Negativie Cognitive Biases In Major Depression

The cognitive processing biases in depression are universally acknowledged in the academic and medical fields. How do negative b iases occur in different temporal stages in information processing stream? What are the characteristics of the cognitive negativity processing biases? How do the emotional factors and cognitive control affect negative biases? What is the mechanism of the cognitive negativity processing biases? The present study is attempt to investigate the mechanism of cognitive processing biases, using both behavior measurements and event-related potential(ERP) measurements..Experiment 1 is designed to analyze the mechanism of attentional bias in a dot-probe paradigm. 21 MDD patients and 21 healthy controls perform the Beck Depression Inventory and Beck Anxiety Inventory. This study is an analysis of the attention modulation of sad face in comparison with fear face and happy face using event-related potential(ERP) measurements. Results of Experiment 1 indicated MDD patients performed better in dot-probe(sad face) than control participants, a fear and a sad face elicited a larger P2 component for validly dot-probe in MDD patients than in healthy participants, whereas a sad face elicited a smaller N2 component for dot-probe in MDD patients than in healthy participants. Experiment 2 is conducted to explore the mechanism of subliminal perception bias in a backward masking paradigm. 17 MDD patients and 17 healthy controls performed the Beck Depression Inventory and Beck Anxiety Inventory. This study investigated the subliminal perception bias modulation of sad in comparison with happy using event-related potential(ERP) measurements. Results of Experiment 2 indicated MDD patients performed better in subliminal perception sad face than control partic ipants, a sad face elicited a larger P2 component was found for sad face in MDD patients than in healthy participants, whereas a sad face elicited a smaller N2 component in MDD patients than in healthy participants. Experiment 3 is designed to explore the mechanism of working memory bias in a 2-back paradigm. 17 MDD patients and 17 healthy controls performed the Beck Depression Inventory and Beck Anxiety Inventory. This study investigated the working modulation of sad in comparison with neutral and happy using event-related potential(ERP) measurements. Results of Experiment 3 indicated MDD patients perform a larger P2 component elicited by negative emotional words than neutral emotional words, and a larger LPC component was founded in MDD patients than in control participants. According to the three results mentioned above, MDD depression patients are characterized by negative biases in virtually all aspects of information processing, including attention, subliminal perception, and working memory in MDD depression patients. At the early stage, MDD depression patients performed quicker and deeper for sad face than healthy participants, then, MDD depression patients showed deficits in cognitive control when processing negative information than healthy participants, MDD depression patients promotes an analytical processing style in which information is processed more carefully, thoroughly.The study have generally provided support for the formulation that depression is characterized by automatic and enhanced processing(automatic mechanism) for sad face in the early stage, then characterized by impaired cognitive control(controlled process), and characterized by analytical processing for conscious information finally.