomical structures in the respiratory tract and respiratory patterns in rodent pups.     

Spectral and coherence EEG analysis of rats differing in the level of seizure readiness

The resting EEGs of several brain structures (motor and visual cortex, caudate nucleus and intralaminar thalamic nuclei) were submitted to spectral and coherence computer analyses in two rat strains. Genetically predisposed to convulsive state KM rats were shown to differ from nonpredisposed Wistar rats in EEG spectral properties. KM rats EEG pattern was characterized by increase of low frequencies (1-2 Hz) power and decrease of faster activity (5-12 Hz) power in cortical spectrograms as well as by decrease of caudate nucleus EEG absolute power. The coherence value between cortical or subcortical structures at below 4 Hz was intensified in KM rats. Reinforcement of cortical auto-oscillating properties manifested by ECoG synchronization in cortical-thalamic resonance interaction as well as weakening of striatal inhibitory system may constitute neurophysiological mechanisms of enhanced convulsive readiness. The probable role of mediator imbalance in these mechanisms is discussed.     

Theoretical analysis of a TIME-FREQUENCY-PCNN auditory cortex model

A particular pulsed neural model of the auditory cortex, the Time-Frequency Pulse Coupled Neural Network (TF-PCNN), has shown to decompose its stimulus from the cochlea into characteristic pulse-coded time-frequency (TF) stop and pass regions. A derived sum of spectrograms representation with these zero- or one-valued TF weightings has already been applied for the denoising of speech in a previous work. This decomposition is now related to the concept of TF projection filters, which allows to reinterpret the model equations. The functionality imposed by the model equations can so be accessed and justified from a TF signal processing perspective, in addition to its biological motivation from experimentally observed neurophysiological behavior and simulations.