Cerebral Cortex Advance Access originally published online on July 6, 2004
Cerebral Cortex 2005 15(1):15-30; doi:10.1093/cercor/bhh103
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Cerebral Cortex V 15 N 1 © Oxford University Press 2005; all rights reserved
Synaptic and Spiking Dynamics underlying Reward Reversal in the Orbitofrontal Cortex
1 Institució Catalana de Recerca i Estudis Avançats (ICREA) Universitat Pompeu Fabra Dept. of Technology Computational Neuroscience Passeig de Circumval.lació, 8, 08003 Barcelona, Spain and 2 University of Oxford Department of Experimental Psychology South Parks Road Oxford OX1 3UD, UK
Address correspondence to Professor Edmund T. Rolls, University of Oxford, Department of Experimental Psychology, South Parks Road, Oxford OX1 3UD, UK. Email: Edmund.Rolls{at}psy.ox.ac.uk.
Cognitive and emotional flexibility involve a coordinated interaction between working memory, attention, reward expectations, and the evaluation of rewards and punishers so that behaviour can be changed if necessary. We describe a model at the integrate-and-fire neuronal level of the synaptic and spiking mechanisms which can hold an expectation of a reward rule in working memory, and can reverse the reward rule if expected rewards are not obtained. An example of a reward rule is that stimulus 1 is currently associated with reward, and stimulus 2 with punishment. The attractor-based reward rule working memory incorporates a spike-frequency synaptic adaptation mechanism which supports the neural switching between rules by being shut down by a general inhibitory input produced by punishment, so that when the attractor starts up again is in the opposite state. The mechanism can implement one-trial reward reversal, which is a property of orbitofrontal cortex neurons. We show how this reward rule input can operate in a biased competition way to influence which one of two stimuli is currently associated with reward and which with punishment, and to map the stimuli correctly to the reward or punishment representations, providing a basis for action selection required to obtain the reinforcer.
Key Words: attention • computational neuroscience • emotion • orbitofrontal cortex • reversal learning set • reward reversal • working memory
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  E. T Rolls Brain mechanisms underlying flavour and appetite Phil Trans R Soc B, July 29, 2006; 361(1471): 1123 - 1136. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. T. Rolls and J.-Z. Xiang Reward-Spatial View Representations and Learning in the Primate Hippocampus J. Neurosci., June 29, 2005; 25(26): 6167 - 6174. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Kadohisa, E. T. Rolls, and J. V. Verhagen Neuronal Representations of Stimuli in the Mouth: The Primate Insular Taste Cortex, Orbitofrontal Cortex and Amygdala Chem Senses, June 1, 2005; 30(5): 401 - 419. [Abstract] [Full Text] [PDF]
|
|