ERP Evidence For Attention Bias Towards Facial Expression In Unipolar And Bipolar Depression

Attention bias,selectively attended certain types of information,is a tendency,and has been concerned as an important component of cognitive function,while it also plays an important role in the generation,development and maintenance of emotional disorders.In recent years,enormous studies shown that depressed individuals have a negative bias on negative emotional information.The exposure of sluggish studies on the attention bias of bipolar depression make the clinical assessment and diagnose unstable,especially the patients with unipolar depression,as well as bipolar depression.Therefore,the attempt to distinguish unipolar and bipolar depression on attention bias by using nerve electrophysiology indicators might have been useful in clinical diagnosis and treatment.The main object of this study is an attempt of distinguishing unipolar and bipolar depression on attention bias by using nerve electrophysiology indicators would be more likely useful in clinical diagnosis and treatment,and further clear the attention bias mechanism of different emotional information in depressed patients: sustained attention or vigilance or both.And in order to find the electrophysiological indicators that can identify unipolar and bipolar depressive disorder,this study used event-related potential to record EEG signals in17 patients with unipolar depression,19 patients with bipolar depression and 22 normal controls under the emotional Stroop test.Brain Vision Analyzer 2.0 and BESA Research 6.0 were used for pre-processing.SPSS 19.0 was used for further data analysis.Comparing the corresponding EPN,P300 amplitude and latency values,and the scalp potential analysis and ERP total mean waveform in patients with unipolar and bipolar depression.The result include three points:(1)The results of behavioral data show that the average reaction time in two patients group was longer.Moreover,in the three different groups,the reaction time of negative facial expression is shortened.(2)Under the condition of happy and neutral facial expression,the EPN latency of patients with unipolar and bipolar depressive depression isshortened;Under the condition of sadness,the P300 amplitude and latency of patients with unipolar and bipolar depression are altered;The EPN latency of the unipolar depression group is longer.(3)The activity of frontal area was increased in patients with unipolar and bipolar disorder compared with the control group in the emotional Stroop task.At last,we conclude:(1)the cognitive processing speed is deficient in patients with both unipolar and bipolar depression,and the attention bias for negative facial expression in two patients group,these indicate that a vigilance of sadness in the patient group.(2)The increased amplitude of P300 in patients with unipolar and bipolar depression shows that there is cognitive deficits on negative facial expression.(3)Patients with unipolar depression suffer with both sustained attention and vigilance for negative facial expression.(4)The shorter EPN latency in patients with bipolar depression indicate that they are more altered to happy facial expression than patients with unipolar depression.