Ventral hippocampal OLM cells control type 2 theta oscillations and response to predator odor

Nat Commun. 2018 Sep 7;9(1):3638. doi: 10.1038/s41467-018-05907-w.


Dorsal and ventral hippocampus regions exert cognition and emotion-related functions, respectively. Since both regions display rhythmic activity, specific neural oscillatory pacemakers may underlie their functional dichotomy. Type 1 theta oscillations are independent of cholinergic transmission and are observed in the dorsal hippocampus during movement and exploration. In contrast, type 2 theta depends on acetylcholine and appears when animals are exposed to emotionally laden contexts such as a predator presence. Despite its involvement in emotions, type 2 theta has not been associated with the ventral hippocampus. Here, we show that optogenetic activation of oriens-lacunosum moleculare (OLM) interneurons in the ventral hippocampus drives type 2 theta. Moreover, we found that type 2 theta generation is associated with increased risk-taking behavior in response to predator odor. These results demonstrate that two theta oscillations subtypes originate in the two hippocampal regions that predominantly underlie either cognitive or emotion-related functions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Hippocampus / physiology*
  • Interneurons / physiology*
  • Male
  • Mice
  • Mice, Transgenic
  • Odorants
  • Optogenetics
  • Receptors, Nicotinic / metabolism
  • Risk-Taking*
  • Theta Rhythm*


  • Receptors, Nicotinic