Molecular layer inhibitory interneurons provide feedforward and lateral inhibition in the dorsal cochlear nucleus

Michael T. Roberts, Laurence O. Trussell

Research output: Contribution to journalArticle

27 Scopus citations

Abstract

In the outer layers of the dorsal cochlear nucleus, a cerebellum-like structure in the auditory brain stem, multimodal sensory inputs drive parallel fibers to excite both principal (fusiform) cells and inhibitory cartwheel cells. Cartwheel cells, in turn, inhibit fusiform cells and other cartwheel cells. At the microcircuit level, it is unknown how these circuit components interact to modulate the activity of fusiform cells and thereby shape the processing of auditory information. Using a variety of approaches in mouse brain stem slices, we investigated the synaptic connectivity and synaptic strength among parallel fibers, cartwheel cells, and fusiform cells. In paired recordings of spontaneous and evoked activity, we found little overlap in parallel fiber input to neighboring neurons, and activation of multiple parallel fibers was required to evoke or alter action potential firing in cartwheel and fusiform cells. Thus neighboring neurons likely respond best to distinct subsets of sensory inputs. In contrast, there was significant overlap in inhibitory input to neighboring neurons. In recordings from synaptically coupled pairs, cartwheel cells had a high probability of synapsing onto nearby fusiform cells or other nearby cartwheel cells. Moreover, single cartwheel cells strongly inhibited spontaneous firing in single fusiform cells. These synaptic relationships suggest that the set of parallel fibers activated by a particular sensory stimulus determines whether cartwheel cells provide feedforward or lateral inhibition to their postsynaptic targets.

Original languageEnglish (US)
Pages (from-to)2462-2473
Number of pages12
JournalJournal of neurophysiology
Volume104
Issue number5
DOIs
StatePublished - Nov 1 2010

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ASJC Scopus subject areas

  • Neuroscience(all)
  • Physiology

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