A computational model with ionic conductances for the fusiform cell of the dorsal cochlear nucleus

1994 ◽  
Vol 96 (3) ◽  
pp. 1501-1514 ◽  
Author(s):  
D. O. Kim ◽  
S. Ghoshal ◽  
S. L. Khant ◽  
K. Parham
Keyword(s):  
Computational Model ◽  
Cochlear Nucleus ◽  
Dorsal Cochlear Nucleus ◽  
Fusiform Cell ◽  
Ionic Conductances

Vertical Cell Responses to Sound in Cat Dorsal Cochlear Nucleus

1999 ◽  
Vol 82 (2) ◽  
pp. 1019-1032 ◽  
Author(s):  
William S. Rhode
Keyword(s):  
Cochlear Nucleus ◽  
Auditory Nerve ◽  
Molecular Layer ◽  
Broadband Noise ◽  
Dorsal Cochlear Nucleus ◽  
Type Ii ◽  
Fusiform Cell ◽  
Sound Sources ◽  
Tuning Curves ◽  
Axonal Arbors

The dorsal cochlear nucleus receives input from the auditory nerve and relays acoustic information to the inferior colliculus. Its principal cells receive two systems of inputs. One system through the molecular layer carries multimodal information that is processed through a neuronal circuit that resembles the cerebellum. A second system through the deep layer carries primary auditory nerve input, some of which is relayed through interneurons. The present study reveals the morphology of individual interneurons and their local axonal arbors and how these inhibitory interneurons respond to sound. Vertical cells lie beneath the fusiform cell layer. Their dendritic and axonal arbors are limited to an isofrequency lamina. They give rise to pericellular nests around the base of fusiform cells and their proximal basal dendrites. These cells exhibit an onset-graded response to short tones and have response features defined as type II. They have tuning curves that are closed contours (0 shaped), thresholds ∼27 dB SPL, spontaneous firing rates of ∼0 spikes/s, and they respond weakly or not at all to broadband noise, as described for type II units. Their responses are nonmonotonic functions of intensity with peak responses between 30 and 60 dB SPL. They also show a preference for the high-to-low direction of a frequency sweep. It has been suggested that these circuits may be involved in the processing of spectral cues for the localization of sound sources.

Physiological studies on neurons in the dorsal cochlear nucleus of cat

1986 ◽  
Vol 56 (2) ◽  
pp. 287-307 ◽  
Author(s):  
W. S. Rhode ◽  
P. H. Smith
Keyword(s):  
Spontaneous Activity ◽  
Cochlear Nucleus ◽  
Response Pattern ◽  
Phase Locking ◽  
Molecular Layer ◽  
Dorsal Cochlear Nucleus ◽  
Fusiform Cell ◽  
Graded Response ◽  
Temporal Encoding ◽  
Onset Response

Results reported here support the conclusion that an individual neuron in the dorsal cochlear nucleus (DCN) can exhibit pauser, buildup, and chopper patterns in response to tone pips. Fusiform cells have been previously identified as the principal cell exhibiting these patterns. Fusiform cells can also exhibit an onset response followed by suppression of spontaneous activity at their characteristic frequency (CF). Off CF only suppression is seen. These neurons are characterized by a restricted excitatory region near threshold. All these cells can exhibit nonmonotonic rate curves, narrow excitatory regions, and inhibitory sidebands. Nonmonotonicity occurred in 34% of pausers, 52% of buildup, 89% of onsets with a graded response, and 50% overall in the DCN cells. Chopper units occur as often as the other types combined in the DCN. Only 14% show nonmonotonic rate curves. Those with high-spontaneous activity also show inhibitory sidebands. Cells with a predominant buildup pattern occur most frequently in the fusiform cell layer, whereas pausers occur throughout the DCN below the molecular layer. Intracellular potentials often reflect the average response pattern. Sharply delimited response areas indicate that these cells may be useful for performing a spectral analysis. These cells show almost no phase locking suggesting that temporal encoding is an unlikely function. It is suggested that the effects of anesthetic on the function of the DCN is not as marked as previously indicated.

