2004 Fiscal Year Final Research Report Summary
Neural bases of shifting visual attention depending on the level of cognitive processes
| Project/Area Number |
14570577
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Neurology
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
SUZUKI Kyoko Tohoku University, Hospital, Lecturer, 病院, 講師 (20271934)
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| Co-Investigator(Kenkyū-buntansha) |
FUJII Toshikatsu Tohoku University, Graduate School of Medicine, Associate Professor, 大学院・医学系研究科, 助教授 (70271913)
NAKASATO Nobukazu Kohnan Hospital, Dept Neurosurgery, Senior Researcher, 脳神経外科, 臨床研究部長(研究職) (80207753)
MORI Etsuro Tohoku University, Graduate School of Medicine, Professor, 大学院・医学系研究科, 教授 (30368477)
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| Project Period (FY) |
2002 – 2004
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| Keywords | Visual attention / Alexia / Simultanagnosia / Electrocortical stimulation / Electrocorticogram / Kanji / Alzheimer's disease / Constructional apraxia |
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| Research Abstract |
We performed clinical and experimental studies to investigate neuronal bases of shifting selective visual attention depending on the level of cognitive processes.
1.Clinical studies
(1)Alzheimer's disease(visual variant)
Patients with slowly pregoressive visuospatial impairment performed various visuopeceptive and visuoconstuctive tasks. When the patients started particular tasks, which require detailed visual analysis, their range of visual attention became extremely narrow. MR images demonstrated severe cerebral atrophy predominantly in parieto-occipital lobes.
(2)Cerebral infarction
Patients with bilateral parietal infarctions demonstrated unique type of simultanagnosia, being unable to notice lines among columns in a newspaper. Experimental investigations revealed that they could detect lines among meaningless figures or patterns, but could not detect lines among Japanese characters.
2.Studies using subdural electrodes
(1)Cortical mapping of visual attention
Mapping of visual attention was
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performed in patients with intractable epilepsy, using compound letter tasks for global/local attention shift and oral line bisection tasks for spatial attention. In limited parts of the right parietal lobe, electrical stimulation induced impairment on either of two tasks, indicating partly independent neural networks for different type of attention.
(2)Event-related electrocorticogram
We recorded electrocorticograms from the bilateral basal temporal cortices in a patient with epilepsy and evaluated the task-related "high-gamma-band" activity (HGBA) accompanying picture naming and lexical decision tasks. Significant differences in HGBA were observed between the Japanese kanji and kana words, and between the kanji words and kanji pseudowords.
3.Neuroimagning studies with functional MRI (fMRI)
We used fMRI to explore the change in brain activation associated with the learning of Korean words written in Han-gul characters (K-words). Functional MRIs were measured twice before learning 20 Korean words and after the learning period for 2 weeks. Reading of K-words only after learning engaged the left angular gyrus, the same area as J-words reading, which indicated the change of visual attention, perception and reading processes over learning. Less
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