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. Author manuscript; available in PMC: 2014 Jun 1.
Published in final edited form as: Sleep Med Rev. 2012 Oct 6;17(3):227–238. doi: 10.1016/j.smrv.2012.06.002

Fig. 2.

Fig. 2

Gamma band activity in the reticular activating system (RAS). A) Representative membrane potential responses of the same pedunculopontine nucleus (PPN) neuron to depolarizing 1 s square step (gray record, left), and to 1 s long ramp (black record, right) obtained in the presence of fast synaptic blockers and tetrodotoxin (TTX). B) Overlapping curves comparing power spectrum amplitudes for oscillations obtained in A, pulses vs ramps. Note the higher amplitude of the oscillations obtained in the same neuron using ramps vs square steps. C) Representative membrane potential responses of the same parafascicular nucleus (Pf) neuron to depolarizing 1 s square step (gray record, left), and to 1 s long ramp (black record, right) obtained in the presence of fast synaptic blockers and TTX. D) Overlapping curves comparing power spectrum amplitudes for oscillations obtained in C, pulses vs ramps. Again, note the higher amplitude of the oscillations obtained using ramps vs square steps. E) Representative subthreshold oscillations at membrane potentials above action potential (AP) threshold (–43 mV). The dotted boxes include 1 s of recordings (upper records) that are also shown at higher resolution (lower records), revealing gamma frequency oscillations at –43 mV holding potential. F) Power spectrum confirming that the subthreshold oscillations were at beta/gamma frequencies, but no higher.