Activity of primary auditory neurons in the cochlear ganglion of the emu Dromaius novaehollandiae: Spontaneous discharge, frequency tuning, and phase locking

1997 ◽  
Vol 101 (3) ◽  
pp. 1560-1573 ◽  
Author(s):  
Geoffrey A. Manley ◽  
Christine Köppl ◽  
Graeme K. Yates
Keyword(s):  
Frequency Tuning ◽  
Phase Locking ◽  
Discharge Frequency ◽  
Spontaneous Discharge ◽  
Auditory Neurons ◽  
Dromaius Novaehollandiae

scholarly journals Intrinsic mechanical sensitivity of auditory neurons as a contributor to sound-driven neural activity

2021 ◽  
Author(s):  
Ebenezer N Yamoah ◽  
Maria C Perez Flores ◽  
Eric Verschooten ◽  
Jeong Han Lee ◽  
Hyo Jeong Kim ◽  
...  
Keyword(s):  
Frequency Tuning ◽  
Phase Locking ◽  
Electrical Current ◽  
Dependent Manner ◽  
Mechanical Stimuli ◽  
Mechanical Sensitivity ◽  
Auditory Neurons ◽  
Diverse Range ◽  
Transmission Mechanisms ◽  
Neuronal Functions

Mechanosensation – by which mechanical stimuli are converted into a neuronal signal – is the basis for the sensory systems of hearing, balance, and touch. Mechanosensation is unmatched in speed and its diverse range of sensitivities, reaching its highest temporal limits with the sense of hearing; however, hair cells (HCs) and the auditory nerve (AN) serve as obligatory bottlenecks for sounds to engage the brain. Like other sensory neurons, auditory neurons use the canonical pathway for neurotransmission and millisecond-duration action potentials (APs). How the auditory system utilizes the relatively slow transmission mechanisms to achieve ultrafast speed and high audio-frequency hearing remains an enigma. Here, we address this paradox and report that the AN is mechanically sensitive, and minute mechanical displacement profoundly affects its response properties. Sound-mimicking sinusoidal mechanical and electrical current stimuli affect phase-locked responses. In a phase-dependent manner, the two stimuli can also evoke suppressive responses. We propose that mechanical sensitivity interacts with synaptic responses to shape responses in the AN, including frequency tuning and temporal phase-locking. The combination of neurotransmission and mechanical sensation to control spike patterns gives the AN a secondary receptor role, an emerging theme in primary neuronal functions.

scholarly journals Controlling and Phase‐Locking a THz Quantum Cascade Laser Frequency Comb by Small Optical Frequency Tuning

2021 ◽  
pp. 2000417
Author(s):  
Luigi Consolino ◽  
Annamaria Campa ◽  
Michele De Regis ◽  
Francesco Cappelli ◽  
Giacomo Scalari ◽  
...  
Keyword(s):  
Quantum Cascade Laser ◽  
Frequency Tuning ◽  
Frequency Comb ◽  
Phase Locking ◽  
Laser Frequency ◽  
Optical Frequency ◽  
Quantum Cascade

Frequency Tuning and Spontaneous Activity in the Auditory Nerve and Cochlear Nucleus Magnocellularis of the Barn Owl Tyto alba

1997 ◽  
Vol 77 (1) ◽  
pp. 364-377 ◽  
Author(s):  
Christine Köppl
Keyword(s):  
Response Latency ◽  
Cochlear Nucleus ◽  
Auditory Nerve ◽  
Frequency Tuning ◽  
Barn Owl ◽  
Nerve Fibers ◽  
Spontaneous Discharge ◽  
Tyto Alba ◽  
Nucleus Magnocellularis ◽  
Auditory Nerve Fibers

