Theta rhythmic clock-like activity was observed in a small group of hippocampal CA1 neurons in freely behaving mice. These neurons were only persistently activated during theta states of waking exploration and rapid eye movement sleep, but were almost silent during the non-theta state of slow-wave sleep. Interestingly, these cells displayed a theta clock-like simple-spike firing pattern, and were capable of firing one spike per theta cycle during theta states. This is the first report of a unique class of hippocampal neurons with a clock-like firing pattern at the theta rhythm.Wespeculate that these cellsmayact as a temporal reference to participate in the theta-related temporal coding in the hippocampus. Significance Statement Theta oscillations, as the predominant rhythms in the hippocampus during waking exploration and rapid eye movement sleep, may be critical for temporal coding/decoding of neuronal information, and theta-phase precession in hippocampal place cells is one of the best demonstrations of such temporal coding. Here,weshow that a unique small class of hippocampalCA1neurons fired with a theta rhythmic clock-like firing pattern during theta states. These firing characteristics support the notion that these neurons may play a critical role in theta-related temporal coding in the hippocampus.
Bibliographical noteFunding Information:
This work was supported by the National Basic Research Development Program of China (Grant 2013CB835101), the National Natural Science Foundation of China (Grant 81271490), and the Basic Research Project of Shanghai Science and Technology Commission (Grants 14JC1401800 and 15JC1400102)
© 2016 the authors.
- Phase precession
- Theta oscillations
ASJC Scopus subject areas
- Medicine (all)