Introduction

We focused on investigating the functional and structural organization of neural circuits responsible for cognitive, emotional, motivational, and motor processes and explaining the neurochemical mechanism that allows these interactions to work within the organized system. This includes mainly the use of in vivo PET techniques for shedding light on the function of a large neuronal population on a global scale or quantifying how organized brain circuits would be mediated in the synaptic process. We use a variety of behavioral, neuroanatomical, neuropharmacological, neuropsychological and electrophysiological techniques as well as neuroimaging techniques with animals. Following the integration of a multidisciplinary field of research that encompasses systems neuroscience, neurochemical imaging, and functional brain mapping, our overall goal is to further understand the pathogenesis of neurodegenerative conditions such as Parkinson disease and psychiatric disorders such as schizophrenia and mood disorder using animal models.

Research Introduction

• Positron emission tomography (PET) is a very useful tool for detecting the in vivo physiological and neurochemical changes in the brain on a global scale. We recently developed a measurement system in our laboratory for detecting the localization of awake monkey brain areas engaging in various visuo-motor tasks using PET. Our series of monkey PET studies detected the monkey brain activation patterns by measuring regional cerebral blood flow (rCBF) during each of the applied tasks originating from single tool-use task, such as intermanual transferred learning, combinational tool-use task in different functions, and remote-controlled operation task in different rules between moves of joystick and shovel. As a whole, we could identify the brain activations responsible for each task, some regions of which were shared throughout a series of tasks, from a concrete one to a more abstract one. These shared brain regions involved the prefrontal cortex, parietal cortex, and cerebellum. These areas may engage the functional organization in the monkey brain induced by consecutive learning reinforcements, presumably leading to increases in their non-specific knowledge.
  
  
• Using a shared cognitive task between human and non-human primates, we compared the localization of their brain functions with the same cognitive scale.
  
  
• We shed light on the neural mechanism underlying the interaction between cognition and motivation in non-human primates using PET.
  
  
• We are interested in the cognitive dysfunction in early Parkinson disease (PD), whose mechanism could be investigated in detail using PET with the non-human primate PD model. We are exploring the relationship between performance in a working memory task and extrastriatal dopamine D2 receptor in a PD model using in vivo PET.

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