Response properties of type II and type III units in dorsal cochlear nucleus

Young, Eric D.; Voigt, Herbert

doi:10.1016/0378-5955(82)90051-x

Cited by 121 publications

(84 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some appear to be continuous, whereas others are stepwise. For example, in the dorsal cochlear nucleus of the cat, Spirou et al (1993) found a continuous tonotopic progression despite the complex FRAs with multiple, discontinuous islands of excitation surrounded by inhibition (Young and Voigt, 1982;Young, 2008). In contrast, Cetas et al (2001) reported a distinct stepwise progression in the tonotopic organization of the ventral division of the auditory thalamus (MGV) in the rabbit.…”

Section: Previous Tonotopic Mapping Studiesmentioning

confidence: 99%

A Discontinuous Tonotopic Organization in the Inferior Colliculus of the Rat

et al. 2008

View full text Add to dashboard Cite

Audible frequencies of sound are encoded in a continuous manner along the length of the cochlea, and frequency is transmitted to the brain as a representation of place on the basilar membrane. The resulting tonotopic map has been assumed to be a continuous smooth progression from low to high frequency throughout the central auditory system. Here, physiological and anatomical data show that best frequency is represented in a discontinuous manner in the inferior colliculus, the major auditory structure of the midbrain. Multiunit maps demonstrate a distinct stepwise organization in the order of best frequency progression. Furthermore, independent data from single neurons show that best frequencies at octave intervals of approximately one-third are more prevalent than others. These data suggest that, in the inferior colliculus, there is a defined space of tissue devoted to a given frequency, and input within this frequency band may be pooled for higher-level processing.

show abstract

Section: Previous Tonotopic Mapping Studiesmentioning

confidence: 99%

A Discontinuous Tonotopic Organization in the Inferior Colliculus of the Rat

et al. 2008

View full text Add to dashboard Cite

show abstract

“…Responses of onset-C, type II, and type IV neurons were simulated in Matlab (MathWorks, Natick, MA) with a model based on the one developed by Hancock and Voigt (1999). The model circuit was the standard DCN model proposed by Young and colleagues, shown in Figure 12 D (Young and Davis, 2002); the wideband inhibitor (WBI) in the circuit was assumed to be the onset-C cell of the VCN (Nelken and Young, 1994;Winter and Palmer, 1995). Similar intrinsic and connection parameters were used as by Hancock and Voigt (1999), except for the following changes: b k , a parameter governing the effect of the variable potassium conductance, was set to 10 instead of 2 for the type IV and WBI cells and 9 instead of 1.75 for the type II cells; the BFs of certain input populations were offset to lower or higher frequencies relative to the BFs of their target cells, as described in Results; and finally, a Gaussian instead of flat distribution of synaptic weights was used for each population of connections.…”

Section: ϫ6mentioning

confidence: 99%

“…This notch produces a sharp minimum in the sound spectrum at the eardrum, which is an important cue for vertical sound localization in cats (Huang and May, 1996;Tollin and Yin, 2003). Spectral notch processing has been associated with the dorsal cochlear nucleus (DCN) (Young and Davis, 2002;Oertel and Young, 2004) and interruption of the output axons of the DCN impairs the ability of behaving cats to orient to sound sources in the vertical plane (Sutherland et al, 1998;May, 2000).…”

Section: Introductionmentioning

confidence: 99%

Spectral Edge Sensitivity in Neural Circuits of the Dorsal Cochlear Nucleus

Reiss¹,

Young²

2005

J. Neurosci.

View full text Add to dashboard Cite

One possible function of the dorsal cochlear nucleus (DCN) is discrimination of head-related transfer functions (HRTFs), spectral cues used for vertical sound localization. Recent psychophysical and physiological studies suggest that steep, rising spectral edges may be the features used to identify HRTFs. Here we showed, using notch noise and noise band stimuli presented over a range of frequencies, that a subclass of DCN type IV neurons responded with a response peak when the rising spectral edge of a notch or band was aligned near best frequency (BF). This edge sensitivity was correlated with weak or inhibited responses to broadband noise and inhibition in receptive fields at frequencies below BF. Some aspects of the inhibition shaping the response peak, namely inhibition to rising edges below BF and to falling edges at BF, could be explained by the properties of type II interneurons with BFs below those of the type IV neurons. However, many type IV neurons also showed inhibitory responses with the rising spectral edge just above BF, and these responses could not be reproduced by current models of DCN circuitry. Therefore, a new component of the DCN circuit is needed to fully explain the responses to rising spectral edges. This shaping of edge sensitivity by inhibition to rising spectral edges both below and above BF suggests the specialization of DCN for spectral edge coding along the tonotopic gradient.

