Data from: The impact of pathological high-frequency oscillations on hippocampal network activity in rats with chronic epilepsy

In epilepsy, brain networks generate pathological high-frequency
oscillations (pHFOs) during interictal periods. To understand how pHFOs
differ from normal oscillations in overlapping frequency bands and
potentially perturb hippocampal processing, we performed high-density
single unit and local field potential recordings from hippocampi of
behaving rats with and without chronic epilepsy. In epileptic animals, we
observed two types of co-occurring fast oscillations, which by comparison
to control animals we could classify as ‘ripple-like’ or ‘pHFO’. We
compared their spectral characteristics, brain state dependence, and
cellular participants. Strikingly, pHFO occurred irrespective of brain
state, were associated with interictal spikes, engaged distinct
subnetworks of principal neurons compared to ripple-like events, increased
the sparsity of network activity, and initiated both general and immediate
disruptions in spatial information coding. Taken together, our findings
suggest that events that result in pHFOs have an immediate impact on
memory processes, corroborating the need for proper classification of
pHFOs to facilitate therapeutic interventions that selectively target
pathological activity.