| 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 |
| 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