Synaptic organization of globular bushy cells in the ventral cochlear nucleus of the cat: A quantitative study

1991 ◽  
Vol 314 (3) ◽  
pp. 598-613 ◽  
Author(s):  
E.-Michael Ostapoff ◽  
D. Kent Morest
Keyword(s):  
Quantitative Study ◽  
Cochlear Nucleus ◽  
Synaptic Organization ◽  
Ventral Cochlear Nucleus ◽  
Bushy Cells

Convergence of auditory nerve fibers onto bushy cells in the ventral cochlear nucleus: implications of a computational model

1993 ◽  
Vol 70 (6) ◽  
pp. 2562-2583 ◽  
Author(s):  
J. S. Rothman ◽  
E. D. Young ◽  
P. B. Manis
Keyword(s):  
Cochlear Nucleus ◽  
Auditory Nerve ◽  
Full Range ◽  
Nerve Fibers ◽  
Membrane Properties ◽  
Delayed Rectifier ◽  
Current Clamp ◽  
Synaptic Inputs ◽  
Ventral Cochlear Nucleus ◽  
Bushy Cells

1. Convergence of auditory nerve (AN) fibers onto bushy cells of the ventral cochlear nucleus (VCN) was investigated with a model that describes the electrical membrane properties of these cells. The model consists of a single compartment, representing the soma, and includes three voltage-sensitive ion channels (fast sodium, delayed-rectifier-like potassium, and low-threshold potassium). These three channels have characteristics derived from voltage clamp data of VCN bushy cells. The model also contains a leakage channel, membrane capacitance, and synaptic inputs. The model accurately reproduces the membrane rectification seen in current clamp studies of bushy cells, as well as their unique current clamp responses. 2. In this study, the number and synaptic strength of excitatory AN inputs to the model were varied to investigate the relationship between input convergence parameters and response characteristics. From 1 to 20 excitatory synaptic inputs were applied through channels in parallel with the voltage-gated channels. Each synapse was driven by an independent AN spike train; spike arrivals produced brief (approximately 0.5 ms) conductance increases. The number (NS) and conductance (AE) of these inputs were systematically varied. The input spike trains were generated as a renewal point process that accurately models characteristics of AN fibers (refractoriness, adaptation, onset latency, irregularity of discharge, and phase locking). Adaptation characteristics of both high and low spontaneous rate (SR) AN fibers were simulated. 3. As NS and AE vary over the ranges 1–20 and 3–80 nS, respectively, the full range of response types seen in VCN bushy cells are produced by the model, with AN inputs typical of high-SR AN fibers. These include primarylike (PL), primarylike-with-notch (Pri-N), and onset-L (On-L). In addition, Onset responses, whose association with bushy cells in uncertain, and “dip” responses, which are not seen in the VCN, are produced. Dip responses occur with large NS and/or AE, and are due to depolarization block. When the AN inputs have the adaptation characteristics of low-SR AN fibers, PL--but not Pri-N or On-L responses--are produced. This suggests that neurons showing Pri-N and On-L responses must receive high-SR AN inputs. 4. The regularity of discharge of the model is compared with that of VCN bushy cells, using a measure derived from the mean and standard deviation of interspike intervals. Regularity is an important constraint on the model because the regularity of VCN bushy cells is the same as that of their AN inputs.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Audiotactile interactions in the mouse cochlear nucleus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Josephine Ansorge ◽  
Calvin Wu ◽  
Susan E. Shore ◽  
Patrik Krieger
Keyword(s):  
Cochlear Nucleus ◽  
Broadband Noise ◽  
Dorsal Cochlear Nucleus ◽  
Variable Response ◽  
Sound Stimulation ◽  
Early Integration ◽  
Ventral Cochlear Nucleus ◽  
Somatosensory Information ◽  
Bushy Cells

AbstractMultisensory integration of auditory and tactile information occurs already at the level of the cochlear nucleus. Rodents use their whiskers for tactile perception to guide them in their exploration of the world. As nocturnal animals with relatively poor vision, audiotactile interactions are of great importance for this species. Here, the influence of whisker deflections on sound-evoked spiking in the cochlear nucleus was investigated in vivo in anesthetized mice. Multichannel, silicon-probe electrophysiological recordings were obtained from both the dorsal and ventral cochlear nucleus. Whisker deflections evoked an increased spiking activity in fusiform cells of the dorsal cochlear nucleus and t-stellate cells in ventral cochlear nucleus, whereas bushy cells in the ventral cochlear nucleus showed a more variable response. The response to broadband noise stimulation increased in fusiform cells and primary-like bushy cells when the sound stimulation was preceded (~ 20 ms) by whisker stimulation. Multi-sensory integration of auditory and whisker input can thus occur already in this early brainstem nucleus, emphasizing the importance of early integration of auditory and somatosensory information.

