The functional role of dopamine in visual perceptual learning and cortical plasticity.

The ventral tegmental area (VTA) contains dopaminergic neurons that fire when events are better than expected, leading to dopamine release in connected sites. This firing has been proposed to be at the basis of different forms of learning. One type, perceptual learning, reflects improved task performance induced by repeated practice. Theories of perceptual learning have proposed that interactions between attention and release of neuromodulators interact to generate this learning. However, sometimes neuromodulator release without attention can be sufficient for perceptual learning. In line with this, we recently found that the coupling of electrical VTA stimulation with a stimulus, in the absence of attention, generates perceptual learning-like behavioral improvements and brain plasticity.

Here, we aim to determine whether such learning effects are specifically generated by dopamine using drugs that alter dopamine signals. Concurrently, in a more ambitious aim, we will use lightbased (optogenetic) techniques to selectively stimulate dopaminergic VTA neurons. Next we will examine how VTA stimulation affects brain plasticity on a macroscopic scale using whole brain functional imaging and on a microscopic scale looking at the electrical responses of single neurons. We will also study how attention and dopamine release interacts in these learning and plasticity processes. This work will provide fundamental information on the mechanisms that regulate learning and brain plasticity.