Neural Mechanisms Of Childhood Trauma Affecting Anxiety And Depression: Effects Of Frontal And Occipital Neural Oscillations During Fear Learning

Childhood trauma is a serious public health,human rights and social issue internationally,involving sexual abuse,physical abuse,emotional abuse,physical neglect and emotional neglect.It cause physical harm,and it also has serious long-term effects on an individual’s neurological,cognitive and emotional,and mental health.Epidemiological studies have shown that childhood trauma is a risk factor for psychiatric disorders such as anxiety and depression.Although the effects of childhood trauma on anxiety and depression have received much attention in magnetic resonance imaging studies,the underlying neural mechanisms have not been clearly concluded to date.Therefore,it is necessary to explore the effects of childhood trauma on individual anxiety and depression and its intrinsic neural mechanisms.Some researchers have proposed that adverse childhood experiences lead to abnormal fear learning and that abnormal fear learning is a important mechanism to explain the pathway by which early adverse experiences influence psychopathology.To date,however,no studies have examined the effects of childhood trauma on fear learning and the neural oscillatory mechanisms by which childhood trauma affects anxiety and depression.Therefore,exploring the mechanisms that mediate neural indicators during fear learning can help to gain insight into the mechanisms by which childhood trauma affects individual anxiety and depression.Study 1 included 134 healthy adult subjects and measured the subjects’ levels of childhood trauma and anxiety-depression through a questionnaire scale-the Childhood Traumatic Experiences Scale(CTQ-SF)and the Depression-Anxiety-Stress Self-Rating Scale-21-and both regression model analyses were conducted.The results found that early adverse experiences had a negative impact on individuals’ mental status,with emotional trauma positively predicting anxiety and depression,indicating that emotional trauma is a high risk factor for mental disorders such as anxiety and depression.Study 2 examined the changes of subjective scores and electrodermal responses during fear conditioning and the relationship between childhood trauma and fear learning.The results showed that the discomfort degree of the threat stimulus was significantly greater than that of the safety stimulus,and the psychological tension degree of the threat stimulus was significantly greater than that of the safety stimulus.In addition,the electrodermal response of the subjects to the threat stimulus was significantly greater than that to the safety stimulus.The results of Study 2 provided a physiological insight into the effects of childhood trauma on skin conduct responses during fear learning.Study 3 investigated the changes of EEG indices during fear conditioning and the relationship between childhood trauma and fear learning.The results showed that from700 ms to 1300 ms after the stimulus,the energy of the alpha band of the threat cue was lower than that of the alpha oscillation of the safety cue.Similarly,from 750 ms to1100ms after stimulus presentation,the power in the alpha band of the threat cue was significantly lower than that in the alpha band of the safety cue.Linear regression model showed that emotional trauma(emotional abuse and emotional neglect)was positively correlated with frontal alpha oscillations,and physical trauma(physical abuse and physical neglect)was negatively correlated with frontal alpha oscillations,after controlling for family economic level,gender and the number of children in the family.In addition,similar results were also found in the occipital lobe,there was a significant positive correlation between emotional trauma and occipital alpha oscillations,and a significant negative correlation between physical trauma and occipital alpha oscillations.The results of Study 3 provided a neural insight into the effects of childhood trauma on the neural oscillations involved in fear learning.Study 4 explored the mediating mechanisms between emotional and physical trauma and anxiety and depression from the perspective of model-building.We developed a mediation model to explain the relationship between childhood trauma and anxiety and depression by using alpha oscillations in frontal and occipital regions during fear learning as mediating variables,emotional trauma and physical trauma as independent variables,and anxiety and depression as dependent variables.The results suggest that frontal alpha oscillations partially mediate the relationship between childhood emotional trauma and anxiety.Similarly,frontal alpha oscillations were found to mediate the relationship between childhood emotional trauma and depression.The results of Study 4 further revealed that major trauma,especially emotional trauma,could predict the risk of anxiety and depression by altering the neural oscillations in the brain during fear conditioning.In summary,this study analyzed electrodermal responses and EEG indices during fear learning in individuals who experienced childhood trauma,revealing that emotional trauma can predict the level of anxiety and depression,as well as the frontal lobe and occipital lobe,which are closely related to fear learning,and alpha rhythm,the main basis of neural activity.These findings are helpful to evaluate which individuals with adverse childhood experiences are at greater risk of abnormal fear learning,and have certain reference value for the diagnosis and intervention of individual anxiety and depression.