Disrupted periodic spatiotemporal pattern and dynamic reorganization of its basic states in generalized epilepsy

Objective.The anti-correlation between the default mode network (DMN) and task-positive network (TPN) is a stable characteristic of normal brain activity. However, in idiopathic generalized epilepsy (IGE), this anti-correlation is often disrupted and strongly associated with epileptic seizures. This study aims to use periodic spatiotemporal patterns (PSTP) analysis to elucidate the relationship between the DMN-TPN anti-correlation and epileptic activity, providing new insights into the neural mechanisms underlying IGE.Approach.Resting-state functional magnetic resonance imaging was used to analyze PSTP in both healthy controls and IGE patients. A pattern-finding algorithm was initially applied to identify repeated spatiotemporal patterns, followed by a novel PSTP-finding algorithm to uncover dynamic periodic patterns through analysis of fluctuations in the DMN-TPN anti-correlation. The Hilbert transform was applied to capture the underlying basic states of these periodic patterns. Additionally, the relationship between period length and intrinsic neural timescales (INT) was explored.Main results.IGE patients exhibited a reduced DMN-TPN anti-correlation, particularly during TPN-dominant states. Additionally, IGE patients exhibited greater dynamic instability in basic states, marked by more frequent transitions between transitional states. Furthermore, lower correlations between period length and INT were observed in cognitive regions of IGE patients.Significance. These findings suggest that dynamic switching between the DMN and TPN in IGE is weaker and less balanced, with disruptions in periodic rhythms linked to cognitive impairments. The proposed PSTP framework provides new insights into the abnormal rhythms of IGE from a spatiotemporal perspective.