Encoding of time-discounted rewards in orbitofrontal cortex is independent of value representation.

@article{citeulike:816096, abstract = {We monitored single-neuron activity in the orbitofrontal cortex of rats performing a time-discounting task in which the spatial location of the reward predicted whether the delay preceding reward delivery would be short or long. We found that rewards delivered after a short delay elicited a stronger neuronal response than those delivered after a long delay in most neurons. Activity in these neurons was not influenced by reward size when delays were held constant. This was also true for a minority of neurons that exhibited sustained increases in firing in anticipation of delayed reward. Thus, encoding of time-discounted rewards in orbitofrontal cortex is independent of the encoding of absolute reward value. These results are contrary to the proposal that orbitofrontal neurons signal the value of delayed rewards in a common currency and instead suggest alternative proposals for the role this region plays in guiding responses for delayed versus immediate rewards.}, address = {Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn Street, HSF-2 S251, Baltimore, Maryland 21201.}, author = {Roesch, M. R. and Taylor, A. R. and Schoenbaum, G. }, citeulike-article-id = {816096}, comment = {* rat neurophysiology study examing the effect of reward delay and magnitude on the activity of orbitofrontal (OFC) neurons * main result: a subpopulation of OFC neurons responds differentially - *around the time of reward* - depending on the delay to reward, but *not* differentially to reward magnitude * note that a minority of recorded OFC neurons were active (above) baseline during the reward epoch, and activity was either increased for immediate rewards (65/92) or increased for delayed rewards (27/92) * authors conclude that OFC does *not* represent encode the value of discounted rewards in a common currency, at least at the level of single neurons}, doi = {http://dx.doi.org/10.1016/j.neuron.2006.06.027}, issn = {0896-6273}, journal = {Neuron}, keywords = {\_note, discounting, neurophysiology, orbitofrontal, rat, reward}, month = {August}, number = {4}, pages = {509--520}, posted-at = {2006-08-24 23:35:29}, priority = {2}, title = {Encoding of time-discounted rewards in orbitofrontal cortex is independent of value representation.}, url = {http://dx.doi.org/10.1016/j.neuron.2006.06.027}, volume = {51}, year = {2006} }

TY - JOUR ID - citeulike:816096 L3 - citeulike-article-id:816096 TI - Encoding of time-discounted rewards in orbitofrontal cortex is independent of value representation. JF - Neuron VL - 51 IS - 4 SP - 509 EP - 520 AD - Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn Street, HSF-2 S251, Baltimore, Maryland 21201. SN - 0896-6273 N2 - We monitored single-neuron activity in the orbitofrontal cortex of rats performing a time-discounting task in which the spatial location of the reward predicted whether the delay preceding reward delivery would be short or long. We found that rewards delivered after a short delay elicited a stronger neuronal response than those delivered after a long delay in most neurons. Activity in these neurons was not influenced by reward size when delays were held constant. This was also true for a minority of neurons that exhibited sustained increases in firing in anticipation of delayed reward. Thus, encoding of time-discounted rewards in orbitofrontal cortex is independent of the encoding of absolute reward value. These results are contrary to the proposal that orbitofrontal neurons signal the value of delayed rewards in a common currency and instead suggest alternative proposals for the role this region plays in guiding responses for delayed versus immediate rewards. KW - _note KW - discounting KW - neurophysiology KW - orbitofrontal KW - rat KW - reward N1 - * rat neurophysiology study examing the effect of reward delay and magnitude on the activity of orbitofrontal (OFC) neurons * main result: a subpopulation of OFC neurons responds differentially - *around the time of reward* - depending on the delay to reward, but *not* differentially to reward magnitude * note that a minority of recorded OFC neurons were active (above) baseline during the reward epoch, and activity was either increased for immediate rewards (65/92) or increased for delayed rewards (27/92) * authors conclude that OFC does *not* represent encode the value of discounted rewards in a common currency, at least at the level of single neurons AU - Roesch, MR AU - Taylor, AR AU - Schoenbaum, G PY - 2006/08/17/ UR - http://dx.doi.org/10.1016/j.neuron.2006.06.027 ER -