The Rare Cry For Help: First Record of An Agonistic Call From A Snake In South America

Discussions about auditory systems and sound dynamics in snakes are frequent. The known frequency of sounds produced by snakes ranges from 0.2 - 7.5 KHz, ranging from imperceptible sounds to humans to audible and observable squeaks. The hiss and whistles are the most common sound and are not considered vocalizations. During a nocturnal survey on June 13, 2021, in the northern Brazilian Amazon, we observed the first record of vocalization in a South American snake. Emitted by the individual from Dipsas catesbyi has a duration of 0.06 seconds, reaching 3036 Hz in its peak frequency, with an amplitude of 2761 to 4152 Hz of frequency in its main emission. Vocalizations were made during the exhalation of air through the larynx. The modulation differs from all patterns observed for snakes resembling the agonistic call of anuran amphibians, which could characterize an evolutionary mimicry of this behavior. Vocal emission via the larynx can generate internal vibrations perceptible to the auditory system of snakes, which, when vocalizing, vibrate the laryngeal cartilage and vocal cord. Our hypothesis is that structured vocal emission through laryngeal air exhalation may be a characteristic shared by other species of the Colubridae family.

Composite receptive fields in the mouse auditory cortex

A central question in sensory neuroscience is how neurons represent complex natural stimuli. This process involves multiple steps of feature extraction to obtain a condensed, categorical representation useful for classification and behavior. It has previously been shown that central auditory neurons in the starling have composite receptive fields composed of multiple features when probed with conspecific songs. Whether this property is an idiosyncratic characteristic of songbirds, a group of highly specialized vocal learners, or a generic characteristic of central auditory systems in different animals is, however, unknown. To address this question, we have recorded responses from auditory cortical neurons in mice, and characterized their receptive fields using mouse ultrasonic vocalizations (USVs) as a natural and ethologically relevant stimulus and pitch-shifted starling songs as a natural but ethologically irrelevant control stimulus. We have found that auditory cortical neurons in the mouse display composite receptive fields with multiple excitatory and inhibitory subunits. Moreover, this was the case with either the conspecific or the heterospecific vocalizations. We then trained the sparse filtering algorithm on both classes of natural stimuli to obtain statistically optimal features, and compared the natural and artificial features using UMAP, a dimensionality-reduction algorithm previously used to analyze mouse USVs and birdsongs. We have found that the receptive-field features obtained with the mouse USVs and those obtained with the pitch-shifted starling songs clustered together, as did the sparse-filtering features. However, the natural and artificial receptive-field features clustered mostly separately. These results indicate that composite receptive fields are likely a generic property of central auditory systems in different classes of animals. They further suggest that the quadratic receptive-field features of the mouse auditory cortical neurons are natural-stimulus invariant.

abordagem fonética de dados clínicos

This study aims at presenting a review, from the methodological point of view, of procedures and demands related to the phonetic approach of clinical data. The possibility of taking into account the interface between speech perception and production may be productive when analyzing data collected from clinical settings or developing researches in which the central questions arose from the clinical practice. The dynamics aspects of speech are considered. The series of studies reported reinforces the indication of a highly integrated and cooperative approach among the several research areas concerned on speech production and perception. The capability of producing speech under disorders caused by damages in phonatory and auditory systems can stimulate researchers to develop approaches that could influence theoretical models, rehabilitation tools and speech technologies development.

Broad frequency sensitivity and complex neural coding in the larval zebrafish auditory system

SUMMARYMost animals have complex auditory systems that identify salient features of the acoustic landscape to direct appropriate responses. In fish, these features include the volume, frequency, complexity, and temporal structure of auditory stimuli transmitted through water. Larval fish have simple brains compared to adults, but swim freely and depend on sophisticated sensory processing for survival. Zebrafish larvae, an important model for studying brain-wide neural networks, have thus far been found to possess a rudimentary auditory system, sensitive to a narrow range of frequencies and without evident sensitivity to auditory features that are salient and ethologically important to adult fish. Here, we have combined a novel method for delivering water-borne sounds, a diverse assembly of acoustic stimuli, and whole-brain calcium imaging to describe the responses of individual auditory neurons across the brains of zebrafish larvae. Our results reveal responses to frequencies ranging from 100Hz to 4kHz, with evidence of frequency discrimination from 100Hz to 2.5kHz. Frequency-selective neurons are located in numerous regions of the brain, and neurons responsive to the same frequency are spatially grouped in some regions. Using functional clustering, we identified categories of neurons that are selective for pure tones of a single frequency, white noise, the sharp onset of auditory stimuli, and stimuli involving a gradual crescendo. These results suggest a more nuanced auditory system than has previously been described in larval fish and provide insights into how a young animal’s auditory system can both function acutely and serve as the scaffold of a more complex adult system.

Stickler Syndrome: A Review of Clinical Manifestations and the Genetics Evaluation

Stickler Syndrome (SS) is a multisystem collagenopathy frequently encountered by ophthalmologists due to the high rate of ocular complications. Affected individuals are at significantly increased risk for retinal detachment and blindness, and early detection and diagnosis are critical in improving visual outcomes for these patients. Systemic findings are also common, with craniofacial, skeletal, and auditory systems often involved. SS is genotypically and phenotypically heterogenous, which can make recognizing and correctly diagnosing individuals difficult. Molecular genetic testing should be considered in all individuals with suspected SS, as diagnosis not only assists in treatment and management of the patient but may also help identify other at-risk family members. Here we review common clinical manifestation of SS and genetic tests frequently ordered as part of the SS evaluation.

Elaborating Analogies of Time Perception

Using a mixture of physiological evidence and analogies of time, the author describes the current version of a model of how we might view our interactions with time in music and beyond. An older model designed for analysis of complex twentieth-century acoustic works is updated to incorporate varied profiles of electroacoustic music. Recent research in auditory systems corroborates that we receive different types of information simultaneously through different channels, each taking more or less periodic sampling from different bands of frequencies – from timbre to phrase length and beyond. In order to acknowledge both the primitive structures of our complex hearing mechanisms and the different profiles of listeners, it is suggested that this multiple-sampling strategy may operate in a parallel way at a much larger scale, thereby allowing us to integrate the listener’s preference for pacing, contrast and densities of activity into the sensory processing of a musical work. The article is enriched by insights from soundscape pioneer Hildegard Westerkamp relating to various aspects of the discussion, from sensory overload to ecological concerns to the natural rallentando of a soundwalk. Finally, a whimsical elaboration based on the analogy of time as a river is presented in order to incorporate a more organic set of characteristics into our appreciation of music and time.

Auditory Perception – Its Functions and Disorders. Towards a Mechanistic Analyses of Auditory Hybrid Systems

The aim of the paper is to present and analyze problems associated with the mechanisms of auditory perception (especially those responsible for speech perception), their specific disorders and functions. I discuss research on speech perception in the broader theoretical context of the mechanistic model of scientific explanation and the perspective of cognitive implantology that explores the possibilities for building hybrid auditory systems.