@misc{oai:repo.qst.go.jp:00071842,
 author = {Hori, Yukiko and Nagai, Yuji and Oh-Nishi, Arata and Suhara, Tetsuya and Minamimoto, Takafumi and 堀 由紀子 and 永井 裕司 and 大西 新 and 須原 哲也 and 南本 敬史},
 month = {Nov},
 note = {The motivation to engage in action can be influenced not only by the value of outcome but also by moods of the subject. We previously reported low motivational state in a monkey model of hypothyroidism, which was characterized by lower instrumental task performance (Minamimoto et al., SFN 2010). Since dopamine has a major role in reward and motivation, we hypothesized that hypothyroidism induces dysfunctions of the dopaminergic system, which in turn lead to low motivation. To address this issue, we examined dopamine receptor density in hypothyroidism model monkeys using positron emission tomography (PET). PET scan data were obtained with [11C]FLB457 (high affinity for extrastriatal D2 receptors) for both pre-hypothyroid control and hypothyroid state. Hypothyroid state was defined as when the monkey's thyroxin level reached less than 2 µg/dl continuously after administration of antithyroid agent (methimazole, 100 mg/day) for 2 months. The analysis of parametric images of control and hypothyroidism revealed increased binding potential of [11C]FLB457 in the ventromedial prefrontal cortex (VMPFC). This result suggests that the upregulation of D2 receptors occurred by the decrease of dopamine release in VMPFC in hypothyroidism, resulting in low motivation for task performance., Neuroscience 2011, SfN's 41th annual meeting},
 title = {Changes in dopaminergic function associated with low motivation in a primate model of hypothyroidism: a PET study},
 year = {2011}
}