Current Status of the Basal Forebrain Cholinergic System: A Preview and Commentary -- The Basal Forebrain Cholinergic System: An Evolving Concept in the Neurobiology of the Forebrain -- Behavioral Neuroanatomy of Cholinergic Innervation in the Primate Cerebral Cortex -- Input/Output Relations of the Magnocellular Nuclei of the Basal Forebrain -- Role of the Basal Forebrain Cholinergic System in Cortical Activation and Arousal -- Functional Implications of Tonic and Phasic Activity Changes in Nucleus Basalis Neurons -- Actions of Acetylcholine on Cortical Neurons: Pieces in the Puzzle About Mechanisms Underlying Learning -- Acetylcholine Modulation of Cellular Excitability Via Muscarinic Receptors: Functional Plasticity in Auditory Cortex -- Basal Forebrain, Memory and Attention -- An Analysis of the Basal Forebrain Contribution to Learning and Memory -- Ocular Dominance Plasticity in Kitten Visual Cortex: Integration of Noradrenergic and Cholinergic Regulation -- Cholinergic Modulation of Synaptic Plasticity in Sensory Neocortex -- The Cholinergic Basal Forebrain as a Cognitive Machine