[A study on the neuronal mechanism of retrieval of long-term digital memory in human by functional magnetic resonance imaging].

To investigate the neuronal mechanism of retrieval of long-term digital memory in healthy volunteers, functional magnetic resonance imaging (fMRI) technique was used in the study. Twenty-two right-handed volunteers were subjected to a long-term digital memory test with block-design. The memory task and control task were adopted in the experiment alternatively. The fMRI data were recorded by a Siemens 1.5T MR machine and analyzed by SPM99. The activated brain regions were shown in the Talairach coordinate. The results showed that the Brodmann's area (BA) 9 region in left middle frontal gyrus was the most activated cortex during the long-term digital memory task. The left medial frontal gyrus, left inferior frontal gyrus, right inferior frontal gyrus, cingulate gyrus, left inferior parietal lobule, left superior parietal lobule, right superior parietal lobule, right middle temporal gyrus, left lingual gyrus, left middle occipital gyrus, right middle brain, cerebellum and right caudate nucleus tail were also involved. The activation in cortices showed obvious left predominance. It is suggested that a series of brain regions with left predominance are involved in long-term digital memory. Left lateral frontal cortex would be the most important structure for information extraction, while the other cortices and their connections may be important for processing and long-term storage of digital information.