Delta-Frequency Augmentation and Synchronization in Seizure Discharges and Telencephalic Transmission

Summary Epileptic seizures constitute a common neurological disease primarily diagnosed by characteristic rhythms or waves in the local field potentials (LFPs) of cerebral cortices or electroencephalograms. With a basolateral amygdala (BLA) kindling model, we found that the dominant frequency of BLA oscillations is in the delta range (1–5 Hz) in both normal and seizure conditions. Multi-unit discharges are increased with higher seizure staging but remain phase-locked to the delta waves in LFPs. Also, the change in synchrony precedes and outlasts the changes in discharging units as well as behavioral seizures. One short train of stimuli readily drives the pyramidal-inhibitory neuronal networks in BLA slices into prolonged reverberating activities, where the burst and interburst intervals may concurrently set a “natural wavelength” for delta frequencies. Seizures thus could be viewed as erroneous temporospatial continuums to normal oscillations in a system with a built-in synchronizing and resonating nature for information relay.
Graphical Abstract
Highlights • Delta oscillations constitute the natural frequencies in basolateral amygdala • Neuronal burst and interburst intervals set the wavelength for delta oscillations • Delta oscillations may be readily transmitted distantly and translated behaviorally • Synchrony precedes and outlasts increase in discharges and seizures in ictogenesis
Behavioral Neuroscience; Systems Neuroscience; Techniques in Neuroscience