Cholinergic modulation of experience-dependent plasticity in human auditory cortex

The factors that influence experience-dependent plasticity in the human brain are unknown. We used event-related functional magnetic resonance imaging (fMRI) and a pharmacological manipulation to measure cholinergic modulation of experience-dependent plasticity in human auditory cortex. In a differential aversive conditioning paradigm, subjects were presented with high (1600 Hz) and low tones (400 Hz), one of which was conditioned by pairing with an electrical shock. Prior to presentation, subjects were given either a placebo or an anticholinergic drug (0.4 mg iv scopolamine). Experience-dependent plasticity, expressed as a conditioning-specific enhanced BOLD response, was evident in auditory cortex in the placebo group, but not with scopolamine. This study provides in vivo evidence that experience-dependent plasticity, evident in hemodynamic changes in human auditory cortex, is modulated by acetylcholine.