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@INPROCEEDINGS{Jitsev:186281,
      author       = {Jitsev, Jenia and Tittgemeyer, Marc and Morrison, Abigail},
      title        = {{D}istinct plasticity mechanisms in the basal ganglia and
                      their functional role in reinforcement learning},
      reportid     = {FZJ-2015-00365},
      year         = {2014},
      abstract     = {Aiming towards a minimal realistic circuitry model of
                      learning from both appetitive and aversive outcomes, we
                      implemented a spiking actor-critic network model of the
                      basal ganglia that incorporates different plasticity
                      mechanisms and segregates both the dorsal and ventral
                      striatum into populations of D1 and D2 medium spiny neurons
                      (MSNs). This segregation allows explicit, separate
                      representation of both positive and negative expected
                      outcome of a given environmental state by the respective
                      population of D1 or D2 MSNs that we hypothesize to reside in
                      the shell region of Nucleus Accumbens. Based on experimental
                      evidence, D1 and D2 MSN populations were assumed to have
                      distinct, opposing dopamine-modulated bidirectional synaptic
                      plasticity.We implemented the network in the NEST simulator
                      and performed experiments involving the application of
                      delayed reward and punishment in a grid world setting, in
                      which a moving agent must reach a goal state while
                      maximizing the total reward obtained. We demonstrate that
                      the network can learn both to approach the delayed positive
                      reward and to consequently avoid punishment. The model
                      highlights thus the functional role of D1/D2 MSN segregation
                      within the striatum in implementing appropriate temporal
                      difference(TD)-like learning from both reward and punishment
                      and explains necessity for opponent direction of
                      DA-dependent plasticity found at synapses converging on
                      distinct striatal MSN types. The approach can be further
                      extended to study how abnormal D1/D2 plasticity may lead to
                      a reorganization of the basal ganglia network towards
                      pathological, dysfunctional states, like for instance those
                      observed in Parkinson disease under condition of progressive
                      dopamine depletion.},
      month         = {Jul},
      date          = {2014-07-05},
      organization  = {9th European Forum of Neuroscience,
                       Milano (Italy), 5 Jul 2014 - 9 Jul
                       2014},
      subtyp        = {After Call},
      cin          = {INM-6 / IAS-6},
      cid          = {I:(DE-Juel1)INM-6-20090406 / I:(DE-Juel1)IAS-6-20130828},
      pnm          = {331 - Signalling Pathways and Mechanisms in the Nervous
                      System (POF2-331) / 89572 - (Dys-)function and Plasticity
                      (POF2-89572) / SMHB - Supercomputing and Modelling for the
                      Human Brain (HGF-SMHB-2013-2017) / RL-BRD-J - Neural network
                      mechanisms of reinforcement learning (BMBF-01GQ1343) /
                      W2Morrison - W2/W3 Professorinnen Programm der
                      Helmholtzgemeinschaft (B1175.01.12)},
      pid          = {G:(DE-HGF)POF2-331 / G:(DE-HGF)POF2-89572 /
                      G:(DE-Juel1)HGF-SMHB-2013-2017 / G:(DE-Juel1)BMBF-01GQ1343 /
                      G:(DE-HGF)B1175.01.12},
      typ          = {PUB:(DE-HGF)6},
      url          = {https://juser.fz-juelich.de/record/186281},
}