Peripheral specialization for fine analysis of doppler-shifted echoes in the auditory system of the “CF-FM” bat Pteronotus parnellii

1975 ◽  
Vol 63 (1) ◽  
pp. 161-192
Author(s):  
N. Suga ◽  
J. A. Simmons ◽  
P. H. Jen
Keyword(s):  
Inner Ear ◽  
Auditory System ◽  
Second Harmonic ◽  
Tuning Curve ◽  
Cochlear Microphonics ◽  
Slow Increase ◽  
Pteronotus Parnellii ◽  
Neural Inhibition ◽  
Fm Bat ◽  
Mechanical Tuning

Pteronotus parnellii uses the second harmonic (61–62 kHz) of the CF component in its orientation sounds for Doppler-shift compensation. The bat's inner ear is mechanically specialized for fine analysis of sounds at about 61–62 kHz. Because of this specialization, cochlear microphonics (CM) evoked by 61–62 kHz tone bursts exhibit prominent transients, slow increase and decrease in amplitude at the onset and cessation of these stimuli. CM-responses to 60–61 kHz tone bursts show a prominent input-output non-linearity and transients. Accordingly, a summated response of primary auditory neurones (N1) appears not only at the onset of the stimuli, but also at the cessation. N1-off is sharply tuned at 60–61 kHz, while N1-on is tuned at 63–64 kHz, which is 2 kHz higher than the best frequency of the auditory system because of the envelope-distortion originating from sharp mechanical tuning. Single peripheral neurones sensitive to 61–62 kHz sounds have an unusually sharp tuning curve and show phase-locked responses to beats of up to 3 kHz. Information about the frequencies of Doppler-shifted echoes is thus coded by a set of sharply tuned neurones and also discharges phase-locked to beats. Neurones with a best frequency between 55 and 64 kHz show not only tonic on-responses but also off-responses which are apparently related to the mechanical off-transient occuring in the inner ear and not to a rebound from neural inhibition.

Postnatal Maturation of Primary Auditory Cortex in the Mustached Bat, Pteronotus parnellii

2010 ◽  
Vol 103 (5) ◽  
pp. 2339-2354 ◽  
Author(s):  
M. Vater ◽  
E. Foeller ◽  
E. C. Mora ◽  
F. Coro ◽  
I. J. Russell ◽  
...  
Keyword(s):  
Auditory Cortex ◽  
Cortical Neurons ◽  
Second Harmonic ◽  
Tuning Curve ◽  
Primary Auditory Cortex ◽  
Constant Frequency ◽  
Low Frequencies ◽  
Postnatal Maturation ◽  
Mustached Bat ◽  
Pteronotus Parnellii

The primary auditory cortex (AI) of adult Pteronotus parnellii features a foveal representation of the second harmonic constant frequency (CF2) echolocation call component. In the corresponding Doppler-shifted constant frequency (DSCF) area, the 61 kHz range is over-represented for extraction of frequency-shift information in CF2 echoes. To assess to which degree AI postnatal maturation depends on active echolocation or/and reflects ongoing cochlear maturation, cortical neurons were recorded in juveniles up to postnatal day P29, before the bats are capable of active foraging. At P1-2, neurons in posterior AI are tuned sensitively to low frequencies (22–45 dB SPL, 28–35 kHz). Within the prospective DSCF area, neurons had insensitive responses (>60 dB SPL) to frequencies <40 kHz and lacked sensitive tuning curve tips. Up to P10, when bats do not yet actively echolocate, tonotopy is further developed and DSCF neurons respond to frequencies of 51–57 kHz with maximum tuning sharpness ( Q10dB) of 57. Between P11 and 20, the frequency representation in AI includes higher frequencies anterior and dorsal to the DSCF area. More multipeaked neurons (33%) are found than at older age. In the oldest group, DSCF neurons are tuned to frequencies close to 61 kHz with Q10dB values ≤212, and threshold sensitivity, tuning sharpness and cortical latencies are adult-like. The data show that basic aspects of cortical tonotopy are established before the bats actively echolocate. Maturation of tonotopy, increase of tuning sharpness, and upward shift in the characteristic frequency of DSCF neurons appear to strongly reflect cochlear maturation.

