Access And Elaboration Stages Of Autobiographical Memory And FMRI In Depression

Depression is one of the most important and commonly occurred mental disorders,which is an important public health problem needing immediate attention. However, the pathogenesis of depression is very complex,which is not clear up to now. Cognitive processing theory holds that because there is negative, and general cognitive schemata in depressive disorders, tend to choose the negative, and general information consistent with their negative emotional state (processing of negative attention bias), and the memories of negative material enhancement (negative memory bias processing), resulting in the negative, general information processing increased, causing the generation and maintenance of depressive symptoms.The results show that memory is the key to the generation and maintenance of depression.Autobiographical memory as a research focus of memory fields is about some past especial situations recalling and it is memory of the personal life events.Many studies found that autobiographical memory was different between the normal and the depressive individuals, the depressive individuals manifested impairment of specific memory retrieval, increasing general memory, which is the stable characteristics and is one of the factors that susceptible to generation and maintenance of depression. studies found Specific and overgeneral autobiographical memories have different neural networks.Under the specific tasks of memory, The strengths of the activated brain areas such as the left middle temporal gyrus, putamen, the right fusiform gyrus and occipital lobe in depressed individuals were weaker than those of the normal. right parietal lobe in depressed individuals were stronger than those of the normal.Under the general memory tasks, The strengths of the activated brain areas such as the the left posterior cingulate cortex, left middle temporal gyrus and Superior occipital lobe in depressed individuals were weaker than those of the normal. the right insula in depressed individuals were stronger than those of the normal.The autobiographical memory retrieval is a dynamic information processing, according to Tulving (1983), retrieving an episodic memory from a cue in order to perform a task requires that one memory be selected for retrieval and other competing memories be inhibited. It is at this point that the recovery of a memory occurs, Next, the selected memory must be maintained and possibly elaborated long enough to perform the required task. Steinvorth use of memory traces active task, using fMRI to detect the two phases of brain activation, found activation in bilateral network in access stage, including the prefrontal cortex, right orbital frontal turn left prefrontal areas, the elaboration stage, mainly activated the left prefrontal cortex area and the left pressure. Daselaar study also found the hippocampus, bilateral Retrosplenial, the right anterior frontal lobe and the medial prefrontal cortex correlate with autobiographical memory access stage, whereas the visual cortex, precuneus and left prefrontal areas correlate with autobiographical memory elaboration stage. The results show that autobiographical memory retrieval of the access and elaboration with different neural networks and have different roles and psychological significance.Many studies found that autobiographical memory was different between the normal and the depressive individuals, the depressive individuals manifested impairment of specific memory retrieval, increasing general memory. So whether this difference is due to autobiographical memory access and elaboration stages of neural structures, or different brain activation patterns caused by it? Currently there is no relevant reports.The present study explored the characteristics of autobiographical memory in depressive individuals with classical AMT task, verify and analyze the behavioral characteristics of access and elaboration stages in autobiographical memory under clues to the word in depressive individuals.and the brain activated area and activation patterns of autobiographical memory were analyzed by functional magnetic resonance experiment, and the features of the brain activated area under different autobiographical memory tasks were discussed. It would preliminary illustrate the brain mechanism of access and elaboration stages of autobiographical memory in depressive individuals. The following outcomes and conclusions were obtained:1. The sensitivity of AMT is higher than SCEPT, it may be more suitable for assessing overgeneral Autobiographical memory in depressive mood populations.2. the Galton cue word we revised has a high reliability and validity. 3. The specific memory scores of the normal group were significantly higher than of the depression group, The general memory scores of the depression group were significantly higher than of the normal group (p <0.01). On the three valence clue words, the specific memory scores of the normal group were significantly higher than the depression group (p <0.01), the general memory scores of the depression group were significantly higher than the normal group (p <0.01).Hints that depression group has overgeneral memory trait, does not appear valence bias.The response to access specific Memory of the normal group was significantly faster than the depression group (p <0.05);There is no significant difference between the normal group and the depression group in responses to access for general memory .This indicates that the depression group recall the specific memory is slower.The response to elaborate specific Memory of the normal group was significantly longer than the depression group (p <0.05); There is no significant difference between the normal group and the depression group in responses to elaborate general memory . Shows that the time of elaborating the specific memory in depression group is shorter, Implies that patients with depression is difficult to recall the details of the specific memory. There is no significant difference between the normal group and the depression group in response to access or elaborate specific or general memory .This prompted the normal group and the depression group to access or elaborate the specific memory and general memory, did not show bias on the potency4. There are significant differences between the activated brain area of the normal and that of the depressed individuals on the access and the elaboration stages of specific autobiographical memory. During the access stage of the specific autobiographical memory , the strengths of the activated brain areas such as the left middle frontal gyrus, left parahippocampal gyrus, left inferior parietal lobule, the left occipital gyrus, bilateral cingulate gyrus and other brains in depressed individuals were weaker than those of the normal, but the Left medial frontal gyrus in depressed individuals was strengther than that of the normal. In the elaboration stage, the strengths of the activated brain areas such as the left middle frontal gyrus, left parahippocampal gyrus in depressed individuals were weaker than those of the normal, but the left superior temporal gyrus in depressed individuals was strengther than that of the normal. 5. There are significant differences between the activated brain area of the normal and that of the depressed individuals on the access and the elaboration stages of general autobiographical memory. During the access stage of the general autobiographical memory , the strengths of the activated brain areas such as the left frontal gyrus, hippocampus and caudate nucleus in depressed individuals were weaker than those of the normal, but the the left superior temporal gyrus in depressed individuals was strengther than that of the normal. In the elaboration stage, the strengths of the activated brain areas such as the left superior temporal gyrus, right medial frontal gyrus in depressed individuals was strengther than that of the normal.6. There are significant differences between the activated brain area of the specific memory and that of the general memory on the access and the elaboration stages of general autobiographical memory in normal gurop. In access stage,the strengths of the activated brain areas such as t the left parahippocampal gyrus, right middle temporal gyrus, left cingulate gyrus, bilateral superior temporal gyrus, left medial frontal gyrus, left inferior frontal gyrus in the specific memory was strengther than that of he general memory. In elaboration stage,the strengths of the activated brain areas such as left insula, left middle frontal gyrus, left parahippocampal gyrus in the specific memory was strengther than that of the general memory,but the strengths of the activated brain areas such as the right superior frontal gyrus, left anterior cingulate gyrus, right fusiform in the general memory was strengther than that of the specific memory.7. There are significant differences between the activated brain area of the specific memory and that of the general memory on the access and the elaboration stages of general autobiographical memory in depression gurop. In access stage,the strengths of the activated brain areas such as left parahippocampal gyrus and left middle occipital gyrus in the specific memory was strengther than that of the general memory,but the strengths of the activated brain areas such as right fusiform in the general memory was strengther than that of the specific memory. In elaboration stage,the strengths of the activated brain areas such as The left parahippocampal gyrus and left cingulate gyrus in specific memory was strengther than that of general memory.In summary, we think that the access and elaboration stages of autobiographical memory in the normal group and the depression group have different psychological significance and different activation of brain regions.