Faculty Bibliography

OBJECTIVE: Abnormalities of cognitive control functions, such as conflict and error monitoring, have been theorized to underlie obsessive-compulsive symptoms but only recently have been considered a potentially relevant psychological construct for understanding other forms of anxiety. The authors sought to determine whether these cognitive control processes elicit the same abnormalities of brain function in patients with pediatric obsessive-compulsive disorder (OCD) as in those with non-OCD anxiety disorders. METHOD: Functional magnetic resonance imaging of the Multisource Interference Task was used to measure conflict- and error-related activations in youth (8-18 years) with OCD (n = 21) and non-OCD anxiety disorders (generalized anxiety disorder, social phobia, separation anxiety disorder; n = 23) compared with age-matched healthy controls (n = 25). RESULTS: There were no differences in performance (accuracy, response times) among groups. However, a significant effect of group was observed in the dorsolateral prefrontal cortex (dlPFC) during error processing, driven by decreased activation in patients with OCD and those with non-OCD anxiety compared with healthy youth. Between patient groups, there was no difference in error-related dlPFC activation. CONCLUSIONS: Hypoactive dlPFC response to errors occurs in pediatric patients with OCD and those with non-OCD anxiety. These findings suggest that insufficient error-related engagement of the dlPFC associates with anxiety across traditional diagnostic boundaries and appears during the early stages of illness.

Age-related improvements in human performance monitoring have been linked to maturation of medial frontal cortex (MFC) in healthy youth, however, imaging studies conflict regarding age-related changes in MFC activation patterns. Topographical analysis of single-subject activation enables measurement of variation in location of MFC activation by age, as well as other potentially influential factors (e.g., performance on task). In this study, 22 youth (ages 8-17 years) and 21 adults (ages 23-51 years) underwent functional magnetic resonance imaging during a performance monitoring task examining interference and errors. Single-subject factors (extent of MFC activation, age and accuracy) were entered into a three-level hierarchical linear model to test the influence of these characteristics on location of MFC activation. Activation shifted from a rostral/anterior to a more dorsal/posterior location with increasing age and accuracy during interference. Inclusion of age and accuracy accounted for almost all of the unexplained variance in location of interference-related activation within MFC. This pattern links improvement of performance-monitoring capacity to age-related increases in posterior MFC and decreases in anterior MFC activation. Taken together, these results show the maturation of performance monitoring capacity to depend on more focal engagement of posterior MFC substrate for cognitive control.

Obsessive-compulsive disorder (OCD) is often associated with pathological uncertainty regarding whether an action has been performed correctly or whether a bad outcome will occur, leading to compulsive "evidence gathering" behaviors aimed at reducing uncertainty. The current study used event-related functional magnetic resonance imaging to investigate neural functioning in OCD patients and controls as subjective certainty was rated in response to sequential pieces of evidence for a decision. Uncertainty was experimentally manipulated so that some decisions were associated with no "objective" uncertainty (all observed evidence pointed to one correct choice), whereas other decisions contained calculable but varying levels of objective uncertainty based on displayed probabilities. Results indicated that OCD patients differed from controls on decisions that contained no objective uncertainty, such that patients rated themselves as more uncertain. Patients also showed greater activation in a network of brain regions previously associated with internally-focused thought and valuation including ventromedial prefrontal cortex, parahippocampus, middle temporal cortex, as well as amygdala and orbitofrontal cortex/ventral anterior insula. In the patient group, a significantly greater number of positive intersubject correlations were found among several of these brain regions, suggesting that this network is more interconnected in patients. OCD patients did not differ from controls on decisions where task parameters led to uncertainty. These results indicate that OCD is associated with hyperactivation in a network of limbic/paralimbic brain regions when making decisions, which may contribute to the greater subjective experience of doubt that characterizes the disorder.

BACKGROUND: Obsessive-compulsive disorder (OCD) is characterized by an excessive focus on upsetting or disturbing thoughts, feelings, and images that are internally-generated. Internally-focused thought processes are subserved by the "default mode network" (DMN), which has been found to be hyperactive in OCD during cognitive tasks. In healthy individuals, disengagement from internally-focused thought processes may rely on interactions between DMN and a fronto-parietal network (FPN) associated with external attention and task execution. Altered connectivity between FPN and DMN may contribute to the dysfunctional behavior and brain activity found in OCD. METHODS: The current study examined interactions between FPN and DMN during rest in 30 patients with OCD (17 unmedicated) and 32 control subjects (17 unmedicated). Timecourses from seven fronto-parietal seeds were correlated across the whole brain and compared between groups. RESULTS: OCD patients exhibited altered connectivity between FPN seeds (primarily anterior insula) and several regions of DMN including posterior cingulate cortex, medial frontal cortex, posterior inferior parietal lobule, and parahippocampus. These differences were driven largely by a reduction of negative correlations among patients compared to controls. Patients also showed greater positive connectivity between FPN and regions outside DMN, including thalamus, lateral frontal cortex, and somatosensory/motor regions. CONCLUSIONS: OCD is associated with abnormal intrinsic functional connectivity between large-scale brain networks. Alteration of interactions between FPN and DMN at rest may contribute to aspects of the OCD phenotype, such as patients' inability to disengage from internally-generated scenarios and thoughts when performing everyday tasks requiring external attention.

