Research On The Effect Of Negative Emotion On Working Memory By Functional Near-infrared Spectroscopy

Working memory is a cognitive system with a limited capacity that is responsible for temporarily holding information available for processing in many high-level cognitive tasks.Emotion is any relatively brief conscious experience characterized by intense mental activity and a high degree of pleasure or displeasure.The interaction of emotion and working memory has become a hot topic in the field of cognitive psychology and cognitive neuroscience.Brain function studies indicate that prefrontal cortex is related to the processing of emotion and working memory.Behavioral and ERP studies indicate that the effect of negative emotion on working memory is related to memory load.However,the current research on brain function is seldom consider the working memory load,so the brain mechanism of the effect of negative emotion on high and low load working memory is not clear.Functional Near-infrared Spectroscopy(fNIRS)is a non-invasive technique measuring brain activity.This thesis aimed to explore the brain mechanism of the effect of negative emotion on high and low load working memory via two fNIRS studies.In the first research,we investigated the effect of task irrelevant negative emotion on working memory via presenting different valence of pictures to subjects before verbal n-back task.Compared with the 0-back task,the 2-back task significantly raised greater activation in the left ventrolateral prefrontal cortex.Compared with the neutral conditions,the negative conditions significantly raised greater activation in the both sides of dorsolateral prefrontal cortex in 0-back task,and in 2-back task,only right dorsolateral prefrontal cortex showed greater activation under negative conditions.In the second research,we investigated the effect of task relevant negative emotional stimuli on working memory via n-back task with emotional pictures expression as stimuli.Compared with the 0-back task,the 2-back task significantly raised greater activation in the left ventrolateral prefrontal cortex.Compared with the neutral conditions,the negative conditions significantly raised greater activation in the both sides of dorsolateral prefrontal cortex and right ventrolateral prefrontal cortex in 0-back task,and in 2-back task,only right dorsolateral prefrontal cortex showed greater activation under negative conditions.The results of two studies indicate that the effect of negative emotion on high and low load working memory is different.Compared with the lower demanding 0-back task,negative emotion has a smaller impact on the higher demanding 2-back task.The increase of working memory load weakens the processing of negative emotion.This thesis provides insights to the brain mechanism of the interaction between emotion and working memory,and gives practical guidance for diagnosis and treatment of clinical psychological diseases.