GABAergic neurons in the olfactory cortex projecting to the lateral hypothalamus in mice

Sci Rep. 2019 May 9;9(1):7132. doi: 10.1038/s41598-019-43580-1.


Olfaction guides goal-directed behaviours including feeding. To investigate how central olfactory neural circuits control feeding behaviour in mice, we performed retrograde tracing from the lateral hypothalamus (LH), an important feeding centre. We observed a cluster of retrogradely labelled cells distributed in the posteroventral region of the olfactory peduncle. Histochemical analyses revealed that the majority of these retrogradely labelled projection neurons expressed glutamic acid decarboxylase 65/67 (GAD65/67), but not vesicular glutamate transporter 1 (VGluT1). We named this region containing GABAergic projection neurons the ventral olfactory nucleus (VON) to differentiate it from the conventional olfactory peduncle. VON neurons were less immunoreactive for DARPP-32, a striatal neuron marker, compared to neurons in the olfactory tubercle and nucleus accumbens, which distinguished the VON from the ventral striatum. Fluorescent labelling confirmed putative synaptic contacts between VON neurons and olfactory bulb projection neurons. Rabies-virus-mediated trans-synaptic labelling revealed that VON neurons received synaptic inputs from the olfactory bulb, other olfactory cortices, horizontal limb of the diagonal band, and prefrontal cortex. Collectively, these results identify novel GABAergic projection neurons in the olfactory cortex that may integrate olfactory sensory and top-down inputs and send inhibitory output to the LH, which may modulate odour-guided LH-related behaviours.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Feeding Behavior
  • GABAergic Neurons / metabolism*
  • GABAergic Neurons / virology
  • Glutamate Decarboxylase / metabolism
  • Hypothalamic Area, Lateral / metabolism*
  • Hypothalamic Area, Lateral / virology
  • Male
  • Mice
  • Olfactory Bulb / metabolism
  • Olfactory Bulb / virology
  • Olfactory Cortex / metabolism*
  • Olfactory Cortex / virology
  • Rabies virus / physiology*
  • Vesicular Glutamate Transport Protein 1 / metabolism


  • Slc17a7 protein, mouse
  • Vesicular Glutamate Transport Protein 1
  • Glutamate Decarboxylase
  • glutamate decarboxylase 1
  • glutamate decarboxylase 2