The effects of concurrent manipulations of cholinergic and noradrenergic systems on neocortical EEG and spatial learning.

In the spatial learning test, young animals were divided into three groups receiving saline, scopolamine (0.15 mg/kg), or scopolamine (0.8 mg/kg). Half of the animals in each group were lesioned with DSP-4 to destroy noradrenergic fibers. DSP-4 lesions did not produce any significant impairment alone or in combination with a lower dose of scopolamine (0.15 mg/kg), but they did further augment the scopolamine (0.8 mg/kg)-induced defect. In the electroencephalography (EEG) experiment, both control rats and DSP-4-lesioned rats were recorded after receiving saline, scopolamine (0.15 mg/kg), and scopolamine (0.8 mg/kg) injections. Scopolamine induced a dose- and behavioral state-dependent EEG slowing, whereas DSP-4 lesions did not change either baseline EEG activity or EEG reactivity to scopolamine.