Data from: Theta oscillations coincide with sustained hyperpolarization in CA3 pyramidal cells, underlying decreased firing

Brain-state fluctuations modulate membrane potential dynamics of neurons,
influencing the functional repertoire of the network. Pyramidal cells
(PCs) in hippocampal CA3 are necessary for rapid memory encoding,
preferentially occurring during exploratory behavior in the
high-arousal theta state. However, the relationship between the
membrane potential dynamics of CA3 PCs and theta has not been
explored. Here, we characterize the changes in the membrane potential
of  PCs in relation to theta using electrophysiological
recordings in awake mice. During theta, most PCs behave in a
stereotypical manner, consistently hyperpolarizing time-locked to the
duration of  theta. Additionally, PCs display lower membrane
potential variance and reduced firing rate. In contrast, during
large irregular activity, a low-arousal state, PCs show heterogeneous
changes in membrane potential. This suggests coordinated
hyperpolarization of PCs during theta, possibly caused by
increased inhibition. This could lead to higher signal-to-noise ratio in
the small population of PCs active during theta as observed in
ensemble recordings.