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Published March 1, 2015 | public
Journal Article

Synaptic Mechanisms for Generating Temporal Diversity of Auditory Representation in the Dorsal Cochlear Nucleus

Abstract

In central auditory pathways neurons exhibit a great diversity of temporal discharge patterns, which may contribute to the parallel processing of auditory signals. How such response diversity emerges in the central auditory circuits remains unclear. Here, we investigated whether synaptic mechanisms can contribute to the generation of the temporal response diversity at the first stage along the central auditory neuraxis. By in vivo whole-cell voltage-clamp recording in the dorsal cochlear nucleus (DCN) of rats, we revealed excitatory and inhibitory synaptic inputs underlying three different firing patterns of fusiform/pyramidal neurons in response to auditory stimuli: "primary-like", "pauser", and "buildup" patterns. We found that primary-like neurons received strong fast-rising excitation, whereas pauser and buildup neurons received accumulating excitation with a relatively weak fast rising phase followed by a slow rising phase. Pauser neurons received stronger fast-rising excitation than buildup cells. On the other hand, inhibitory inputs to the three types of cell exhibited similar temporal patterns all with a strong fast-rising phase. Dynamic-clamp recordings demonstrated that the differential temporal patterns of excitation could primarily account for the different discharge patterns. In addition, discharge pattern in a single neuron varied in a stimulus-dependent manner, which could be attributed to the modulation of excitation/inhibition balance by different stimuli. Further examination of excitatory inputs to vertical/tuberculoventral and cartwheel cells suggested that fast-rising and accumulating excitation might be conveyed by auditory nerve and parallel fibers respectively. A differential summation of excitatory inputs from the two sources may thus contribute to the generation of response diversity.

Additional Information

© 2014 by the American Physiological Society. This work was supported by grants to L.I.Z. from the US National Institutes of Health/NIDCD (R01DC008983), and the David and Lucile Packard Foundation (Packard Fellowships for Science and Engineering). H.W.T was supported by a grant from the US National Institutes of Health (R01EY019049). W.Y. was supported by grants from the National Natural Science Foundation of China (NSFC: 30973301, 81271080, 81470694).

Additional details

Created:
August 20, 2023
Modified:
October 18, 2023