A meta-analysis by Gürsel et al. (2018) found altered functional connectivity in OCD patients within and between default mode (DMN), salience (SN), and frontoparietal networks (FPN), as well as evidence for aberrant fronto-striatal circuitry.

Testing the replicability of meta-analysis rsfMRI findings in OCD patients.

We measured functional connectivity during resting-state fMRI in a sample of OCD patients (n=24) and controls matched for age and sex (n=33). The CONN toolbox implemented in SPM was used to perform seed-to-voxel analysis using 30 seed regions based on the previous meta-analytic findings.

OCD patients showed reduced functional connectivity between SN and DMN compared to controls, replicating previous findings. We did not observe significant group differences of functional connectivity within the DMN, SN, or FPN. The strongest finding consisted of altered connectivity between DMN and SN to the visual network. OCD patients showed reduced functional connectivity between the left lateral parietal seed (LPl) and the inferior lateral occipital pole left (iLOCl) compared to controls. Furthermore, the LPl was found to be hyperconnected with the right superior lateral occipital cortex (sLOCr) and the right precuneus. This finding was positively correlated to OCD symptom severity, especially compulsions.

Our findings replicated partly the meta-analysis findings, specifically reduced connectivity between SN and DMN. Using seeds based on the meta-analysis, we identified aberrations between the SN and, in particular, the DMN to the visual network. This raises the question about the visual system’s involvement in OCD symptoms and the abnormal connectivity of a unimodal region to the multimodal DMN.

No significant relationships.

Altered reward-based learning and stress play an important role in psychiatric illnesses, such as psychosis or addiction. Stress sometimes increases learning from rewards, other times it does not show an effect (Starcke & Brand, 2016). A task addressing reward-based learning is the reversal learning task, which uses probabilistic rewards as feedback and incorporates sudden changes in reward contingencies. The effects of acute stress on reversal learning have rarely been addressed.

Here, we investigated the effect of acute social stress in a within-subject design in healthy participants.

A sample of n = 28 male non-clinical participants performed the task in a control condition versus the Trier Social Stress Test (TSST), a validated method to induce psychosocial stress. In our version of the reversal learning task (Reiter, 2016), participants choose between two anti-correlated stimuli in order to obtain rewards in three blocks. Reward contingencies remain stable for the first 55 trials and the last 35 trials. During the second block, in between the stable blocks, four changes of reward contingencies require participants to flexibly adapt their behavior. Performance was measured in correct responses, switches after losses and wins.

Cortisol and subjective stress responses showed that the stress induction was successful. Preliminary analyses showed no significant effect of stress induction on any of the performance measures.

These results demonstrate that reversal learning, at least regarding overall performance measures in our task, is robust to stress-related changes. Modeling and fMRI analyses could yield further insights into more subtle changes after stress induction.

No significant relationships.

Fluid intelligence expresses the capacity for interpretation of novel stimuli and flexible behavioral adaptation to such cues. Phasic dopamine firing closely matches a temporal difference prediction error (PE) signal important for learning and rapid behavioral adaptation. Both fluid intelligence and dopaminergic neurotransmission decline with age. So far, no study investigated the relationship between fluid IQ, PE signal and direct measures of dopaminergic neurotransmission. Here we used a multimodal imaging approach that combines positron emission tomography and functional magnetic resonance imaging.

A group of healthy controls was investigated with both 6-[18F]FluoroDOPA PET and functional MRI with a probabilistic reversal task. The task required a constant behavioral adaptation to changes in reward contingencies, while choosing between two abstract stimuli. A reinforcement learning algorithm was used to compute a trial-by-trial prediction error, which was the used as a regressor in the fMRI data analysis with SPM8.

The prediction error signal was associated with functional activation in the basal ganglia including the ventral striatum and putamen. Fluid intelligence was associated with the PE signal in the ventral striatum, which correlated with age-related changes in dopamine synthesis capacity in the prefrontal cortex.

These findings provide insight into the role of age-related changes in dopaminergic neurotransmission on behavioral adaptation. The multimodal imaging approach allows the characterization of interactions between dopamine metabolism and learning-related neuronal activation and may thus be a useful tool to clarify mechanisms underlying learning and plasticity in old age, which are crucial to our understanding of successful aging.