Neurophysiological Studies on Echolocation Systems in Awake Bats Producing CF-FM Orientation Sounds

1974 ◽  
Vol 61 (2) ◽  
pp. 379-399
Author(s):  
N. SUGA ◽  
J. A. SIMMONS ◽  
T. SHIMOZAWA
Keyword(s):  
Second Harmonic ◽  
Vocal Response ◽  
Acoustic Reflex ◽  
Constant Frequency ◽  
Vocal Responses ◽  
Acoustic Stimuli ◽  
Pteronotus Parnellii ◽  
Neurophysiological Studies ◽  
Neural Inhibition ◽  
Central Grey Matter

1. The bats Pteronotus parnellii, P. suapurensis and Noctilio leporinus emit orientation sounds first containing a constant-frequency (CF) and then a frequency-modulated (FM) component. 2. P. parnellii produced a long CF with a second harmonic at 62 kHz to which its auditory system was sharply tuned. In the other two species, the CF was shorter and there was no sharp tuning. 3. Electrical stimulation of the midbrain reticular formation and/or the central grey matter elicited vocalizations which were indistinguishable from those used for echolocation. 4. The electrically-elicited vocalization was enhanced by acoustic stimuli. In P. parnellii, this vocal response was sharply tuned at 62-63 kHz and also to downward sweeping FM sounds. In P. suapurensis and N. leporinus, the vocal responses were prominent only to downward sweeping FM sounds. This indicates that the FM is important to echolocation in all these bats and that the CF component is more essential to echolocation in P. parnellii than to that in P. suapurensis and N. leporinus. 5. The responses of primary auditory neurons to the onset and cessation of pure tone stimuli were due to mechanical events, not due to a rebound from neural inhibition. 6. Masking experiments with P. parnellii indicate that the neural response at the cessation of a CF-FM sound similar to its orientation sound mainly consisted of the response to the FM component and not the off-response to the CF component. 7. During vocalization, self-stimulation was reduced by contraction of middle-ear muscles. This was not due to the acoustic reflex which started to occur with a 6 msec latency.

scholarly journals Deafness-in-a-dish: modeling hereditary deafness with inner ear organoids

2021 ◽  
Author(s):  
Daniel R. Romano ◽  
Eri Hashino ◽  
Rick F. Nelson
Keyword(s):  
Animal Models ◽  
Inner Ear ◽  
Auditory System ◽  
Hearing Aids ◽  
Molecular Mechanisms ◽  
Functional Disability ◽  
Experimental Studies ◽  
Hereditary Deafness ◽  
Human Auditory System ◽  
Human Inner Ear

AbstractSensorineural hearing loss (SNHL) is a major cause of functional disability in both the developed and developing world. While hearing aids and cochlear implants provide significant benefit to many with SNHL, neither targets the cellular and molecular dysfunction that ultimately underlies SNHL. The successful development of more targeted approaches, such as growth factor, stem cell, and gene therapies, will require a yet deeper understanding of the underlying molecular mechanisms of human hearing and deafness. Unfortunately, the human inner ear cannot be biopsied without causing significant, irreversible damage to the hearing or balance organ. Thus, much of our current understanding of the cellular and molecular biology of human deafness, and of the human auditory system more broadly, has been inferred from observational and experimental studies in animal models, each of which has its own advantages and limitations. In 2013, researchers described a protocol for the generation of inner ear organoids from pluripotent stem cells (PSCs), which could serve as scalable, high-fidelity alternatives to animal models. Here, we discuss the advantages and limitations of conventional models of the human auditory system, describe the generation and characteristics of PSC-derived inner ear organoids, and discuss several strategies and recent attempts to model hereditary deafness in vitro. Finally, we suggest and discuss several focus areas for the further, intensive characterization of inner ear organoids and discuss the translational applications of these novel models of the human inner ear.

scholarly journals A toy model for the auditory system that exploits stochastic resonance

