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. Author manuscript; available in PMC: 2015 Jan 1.
Published in final edited form as: Adv Exp Med Biol. 2014;813:43–54. doi: 10.1007/978-94-017-8914-1_3

Figure 2.

Figure 2

Power spectral density (PSD) from 5 minutes of human hippocampus during sleep recorded with intracranial EEG (0.05 - 10,000 Hz, sampled at 32 kHz) using micro- and clinical macro- electrodes. The wide bandwidth recording exhibits 1/f β behavior with different scaling regions characterized by different scaling exponents β = 1 and 2. The inset shows an expansion of the PSD in the 0.05 - 40 Hz range and spectral peaks from a low delta frequency oscillation (~ 0.75 Hz) and a theta-alpha frequency oscillation (7.45 Hz). The characteristic 0.75 Hz oscillation is persistent throughout the 5 minutes and modulates the 7.45 Hz intermittent oscillation. (Unpublished Data)