数字工作记忆与长时数字记忆的fMRI比较研究

目的通过比较数字工作记忆与长时数字记忆的脑区激活的特点及差异,探索短时数字记忆与长时数字记忆的不同神经机制。方法实验采用组块设计,利用功能磁共振技术(fMRI)对12名右利手志愿者进行2位数的数字工作记忆和长时数字记忆实验时的fMRI数据进行采集,两组任务均设相应对照任务,数据采用SPM99软件进行数据分析和Ta-lairach坐标进行脑功能区定位。结果进行两组任务时,志愿者以左侧优势的额叶和顶叶,扣带回、双侧枕叶、纹状体、丘脑以及小脑均有激活。进行数字工作记忆时,在额叶的背外侧面左半球优势比长时数字记忆显著,而在进行长时数字记忆时,顶叶的激活要明显高于数字工作记忆。结论各个不同的脑区在进行不同时程的数字记忆任务时所参与的阶段和所起的作用不同,左侧优势的额叶背外侧面可能在数字工作记忆中起到重要的作用,而顶叶则可能在长时数字记忆中作用更加重要。

Comparison between digital working memory task and long-term digital memory task by fMRI

Objective To explore the different mechanism of the short-term digital memory and long-term digital memory by comparing different activation of the brain regions between a digital working memory task and a long-term digital memory task. Methods 12 right-handed volunteers participated in a test of digital working memory and a test of long-term digital memory respectively. Two control tasks were performed for the block-design. The T2* data were recorded by functional magnetic resonance imaging (fMRI) technique. SPM 99 was used to analyze the data and the activated brain regions were shown in the Talaraich coordinate. Results The frontal lobe and the parietal lobe with left hemisphere predominance, the cingulate gyrus, bilateral occipital lobe, striatum and cerebellum were activated by both the tasks relative to their control tasks. The left predominance in the dorsolateral frontal lobe was more significant in the digital working memory task than that in the long-term digital memory task, while the parietal lobe was more activated in the long-term digital memory task than that in the digital working memory task. Conclusion Different brain regions played different roles in digital memory tasks with different terms, and might be involved in different stages. Dorsolateral frontal lobe with left predominance might play more important role in the digital working memory, and the parietal lobe might be more important in the long-term digital memory.