The Aging Effect Of Negative Emotional Memory Processing In A Visual-spatial Associative Memory Task

With the aging of China’s population,the mental and physical health of the elderly has attracted extensive attention from the scientific research field and the society.Among them,memory is an important precondition for the elderly to carry out normal social life,and emotion is an important guarantee for the elderly to maintain the quality of life,both of which are hot issues in aging research.Previous studies have shown that most cognitive abilities,including memory,attention,decision-making,etc.,decline in the elderly,but the emotional function is basically retained,and even better than that of the young,reflecting the age-related positivity effect--the bias towards positive emotions and/or avoidance of negative emotions.In recent years,more studies have focused on the discussion of the positive bias in the emotional processing of the elderly,while the discussion of the negative avoidance is relatively less,and the underlying neural mechanism is still unclear.Since spatial memory is one of the sensitive tasks to detect hippocampal activity,and associative memory is a type of memory that is severely impaired during aging,this study explored the processing of negative emotions and its underlying neural mechanisms in the elderly under the framework of visual-spatial associative memory task.In the first study,participants’ location memory was tested by using the visuospatial associative memory task paradigm(Negative vs.Neutral)and whether the effect was affected by age(Older vs.Younger)and time(Pretest vs.Post test).The results showed that there was a significant interaction between age and valence.Specifically,the neutral images were better than the negative ones in both the accuracy and distance bias of location memory.In contrast,the pattern of the elderly was opposite,and the negative images were better than the neutral ones in the accuracy index and distance deviation index of location memory.The results suggest that when the elderly process negative images,they may avoid the image itself,and put more cognitive resources into the memory of the location,which shows a better negative image location memory.In study 2,functional MRI was used to further investigate the neural mechanism of the aging effect of negative emotional processing in visuospatial associative memory tasks.First,the results of the behavioral study replicated the first finding that older adults remembered the location of negative images better than neutral ones.Further analysis showed that older adults forgot less about the position of negative images than did younger adults about the position of neutral images after 12 hours.Second,brain activation analysis under task state showed that the left superior temporal gyrus,left hippocampus,right lenticulate nucleus,bilateral middle frontal gyrus,left anterior cingulate gyrus,left collateral cingulate gyrus,and right middle temporal gyrus were activated in both young and old subjects,respectively.These brain regions are key to memory function.In the negative condition,compared with the younger group,the activation of the left hippocampus and the left superior temporal gyrus was significantly reduced in the older group,while the activation of the right middle frontal gyrus and the right lenticulate nucleus was significantly increased.The results of brain-behavior correlation analysis showed that under the negative condition,the left superior temporal gyrus and the right middle temporal gyrus showed greater activation,the higher the accuracy,that is,the better the memory test performance.Combined with the results of behavioral and brain activation,the neural activity in the temporal lobe and hippocampus of the elderly was lower than that of the young,while the frontal lobe was more active,which may play a compensating role in the process of location recall of negative emotional images.On the basis of study 2,study 3 further revealed the neural coordination mechanism between the elderly and the young in the process of spatial location recall of negative emotional stimuli.In this study,we first investigated the functional connectivity of brain networks during spatial location recall in the elderly and young adults.Furthermore,we conducted psychophysiological interaction(PPI)with the amygdala as the seed point,aiming to explore whether the functional connections between the amygdala and other brain regions were affected by experimental conditions.Among them,the large-scale brain network functional connectivity research results showed that under negative conditions,the elderly’s frontal network functional connectivity was significantly greater than that of the young,and the accuracy and memory rate of image location were negatively correlated.Under neutral condition,there was no significant among difference age groups.Analysis of the strength of functional connections between PPI showed that the amygdala and hippocampus in young adults were significantly increased under neutral conditions compared to negative conditions,while the strength of functional connections between the amygdala and the hippocampus in older adults were not different from negative conditions and neutral conditions.But it was significantly decreased compared with young people.These results suggest that the functional connectivity between the amygdala and the hippocampus is weakened,while the functional connectivity of the frontal parietal network is enhanced during the processing of negative emotional memory.In conclusion,compared with the young,the elderly have better spatial location memory of negative images.This maybe related to the avoidance of negative images and more attention and cognitive processing of location memory.Brain imaging results show that older adults work in a similar way to younger adults during the spatial location recall phase of neutral images,while the temporal lobe,hippocampus and amygdala were less efficient than the young people in the negative image spatial position recall stage.Meanwhile,the frontal lobe and parietal lobe may play a corresponding compensating role.The results of this study provide evidence for the theory of social emotional selection in the processing of negative emotions,and provide guidance for the regulation and intervention of negative emotions in the elderly.