Data from: Cannabinoids disrupt memory encoding by functionally isolating hippocampal CA1 from CA3

Much of the research on cannabinoids (CBs) has focused on their effects at
the molecular and synaptic level. However, the effects of CBs on the
dynamics of neural circuits remains poorly understood. This study aims to
disentangle the effects of CBs on the functional dynamics of the
hippocampal Schaffer collateral synapse by using data-driven nonparametric
modeling. Multi-unit activity was recorded from rats doing an working
memory task in control sessions and under the influence of exogenously
administered tetrahydrocannabinol (THC), the primary CB found in
marijuana. It was found that THC left firing rate unaltered and only
slightly reduced theta oscillations. Multivariate autoregressive models,
estimated from spontaneous spiking activity, were then used to describe
the dynamical transformation from CA3 to CA1. They revealed that THC
served to functionally isolate CA1 from CA3 by reducing feedforward
excitation and theta information flow. The functional isolation was
compensated by increased feedback excitation within CA1, thus leading to
unaltered firing rates. Finally, both of these effects were shown to be
correlated with memory impairments in the working memory task. By
elucidating the circuit mechanisms of CBs, these results help close the
gap in knowledge between the cellular and behavioral effects of CBs.