Neurophysiological studies demonstrated that increases in cholinergic transmission in
sensory areas enhance the cortical processing of thalamic inputs. Cholinergic activity also
suppresses the retrieval of internal associations, thereby further promoting sensory input
processing. Behavioral studies documented the role of cortical cholinergic inputs in
attentional functions and capacities by demonstrating, for example, that the integrity of the
cortical cholinergic input system is necessary for attentional performance, and that the …