Prenatal alcohol exposure disrupts hippocampal sharp-wave ripple-associated spike dynamics

Prenatal alcohol exposure (PAE) is among the most common developmental insults to the nervous system and is characterized by memory disruption. There is a pressing need to identify physiological alterations that help explain this memory impairment. Hippocampal sharp-wave ripples (SPW-Rs) are a compelling candidate for this purpose as they are the electrophysiological signatures of memory consolidation. We report that rats exposed to moderate prenatal alcohol display abnormalities restricted to SPW-R episodes that manifest as decreased recruitment of CA1 pyramidal cells and interneurons to SPW-R events, altered excitation during SPW-Rs, and decreased cell assembly activation rate. These differences observed at the single neuron and the population level may limit the ability of memory trace reactivation during SPW-Rs through the disruption of the intrinsic structure of cell sequences. Together, our results suggest that alterations in hippocampal SPW-R spike dynamics may underlie alcohol exposure-related memory deficits.