Functional magnetic resonance imaging study of group independent components underpinning item responses to paranoid-depressive scale

BACKGROUND Our study expand upon a large body of evidence in the field of neuropsychiatric imaging with cognitive,affective and behavioral tasks,adapted for the functional magnetic resonance imaging(MRI)(fMRI)experimental environment.There is sufficient evidence that common networks underpin activations in task-based fMRI across different mental disorders.AIM To investigate whether there exist specific neural circuits which underpin differ-ential item responses to depressive,paranoid and neutral items(DN)in patients respectively with schizophrenia(SCZ)and major depressive disorder(MDD).METHODS 60 patients were recruited with SCZ and MDD.All patients have been scanned on 3T magnetic resonance tomography platform with functional MRI paradigm,comprised of block design,including blocks with items from diagnostic paranoid(DP),depression specific(DS)and DN from general interest scale.We performed a two-sample t-test between the two groups-SCZ patients and depressive patients.Our purpose was to observe different brain networks which were activated during a specific condition of the task,respectively DS,DP,DN.RESULTS Several significant results are demonstrated in the comparison between SCZ and depressive groups while performing this task.We identified one component that is task-related and independent of condition(shared between all three conditions),composed by regions within the temporal(right superior and middle temporal gyri),frontal(left middle and inferior frontal gyri)and limbic/salience system(right anterior insula).Another com-ponent is related to both diagnostic specific conditions(DS and DP)e.g.It is shared between DEP and SCZ,and includes frontal motor/language and parietal areas.One specific component is modulated preferentially by to the DP condition,and is related mainly to prefrontal regions,whereas other two components are significantly modulated with the DS condition and include clusters within the default mode network such as posterior cingulate and precuneus,several occipital areas,including lingual and fusiform gyrus,as well as parahippocampal gyrus.Finally,component 12 appeared to be unique for the neutral condition.In addition,there have been determined circuits across components,which are either common,or distinct in the preferential processing of the sub-scales of the task.CONCLUSION This study has delivers further evidence in support of the model of trans-disciplinary cross-validation in psychiatry.

Differential aberrant connectivity of precuneus and anterior insula may underpin the diagnosis of schizophrenia and mood disorders

BACKGROUND Over the past decade,resting-state functional magnetic resonance imaging(rsfMRI)has concentrated on brain networks such as the default mode network(DMN),the salience network(SN),and the central executive network(CEN),allowing for a better understanding of cognitive deficits observed in mental disorders,as well as other characteristic psychopathological phenomena such as thought and behavior disorganization.AIM To investigate differential patterns of effective connectivity across distributed brain networks involved in schizophrenia(SCH)and mood disorders.METHODS The sample comprised 58 patients with either paranoid syndrome in the context of SCH(n=26)or depressive syndrome(Ds)(n=32),in the context of major depressive disorder or bipolar disorder.The methods used include rs-fMRI and subsequent dynamic causal modeling to determine the direction and strength of connections to and from various nodes in the DMN,SN and CEN.RESULTS A significant excitatory connection from the dorsal anterior cingulate cortex to the anterior insula(aI)was observed in the SCH patient group,whereas inhibitory connections from the precuneus to the ventrolateral prefrontal cortex and from the aI to the precuneus were observed in the Ds group.CONCLUSION The results delineate specific patterns associated with SCH and Ds and offer a better explanation of the underlying mechanisms of these disorders,and inform differential diagnosis and precise treatment targeting.

Implications from translational cross-validation of clinical assessment tools for diagnosis and treatment in psychiatry

Traditional therapeutic methods in psychiatry,such as psychopharmacology and psychotherapy help many people suffering from mental disorders,but in the long-term prove to be effective in a relatively small proportion of those affected.Therapeutically,resistant forms of mental disorders such as schizophrenia,major depressive disorder,and bipolar disorder lead to persistent distress and dysfunction in personal,social,and professional aspects.In an effort to address these problems,the translational approach in neuroscience has initiated the inclusion of novel or modified unconventional diagnostic and therapeutic techniques with promising results.For instance,neuroimaging data sets from multiple modalities provide insight into the nature of pathophysiological mechanisms such as disruptions of connectivity,integration,and segregation of neural networks,focusing on the treatment of mental disorders through instrumental biomedical methods such as electro-convulsive therapy(ECT),transcranial magnetic stimulation(TMS),transcranial direct current stimulation(tDCS)and deep brain stimulation(DBS).These methodologies have yielded promising results that have yet to be understood and improved to enhance the prognosis of the severe and persistent psychotic and affective disorders.The current review is focused on the translational approach in the management of schizophrenia and mood disorders,as well as the adaptation of new transdisciplinary diagnostic tools such as neuroimaging with concurrently administered psychopathological questionnaires and integration of the results into the therapeutic framework using various advanced instrumental biomedical tools such as ECT,TMS,tDCS and DBS.