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Computational research on neural mechanism and learning principle for human language acquisition

人类语言习得神经机制和学习原理的计算研究

基本信息

批准号：
15500166
负责人：
FUTAMI Ryoko
金额：
$ 2.37万
依托单位：
Fukushima University (2005)Tohoku University (2003-2004)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

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.

为了定量研究大脑的高级功能，如语言处理，被试对任务的反应时（RT）的特性可以被用作一个很好的测量难度。本研究在亮度辨别反应时任务中，测量了依赖于刺激持续时间的反应时和错误率。在每次试验中，向参与者呈现两个具有不同亮度的光斑，时间短（150 ms）或长（1 s）。当刺激持续时间是“短”，参与者的反应更迅速，较差的歧视性能比他们在较长的时间。结果表明，在亮度辨别反应时任务中，视觉皮层的不同感觉反应是导致反应速度和准确性对刺激持续时间依赖性的原因。结果表明，简单的赢家通吃型神经网络模型接收来自初级视皮层的瞬时和持续刺激信息，成功地再现了正确反应和错误率的RT分布。此外，从模型网络中获得的时间锋电位序列与运动辨别和奇怪球检测任务等其他视觉决策任务中猴子前额叶或顶叶区的神经活动非常相似。至于小刺激起始不同步（SOA）对两选择亮度辨别RT任务的影响，通过引入全局抑制剂以防止感觉信息的不必要的整合，和具有前馈互抑制的神经元链作为两个闪光的并行检测器，引入到我们提出的模型中。修订后的模型不仅再现了这些两个选择亮度辨别任务的反应，有和没有SOA，但也在阈上单刺激检测任务的反应范围广泛的刺激亮度。