The Correlation Between Event-related Potential P300and Gray Matter Volume In Drug Naive First Episode MDD Female Patients

Objectives:The study had two main objectives. The primary aim was to investigate gray matter volume changes in drug-naive female patients with first-episode major depression by employing the voxel-based morphometry (VBM) method. The second aim was to explore the relationships among gray matter volumetric abnormalities, the latency and amplitude of auditory event-related potential (ERP) P300, and the severity of depressive symptoms in subjects, so as to probe the neuropathological basis of cognitive impairment in the drug-naive female patients with first-episode major depression.Method:25drug-naive female patients with first-episode major depression diagnosed with DSM-IV (Diagnostic and Statistical Manual of Mental Disorder, forth edition) were recruited from the psychiatry outpatient clinic of the First Affiliated Hospital of Kunming Medical University, and28gender-, age-, education level-matched healthy controls were included in this study. All participants were assigned to receive3D structural magnetic resonance imaging (MRI) brain scans, and the patients received P300test. MRI data were processed automatically by using the software VBM5running on Matlab2009a. Grey matter images of the patient group and the control group were extracted respectively after the normalization, segmentation, and smoothing steps, followed by two-sample t test to detect regions where group differences exit pertaining to the grey matter volume. Correlation analysis between the latency and amplitude of P300and grey matter volume abnormalities was performed to find the specific brain regions that were correlated with the cognitive P300ERP. Spearman correlation analysis was conducted to examine the relationship between P300and the severity of depressive symptoms, which was assessed by the Hamilton Depression Rating Scale (HAMD).Result:1. In comparison with norm, extended P2latency and increased P3amplitude of P300(p<0.05) were observed in the patient group, but there was no significant difference (p>0.05) when comparing other P300components. No statistically significant correlation (p>0.05) was found between each of P300components and HAMD scores (total and factor).2. In contrast with healthy controls, decreased grey matter volume were detected in the right frontal operculum and the right precentral gyrus of drug-native female patients with first-episode major depression.3. Within the patient group, different P300components were interrelated with different regions of grey matter volume abnormalities, among which both the P3and N2latencies were positively correlated with bilateral putamen nuclei. The P3latency was also positively associated with bilateral middle temporal gyrus, the left middle frontal gyrus, and the left fusiform gyrus. Negative correlations between the P3amplitude and aberrant brain regions were restricted to the left angular gyrus and the right superior frontal gyrus. Other correlations that were found in this study included (a) positive relationships:N2latency with the left posterior cingulate gyrus, the right fusiform gyrus, occipital lobe, and the left cerebellum; N1latency with the left cerebellum; P2latency with bilateral superior temporal gyri, the left precuneus, lingual gyrus, posterior cingulate gyrus, paracentral lobule, and the right middle temporal gyrus;(b) negative relationships:N1latency with the left inferior temporal gyrus, parahippocampal gyrus, and the right superior and middle temporal gyri; P2latency with the left anterior cingulate gyrus.4. There were also different statistical correlations between HAMD scores (total and factor) and different regions of grey matter volume abnormalities,(a) negative relationships:HAMD total score with the right superior occipital gyrus; the anxiety/somatization factor score with the left fusiform gyrus, the right caudate nucleus, cerebellar vermis, and bilateral cerebellums; the retardation factor score with bilateral occipital lobes; the cognition factor score with the right superior occipital gyrus; the weight factor score with bilateral parahippocampal gyri;(b) positive relationships:the retardation factor score with the left frontal lobe, anterior central gyrus, anterior cingulate gyrus, superior and middle temporal gyri, bilateral orbitofrontal cortex, and the triangular part of bilateral inferior frontal gyri; the cognition factor score with the opercular part of left inferior frontal gyrus and the left posterior central gyrus; the insomnia factor score with anterior end of the left superior temporal gyrus and the right posterior central gyrus.Conclusion:1. Reduced regional grey matter volumes in the drug-naive female patients with first-episode major depression relative to healthy controls suggest that characteristic abnormalities of grey matter volume exist in certain brain regions of the first-episode unmedicated female patients with MDD.2. Correlations between the regional grey matter volume abnormalities and patients’HAMD scores (total and factor respectively) reveal that different neurostructual bases may underlie various depressive symptoms.3. There is no significant correlation between patients’disturbed P300potentials and their symptom severity. Different types of correlation between P300components and regional grey matter volume abnormalities suggest specific brain regions may have different impacts on each of P300components, indicating that the cognitive impairments in female depression patients are influenced by multiple neural structures or circuits, with particular involvement of temporal lobes and basal ganglia. Our results support the argument that the cognitive dysfunction in female depression patients is relatively independent, and it has different neurostructural basis from that of depressive symptoms.