用近红外功能成像技术研究语义和知觉编码过程中左前额叶的活动

目的用近红外光学功能成像技术研究语义与知觉编码过程中的左前额叶活动.方法实时记录22名青年被试者(男女各半)在语义和知觉加工过程中760 nm和850 nm两个波长近红外连续光透过额骨和左前额皮层后的漫射光强变化,并以此表征该皮层区血容(CBV)和血氧的变化.语义加工要求被试者用两个非相关的汉字词对组成一个有意义的句子;知觉加工则要求被试者判断两个词是否具有相同的结构组合以及两个词对中左右结构的差别. 结果结果显示,与知觉加工相比,语义加工时左下前额叶活动增多.该区域大致对应布德曼45、47区的一部分. 结论成功地利用近红外功能成像技术观测了语义与知觉编码过程中的左前额叶活动,获得了与fMRI和断层成象技术(PET)研究相近的结果,进一步证实了左前额叶在语义加工中的作用.

Left Prefrontal Cortex Activation during Semantic Encoding Accessed with Functional Near Infrared Imaging

Objective To investigate the left prefrontal lobe activation during semantic and non-semantic encoding tasks with functional near-infrared imaging (fNIRI) technique. Method 22 healthy subjects were assigned semantic encoding and non-semantic encoding tasks. During semantic encoding tasks, subjects were asked to make a meaningful sentence including two unrelated Chinese word pairs, while during non-semantic encoding task they were asked to judge whether the two Chinese word pairs had the same morphological structure or not. Light intensity of two wavelengths (760 nm and 850 nm) diffused through skull and left prefrontal lobe were real-time recorded and used to reconstruct the brain activation image during the experiment. Result With the fNIRI, significant activations were observed in the left inferior prefrontal cortex (Brodmann' areas 45 and 47) during the two tasks, but the evoked activations were more significant for semantic than non-semantic task. These observations were consistent with the results reported by others with functional megnetic resonance imaging(fMRI) and positron-emission tomographyPET.Conclusion The results suggest that fNIRI provides an important, non-invasive way to map the prefrontal activation during cognitive tasks.