Parallel mitral and tufted cell pathways route distinct odor information to different targets in the olfactory cortex

J Neurosci. 2012 Jun 6;32(23):7970-85. doi: 10.1523/JNEUROSCI.0154-12.2012.

Abstract

Odor signals are conveyed from the olfactory bulb to the olfactory cortex (OC) by mitral cells (MCs) and tufted cells (TCs). However, whether and how the two types of projection neuron differ in function and axonal connectivity is still poorly understood. Odor responses and axonal projection patterns were compared between MCs and TCs in mice by visualizing axons of electrophysiologically identified single neurons. TCs demonstrated shorter onset latency for reliable responses than MCs. The shorter latency response of TCs was maintained in a wide range of odor concentrations, whereas MCs responded only to strong signals. Furthermore, individual TCs projected densely to focal targets only in anterior areas of the OC, whereas individual MCs dispersedly projected to all OC areas. Surprisingly, in anterior OC areas, the two cell types projected to segregated subareas. These results suggest that MCs and TCs transmit temporally distinct odor information to different OC targets.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Axons / physiology
  • Butyrates
  • Cluster Analysis
  • Data Interpretation, Statistical
  • Dendrites / physiology
  • Dendrites / ultrastructure
  • Electrophysiological Phenomena
  • Image Processing, Computer-Assisted
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neuroimaging
  • Neurons / physiology*
  • Odorants*
  • Olfactory Bulb / physiology
  • Olfactory Pathways / cytology*
  • Olfactory Pathways / physiology*
  • Oxygen Consumption / physiology
  • Presynaptic Terminals / physiology
  • ROC Curve
  • Single-Cell Analysis
  • Smell / physiology*
  • Thiazoles

Substances

  • 2,4,5 trimethylthiazoline
  • Butyrates
  • Thiazoles
  • 2-methylbutanoic acid