OBJECTIVE: Pediatric obsessive-compulsive disorder is characterized by abnormalities of frontal-striatal-thalamic circuitry that appear near illness onset and persist over its course. Distinct frontal-striatal-thalamic loops through cortical centers for cognitive control (anterior cingulate cortex) and emotion processing (ventral medial frontal cortex) follow unique maturational trajectories, and altered connectivity within distinct loops may be differentially associated with OCD at specific stages of development. METHOD: Altered development of striatal and thalamic connectivity to medial frontal cortex was tested in 60 OCD patients compared with 61 healthy control subjects at child, adolescent, and adult stages of development, using resting-state functional connectivity MRI. RESULTS: OCD in the youngest patients was associated with reduced connectivity of dorsal striatum and medial dorsal thalamus to rostral and dorsal anterior cingulate cortex, respectively. Increased connectivity of dorsal striatum to ventral medial frontal cortex was observed in patients at all developmental stages. In child patients, reduced connectivity between dorsal striatum and rostral anterior cingulate cortex correlated with OCD severity. CONCLUSIONS: Frontal-striatal-thalamic loops involved in cognitive control are hypoconnected in young patients near illness onset, whereas loops implicated in emotion processing are hyperconnected throughout the illness.

BACKGROUND: Patients with obsessive-compulsive disorder (OCD) show abnormal functioning in ventral frontal brain regions involved in emotional/motivational processes, including anterior insula/frontal operculum (aI/fO) and ventromedial frontal cortex (VMPFC). While OCD has been associated with an increased neural response to errors, the influence of motivational factors on this effect remains poorly understood. METHODS: To investigate the contribution of motivational factors to error processing in OCD and to examine functional connectivity between regions involved in the error response, functional magnetic resonance imaging data were measured in 39 OCD patients (20 unmedicated, 19 medicated) and 38 control subjects (20 unmedicated, 18 medicated) during an error-eliciting interference task where motivational context was varied using monetary incentives (null, loss, and gain). RESULTS: Across all errors, OCD patients showed reduced deactivation of VMPFC and greater activation in left aI/FO compared with control subjects. For errors specifically resulting in a loss, patients further hyperactivated VMPFC, as well as right aI/FO. Independent of activity associated with task events, OCD patients showed greater functional connectivity between VMPFC and regions of bilateral aI/FO and right thalamus. CONCLUSIONS: Obsessive-compulsive disorder patients show greater activation in neural regions associated with emotion and valuation when making errors, which could be related to altered intrinsic functional connectivity between brain networks. These results highlight the importance of emotional/motivational responses to mistakes in OCD and point to the need for further study of network interactions in the disorder.

BACKGROUND: Exaggerated concern for correct performance has been linked to hyperactivity of the medial frontal cortex (MFC) in adult obsessive-compulsive disorder (OCD), but the role of the MFC during the early course of illness remains poorly understood. We tested whether hyperactive MFC-based performance monitoring function relates to altered MFC connectivity within task control and default mode networks in pediatric patients. METHODS: Eighteen pairs of OCD and matched healthy youth underwent functional magnetic resonance imaging during performance monitoring and at rest. Task-related hyperactivations in the posterior and ventral MFC were used as seeds for connectivity analyses during task and resting state. RESULTS: In posterior MFC, patients showed greater activation of dorsal anterior cingulate cortex (dACC) than control subjects, with greater activation predicting worse performance. In ventral MFC, control subjects exhibited deactivation, whereas patients activated this region. Compared with control subjects, patients showed increased dACC-ventral MFC connectivity during task and decreased dACC-right anterior operculum and ventral MFC-posterior cingulate connectivity during rest. CONCLUSIONS: Excessive activation and increased interactions of posterior and ventral MFC during performance monitoring may combine with reduced resting state connectivity of these regions within networks for task control and default mode to reflect early markers of OCD. Alteration of reciprocal interactions between these networks could potentiate the intrusion of ventral MFC-based affectively laden, self-referential thoughts, while disrupting posterior MFC-based performance-monitoring function in young patients.

Patients with obsessive-compulsive disorder (OCD) show an increased error-related negativity (ERN), yet previous studies have not controlled for medication use, which may be important given evidence linking performance monitoring to neurotransmitter systems targeted by treatment, such as serotonin. In an examination of 19 unmedicated OCD patients, 19 medicated OCD patients, 19 medicated patient controls without OCD, and 21 unmedicated healthy controls, we found greater ERNs in OCD patients than in controls, irrespective of medication use. Severity of generalized anxiety and depression was associated with ERN amplitude in controls but not patients. These data confirm previous findings of an exaggerated error response in OCD, further showing that it cannot be attributed to medication. The absence in patients of a relationship between ERN amplitude and anxiety/depression, as was found in controls, suggests that elevated error signals in OCD may be disorder-specific.

Some decisions are made after obtaining several pieces of information, whereas others are reached quickly. Such differences may depend on the quality of information acquired, as well as individual variability in how cautiously evidence is evaluated. The current study examined neural activity while subjects accumulated sequential pieces of evidence and then made a decision. Uncertainty was updated with each piece of evidence, with individual ratings of subjective uncertainty characterizing underconfidence when observing evidence. Increased uncertainty during evidence accumulation was associated with activity in dorsal anterior cingulate cortex, whereas greater uncertainty when executing a decision uniquely elicited lateral frontal and parietal activity. Greater underconfidence when observing evidence correlated with activity in ventromedial prefrontal cortex. These results suggest that neural mechanisms of uncertainty depend on the stage of decision-making (belief updating vs decision) and that greater subjective uncertainty when evaluating evidence is associated with activity in ventromedial brain regions, even in the absence of overt risk.