Computational model of response maps in the dorsal cochlear nucleus

2006 ◽  
Vol 95 (3) ◽  
pp. 233-242 ◽  
Author(s):  
Xiaohan Zheng ◽  
Herbert F. Voigt
Keyword(s):  
Computational Model ◽  
Cochlear Nucleus ◽  
Dorsal Cochlear Nucleus

scholarly journals Dorsal Cochlear Nucleus Fusiform-cell Plasticity is Altered in Salicylate-induced Tinnitus

Neuroscience ◽  
2019 ◽  
Vol 407 ◽  
pp. 170-181 ◽  
Author(s):  
David T. Martel ◽  
Thibaut R. Pardo-Garcia ◽  
Susan E. Shore
Keyword(s):  
Cochlear Nucleus ◽  
Dorsal Cochlear Nucleus ◽  
Cell Plasticity ◽  
Fusiform Cell

Cartwheel and superficial stellate cells of the dorsal cochlear nucleus of mice: intracellular recordings in slices

1993 ◽  
Vol 69 (5) ◽  
pp. 1384-1397 ◽  
Author(s):  
S. Zhang ◽  
D. Oertel
Keyword(s):  
Cochlear Nucleus ◽  
Nerve Root ◽  
Action Potentials ◽  
Stellate Cell ◽  
Molecular Layer ◽  
Dorsal Cochlear Nucleus ◽  
Fusiform Cell ◽  
Parasagittal Plane ◽  
Axonal Arbors ◽  
Cartwheel Cells

1. Intracellular recordings were made from identified cartwheel and stellate cells in the molecular and fusiform cell layers of the murine dorsal cochlear nucleus (DCN). The aim of the study was to identify and characterize their synaptic inputs and to learn how synaptic inputs and intrinsic electrical properties interact to generate firing patterns. 2. Eight cells labeled by the intracellular injection of biocytin were cartwheel cells. Their axon terminals extended from the deep part of the molecular layer through the fusiform cell layer. Their dendrites extended through the molecular layer and had spines. Both the dendritic and axonal arbors were small, having diameters of approximately 150 microns in the parasagittal plane. 3. When depolarized, cartwheel cells often fired bursts of rapid action potentials superimposed on a slow depolarization. The peaks of action potentials were usually overshooting. Individually occurring action potentials were followed by two afterhyperpolarizations, as in other cells of the DCN. During bursts, action potentials did not have two distinct repolarizing phases. 4. Excitatory postsynaptic potentials (EPSPs) were recorded from cartwheel cells spontaneously and after shocks to the nerve root or to the ventral cochlear nucleus (VCN). The EPSPs rose slowly. When they were suprathreshold they evoked action potentials singly or in bursts. EPSPs evoked by shocks to the nerve root or to the VCN had long latencies, the rise of EPSPs beginning between 5 and 10 ms after the shock. No inhibitory synaptic potentials, either spontaneous or driven with electrical stimulation, were detected in cells whose resting potentials were between -50 and -70 mV. 5. The locations from which excitatory input can be driven electrically are consistent with cartwheel cells receiving excitatory synaptic input from granule cells. 6. One labeled cell was a superficial stellate cell. It had smooth, straight dendrites that radiated parallel to the layers of the DCN; its axonal arbor was also planar and was restricted to the molecular layer. Both the dendritic and axonal arbors of this stellate cell were large, > 500 microns diam in the parasagittal plane. 7. The superficial stellate cell fired trains of action potentials at regular intervals that, like other cells of the DCN, were overshooting and were followed by double undershoots. 8. Shocks to the nerve root and to the surface of the VCN evoked EPSPs after 3.5 and 2 ms, respectively, in the superficial stellate cell. Chemical stimulation of the VCN also evoked excitation. No inhibitory synaptic input, spontaneous or driven, was detected.

