Theta, Gamma, and Cross-Frequency Coupling in the Hippocampus
The hippocampus is a prominent brain structure in the medial temporal lobe known to be important for episodic memory function. Theta (3–12 Hz) and gamma rhythms (25–160 Hz) commonly refer to specific frequency bands of EEG or local field potential (LFP) activity that is generated by neural circuits in the hippocampus during periods of increased neural activity. These neural rhythms function to organize hippocampal spike timing using different temporal scales.
Brain rhythms play an important role in spike timing and brain communication (Buzsaki 2006; Gray et al. 1989; O’Keefe and Recce 1993). Different brain regions produce distinctly different brain rhythm frequencies that are thought to reflect unique forms of processing important for the localization, parceling, and routing of information within and between regions. Delta (~.5–2 Hz), theta (3–12 Hz), beta (15–25 Hz), and gamma rhythms (25–160 Hz) have been investigated for decades. It is...