Tonotopic and non-auditory organization of the mouse dorsal inferior colliculus revealed by two-photon imaging

Elife. 2019 Oct 15:8:e49091. doi: 10.7554/eLife.49091.

Abstract

The dorsal (DCIC) and lateral cortices (LCIC) of the inferior colliculus are major targets of the auditory and non-auditory cortical areas, suggesting a role in complex multimodal information processing. However, relatively little is known about their functional organization. We utilized in vivo two-photon Ca2+ imaging in awake mice expressing GCaMP6s in GABAergic or non-GABAergic neurons in the IC to investigate their spatial organization. We found different classes of temporal responses, which we confirmed with simultaneous juxtacellular electrophysiology. Both GABAergic and non-GABAergic neurons showed spatial microheterogeneity in their temporal responses. In contrast, a robust, double rostromedial-caudolateral gradient of frequency tuning was conserved between the two groups, and even among the subclasses. This, together with the existence of a subset of neurons sensitive to spontaneous movements, provides functional evidence for redefining the border between DCIC and LCIC.

Keywords: auditory system; functional anatomy; inferior colliculus; mouse; neuroscience.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acoustic Stimulation
  • Action Potentials
  • Animals
  • Auditory Pathways / anatomy & histology*
  • Auditory Pathways / physiology
  • Brain Mapping*
  • Inferior Colliculi / anatomy & histology*
  • Inferior Colliculi / physiology
  • Mice, Inbred C57BL
  • Neurons / physiology*
  • Optical Imaging
  • Wakefulness