Köppl, Christine. Frequency tuning and spontaneous activity in the auditory nerve and cochlear nucleus magnocellularis of the barn owl Tyto alba. J. Neurophysiol. 77: 364–377, 1997. Single-unit recordings were obtained from the brain stem of the barn owl at the level of entrance of the auditory nerve. Auditory nerve and nucleus magnocellularis units were distinguished by physiological criteria, with the use of the response latency to clicks, the spontaneous discharge rate, and the pattern of characteristic frequencies encountered along an electrode track. The response latency to click stimulation decreased in a logarithmic fashion with increasing characteristic frequency for both auditory nerve and nucleus magnocellularis units. The average difference between these populations was 0.4–0.55 ms. The most sensitive thresholds were ∼0 dB SPL and varied little between 0.5 and 9 kHz. Frequency-threshold curves showed the simple V shape that is typical for birds, with no indication of a low-frequency tail. Frequency selectivity increased in a gradual, power-law fashion with increasing characteristic frequency. There was no reflection of the unusual and greatly expanded mapping of higher frequencies on the basilar papilla of the owl. This observation is contrary to the equal-distance hypothesis that relates frequency selectivity to the spatial respresentation in the cochlea. On the basis of spontaneous rates and/or sensitivity there was no evidence for distinct subpopulations of auditory nerve fibers, such as the well-known type I afferent response classes in mammals. On the whole, barn owl auditory nerve physiology conformed entirely to the typical patterns seen in other bird species. The only exception was a remarkably small spread of thresholds at any one frequency, this being only 10–15 dB in individual owls. Average spontaneous rate was 72.2 spikes/s in the auditory nerve and 219.4 spikes/s for nucleus magnocellularis. This large difference, together with the known properties of endbulb-of-Held synapses, suggests a convergence of ∼2–4 auditory nerve fibers onto one nucleus magnocellularis neuron. Some auditory nerve fibers as well as nucleus magnocellularis units showed a quasiperiodic spontaneous discharge with preferred intervals in the time-interval histogram. This phenomenon was observed at frequencies as high as 4.7 kHz.

scholarly journals Tone-Specific and Nonspecific Plasticity of the Auditory Cortex Elicited by Pseudoconditioning: Role of Acetylcholine Receptors and the Somatosensory Cortex

2008 ◽  
Vol 100 (3) ◽  
pp. 1384-1396 ◽  
Author(s):  
Weiqing Ji ◽  
Nobuo Suga
Keyword(s):  
Auditory Cortex ◽  
Receptor Antagonist ◽  
Fear Conditioning ◽  
Somatosensory Cortex ◽  
Acetylcholine Receptors ◽  
Neural Circuit ◽  
Frequency Tuning ◽  
Cholinergic Receptor ◽  
Auditory Neurons ◽  
Specific Change

Experience-dependent plastic changes in the central sensory systems are due to activation of both the sensory and neuromodulatory systems. Nonspecific changes of cortical auditory neurons elicited by pseudoconditioning are quite different from tone-specific changes of the neurons elicited by auditory fear conditioning. Therefore the neural circuit evoking the nonspecific changes must also be different from that evoking the tone-specific changes. We first examined changes in the response properties of cortical auditory neurons of the big brown bat elicited by pseudoconditioning with unpaired tonal (CSu) and electric leg (USu) stimuli and found that it elicited nonspecific changes to CSu (a heart-rate decrease, an auditory response increase, a broadening of frequency tuning, and a decrease in threshold) and, in addition, a small tone-specific change to CSu (a small short-lasting best-frequency shift) only when CSu frequency was 5 kHz lower than the best frequency of a recorded neuron. We then examined the effects of drugs on the cortical changes elicited by the pseudoconditioning. The development of the nonspecific changes was scarcely affected by atropine (a muscarinic cholinergic receptor antagonist) and mecamylamine (a nicotinic cholinergic receptor antagonist) applied to the auditory cortex and by muscimol (a GABAA-receptor agonist) applied to the somatosensory cortex. However, these drugs abolished the small short-lasting tone-specific change as they abolished the large long-lasting tone-specific change elicited by auditory fear conditioning. Our current results indicate that, different from the tone-specific change, the nonspecific changes depend on neither the cholinergic neuromodulator nor the somatosensory cortex.

scholarly journals Isoflurane Depresses the Response of Inspiratory Hypoglossal Motoneurons to Serotonin In Vivo 

