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Reinforcement learning theory plays a key role in understanding the behavioral and neural mechanisms of choice behavior in animals and humans. Especially, intermediate variables of learning models estimated from behavioral data, such as the expectation of reward for each candidate choice (action value), have been used in searches for the neural correlates(More)
BACKGROUND Recent developments in near-infrared spectroscopy (NIRS) have enabled the noninvasive clarification of brain functions in psychiatric disorders with measurement of hemoglobin concentrations as cerebral blood volume. METHODS Ten patients with depression, 13 patients with schizophrenia, and 16 age- and gender-matched healthy control subjects(More)
Accumulating evidence shows that the neural network of the cerebral cortex and the basal ganglia is critically involved in reinforcement learning. Recent studies found functional heterogeneity within the cortico-basal ganglia circuit, especially in its ventromedial to dorsolateral axis. Here we review computational issues in reinforcement learning and(More)
Melanin-concentrating hormone (MCH) is a cyclic amino acid neuropeptide localized in the lateral hypothalamus. Although MCH is thought to be an important regulator of feeding behavior, the involvement of this peptide in body weight control has been unclear. To examine the role of MCH in the development of obesity, we assessed the effect of chronic(More)
  • Satoshi Mashiko, Akane Ishihara, Akira Gomori, Ryuichi Moriya, Makoto Ito, Hisashi Iwaasa +7 others
  • 2005
Melanin-concentrating hormone (MCH) is a cyclic orexigenic peptide expressed in the lateral hypothalamus, which plays an important role in regulating energy balance. To elucidate the physiological role of MCH in obesity development, the present study examined the effect of a selective MCH1 receptor (MCH1R) antagonist in the diet-induced obesity mouse model.(More)
N-3 polyunsaturated fatty acids (PUFA), such as docosahexaenoic acid (DHA, 22:6n-3), have been reported to play roles in preventing cardiovascular diseases. The major source of DHA is fish oils but a recent increase in the global demand of DHA and decrease in fish stocks require a substitute. Thraustochytrids, unicellular marine protists belonging to the(More)
Frontal lobe dysfunction has been implicated as one of the pathophysiological bases of bipolar disorder. Detailed time courses of brain activation in the bipolar disorder group were investigated using multichannel near-infrared spectroscopy (NIRS), a recently developed functional neuroimaging technology with a high time resolution, and were compared with(More)
In this article, the authors examine whether and how humans use model-free, reflexive strategies and model-based, deliberative strategies in motor sequence learning. They asked subjects to perform the grid-sailing task, which required moving a cursor to different goal positions in a 5 × 5 grid using different key-mapping (KM) rules between 3 finger keys and(More)
The time courses of brain activation were monitored during a finger tapping task using multichannel near-infrared spectroscopy with a time resolution of 0.1s in 30 healthy volunteers. Task-induced brain activations were demonstrated as significant increases in oxygenated hemoglobin concentration ([oxy-Hb]) in a broad area around the motor cortex and(More)
The ascending projections to the lateral lemniscal nuclei and the inferior colliculus were investigated in the albino rat by using Fluoro-Gold, either alone or in combination with other retrograde tract tracers. Injections were made into the central nucleus of the inferior colliculus (ICC), the dorsal nucleus of the lateral lemniscus (DNLL), the(More)