Reinforcement learning in dendritic structures

Schiess, Mathieu; Urbanczik, Robert; Senn, Walter (2010). Reinforcement learning in dendritic structures. In: 7th Forum of European Neuroscience. Amsterdam, Netherlands. July 3-7, 2010.

The discovery of binary dendritic events such as local NMDA spikes in dendritic subbranches led to the suggestion that dendritic trees could be computationally equivalent to a 2-layer network of point neurons, with a single output unit represented by the soma, and input units represented by the dendritic branches. Although this interpretation endows a neuron with a high computational power, it is functionally not clear why nature would have preferred the dendritic solution with a single but complex neuron, as opposed to the network solution with many but simple units. We show that the dendritic solution has a distinguished advantage over the network solution when considering different learning tasks. Its key property is that the dendritic branches receive an immediate feedback from the somatic output spike, while in the corresponding network architecture the feedback would require additional backpropagating connections to the input units. Assuming a reinforcement learning scenario we formally derive a learning rule for the synaptic contacts on the individual dendritic trees which depends on the presynaptic activity, the local NMDA spikes, the somatic action potential, and a delayed reinforcement signal. We test the model for two scenarios: the learning of binary classifications and of precise spike timings.
We show that the immediate feedback represented by the backpropagating action potential supplies the individual dendritic branches with enough information to efficiently adapt their synapses and to speed up the learning process.

Item Type:

Conference or Workshop Item (Poster)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Physiology

UniBE Contributor:

Schiess, Mathieu; Urbanczik, Robert and Senn, Walter

Subjects:

600 Technology > 610 Medicine & health

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:11

Last Modified:

20 Jun 2016 09:55

URI:

https://boris.unibe.ch/id/eprint/1918 (FactScience: 204002)

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