Cerebral Activations Of Nightmare Disorder Patients In Different Conditions

Background Nightmare disorder is a kind of sleep disorders,but is seriously neglected,and is closely associated with many psychiatric disorders including suicide.Previous nightmare-focused studies are mainly depended on subjective assessment,but its objective index is needed since it might provide evidence to support its diagnosis and treatment,as well as to disclose its underlying neuro-mechanism.According to the sleep-wake continuity theory,brain areas with abnormal activities during dreaming will also perform abnormally during waking time.During sleep,the spontaneous electroencephalogram has been characterized by hyperarousal and dysfunction of emotional regulation;during awakening,behavioral studies have shown the executive dysfunction and decreased stress tolerance in frequent nightmare sufferers.Moreover,emotion processing studies have shown that the neural activities were characterized as dysfunction of emotional regulation in frequent nightmare sufferers.However,there is no study focused on the spontaneous brain activities of nightmare disorder patients during daytime,or the cerebral activities during resting state which reflect the basic neuropathological process in these patients.Previous results have shown that the brain activities during task performing reflect the cognitive process,and the activities during emotional situation reflect the emotional processing in nightmare disorder patients,but these activities are not accounted in these patients yet.In the current study,we would like to investigate the characteristics of cerebral activities and their changes from resting state to task performing,from peace to emotional processing in these patients.The consistency of brain activity during these processes is crucial to reveal the neuropathological mechanism of the disorder.Aims 1.To investigate the cerebral activity of nightmare disorder patient during resting-state,for obtaining more understanding of basic neuropathological changes of the disorder.2.To investigate the brain activity characteristics nightmare disorder patients of from resting state to task performing,compare similarities and differences of brain activities during these states between nightmare disorder patients and healthy volunteers,for obtaining more understanding of neuro-mechanism of the disorder.3.To investigate the brain activity characteristics of nightmare disorder patients from peace to emotional processing,compare similarities and differences of brain activities during these states,for characterizing the neural activities in these patients during emotional processing or regulating.Methods 1.Nightmare disorder patients and healthy volunteers were invited to complete Nightmare Disorder Questionnaire(which including physical effect,negative emotion,meaning interpretation and horrible stimulation),undergo the resting-state functional magnetic resonance imaging(f MRI)test.The amplitude of low frequency fluctuation(ALFF),fractional amplitude of low-frequency fluctuation(f ALFF)and regional homogeneity(Re Ho)were compared between two groups regarding cerebral area activations.We then searched for relationship between nightmare experience and cerebral activities in the two groups.2.We measured the nightmare experience of nightmare disorder patients and healthy volunteers,invited them to undergo an oddball task with the f MRI test,and compared their cerebral activities during the task performance.Meanwhile,we searched for the relationship between nightmare experience and cerebral activity during task performance in two groups.3.We measured the nightmare experience of nightmare disorder patients and healthy volunteers,and invited them to participate in task performance under different emotional situations(including disgust,erotica,fear,sadness,happiness and neutral)with the f MRI test.We then compared the cerebral activities between nightmare disorder patients and healthy volunteers during different emotional situations,in order to investigate the characteristics of processing and regulation of different external emotional situation in nightmare disorder patients.Results 1.Nightmare disorder patients had more elevated scores of Physical Effect,and they had more reduced ALFF value in angular gyrus,enhanced ALFF value in paracentral lobule;reduced Re Ho value in angular gyrus and orbital frontal gyrus,enhanced Re Ho value in middle cingulate cortex.In addition,the whole brain analysis revealed that the Meaning Interpretation of Nightmare Experience Qustionnaiare was negatively correlated with ALFF value of right middle frontal gyrus,and Horrible Stimulation was also negatively correlated with Re Ho value of anterior cingulate cortex in nightmare disorder patients.2.Nightmare disorder patients had more elevated scores of Physical Effect,and they had more decreased cerabral activities in attention task,which included bilateral superior frontal gyri,bilateral middle frontal gyri,left inferior frontal gyrus,bilateral precentral gyri,right postcentral gyrus,bilateral supplementary areas,right supramarginal gyrus,bilateral middle cingulate cortex,left medial supeior frontal gyrus and right precuneus.The whole brain analysis revealed that nightmare frequency was positively correlated to brain activities of left insula,putemen,pallidum and temporal pole in nightamre disorder patients.3.Nightmare disorder patients had more elevated scores of Physical Effect and Meaning Interpretation,and they had stronger activations in bilateral inferior frontal gyri,right precentral gyrus and right supplementary area during fear situation.During other emotion situations,nightmare disorder patients showed a tendency of increasing(but not significant)activity in various areas.Conclusions 1.Nightmare disorder patients showed abnormal brain function in resting state,reflecting enhanced activities in somatosensory but reduced in emotional regulation areas.These results indicate that patients have more enhanced sensory sensitivity and dysfunction of emotional regulation.2.Nightmare disorder patients showed more decreased brain activity in attention task,suggesting that patients might have limited cognitive resource mobilization during cognitive processing.3.Nightmare disorder patient showed increased(or a tendency of increased)activity in several areas,indicating that to some extent the external emotional-situations(especially fear)have promoted the cognitive processing in patients.