Abstract

Understanding the world around us depends on the brain resolving ambiguous information from our senses to inform our decisions and actions. The brain learns to interpret sensory signals by using past experience to optimize perceptual decisions. But how does practice mold the adult human brain and result in improved decisions? We combine ultra high-field structural, functional and neurochemical brain imaging with computational modeling to interrogate the fine-scale human brain circuits that support learning for perceptual decisions. We provide evidence for interactions between subcortical and cortical circuits that gate sensory plasticity and perceptual decision making. We show that thalamocortical plasticity mediates gain control in visual cortex for detecting objects in clutter, while occipital-parietal interactions mediate fine feature retuning through recurrent inhibitory processing in visual cortex. These findings propose a dynamic interplay of adaptive structural and functional plasticity mechanisms for optimized and flexible decision making in the adult human brain.