@misc{MellWartenburgerMarschneretal.2009,
  author    = {Mell, Thomas and Wartenburger, Isabell and Marschner, Alexander and Villringer, Arno and Reischies, Friedel M. and Heekeren, Hauke R.},
  title     = {Altered function of ventral striatum during reward-based decision making in old age},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-45235},
  year      = {2009},
  abstract  = {Normal aging is associated with a decline in different cognitive domains and local structural atrophy as well as decreases in dopamine concentration and receptor density. To date, it is largely unknown how these reductions in dopaminergic neurotransmission affect human brain regions responsible for reward-based decision making in older adults. Using a learning criterion in a probabilistic object reversal task, we found a learning stage by age interaction in the dorsolateral prefrontal cortex (dIPFC) during decision making. While young adults recruited the dlPFC in an early stage of learning reward associations, older adults recruited the dlPFC when reward associations had already been learned. Furthermore, we found a reduced change in ventral striatal BOLD signal in older as compared to younger adults in response to high probability rewards. Our data are in line with behavioral evidence that older adults show altered stimulus-reward learning and support the view of an altered fronto-striatal interaction during reward-based decision making in old age, which contributes to prolonged learning of reward associations.},
  language  = {en}
}
@article{MellHeekerenMarschneretal.2005,
  author    = {Mell, Thomas and Heekeren, Hauke R. and Marschner, Alexander and Wartenburger, Isabell and Villringer, Arno and Reischies, Friedel M.},
  title     = {Effect of aging on stimulus-reward association learning},
  issn      = {0028-3932},
  year      = {2005},
  abstract  = {The flexible learning of stimulus-reward associations when required by situational context is essential for everyday behavior. Older adults experience a progressive decline in several cognitive functions and show deficiencies in neuropsychological tasks requiring flexible adaptation to external feedback, which could be related to impairments in reward association learning. To study the effect of aging on stimulus-reward association learning 20 young and 20 older adults performed a probabilistic object reversal task (pORT) along with a battery of tests assessing executive functions and general intellectual abilities. The pORT requires learning and reversing associations between actions and their outcomes. Older participants collected fewer points, needed more trials to reach the learning criterion, and completed less blocks successfully compared to young adults. This difference remained statistically significant after correcting for the age effect of other tests assessing executive functions. This suggests that there is an age-related difference in reward association learning as measured using the pORT, which is not closely related to other executive functions with respect to the age effect. In human aging, structural alterations of reward detecting structures and functional changes of the dopaminergic as well as the serotonergic system might contribute to the deficit in reward association learning observed in this study. (C) 2004 Elsevier Ltd. All rights reserved},
  language  = {en}
}
@article{MarschnerMellWartenburgeretal.2005,
  author    = {Marschner, Alexander and Mell, Thomas and Wartenburger, Isabell and Villringer, Arno and Reischies, Friedel M. and Heekeren, Hauke R.},
  title     = {Reward-based decision-making and aging},
  issn      = {0361-9230},
  year      = {2005},
  language  = {en}
}
@article{HeekerenWartenburgerMarschneretal.2007,
  author    = {Heekeren, Hauke R. and Wartenburger, Isabell and Marschner, Alexander and Mell, Thomas and Villringer, Arno and Reischies, Friedel M.},
  title     = {Role of ventral striatum in reward-based decision making},
  issn      = {0959-4965},
  year      = {2007},
  language  = {en}
}