Table 1:

Oscillatory Events Potentially Linked to Symptomatic Neurodegenerative Disease

Oscillatory Event Type	Defining Characteristics	Role in Cognitive Functions	Link to Neurodegenerative Disease
Slow Wave Activity (SWA)	Orchestrates cortical activations through upstates and downstates, synchronizing large brain regions.[97, 120, 136]	Essential for sleep-dependent memory processing and synaptic regulation.[117, 131, 137-139]	Degradation of SWA linked to early Alzheimer’s disease pathology through cortical amyloid and tau accumulation and possible LC dysfunction.[14, 81–83, 99–101]
Theta Bursts	Oscillatory events preceding slow waves, observed in cortical and subcortical regions.[108–110]	Proposed parallel function in sleep to wake-state bursts of theta activity for hippocampal-dependent memory retrieval.[111]	Loss of power and timing imprecision in MCI and early AD, indicating potential disruptions in hippocampal neural circuits.[91]
Sleep Spindles	Discrete oscillatory events synchronized in cortical and subcortical structures during NREM sleep;[108–110, 114, 115] occur in isolation and coupled to slow wave events.[123, 124]	Integral to memory processing and consolidation, linking hippocampal and limbic structures with association cortexes during memory replay.[116, 117, 131, 140]	Aging linked to lower-frequency spindle coupling; abnormalities in spindle phase alignment and frequency consistency associated with memory impairment and AD pathology.[81, 91, 92, 128]
Gamma Ripples	Bursts of high-frequency gamma activity associated with slow waves and spindles; occur as sharp wave ripples (SWR) coupled to slow waves and gamma ripples coupled to spindles.[108, 109, 129]	Facilitate the binding of cortical regions and synchronization of neuronal activity during memory reactivation and consolidation.[129, 131, 140]	Abnormalities in sharp wave ripples associated with AD pathology;[132, 133] APOE4 expression impacts hippocampal microstructure and ripple production.[134, 135]