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

1.Research Institution Tohoku University
2.Research Area Life Sciences
3.Research Field Higher Brain Functions
4.Term of Project FY 1997 〜 FY 2001
5.Project Number 97L00202
6.Title of Project Analysis of Memory and Memory Disorders by PET, MEG, and other Methods

7.Project Leader
Name Institution,Department Title of Position
Atsushi, Yamadori Tohoku University, Graduate school of Medicine Professor

8.Core Members

Names Institution,Department Title of Position
Ryuta, Kawashima Tohoku University, New Industry Creation Hatchery Center Professor
Toshikatsu, Fujii Tohoku University, Graduate school of Medicine Associate Professor

9.Summary of Research Results

Our research on human memory included five tentative categories, i.e. working memory, fact (or semantic memory) memory, episodic memory, motor memory, and prospective memory. We found working memory recruits different networks for different contents such as verbal, visual, and olfactory materials. Also networks for processing and holding materials were found to be different. For processing, strong involvement of the prefrontal lobe was demonstrated. We also found the gradual decline of the capacity of working memory in older population. We found the importance of the right fusiform gyrus in memory of human faces. On the other hand recalling of the name of acquaintances and famous people activated the left temporal pole as well as parieto-occipital area. For the memory of landscapes and streets we found the activation in the medial temporal lobe and parahippocampal gyrus. For episodic memory, we tried to separate neurological substrates for encoding, storing and decoding. Manipulation of the degree of the depth of processing at the encoding stage clearly showed the activity changes in the prefrontal, parietal, and hippocampal areas of the left hemisphere. For storing, we found strong activation of the bilateral prefrontal areas and the left hippocampus. For decoding, we found the recall of contextual information such as a place and time activated different networks that included bilateral basal forebrain, right frontal lobe, right cingulate gyrus, right temporal lobe, and the left insular area. For memory of sequential movements, we found the distributed activities in the prefrontal, premotor, and parietal association areas, in addition to the basal ganglia and cerebellum. We also demonstrated the dynamic change of activation patterns as the motor learning proceeded. For memory related with future action, i.e. prospective memory, we found the correlated activations in the bilateral frontal lobes and left hippocampus. Qualitatively different cues such as an event or a time for the remembrance and execution of a plan changed the degree of activation in these areas. These data revealed that human memory mobilizes diffusely distributed networks that are different in degree and extent depending on the modality of the content and the difference of processing.

10.Key Words

(1)Neuroimaging、(2)Positron emission tomography、(3)Functional MRI
(4)Magnetoencephalography、(5)Working memory、(6)Episodic memory
(7)Amnesia、(8)Frontal lobe、(9)Temporal lobe