2005 Fiscal Year Final Research Report Summary
Computational research on neural mechanism and learning principle for human language acquisition
| Project/Area Number |
15500166
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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 |
Cognitive science
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| Research Institution | Fukushima University (2005)
Tohoku University (2003-2004) |
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Principal Investigator |
FUTAMI Ryoko Fukushima University, Faculty of Symbiotic Systems Science, Professor, 共生システム理工学類, 教授 (20156938)
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| Project Period (FY) |
2003 – 2005
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| Keywords | temporal sequence / audio and visual systems / memory / neural network / modeling |
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| Research Abstract |
To quantitatively investigate the higher-order functions of the brain such as language processing, characteristics of reaction time (RT) of the subjects for tasks can be used as a good measure of difficulty. In this research, RT and error rate that depend on stimulus duration were measured in a luminance-discrimination reaction time task. Two patches of light with different luminance were presented to participants for short (150ms) or long (1s) period on each trial. When the stimulus duration was 'short', the participants responded more rapidly with poorer discrimination performance than they did in the longer duration. The results suggested that different sensory responses in the visual cortices were responsible for the dependence of response speed and accuracy on the stimulus duration during the luminance-discrimination reaction time task. It was shown that the simple winner-take-all-type neural network model receiving transient and sustained stimulus information from the primary visual cortex successfully reproduced RT distributions for correct responses and error rates. Moreover, temporal spike sequences obtained from the model network closely resembled to the neural activity in the monkey prefrontal or parietal area during other visual decision tasks such as motion discrimination and oddball detection tasks.
As for the influences from small stimulus onset asynchrony (SOA) in a two-choice luminance-discrimination RT tasks, the dependence on SOAs was measured and successfully reproduced by introducing global inhibitors to prevent unnecessary integration of sensory information, and neuron chains with feedforward mutual inhibition as an asynchronism detector of two flashes, into the model that we proposed. The revised model not only reproduced responses of these two-choice luminance- discrimination tasks both with and without a SOA but also responses in a suprathreshold single-stimulus detection task for a wide range of stimulus luminance.
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Research Products
(7 results)
