RESUMO
Objective To investigate the serum levels of neuregulin-1 (NRG-1) and the gamma activity of the prefrontal cortex of electroencephalogram (EEG) in the resting state in first-episode schizophrenia patients and exam﹣ine their correlation with clinical symptoms and cognitive function. Methods The serum levels of NRG-1 were mea﹣sured in 53 patients and 58 controls. The gamma activity was first collected from the lead of FP1 and FP2 of the pre﹣frontal cortex of EEG and was then measured by using time-frequency analysis. The psychotic symptoms were as﹣sessed by positive and negative syndrome scale (PANSS). The MATRICS consensus cognitive battery (MCCB) was used to assess the cognitive function. Results The serum levels of NRG-1 was significantly lower in the case group than in the control [(7.36±3.96) pg/mL vs. (11.02±8.78) pg/mL, P=0.006]. The gamma activity was significantly different be﹣tween the case group and the control group [39(73.6%) vs. 14(26.4%), P<0.001]. The scores of TMT in MCCB was significantly higher while the scores of BACS SC, HVLT-R, NAB, BVMT-R and CF scores were significantly lower in the case group than the control group (P<0.01). There was a negative correlation between the serum NRG-1 level and the gamma activity in the case group (r=-0.542, P<0.001). There was a negative correlation between the serum NRG-1 level with PANSS (r=-0.360, P=0.009), while the gamma activity was positively correlated with PANSS (r=0.278, P=0.046) in the case group. The serum NRG-1 level was significantly positively correlated with the scores of HVLT-R in the case group (r=0.332, P=0.016), and the gamma activity was significantly negatively correlated with the scores of HVLT-R (r=-0.442, P=0.001) and NAB (r=-0.307, P=0.027). Conclusion The serum NRG-1 level and the gamma activity are correlated with the clinical symptoms and cognitive impairment of patients with first-episode schizophrenia to some degree, suggesting that abnormal neurobiochemical and neuroelectrophysiological reactions exist and interact with each other in the early stage of schizophrenia.
RESUMO
Neural oscillations are a fundamental mechanism for enabling coordinated activity during normal brain functioning and are therefore a crucial target for schizophrenia research. Schizophrenia has been known to be associated with disturbances of neural oscillations, and these disturbances of neural oscillations could be implicated with cognitive deficit. Synchronized oscillations have been shown to establish the precision in spike timing that is crucial for use-dependent synaptic plasticity. Gamma oscillations have been proposed to represent reference signals for temporal encoding, sensory binding of features into a coherent percept, and storage and recall of information. Conversely, disruption of gamma oscillations could underlie some psychiatric disorders, such as schizophrenia and Alzheimer's disease. Gamma-aminobutyric acid interneurons are known to be important for the synthesis of gamma band. Among them, the fast-spiking cells that contain the calcium-binding protein parvalbumin (PV) appear to play a particularly critical role in the generation of synchronized gamma activity. Knowledge about PV neurons is insufficient yet. However, evidences for the role of gamma band impairement specific to the schizophrenia is accumulating. Through more assertive researches, we anticipate that futher roles of gamma band could be come out someday.