show abstract

“…Postsynaptically, the iso-intensity curves show a 25-50% reduction from the probe-tone-evoked discharge level over a wide frequency range of the response area. tuberculoventral cells in the dorsal cochlear nucleus (Young and Voigt, 1982;Oertel, 1988, 1990;Oertel and Wickesberg, 1993) and broadband inhibition from inhibitory stellate cells within the ventral cochlear nucleus (Smith and Rhode, 1989;Wickesberg and Oertel, 1990;Nelken and Young, 1994;Ferragamo et al, 1998).…”

Section: Possible Sources Of Inhibitionmentioning

confidence: 99%

Interaction of Excitation and Inhibition in Anteroventral Cochlear Nucleus Neurons That Receive Large Endbulb Synaptic Endings

et al. 2002

View full text Add to dashboard Cite

Spherical bushy cells (SBCs) of the anteroventral cochlear nucleus (AVCN) receive their main excitatory input from auditory nerve fibers (ANFs) through large synapses, endbulbs of Held. These cells are also the target of inhibitory inputs whose function is not well understood. The present study examines the role of inhibition in the encoding of low-frequency sounds in the gerbil's AVCN. The presynaptic action potentials of endbulb terminals and postsynaptic action potentials of SBCs were monitored simultaneously in extracellular single-unit recordings in vivo. An input-output analysis of presynaptic and postsynaptic activity was performed for both spontaneous and acoustically driven activity. Two-tone stimulation and neuropharmacological experiments allowed the effects of neuronal inhibition and cochlear suppression on SBC activity to be distinguished.Ninety-one percent of SBCs showed significant neuronal inhibition. Inhibitory sidebands enclosed the high-or lowfrequency, or both, sides of the excitatory areas of these units; this was reflected as a presynaptic to postsynaptic increase in frequency selectivity of up to one octave. Inhibition also affected the level-dependent responses at the characteristic frequency. Although in all units the presynaptic recordings showed monotonic rate-level functions, this was the case in only half of the postsynaptic recordings. In the other half of SBCs, postsynaptic inhibitory areas overlapped the excitatory areas, resulting in nonmonotonic rate-level functions. The results demonstrate that the sound-evoked spike activity of SBCs reflects the integration of acoustically driven excitatory and inhibitory input. The inhibition specifically affects the processing of the spectral, temporal, and intensity cues of acoustic signals. Key words: prepotential units; endbulb of Held; cochlear suppression; neuronal inhibition; in vivo physiology; bicuculline; strychnine; gerbil; spherical bushy cells; cochlear nucleusThe cochlear nucleus consists of three subdivisions: the anteroventral cochlear nucleus (AVCN), the posteroventral cochlear nucleus, and the dorsal cochlear nucleus, each of which establishes the origins of several monaural and binaural ascending pathways (for review, see Irvine, 1986). It was believed previously that the AVCN serves primarily as a relay transmitting a highfidelity copy of the activity of the auditory nerve to more central auditory brainstem nuclei (Pfeiffer, 1966a,b;Rose et al., 1974). This was demonstrated by morphological data which show that the principal neurons of the AVCN, the spherical bushy cells (SBCs), are innervated by only two to four auditory nerve fibers (ANFs) that form large synaptic endbulbs on the somata of the neurons (Brawer and Morest, 1975;Ryugo and Sento, 1991;Bazwinsky et al., 1999). Because of this specific synaptic configuration, electrophysiological recordings using extracellular electrodes can detect the postsynaptic action potentials of SBCs together with a preceding "prepotential" (PP), indicating the presynaptic afferent ANF ...

show abstract

Response properties of type II and type III units in dorsal cochlear nucleus

Cited by 121 publications

References 23 publications

A Discontinuous Tonotopic Organization in the Inferior Colliculus of the Rat

A Discontinuous Tonotopic Organization in the Inferior Colliculus of the Rat

Spectral Edge Sensitivity in Neural Circuits of the Dorsal Cochlear Nucleus

Interaction of Excitation and Inhibition in Anteroventral Cochlear Nucleus Neurons That Receive Large Endbulb Synaptic Endings

Contact Info

Product

Resources

About