Biologically plausible multi-dimensional reinforcement learning in neural networks
Rombouts, J. O., Van Ooyen, A., Roelfsema, P. R., and Bohte, S. M. (2012). In: Villa, A. E., et al., eds. Artificial Neural Networks - ICANN 2012, Lausanne, Switzerland, September 2012, Vol. 7552 of Lecture Notes in Computer Science, pp. 443-450. [Full text: PDF]
How does the brain learn to map multi-dimensional sensory inputs to multi-dimensional motor outputs when it can only observe single rewards for the coordinated outputs of the whole network of neurons that make up the brain? We introduce Multi-AGREL, a novel, biologically plausible multi-layer neural network model for multi-dimensional reinforcement learning. We demonstrate that Multi-AGREL can learn non-linear mappings from inputs to multi-dimensional outputs by using only scalar reward feedback. We further show that in Multi-AGREL, the changes in the connection weights follow the gradient that minimizes global prediction error, and that all information required for synaptic plasticity is locally present.