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Communication between cortical and subcortical regions is integral to a wide range of psychological processes and has been implicated in a number of psychiatric conditions. Studies in animals have provided insight into the biochemical and connectivity processes underlying such communication. However, to date no experiments that link these factors in humans in vivo have been carried out. To investigate the role of glutamate in individual differences in communication between the cortex – specifically the medial prefrontal cortex (mPFC) – and subcortical regions in humans, a combination of resting-state fMRI, DTI and MRS was performed. The subcortical target regions were the nucleus accumbens (NAc), dorsomedial thalamus (DMT), and periaqueductal grey (PAG). It was found that functional connectivity between the mPFC and each of the NAc and DMT was positively correlated with mPFC glutamate concentrations, whilst functional connectivity between the mPFC and PAG was negatively correlated with glutamate concentration. The correlations involving mPFC glutamate and FC between the mPFC and each of the DMT and PAG were mirrored by correlations with structural connectivity, providing evidence that the glutamatergic relationship may, in part, be due to direct connectivity. These results are in agreement with existing results from animal studies and may have relevance for MDD and schizophrenia. [ABSTRACT FROM AUTHOR]

Objectives. Borderline personality disorder (BPD) is characterized by a pervasive affective dysregulation. While recent imaging studies demonstrated the neural correlates of abnormal emotion processing in BPD and recently one study reported alterations of the reward circuit in this patient group, the exact neural mechanisms underlying the impact of abnormal emotion on reward behavior remain unclear. Methods. We therefore conducted an fMRI study in healthy controls and BPD patients to investigate the modulation of the anticipation of reward by simultaneously presented emotional pictures. Results. BPD patients revealed a disturbed differentiation between reward and non-reward anticipation in the bilateral pregenual anterior cingulate cortex if a positive or negative emotional picture is presented simultaneously. In the ventral striatum and the bilateral ventral tegmental area, BPD patients and healthy controls are able to differentiate between reward and non-reward even under emotional stimulation, but BPD patients show a reduced deactivation in the above mentioned regions compared to healthy controls. Conclusions. Altered emotion processing in BPD patients is likely to affect the reward system. More basic deficits in reward circuitry and other midline regions' level of resting state activity may contribute to this effect. [ABSTRACT FROM AUTHOR]

Objectives. In addition to affective-cognitive symptoms, patients with major depressive disorder (MDD) suffer from somato-vegetative symptoms, suggesting abnormal interoceptive awareness of their “material me”. While recent imaging studies have extensively investigated affective-cognitive symptoms in MDD, the neural correlates of somato-vegetative symptoms and abnormal interoception remain unclear. Since the “material me” has been especially associated with the anterior insula in healthy subjects, we hypothesized abnormalities in this region during interoceptive awareness in MDD. Methods. We therefore investigated behavioural and neural correlates of interoception in healthy and depressed subjects using the Body Perception Questionnaire (BPQ) and a well established heartbeat perception task in fMRI. Results. MDD patients showed significantly higher scores in the BPQ and reduced neural activity during rest periods, particularly in the bilateral anterior insula. In contrast to healthy subjects, BPQ scores no longer correlated with activity during rest periods in the anterior insula. Both BPQ scores and left anterior insula signal changes correlated with depression severity. Conclusions. We demonstrate for the first time abnormal body perception and altered activity in the insula during rest in MDD. Our results suggest that these behavioural and neural abnormalities are closely related to these patients’ somato-vegetative abnormalities and their abnormal “material me”. [ABSTRACT FROM AUTHOR]