Thursday, May 8, 2014
Beckman Laboratory 24
Behavioral Social Neuroscience Seminar Series
How Multiple Forms of Learning Guide Decisions
Daphna Shohamy, Columbia University
Learning is central to adaptive behavior. From robots to humans, the ability to learn from experience turns a rigid response system into a flexible, adaptive one. How are decisions shaped by past experience? What are the neurobiological and cognitive mechanisms that allow everyday experiences to change the way we perceive and act in the world? Work in my lab aims to address these questions. We take as a starting point a longstanding idea in cognitive and systems neuroscience: that the brain learns in different ways by using multiple specialized learning systems. Recent research has focused on the role of the striatum and midbrain dopamine regions in habitual learning of stimulus-reward associations. However, emerging evidence suggests that the hippocampus – widely known for its role in building episodic memories – is also modulated by reward and modulated by dopamine. This raises new hypotheses about the role of the hippocampus in learning, the unique contributions of the hippocampus and the striatum, and the nature of the relationship between them. Work in my lab has made progress on these questions by adopting an integrative approach that combines functional imaging (fMRI) in healthy individuals with studies of learning in patients with selective damage to the striatum or the hippocampus. Converging data from these approaches suggests that both the striatum and the hippocampus contribute to learning, with distinct implications for how learning guides decisions and actions.