The Neural Mechanism Of Cognitive And Emotion In Different Situation Of Feigning Memory Impairment

Background and ObjectiveFeigning memory impairment is common in neuropsychological assessment. Feigning memory impairment as a kind of high-level cognitive activity can cause various kinds of emotions, such as tension, fear and anxiety when carrying on complex cognitive activities simultaneously. Series of studies focusing on the neural correlation and mechanism of feigning memory impairment have found that, there is a frontal-parietal-subcritical circuit during feign working memory impairment. But the brain regions related to emotion were not significantly activated. It is still not clearly understood whether the brain regions related to emotions is significantly activated in the process of feigning memory impairment or whether the brain regions related to emotions can be recognized as characteristic brain regions of feigning memory impairment. On account of this question, our primary objective is to investigate the neural mechanism of cognitive and emotion in different situation of feigning memory impairment, and explore the function of brain regions related to emotions (I. g amygdala) in psychological conflict of feigning memory impairment.Materials and methodsA total of 27 healthy university students (16 men, 11 women) took part in this study(all of them are right-handed,digital span≥7). All the subjects were divided into three groups: the"award group"under the situation of psychological benefits, the"award and punishment group"under the situation of psychological benefits and anxiety derived from being worried about punishment, as well as the"no award and no punishment group"under the situation of no award and no punishment. A word forced-choice pattern was employed in this study, and all the subjects were asked to respond to the stimulus task in the method of answering honestly,answering incorrectly,answering randomly and answering skillfully. A functional magnetic resonance imaging (fMRI) test was used simultaneously and the behavioral data (i.e. reaction time) were recorded while scanning. What's more, the strategies applied when carrying out random response and forging response were recorded after scanning.Results1.The behavioral data from the word forced-choice pattern indicated that the reaction time (RT) of random response was the shortest, and the reaction time of skill response was the longest. The reaction time from long to short in turn was skill response,truth response,wrong response and random response. Compared with truth response, the accuracy of skill response,random response and wrong response declined. But the difference of accuracy between random response and skill response was not significant. The accuracy of truth response was the highest, and the wrong response was the lowest.2. Imaging data indicated that the activated brain regions were different when responding skillfully under different situations. But the amygdala thought as the control center of emotion was not significantly activated. When compared with truth response in award and punishment group, the brain regions significantly activated were more than truth response, and the main regions were the left middle frontal, the right anteromedial frontal, the bilateral parietal lobe and the front occipital. In comparison with award group, there were more brain regions significantly activated in award and punishment group, and most activated regions were in the right hemisphere.Conclusions1. Deception was a complex cognitive process that involves in multiple psychological factors, such as sensory perception, memory, thought, imagination and so on.2. There exists a frontal-parietal-subcritical circuit during Feigning memory impairment.3. The anticipation and the emotion of fear and anxiety would be aroused in the situation of award and punishment, and the cognitive activity of brain was increased under the background of psychological conflict.