2007 ◽  
Vol 106 (4) ◽  
pp. 736-745 ◽  
Author(s):  
Ivo F. Brandes ◽  
Edward J. Zuperku ◽  
Astrid G. Stucke ◽  
Francis A. Hopp ◽  
Danica Jakovcevic ◽  
...  
Keyword(s):  
Neuronal Response ◽  
Discharge Frequency ◽  
K Channel ◽  
Neuronal Membrane ◽  
Spontaneous Discharge ◽  
Channel Conductance ◽  
Membrane Hyperpolarization ◽  
K Channels ◽  
Hypoglossal Motoneurons

Background Endogenous serotonin (5-HT) provides important excitatory drive to inspiratory hypoglossal motoneurons (IHMNs). In vitro studies show that activation of postsynaptic 5-HT receptors decreases a leak K+ channel conductance and depolarizes hypoglossal motoneurons (HMNs). In contrast, volatile anesthetics increase this leak K+ channel conductance, which causes neuronal membrane hyperpolarization and depresses HMN excitability. Clinical studies show upper airway obstruction, indicating HMN depression, even at subanesthetic concentrations. The authors hypothesized that if anesthetic activation of leak K+ channels caused neuronal depression in vivo, this effect could be antagonized with serotonin. In this case, the neuronal response to picoejected serotonin would be greater during isoflurane than with no isoflurane. Methods Studies were performed in decerebrate, vagotomized, paralyzed, and mechanically ventilated dogs during hypercapnic hyperoxia. The authors studied the effect of approximately 0.3 minimum alveolar concentration (MAC) isoflurane on the spontaneous discharge frequency patterns of single IHMNs and on the neuronal response to picoejection of 5-HT. Results Normalized data (mean +/- SD, n = 19) confirmed that 0.3 +/- 0.1 MAC isoflurane markedly reduced the spontaneous peak discharge frequency by 48 +/- 19% (P < 0.001) and depressed the slope of the spontaneous discharge patterns. The increase in neuronal frequency in response to 5-HT was reduced by 34 +/- 22% by isoflurane (P < 0.001). Conclusion Subanesthetic concentrations of isoflurane strongly depressed canine IHMNs in vivo. The neuronal response to 5-HT was also depressed by isoflurane, suggesting that anesthetic activation of leak K+ channels, which is expected to result in a larger 5-HT response, was not a dominant mechanism in this depression.

scholarly journals Sensory experience in Development Balances excitation and Inhibition to stabilize Frequency Tuning in central Auditory neurons

2011 ◽  
Vol 5 ◽  
pp. JEN.S6833
Author(s):  
Kenjiro Seki ◽  
Troy Templeton ◽  
Liisa A. Tremere ◽  
Raphael Pinaud
Keyword(s):  
Receptive Field ◽  
Cortical Neurons ◽  
Frequency Tuning ◽  
Sensory Cues ◽  
Auditory Neurons ◽  
Developmentally Regulated ◽  
Brain Circuits ◽  
New Findings ◽  
Central Auditory Neurons ◽  
Inhibitory Networks

The balance between excitation and inhibition is critical in shaping receptive field tuning properties in sensory neurons and, ultimately, in determining how sensory cues are extracted, transformed and interpreted by brain circuits. New findings suggest that developmentally-regulated, experience-dependent changes in intracortical inhibitory networks are key to defning receptive field tuning properties of auditory cortical neurons.

Anesthesia Changes Frequency Tuning of Neurons in the Rat Primary Auditory Cortex

2001 ◽  
Vol 86 (2) ◽  
pp. 1062-1066 ◽  
Author(s):  
Bernhard H. Gaese ◽  
Joachim Ostwald
Keyword(s):  
Auditory Processing ◽  
Cortical Neurons ◽  
Frequency Tuning ◽  
Primary Auditory Cortex ◽  
Acoustic Stimulation ◽  
Experimental Manipulation ◽  
Central Auditory Processing ◽  
Auditory Neurons ◽  
Response Properties ◽  
Central Auditory Neurons

