The effects of electrical stimulation of the nucleus basalis on the electroencephalogram, heart rate, and respiration.

The nucleus basalis (NB) mediates cortical electroencephalograph (EEG) activation; NB stimulation also modulates cortical responses to sensory stimuli and can induce learning-related receptive field plasticity. However, little is known about the behavioral effects of NB stimulation. This study concerns the effects of NB stimulation on cardiac and respiratory behavior and quantifies its EEG effects in freely moving rats. The EEG exhibited stimulation-induced decreases in theta and alpha power and increases in gamma power. NB stimulation elicited biphasic heart rate changes and disrupted ongoing respiration patterns. Neither EEG nor behavioral effects exhibited habituation or facilitation. These results indicate that the NB may serve not only as a cortical, but also as a behavioral, activation system that is normally engaged during learning.