• Top page
  • Timetable
  • Per session
  • Per presentation
  • How to
  • Meeting Planner



報酬 2
Reward 2

開催日 2014/9/12
時間 16:00 - 17:00
会場 Room H(304)
Chairperson(s) 坂上 雅道 / Masamichi Sakagami (玉川大学脳科学研究所 / Tamagawa University, Brain Science Institute, Japan)
設楽 宗孝 / Munetaka Shidara (筑波大学医学医療系 / University of Tsukuba, Faculty of Medicine, Japan)

Neural representation of Economic Values in monkey ventromedial prefrontal cortex

  • O2-H-4-1
  • 山田 洋 / Hiroshi Yamada:1,2,3 Louie Kenway / Kenway Louie:3 Tymula Agnieszka / Agnieszka Tymula:3,4 Glimcher Paul W / Paul W Glimcher:3 
  • 1:筑波大学 医学医療系 生命医科学域 / Tsukuba Univ, Japan 2:筑波大学大学院 人間総合科学研究科 / Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan 3:Center for Neural Science, New York University, New York, NY, USA / Center for Neural Science, New York University, New York, NY, USA 4:School of Economics, University of Sydney, Sydney, NSW, Australia. / School of Economics, University of Sydney, Sydney, NSW, Australia. 

Neural correlates of value have been extensively examined in wide range of diverse brain regions, and it is suggested that orbitofrontal cortex (OFC), which encodes values of goods, is crucially involved in economic decision making. However, it is unclear how the medial part of the OFC encodes the economic values for decision makings. To this end, we recorded single neuron activity from medial area 14 (i.e. ventromedial prefrontal cortex, vmPFC) while monkeys performed a visual gambling task. During the behavioral task, monkeys chose either a "risky" or a "certain" option based on the values and reward probabilities associated with the options. While fixating a central point, the monkeys received visual cues indicating the payoff magnitude of fluid reward offered by two options located on the left and right sides which varied from trial-to-trial with a particular option ranging from 0 ml to 0.60ml in 0.06ml increments. The probability that the risky option would yield a reward was fixed at 50% across lotteries. After extensive training, the monkeys showed risk-neutral or slightly risk-averse behavior. Out of 102 vmPFC neurons, 22% and 35% represented the values of the risky option during and after decision-making, respectively. Two-thirds of these showed a specific form of value coding in which neuronal activity was normalized by the range of possible reward outcomes recently encountered. However, the normalization of neural activity became imperfect as the payoff magnitude increased. In contrast, about 30% of the neurons represented the value of safe option throughout task trials. These results suggested that neural mechanisms underlying subjective valuation of risk are embedded in vmPFC neurons.

Copyright © Neuroscience2014. All Right Reserved.