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The role of auditory nerve innervation and dendritic filtering in shaping onset responses in the ventral cochlear nucleus

Sumner, CJ and Meddis, R and Winter, IM (2009) 'The role of auditory nerve innervation and dendritic filtering in shaping onset responses in the ventral cochlear nucleus.' Brain Research, 1247. pp. 221-234. ISSN 0006-8993

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Abstract

Neurons in the ventral cochlear nucleus (VCN) that respond primarily at the onset of a pure tone stimulus show diversity in terms of peri-stimulus-time-histograms (PSTHs), rate-level functions, frequency tuning, and also their responses to broad band noise. A number of different mechanisms have been proposed as contributing to the onset characteristic: e.g. coincidence, depolarisation block, and low-threshold potassium currents. We show that a simple point neuron receiving convergent inputs from high-spontaneous rate auditory nerve (AN) fibers, with no special currents and no peri-stimulatory shifts in firing threshold, is sufficient to produce much of the diversity seen experimentally. Three sub-classes of onset PSTHs: onset-ideal (OI), onset-chopper (OC) and onset-locker (OL) are reproduced by variations in innervation patterns and dendritic filtering. The factors shaping responses were explored by systematically varying key parameters. An OI response in this model requires a narrow range of AN input best frequencies (BF) which only produce suprathreshold depolarizations during the stimulus onset. For OC and OL responses, receptive fields were wider. Considerable low pass filtering of AN inputs away from BF results in an OL, whilst relatively unfiltered inputs produce an OC response. Rate-level functions in response to pure tones can be sloping, or plateau. These can be also reproduced in the model by the manipulation of the AN innervation. The model supports the coincidence detection hypothesis, and suggests that differences in excitatory innervation and dendritic filtering constant are important factors to consider when accounting for the variation in response characteristics seen in VCN onset units.

Item Type: Article
Uncontrolled Keywords: Onset Stellate Cochlear nucleus Point-neuron PSTH Rate-level functions
Subjects: B Philosophy. Psychology. Religion > BF Psychology
Divisions: Faculty of Science and Health
Faculty of Science and Health > Psychology, Department of
SWORD Depositor: Elements
Depositing User: Elements
Date Deposited: 13 Nov 2011 16:14
Last Modified: 15 Jan 2022 01:07
URI: http://repository.essex.ac.uk/id/eprint/1454

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