The vast majority of investigations on central auditory processing so far were conducted under the influence of an anesthetic agent. It remains unclear, however, to what extend even basic response properties of central auditory neurons are influenced by this experimental manipulation. We used a combination of chronic recording in unrestrained animals, computer-controlled randomized acoustic stimulation, and statistical evaluation of responses to directly compare the response characteristics of single neurons in the awake and anesthetized state. Thereby we were able to quantify the effects of pentobarbital/chloral hydrate anesthesia (Equithesin) on rat auditory cortical neurons. During Equithesin anesthesia, only a portion of central neurons were active and some of their basic response properties were changed. Only 29% of the neurons still had a frequency response area. Their tuning sharpness was increased under anesthesia. Most changes are consistent with an enhancement of inhibitory influences during Equithesin anesthesia. Thus when describing response properties of central auditory neurons, the animal's anesthetic state has to be taken into account.

scholarly journals Corticofugal Modulation of the Paradoxical Latency Shifts of Inferior Collicular Neurons

2008 ◽  
Vol 100 (2) ◽  
pp. 1127-1134 ◽  
Author(s):  
Xiaofeng Ma ◽  
Nobuo Suga
Keyword(s):  
Electric Stimulation ◽  
Frequency Tuning ◽  
Tuning Curve ◽  
Cortical Stimulation ◽  
Auditory Neurons ◽  
Response Latencies ◽  
Distance Information ◽  
Specific Frequency ◽  
Latency Shift ◽  
Corticofugal Feedback

The central auditory system creates various types of neurons tuned to different acoustic parameters other than a specific frequency. The response latency of auditory neurons typically shortens with an increase in stimulus intensity. However, ∼10% of collicular neurons of the little brown bat show a “paradoxical latency-shift (PLS)”: long latencies to intense sounds but short latencies to weak sounds. These neurons presumably are involved in the processing of target distance information carried by a pair of an intense biosonar pulse and its weak echo. Our current studies show that collicular PLS neurons of the big brown bat are modulated by the corticofugal (descending) system. Electric stimulation of cortical auditory neurons evoked two types of changes in the PLS neurons, depending on the relationship in the best frequency (BF) between the stimulated cortical and recorded collicular neurons. When the BF was matched between them, the cortical stimulation did not shift the BFs of the collicular neurons and shortened their response latencies at intense sounds so that the PLS became smaller. When the BF was unmatched, however, the cortical stimulation shifted the BFs of the collicular neurons and lengthened their response latencies at intense sounds, so that the PLS became larger. Cortical electric stimulation also modulated the response latencies of non-PLS neurons. It produced an inhibitory frequency tuning curve or curves. Our findings indicate that corticofugal feedback is involved in shaping the spectrotemporal patterns of responses of subcortical auditory neurons presumably through inhibition.

scholarly journals A distinct class of bursting neurons with strong gamma synchronization and stimulus selectivity in monkey V1

2019 ◽  
Author(s):  
Irene Onorato ◽  
Sergio Neuenschwander ◽  
Jennifer Hoy ◽  
Bruss Lima ◽  
Katia-Simone Rocha ◽  
...  
Keyword(s):  
Sensory Processing ◽  
Phase Locking ◽  
Inhibitory Neurons ◽  
Orientation Tuning ◽  
Spontaneous Discharge ◽  
Distinct Cell Type ◽  
Discharge Rates ◽  
Distinct Cell ◽  
Gamma Rhythm ◽  
Primate Visual Cortex

AbstractCortical computation depends on interactions between excitatory and inhibitory neurons. The contributions of distinct neuron-types to sensory processing and network synchronization in primate visual-cortex remain largely undetermined. We show that in awake monkey V1, there exists a distinct cell-type (≈30% of neurons) that has narrow-waveform action-potentials, high spontaneous discharge-rates, and fires in high-frequency bursts. These neurons are more stimulus-selective and phase-locked to gamma (30-80Hz) oscillations as compared to other neuron types. Unlike the other neuron-types, their gamma phase-locking is highly predictive of their orientation tuning. We find evidence for strong rhythmic inhibition in these neurons, suggesting that they interact with interneurons to act as excitatory pacemakers for the V1 gamma rhythm. These neurons have not been observed in other primate cortical areas and we find that they are not present in rodent V1. However, they resemble the excitatory “chattering” neurons previously identified by intracellular recordings in cat V1. Given its properties, this neuron type should be pivotal for the encoding and transmission of V1 stimulus information.

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