Reward-related Predictors of Relapse in Smokers

Quitting smoking remains an on-going challenging for many cigarette smokers. Numerous individualized characteristics have been suggested as predictors for successful smoking abstinence. One such factor requiring further investigation is reward responsivity, given that individuals with addiction show behavioral and neurobiological alterations in reward function.This study used previously collected data from 122 daily smokers to investigate whether individuals willing to abstain from smoking in exchange for money would display increased reward responsivity during a baseline, non-abstinent visit, relative to individuals who smoked immediately. Participants Probabilistic Reward Task (PRT) performance was used to measure reward responsivity to monetary rewards and a laboratory-based measures of abstinence called the Relapse Analogue Task (RAT) was used to evaluate whether individuals are willing to abstain from smoking in exchange for money. The PRT was analyzed using both traditional analyses and a more fine-grained computational model: Hierarchical Drift Diffusion Modeling (HDDM). Participants fell into 2 groups based on a bimodal distribution of smoking immediately (0-minute waiters) or abstaining the full duration of the RAT (50-minute waiters) and were compared on standard and HDDM PRT measures of reward responsivity. Results showed that 0-minute and 50-minute waiters did not differ on standard nor HDDM measures of reward responsivity, however, 50-minute waiters showed higher values than 0-minute waiters for both standard and HDDM measures of perceptual processing, which were used as control variables. These results suggest individuals who are more likely to abstain from smoking have better perceptual processing abilities, which may be linked to underlying dopaminergic function

Hyperactivation of Posterior Default Mode Network During Self-Referential Processing in Children at Familial High-Risk for Psychosis

Patients with schizophrenia spectrum disorders show disturbances in self-referential processing and associated neural circuits including the default mode network (DMN). These disturbances may precede the onset of psychosis and may underlie early social and emotional problems. In this study, we examined self-referential processing in a group of children (7–12 years) at familial high risk (FHR) for psychosis (N = 17), compared to an age and sex-matched group of healthy control (HC) children (N = 20). The participants were presented with a list of adjectives and asked to indicate whether or not the adjectives described them (self-reference condition) and whether the adjectives described a good or bad trait (semantic condition). Three participants were excluded due to chance-level performance on the semantic task, leaving N = 15 FHR and N = 19 HC for final analysis. Functional MRI (fMRI) was used to measure brain activation during self-referential vs. semantic processing. Internalizing and externalizing problems were assessed with the Child Behavior Checklist (CBCL). Evaluating main effects of task (self > semantic) showed activation of medial prefrontal cortex in HC and precuneus/posterior cingulate cortex (PCC) in FHR. Group-comparison yielded significant results for the FHR > HC contrast, showing two clusters of hyperactivation in precuneus/ PCC (p = 0.004) and anterior cerebellum / temporo-occipital cortex (p = 0.009). Greater precuneus/PCC activation was found to correlate with greater CBCL internalizing (r = 0.60, p = 0.032) and total (r = 0.69, p = 0.009) problems. In all, this study shows hyperactivity of posterior DMN during self-referential processing in pre-adolescent FHR children. This finding posits DMN-related disturbances in self-processing as a developmental brain abnormality associated with familial risk factors that predates not just psychosis, but also the prodromal stage. Moreover, our results suggest that early disturbances in self-referential processing may be related to internalizing problems in at-risk children

Altered resting-state functional connectivity in young children at familial high risk for psychotic illness: A preliminary study

© 2019 Elsevier B.V. Multiple lines of evidence suggest that illness development in schizophrenia and other psychotic disorders predates the first psychotic episode by many years. In this study, we examined a sample of 15 pre-adolescent children, ages 7 through 12 years, who are at familial high-risk (FHR) because they have a parent or sibling with a history of schizophrenia or related psychotic disorder. Using multi-voxel pattern analysis (MVPA), a data-driven fMRI analysis, we assessed whole-brain differences in functional connectivity in the FHR sample as compared to an age- and sex-matched control (CON) group of 15 children without a family history of psychosis. MVPA analysis yielded a single cluster in right posterior superior temporal gyrus (pSTG/BA 22) showing significant group-differences in functional connectivity. Post-hoc characterization of this cluster through seed-to-voxel analysis revealed mostly reduced functional connectivity of the pSTG seed to a set of language and default mode network (DMN) associated brain regions including Heschl's gyrus, inferior temporal gyrus extending into fusiform gyrus, (para)hippocampus, thalamus, and a cerebellar cluster encompassing mainly Crus I/II. A height-threshold of whole-brain p < .001 (two-sided), and FDR-corrected cluster-threshold of p < .05 (non-parametric statistics) was used for post-hoc characterization. These findings suggest that abnormalities in functional communication in a network encompassing right STG and associated brain regions are present before adolescence in at-risk children and may be a risk marker for psychosis. Subsequent changes in this functional network across development may contribute to either disease manifestation or resilience in children with a familial vulnerability for psychosis