Evidence for layer-specific differences in auditory corticocollicular neurons

B. J. Slater, A. M. Willis, D. A. Llano

Research output: Contribution to journalArticlepeer-review

Abstract

Recent data suggest that there may be distinct processing streams emanating from auditory cortical layers 5 and 6 that influence the auditory midbrain. To determine whether these projections have different physiological properties, we injected rhodamine-tagged latex tracer beads into the inferior colliculus of >30-day-old mice to label these corticofugal cells. Whole-cell recordings were performed on 62 labeled cells to determine their basic electrophysiological properties and cells were filled with biocytin to determine their morphological characteristics. Layer 5 auditory corticocollicular cells have prominent Ih-mediated sag and rebound currents, have relatively sluggish time constants, and can generate calcium-dependent rhythmic bursts. In contrast, layer 6 auditory corticocollicular cells are non-bursting, do not demonstrate sag or rebound currents and have short time constants. Quantitative analysis of morphology showed that layer 6 cells are smaller, have a horizontal orientation, and have very long dendrites (>500μm) that branch profusely both near the soma distally near the pia. Layer 5 corticocollicular cells are large pyramidal cells with a long apical dendrite with most branching near the pial surface. The marked differences in physiological properties and dendritic arborization between neurons in layers 5 and 6 make it likely that each type plays a distinct role in controlling auditory information processing in the midbrain.

Original languageEnglish (US)
Pages (from-to)144-154
Number of pages11
JournalNeuroscience
Volume229
DOIs
StatePublished - Jan 15 2013

Keywords

  • Auditory
  • Cortex
  • Corticocollicular
  • Corticofugal
  • Corticotectal
  • Inferior colliculus

ASJC Scopus subject areas

  • Neuroscience(all)

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