In alcoholism, one relevant mechanism contributing to relapse is the exposure to stimuli that are associated with alcohol intake. Such conditioned cues can elicit conditioned responses like alcohol craving and consumption. In the last decade, considerable progress has been made in identifying basic neuronal mechanisms that underlie cue-induced alcohol craving.

We explored whether functional brain activation during exposure to alcohol-associated stimuli is related to the prospective relapse risk in detoxified alcohol-dependent patients.

46 alcohol-dependent and 46 healthy volunteers participated in a fMRI study using a cue reactivity paradigm, in which visual alcohol-related and control stimuli were presented. Patients were followed for 3 months. Afterwards data was analysed regarding the subsequent relapse, resulting in 16 abstainers and 30 relapsers.

Alcohol-related versus neutral stimuli activated a frontocortical-limbic network including inferior, medial and middle frontal gyrus as well as putamen in the group of patients relative to healthy controls. Moreover, abstainers showed a stronger activation in orbitofrontal cortex as well as midbrain during the presentation of alcohol-related cues whereas relapsers revealed a stronger activation of cingulate gyrus.

This study suggests that cue-induced activation of orbitofrontal cortex and dopaminergic innervated midbrain is negatively associated with the prospective relapse risk in alcohol-dependent patients. This could indicate a more pronounced and conscious processing of alcohol cues which might serve as a warning signal and a behavioural controlling function. In contrast, prospective relapsers showed a stronger activation of cingulate gyrus, a region involved in the attribution of motivational value.

A dimensional approach in psychiatry strives to identify neurobiological signatures of core (dys)functions such as responses to emotional stimuli across nosological boundaries.

We compared responses to emotional stimuli between major psychiatric disorders and investigated whether there is a psychopathological correlate irrespective of diagnostic group.

We used functional magnetic resonance imaging (fMRI) to assess the functional correlates of responses to unexpected pleasant and aversive emotional pictures in n=175 subjects suffering from alcohol dependence (n=29), schizophrenia (n=37), major depressive disorder (MDD; n=25), bipolar disorder (acute manic episode; n=12), panic disorder (n=12) or attention deficit/hyperactivity disorder (ADHD; n=20) and in healthy controls (n=40). The level of anxiety was measured in all diagnostic groups with the State-Trait Anxiety Inventory, and severity of depressive mood was measured with Beck's depressions inventory in all diagnostic groups with the exception of bipolar patients.

Over all diagnostic groups, a significant activation of BA10 was observed during the presentation of unexpected pleasant pictures, whereas a significant activation of the left amygdala and left insula was found during the presentation of unexpected aversive pictures. We did not find significant effects of group, nor a correlation of neuronal activation with depressed mood or anxiety.

In spite of reported alterations in emotion processing in different psychiatric diseases, responses to emotional pictures did not differ across nosological boundaries in our study. However, a dimensional approach that targets e.g. personality traits or basic learning mechanisms and their neuropsychological correlates across traditional disease categories may be more promising.

The authors have not supplied their declaration of competing interest.

Panic disorder with agoraphobia is characterized by panic attacks and anxiety in situations where escape might be difficult. However, neuroimaging studies specifically focusing on agoraphobia are rare. Here we used functional magnetic resonance imaging (fMRI) with disorder-specific stimuli to investigate the neural substrates of agoraphobia.

We compared the neural activations of 72 patients suffering from panic disorder with agoraphobia with 72 matched healthy control subjects in a 3-T fMRI study. To isolate agoraphobia-specific alterations we tested the effects of the anticipation and perception of an agoraphobia-specific stimulus set. During fMRI, 48 agoraphobia-specific and 48 neutral pictures were randomly presented with and without anticipatory stimulus indicating the content of the subsequent pictures (Westphal paradigm).

During the anticipation of agoraphobia-specific pictures, stronger activations were found in the bilateral ventral striatum and left insula in patients compared with controls. There were no group differences during the perception phase of agoraphobia-specific pictures.

This study revealed stronger region-specific activations in patients suffering from panic disorder with agoraphobia in anticipation of agoraphobia-specific stimuli. Patients seem to process these stimuli more intensively based on individual salience. Hyperactivation of the ventral striatum and insula when anticipating agoraphobia-specific situations might be a central neurofunctional correlate of agoraphobia. Knowledge about the neural correlates of anticipatory and perceptual processes regarding agoraphobic situations will help to optimize and evaluate treatments, such as exposure therapy, in patients with panic disorder and agoraphobia.