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Topic: error signal

Seminar
2 seminars

In Biology and Cognition

Seminar · Computational Neuroscience

Mapping learning and decision-making algorithms onto brain circuitry

Ilana Witten · Princeton

Fri, Nov 18, 2022 · 06:30 UTC

In the first half of my talk, I will discuss our recent work on the midbrain dopamine system. The hypothesis that midbrain dopamine neurons broadcast an error signal for the prediction of reward is among the great successes of computational neuroscience. However, our recent results contradict a core aspect of this theory: that the neurons uniformly convey a scalar, global signal. I will review this work, as well as our new efforts to update models of the neural basis of reinforcement learning with our data. In the second half of my talk, I will discuss our recent findings of state-dependent de

Seminar · Computational Neuroscience

Population coding in the cerebellum: a machine learning perspective

Reza Shadmehr · Johns Hopkins School of Medicine

Wed, Apr 6, 2022 · 15:00 UTC

The cerebellum resembles a feedforward, three-layer network of neurons in which the “hidden layer” consists of Purkinje cells (P-cells) and the output layer consists of deep cerebellar nucleus (DCN) neurons. In this analogy, the output of each DCN neuron is a prediction that is compared with the actual observation, resulting in an error signal that originates in the inferior olive. Efficient learning requires that the error signal reach the DCN neurons, as well as the P-cells that project onto them. However, this basic rule of learning is violated in the cerebellum: the olivary projections to