Summary of Research Project Results under JSPS FY2001
"Research for the Future Program"

1.Research Institution Fukui Medical University
2.Research Area Life Sciences
3.Research Field Higher Brain Functions
4.Term of Project FY 1997 〜 FY 2001
5.Project Number 97L00203
6.Title of Project Studies on Plasticity of Higher Function in Human Brain Using PET and Functional MRI

7.Project Leader
Name Institution,Department Title of Position
Yoshiharu, Yonekura Fukui Medical University, Biomedical Imaging Research Center Professor

8.Core Members

Names Institution,Department Title of Position
Norihiro, Sadato National Institute of Physiological Sciences, Department of Cerebral Cortex Professor
Yasuhisa, Fujibayashi Fukui Medical University, Biomedical Imaging Research Center Professor

9.Summary of Research Results

The brain is a dynamically changing structure responding to continuous alterations of the peripheral input and internal signal communication. The present project utilized noninvasive neuroimaging techniques, such as positron emission tomography (PET) and functional magnetic resonance imaging (MRI), to depict functional reorganization of the brain due to deaffentation, and examined the plastic changes in relation to learning and aging proces. Functional MRI studies in the blind subjects demonstrated that the tactual information process is taken in the association visual cortex and further transferred to primary visual cortex in the subjects who lost their vision before the age of 15. Similar studies of sign languages showed that the sign activated the auditory cortex of the deaf subjects. These findings may provide biological basis for training in the handicapped, and also shed lights on how the brain organizes itself to integrate multimodal sensory input for communication. On the other hand, studies in the aged subjects revealed that parietal and temporal cortices were not utilized for the picture encoding task, and the neural activities in the hippocampus and the amygdala were also decreased during the face recognition task. These data suggested the aging-related alterations of higher brain. Furthermore, the present project extended to the imaging of a rapidly changing pattern accompanying normal human brain maturation by means of functional MRI on infants. In order to examine the molecular basis of the neuronal plasticity, a new imaging technique of positron radionuclide labeled tracers was introduced and applied to the fresh brain slices of the small animals, which successfully demonstrated the metabolic changes due to hypoxia and/or ischemia. In conclusion, noninvasive functional neuroimaging technique could be a powerful tool to investigate the functional reorganization and developmental neurophysiology.

10.Key Words

(1)higher brain function、(2)brain activation study、(3)plasticity