Intracellularly Labeled Fusiform Cells in Dorsal Cochlear Nucleus of the Gerbil. II. Comparison of Physiology and Anatomy

2002 ◽  
Vol 87 (5) ◽  
pp. 2520-2530 ◽  
Author(s):  
Kenneth E. Hancock ◽  
Herbert F. Voigt
Keyword(s):  
Cochlear Nucleus ◽  
Input Resistance ◽  
Apical Dendrite ◽  
Broadband Noise ◽  
Dorsal Cochlear Nucleus ◽  
Cell Physiology ◽  
Spatial Gradient ◽  
Fusiform Cell ◽  
Spontaneous Rate ◽  
Basal Dendrites

Fusiform cells represent the major class of dorsal cochlear nucleus (DCN) projection neuron. Although much is understood about their physiology and anatomy, there remain unexplored issues with important functional implications. These include interspecies differences in DCN physiology and the nature of the cell-to-cell variations in fusiform cell physiology. To address these issues, a quantitative examination was made of the physiology and anatomy of 17 fusiform cells from a companion study. The results suggest that the basal dendrites of gerbil fusiform cells may be electrotonically more compact than those of the cat. This relative decrease in the filtering of excitatory inputs might account for the lower incidence of type IV units in that species. These data also suggest that the gerbil DCN lacks the high-frequency specialization described in the cat, because the tonotopic arrangement of the gerbil fusiform cells quantitatively matches the place-frequency map for the gerbil cochlea. Certain physiological properties have anatomical correlates. First, the basal dendrites of low spontaneous rate cells are directed away from the soma only in the caudal direction, while the high spontaneous rate cells have basal dendrites extending rostrally and caudally. Second, input resistance was dominated by the surface area of the apical dendrite. Third, the discharge pattern was correlated with apical dendrite orientation. Finally, there was a spatial gradient of sensitivity to broadband noise organized at least partially within an isofrequency axis. Such trends indicate that neighboring fusiform cells are endowed with different signal processing capabilities.

scholarly journals Intrinsic and synaptic properties of vertical cells of the mouse dorsal cochlear nucleus

2012 ◽  
Vol 108 (4) ◽  
pp. 1186-1198 ◽  
Author(s):  
Sidney P. Kuo ◽  
Hsin-Wei Lu ◽  
Laurence O. Trussell
Keyword(s):  
Cochlear Nucleus ◽  
Action Potentials ◽  
Fluorescent Protein ◽  
Nerve Fibers ◽  
Dorsal Cochlear Nucleus ◽  
Mammalian Brain ◽  
Fusiform Cell ◽  
Whole Cell Patch Clamp ◽  
Green Fluorescent ◽  
Vertical Cell

Multiple classes of inhibitory interneurons shape the activity of principal neurons of the dorsal cochlear nucleus (DCN), a primary target of auditory nerve fibers in the mammalian brain stem. Feedforward inhibition mediated by glycinergic vertical cells (also termed tuberculoventral or corn cells) is thought to contribute importantly to the sound-evoked response properties of principal neurons, but the cellular and synaptic properties that determine how vertical cells function are unclear. We used transgenic mice in which glycinergic neurons express green fluorescent protein (GFP) to target vertical cells for whole cell patch-clamp recordings in acute slices of DCN. We found that vertical cells express diverse intrinsic spiking properties and could fire action potentials at high, sustained spiking rates. Using paired recordings, we directly examined synapses made by vertical cells onto fusiform cells, a primary DCN principal cell type. Vertical cell synapses produced unexpectedly small-amplitude unitary currents in fusiform cells, and additional experiments indicated that multiple vertical cells must be simultaneously active to inhibit fusiform cell spike output. Paired recordings also revealed that a major source of inhibition to vertical cells comes from other vertical cells.

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