Beta and Gamma Range EEG Power-Spectrum Correlation with Spiking Discharges in DBA/2J Mice Absence Model: Role of GABA_B Receptors

Summary: Purpose: To describe the correlations between spiking pattern and EEG power spectrum frequency in DBA/2J mice, a model for murine absence seizures, after γ-aminobutyric acid (GABA)_B modulation.

Methods: The animals were first tested with the GABA_B agonist l-baclofen followed by the GABA_B antagonist SCH 50911. Moreover, digital EEGs recorded under experimental conditions were processed at baseline and 10 and 20 min after l-baclofen injection. This procedure was followed by injection of the GABA_B antagonist SCH50911 and by an additional EEG evaluation at 10 and 20 min from drug administration. The power spectra analysis of signals was obtained for delta (0.5–3 Hz), theta (3.5–7.5 Hz), alpha (8–12 Hz), beta (13–20 Hz), and gamma (21–50 Hz) frequencies.

Results: The spiking pattern and power spectrum of beta activity was increased by ≤80% after administration of 5 mg/kg l-baclofen, whereas gamma power frequency decreased to the same extent. After administration of 50 mg/kg SCH 50911, spiking activity and beta power frequencies were markedly reduced (>80%), whereas gamma power increased (correlation, 0.92; p < 0.001). The remaining frequency bands were unaffected.

Conclusions: This study confirms the potential of GABA_B antagonists in contrasting seizure absence in rodent models and suggests the application of drugs with a similar mechanism in humans. In addition, because GABA_B antagonists not only contrast seizure in rodent models of absence but also improve “cognitive” performance, it could be hypothesized that gamma increase, correlated with optimized cortical binding during coherent percepts, may produce potential cognition-enhancing effects.