Abstract
New evidence indicates that noninvasive brain stimulation can induce safe and reversible improvements in learning during the performance of visual tasks. However, the cognitive mechanisms underlying these learning effects are unknown. Here we show that the improvements in learning are due to changes in how rapidly long-term memory representations replace working memory representations in controlling visual processing. Using transcranial direct-current stimulation of medial-frontal cortex, we selectively enhanced the neural activity related to long-term memory and induced single-trial learning during a memory-guided visual search task. In contrast, medial-frontal stimulation did not change the neural index of working memory in attentional control. Moreover, parietal cortex stimulation spared all measures of top-down control and learning, demonstrating the specificity of the medial-frontal effects on learning during visual processing. In a subsequent experiment, we replicated and generalized our results to a task in which subjects searched for targets among complex real-world objects. Our findings provide new insight into the nature of the memory representations underlying plasticity and learning to control visual attention.
Meeting abstract presented at VSS 2014