Prediction of functional connectivity of fronto-limbic network in the outcome of subjects with clinical high-risk for psychosis / 上海交通大学学报（医学版）

Objective: To explore the role of functional connectivity (FC) within the fronto-limbic network in predicting the onset of psychosis in the subjects with clinical high-risk for psychosis (CHR). Methods: A total of 164 CHR subjects and 89 healthy controls (HC) who underwent resting-state functional MRI were recruited. FCs between frontal [medial prefrontal cortex and bilateral or-bitofrontal cortex (OFC)] and limbic (bilateral hippocampus and bilateral amygdala) brain regions at baseline were calculated. CHR subjects were further divided into 3 subgroups, i.e., CHR converters (CHR-C) group, symptomatic CHR (CHR-S) group and remitted CHR (CHR-R) group according to clinical outcome after one-year follow-up. The FCs of fronto-limbic network were compared between the groups and among the subgroups, and their interaction with brain regions, as well as their correlations with positive and negative symptoms were analyzed. Results: There was no significant main effect of group (P=0.110), but a significant interaction of subgroups and brain regions (P=0.049). CHR-C group had lower FC between bilateral OFC and bilateral amygdala than HC group and CHR-R group (all P<0.05). The FCs between left OFC and left hippocampus in the three CHR subgroups were all lower than that in HC group (all P<0.05). In addition, the FC between left OFC and right amygdala was positively correlated with the severity of negative symptoms in CHR-C group, while the FCs between left OFC and bilateral hippocampus and between right OFC and left hippocampus were negatively correlated with the severity of positive symptoms in CHR-C group. Conclusion: The decrease of OFC-hippocampus connectivity may be common in the subjects with CHR, while the decrease of OFC-amygdala connectivity may predict CHR subjects will convert to schizophrenia in the later stage.

Promising Neuroimaging Biomarkers in Depression

The neuroimaging has been applied in the study of pathophysiology in major depressive disorder (MDD). In this review article, several kinds of methodologies of neuroimaging would be discussed to summarize the promising biomarkers in MDD. For the magnetic resonance imaging (MRI) and magnetoencephalography field, the literature review showed the potentially promising roles of frontal lobes, such as anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC) and orbitofrontal cortex (OFC). In addition, the limbic regions, such as hippocampus and amygdala, might be the potentially promising biomarkers for MDD. The structures and functions of ACC, DLPFC, OFC, amygdala and hippocampus might be confirmed as the biomarkers for the prediction of antidepressant treatment responses and for the pathophysiology of MDD. The functions of cognitive control and emotion regulation of these regions might be crucial for the establishment of biomarkers. The near-infrared spectroscopy studies demonstrated that blood flow in the frontal lobe, such as the DLPFC and OFC, might be the biomarkers for the field of near-infrared spectroscopy. The electroencephalography also supported the promising role of frontal regions, such as the ACC, DLPFC and OFC in the biomarker exploration, especially for the sleep electroencephalogram to detect biomarkers in MDD. The positron emission tomography (PET) and single-photon emission computed tomography (SPECT) in MDD demonstrated the promising biomarkers for the frontal and limbic regions, such as ACC, DLPFC and amygdala. However, additional findings in brainstem and midbrain were also found in PET and SPECT. The promising neuroimaging biomarkers of MDD seemed focused in the fronto-limbic regions.

Fear Network Model in Panic Disorder: The Past and the Future

The core concept for pathophysiology in panic disorder (PD) is the fear network model (FNM). The alterations in FNM might be linked with disturbances in the autonomic nervous system (ANS), which is a common phenomenon in PD. The traditional FNM included the frontal and limbic regions, which were dysregulated in the feedback mechanism for cognitive control of frontal lobe over the primitive response of limbic system. The exaggerated responses of limbic system are also associated with dysregulation in the neurotransmitter system. The neuroimaging studies also corresponded to FNM concept. However, more extended areas of FNM have been discovered in recent imaging studies, such as sensory regions of occipital, parietal cortex and temporal cortex and insula. The insula might integrate the filtered sensory information via thalamus from the visuospatial and other sensory modalities related to occipital, parietal and temporal lobes. In this review article, the traditional and advanced FNM would be discussed. I would also focus on the current evidences of insula, temporal, parietal and occipital lobes in the pathophysiology. In addition, the white matter and functional connectome studies would be reviewed to support the concept of advanced FNM. An emerging dysregulation model of fronto-limbic-insula and temporooccipito-parietal areas might be revealed according to the combined results of recent neuroimaging studies. The future delineation of advanced FNM model can be beneficial from more extensive and advanced studies focusing on the additional sensory regions of occipital, parietal and temporal cortex to confirm the role of advanced FNM in the pathophysiology of PD.

Current progress in neuroimaging research on treatment resistant depression / 生物医学工程学杂志

Depression is a common psychiatric disorder, and approximately 30% patients with depression do not respond effectively to standard antidepressant medication; this condition is termed treatment resistant depression (TRD) and its neurobiological mechanism remains unclear. Neuroimaging techniques can non-invasively explore changes in brain structure, function and metabolism. These techniques have been applied in neurobiological research of TRD and revealed critical abnormalities in brain structure, function and metabolism in fronto-limbic system. In this paper, we reviewed the latest progress in neuroimaging researches on TRD, providing new insight and imaging evidence for further neurobiological studies of TRD.