Destruction of the nucleus basalis abolished normal spectral power only in the frontal cortex, where choline acetyltransferase (ChAT) activity was lower. In lesioned animals, delta-power was increased and alpha-power decreased. The increase in delta-power during immobility correlated with a reduction in ChAT activity. High-voltage spindles occurred more frequently after cholinergic denervation. The results suggest that spectral power and high-voltage spindle analysis might serve as a useful tool for evaluating the efficacy of pharmacological strategies aimed at alleviating the cholinergic deficit.