Spike-wave-discharges (SWD) are the electrophysiological hallmark of absence epilepsy. The leading theory on SWD generation suggests a seizure onset-zone in the deep somatosensory cortex (S1) with 5-9Hz oscillations often preceding SWDs (preictally). These may act as biomarkers, priming distant cortical regions, with the involvement of the centromedian thalamic nucleus (CM). However, these oscillations are also observed interictally. Our study aimed to characterize preictal and interictal 5-9Hz oscillations, exploring power variations across brain-regions. Additionally, we investigated if interictal oscillations pose high-risk moments for SWD generation and assessed their differences in excitability and synchronicity compared to preictal 5-9Hz oscillations and periods of passive wakefulness (pw). 24-hour Local-Field-Potential (LFP) recordings were acquired in S1, CM and secondary motor-cortex of absence-epileptic GAERS rats and subjected to time-frequency power analysis. Differences between the two types of 5-9Hz oscillations were identified using Cluster-based permutation statistics. Subsequently, Evoked potentials, occurrence of epileptic afterdischarges (AD) and Connectivity levels were compared after single or double pulse electrical stimulation applied locally to S1, during 5-9Hz oscillations or pw. We found that interictal 5-9Hz oscillations have a higher power compared to preictals, across all recorded sites. While there was no significant difference in excitability between the conditions, interictal 5-9Hz oscillations carry an increased likelihood for the induction of ADs and show a significantly higher level of S1-CM connectivity compared to pw. These results show that 5-9Hz oscillations are high-risk moments for SWD generation and that they can serve as SWD biomarker, opening the way for refinement of SWD prediction algorithms.