title: Investing in the future: stimulation of the medial prefrontal cortex reduces discounting of delayed rewards.
abstract: Generally, rewards that are received sooner are often preferred over future rewards, and the time between the choice and the reception of the reward is an important factor that influences our decisions, a phenomenon called delay discounting (DD). In DD, the medial prefrontal cortex (MePFC) and striatal dopamine neurotransmission both play an important role. We used repetitive transcranial magnetic stimulation (rTMS) to transiently activate the MePFC to evaluate its behavioral effect on the DD paradigm, and subsequently to measure its effect on striatal dopamine. Twenty-four right-handed young healthy subjects (11 females; age: 22.1±2.9 years) underwent DD following 10 Hz-rTMS of the MePFC and vertex stimulation (control condition). Thereafter, 11 subjects (5 females; age: 22.2±2.87 years) completed the PET study at rest using [(11)C]-(+)-PHNO following 10 Hz-rTMS of the MePFC and vertex. Modulation of the MePFC excitability influenced the subjective level of DD for delayed rewards and interfered with synaptic dopamine level in the striatum. The present study yielded findings that might reconcile the role of these areas in inter-temporal decision making and dopamine modulation, suggesting that the subjective sense of time and value of reward are critically controlled by these important regions.
authors.affiliation: 1] Division of Brain, Imaging and Behaviour-Systems Neuroscience, Toronto Western Research Institute, UHN, University of Toronto, Ontario, Canada [2] Research Imaging Centre, Centre for Addiction and Mental Health, University of Toronto, ON, Canada.
authors.forename: Sang Soo
authors.initials: SS
authors.lastname: Cho
authors.affiliation: 1] Division of Brain, Imaging and Behaviour-Systems Neuroscience, Toronto Western Research Institute, UHN, University of Toronto, Ontario, Canada [2] Research Imaging Centre, Centre for Addiction and Mental Health, University of Toronto, ON, Canada.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Koshimori
authors.affiliation: 1] Division of Brain, Imaging and Behaviour-Systems Neuroscience, Toronto Western Research Institute, UHN, University of Toronto, Ontario, Canada [2] Research Imaging Centre, Centre for Addiction and Mental Health, University of Toronto, ON, Canada.
authors.forename: Kelly
authors.initials: K
authors.lastname: Aminian
authors.affiliation: 1] Division of Brain, Imaging and Behaviour-Systems Neuroscience, Toronto Western Research Institute, UHN, University of Toronto, Ontario, Canada [2] Research Imaging Centre, Centre for Addiction and Mental Health, University of Toronto, ON, Canada.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Obeso
authors.affiliation: Research Imaging Centre, Centre for Addiction and Mental Health, University of Toronto, ON, Canada.
authors.forename: Pablo
authors.initials: P
authors.lastname: Rusjan
authors.affiliation: Movement Disorder Unit & E.J. Safra Parkinson Disease Program, Toronto Western Hospital, UHN, University of Toronto, ON, Canada.
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Lang
authors.affiliation: Temerty Centre for Therapeutic Brain Intervention, Department of Psychiatry, Centre for Addiction and Mental Health, University of Toronto, ON, Canada.
authors.forename: Zafiris J
authors.initials: ZJ
authors.lastname: Daskalakis
authors.affiliation: Research Imaging Centre, Centre for Addiction and Mental Health, University of Toronto, ON, Canada.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Houle
authors.affiliation: 1] Division of Brain, Imaging and Behaviour-Systems Neuroscience, Toronto Western Research Institute, UHN, University of Toronto, Ontario, Canada [2] Research Imaging Centre, Centre for Addiction and Mental Health, University of Toronto, ON, Canada [3] Movement Disorder Unit & E.J. Safra Parkinson Disease Program, Toronto Western Hospital, UHN, University of Toronto, ON, Canada.
authors.forename: Antonio P
authors.initials: AP
authors.lastname: Strafella
mesh_terms: D002250:Carbon Radioisotopes / Q000378:metabolism; D003342:Corpus Striatum / Q000378:metabolism; D065786:Delay Discounting / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism; D005260:Female; D059907:Functional Neuroimaging; D006801:Humans; D008297:Male; D010078:Oxazines / Q000378:metabolism; D049268:Positron-Emission Tomography; D017397:Prefrontal Cortex / Q000378:metabolism / Q000502:physiology*; D012201:Reward; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
chemical_list: D002250:Carbon Radioisotopes; D010078:Oxazines; C042631:naxagolide; D004298:Dopamine