Differential contributions of voltage-gated potassium channel subunits in enhancing temporal coding in the bushy cells of the ventral cochlear nucleus

2021 ◽  
Author(s):  
Mingyu Fu ◽  
Lu Zhang ◽  
Xiao Xie ◽  
Ningqian Wang ◽  
Zhongju Xiao
Keyword(s):  
Cochlear Nucleus ◽  
Spike Timing ◽  
Temporal Coding ◽  
Membrane Properties ◽  
Membrane Excitability ◽  
Patch Clamp Recording ◽  
Voltage Gated ◽  
Ventral Cochlear Nucleus ◽  
Kv Channels ◽  
Bushy Cells

Temporal coding precision of bushy cells in the ventral cochlear nucleus (VCN), critical for sound localization and communication, depends on the generation of rapid and temporally precise action potentials (APs). Voltage-gated potassium (Kv) channels are critically involved in this. The bushy cells in rat VCN express Kv1.1, 1.2, 1.3, 1.6, 3.1, 4.2 and 4.3 subunits. The Kv1.1 subunit contributes to the generation of a temporally precise single AP. However, the understanding of the functions of other Kv subunits expressed in the bushy cells is limited. Here, we investigated the functional diversity of Kv subunits concerning their contributions to temporal coding. We characterized the electrophysiological properties of the Kv channels with different subunits using whole-cell patch-clamp recording and pharmacological methods. The neuronal firing pattern changed from single to multiple APs only when the Kv1.1 subunit was blocked. The Kv subunits, including the Kv1.1, 1.2, 1.6 or 3.1, were involved in enhancing temporal coding by lowering membrane excitability, shortening AP latencies, reducing jitter and regulating AP kinetics. Meanwhile, all the Kv subunits contributed to rapid repolarization and sharpening peaks by narrowing half-width and accelerating fall rate, while the Kv1.1 subunit also affected the depolarization of AP. The Kv1.1, 1.2 and 1.6 subunits endowed bushy cells with a rapid time constant and a low input resistance of membrane for enhancing spike timing precision. The present results indicate that the Kv channels differentially affect intrinsic membrane properties to optimize the generation of rapid and reliable APs for temporal coding.

scholarly journals Ventral cochlear nucleus bushy cells encode hyperacusis in guinea pigs

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
David T. Martel ◽  
Susan E. Shore
Keyword(s):  
Hearing Loss ◽  
Cochlear Nucleus ◽  
Wide Frequency Range ◽  
Neural Firing ◽  
Frequency Range ◽  
Neural Basis ◽  
Firing Rates ◽  
Ventral Cochlear Nucleus ◽  
Psychophysical Studies ◽  
Bushy Cells

AbstractPsychophysical studies characterize hyperacusis as increased loudness growth over a wide-frequency range, decreased tolerance to loud sounds and reduced behavioral reaction time latencies to high-intensity sounds. While commonly associated with hearing loss, hyperacusis can also occur without hearing loss, implicating the central nervous system in the generation of hyperacusis. Previous studies suggest that ventral cochlear nucleus bushy cells may be putative neural contributors to hyperacusis. Compared to other ventral cochlear nucleus output neurons, bushy cells show high firing rates as well as lower and less variable first-spike latencies at suprathreshold intensities. Following cochlear damage, bushy cells show increased spontaneous firing rates across a wide-frequency range, suggesting that they might also show increased sound-evoked responses and reduced latencies to higher-intensity sounds. However, no studies have examined bushy cells in relationship to hyperacusis. Herein, we test the hypothesis that bushy cells may contribute to the neural basis of hyperacusis by employing noise-overexposure and single-unit electrophysiology. We find that bushy cells exhibit hyperacusis-like neural firing patterns, which are comprised of enhanced sound-driven firing rates, reduced first-spike latencies and wideband increases in excitability.

Voltage-Sensitive Conductances of Bushy Cells of the Mammalian Ventral Cochlear Nucleus

2007 ◽  
Vol 97 (6) ◽  
pp. 3961-3975 ◽  
Author(s):  
Xiao-Jie Cao ◽  
Shalini Shatadal ◽  
Donata Oertel
Keyword(s):  
Cochlear Nucleus ◽  
Low Voltage ◽  
Nerve Fibers ◽  
Superior Olivary Complex ◽  
Voltage Sensitivity ◽  
Sound Sources ◽  
Temporal Precision ◽  
Ventral Cochlear Nucleus ◽  
Cation Conductance ◽  
Bushy Cells

Bushy cells in the ventral cochlear nucleus convey firing of auditory nerve fibers to neurons in the superior olivary complex that compare the timing and intensity of sounds at the two ears and enable animals to localize sound sources in the horizontal plane. Three voltage-sensitive conductances allow bushy cells to convey acoustic information with submillisecond temporal precision. All bushy cells have a low-voltage-activated, α-dendrotoxin (α-DTX)-sensitive K+ conductance ( gKL) that was activated by depolarization past −70 mV, was half-activated at −39.0 ± 1.7 (SE) mV, and inactivated ∼60% over 5 s. Maximal gKL varied between 40 and 150 nS (mean: 80.8 ± 16.7 nS). An α-DTX-insensitive, tetraethylammonium (TEA)-sensitive, K+ conductance ( gKH) was activated at voltages positive to −40 mV, was half-activated at −18.1 ± 3.8 mV, and inactivated by 90% over 5 s. Maximal gKH varied between 35 and 80 nS (mean: 58.2 ± 6.5 nS). A ZD7288-sensitive, mixed cation conductance ( gh) was activated by hyperpolarization greater than −60 mV and half-activated at −83.1 ± 1.1 mV. Maximum gh ranged between 14.5 and 56.6 nS (mean: 30.0 ± 5.5 nS). 8-Br-cAMP shifted the voltage sensitivity of gh positively. Changes in temperature stably altered the steady-state magnitude of Ih. Both gKL and gKH contribute to repolarizing action potentials and to sharpening synaptic potentials. Those cells with the largest gh and the largest gKL fired least at the onset of a depolarization, required the fastest depolarizations to fire, and tended to be located nearest the nerve root.

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