Redefining Learning Models

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The Transmitter is an online publication that aims to deliver useful information, insights and tools to build bridges across neuroscience and advance research. Visit thetransmitter.org to explore the latest neuroscience news and perspectives, written by journalists and scientists. 

The Transmitter has provided a transcript for this episode.

Vijay Namoodiri runs the Nam Lab at the University of California San Francisco, and Ali Mojebi is an assistant professor at the University of Wisconsin-Madison. Ali as been on the podcast before a few times, and he's interested in how neuromodulators like dopamine affect our cognition. And it was Ali who pointed me to Vijay, because of some recent work Vijay has done reassessing how dopamine might function differently than what has become the classic story of dopamine's function as it pertains to learning. The classic story is that dopamine is related to reward prediction errors. That is, dopamine is modulated when you expect reward and don't get it, and/or when you don't expect reward but do get it. Vijay calls this a "prospective" account of dopamine function, since it requires an animal to look into the future to expect a reward. Vijay has shown, however, that a retrospective account of dopamine might better explain lots of know behavioral data. This retrospective account links dopamine to how we understand causes and effects in our ongoing behavior. So in this episode, Vijay gives us a history lesson about dopamine, his newer story and why it has caused a bit of controversy, and how all of this came to be.

I happened to be looking at the Transmitter the other day, after I recorded this episode, and low and behold, there was an article titles Reconstructing dopamine’s link to reward. Vijay is featured in the article among a handful of other thoughtful researchers who share their work and ideas about this very topic. Vijay wrote his own piece as well: Dopamine and the need for alternative theories. So check out those articles for more views on how the field is reconsidering how dopamine works.

• Nam Lab.
• Mohebi & Associates (Ali's Lab).
• Twitter:
  • @vijay_mkn
  • @mohebial
• Transmitter
  • Dopamine and the need for alternative theories.
  • Reconstructing dopamine’s link to reward.
• Related papers
  • Mesolimbic dopamine release conveys causal associations.
  • Mesostriatal dopamine is sensitive to changes in specific cue-reward contingencies.
  • What is the state space of the world for real animals?
  • The learning of prospective and retrospective cognitive maps within neural circuits
• Further reading
  • (Ali's paper): Dopamine transients follow a striatal gradient of reward time horizons.
  • Ali listed a bunch of work on local modulation of DA release:
    • Local control of striatal dopamine release.
    • Synaptic-like axo-axonal transmission from striatal cholinergic interneurons onto dopaminergic fibers.
    • Spatial and temporal scales of dopamine transmission.
    • Striatal dopamine neurotransmission: Regulation of release and uptake.
    • Striatal Dopamine Release Is Triggered by Synchronized Activity in Cholinergic Interneurons.
    • An action potential initiation mechanism in distal axons for the control of dopamine release.

Read the transcript, produced by The Transmitter.

0:00 - Intro 3:42 - Dopamine: the history of theories 32:54 - Importance of learning and behavior studies 39:12 - Dopamine and causality 1:06:45 - Controversy over Vijay's findings