2021 ◽  
Author(s):  
Francesco Veronesi ◽  
Edoardo Milotti
Keyword(s):  
Inner Ear ◽  
Stochastic Resonance ◽  
Auditory System ◽  
Signal To Noise Ratio ◽  
Hearing Threshold ◽  
Moderate Amount ◽  
Sound Perception ◽  
Non Linear ◽  
Dynamical Description ◽  
Stochastic Phenomena

Abstract The transduction process that occurs in the inner ear of the auditory system is a complex mechanism which requires a non-linear dynamical description. In addition to this, the stochastic phenomena that naturally arise in the inner ear during the transduction of an external sound into an electro-chemical signal must also be taken into account. The presence of noise is usually undesirable, but in non-linear systems a moderate amount of noise can improve the system's performance and increase the signal-to-noise ratio. The phenomenon of stochastic resonance combines randomness with non-linearity and is a natural candidate to explain at least part of the hearing process which is observed in the inner ear. In this work, we present a toy model of the auditory system which shows how stochastic resonance can be instrumental to sound perception, and suggests an explanation of the frequency dependence of the hearing threshold.

scholarly journals Navigating Hereditary Hearing Loss: Pathology of the Inner Ear

2021 ◽  
Vol 15 ◽  
Author(s):  
Teresa Nicolson
Keyword(s):  
Hearing Loss ◽  
Animal Models ◽  
Inner Ear ◽  
Auditory System ◽  
Cranial Nerve ◽  
Hereditary Hearing Loss ◽  
Hearing Organ ◽  
Peripheral Auditory System ◽  
The Brain

Inherited forms of deafness account for a sizable portion of hearing loss among children and adult populations. Many patients with sensorineural deficits have pathological manifestations in the peripheral auditory system, the inner ear. Within the hearing organ, the cochlea, most of the genetic forms of hearing loss involve defects in sensory detection and to some extent, signaling to the brain via the auditory cranial nerve. This review focuses on peripheral forms of hereditary hearing loss and how these impairments can be studied in diverse animal models or patient-derived cells with the ultimate goal of using the knowledge gained to understand the underlying biology and treat hearing loss.

scholarly journals Transcriptional Expression Changes During Compensatory Plasticity in the Central Nervous System of the Adult Cricket Gryllus Bimaculatus: I. Auditory System Plasticity in the Prothoracic Ganglia

2021 ◽  
Author(s):  
Felicia Wang ◽  
Harrison Fisher ◽  
Maeve Morse ◽  
Lisa L. Ledwidge ◽  
Jack O’Brien ◽  
...  
Keyword(s):  
Auditory System ◽  
Molecular Mechanisms ◽  
Tuning Curve ◽  
Differential Expression Analysis ◽  
Protein Translation ◽  
Field Cricket ◽  
Gryllus Bimaculatus ◽  
Prothoracic Ganglion ◽  
Auditory Afferents ◽  
Go Terms

Abstract Most adult organisms are limited in their capacity to recover from neurological damage. The auditory system of the Mediterranean field cricket, Gryllus bimaculatus, presents a compelling model for investigating neuroplasticity due to its unusual capabilities for structural reorganization into adulthood. Specifically, the dendrites of the central auditory neurons of the prothoracic ganglion sprout in response to the loss of auditory afferents. Deafferented auditory dendrites grow across the midline, a boundary they normally respect, and form functional synapses with the contralateral auditory afferents, restoring tuning-curve specificity. The molecular pathways underlying these changes are entirely unknown. Here, we used a multiple k-mer approach to re-assemble a previously reported prothoracic ganglion transcriptome that included ganglia collected one, three, and seven days after unilateral deafferentation in adult, male animals. We used EdgeR and DESeq2 to perform differential expression analysis and we examined Gene Ontologies to further understand the potential molecular basis of this compensatory anatomical plasticity. Enriched GO terms included those related to protein translation and degradation, enzymatic activity, and Toll signaling. Extracellular space GO terms were also enriched and included the upregulation of several protein yellow family members one day after deafferentation. Investigation of these regulated GO terms help to provide a broader understanding of the types of pathways that might be involved in this compensatory growth and can be used to design hypotheses around identified molecular mechanisms that may be involved in this unique example of adult structural plasticity.

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