Research from JAMA Psychiatry — Altered Corticostriatal Functional Connectivity in Obsessive-compulsive Disorder

Research from JAMA Psychiatry — Mapping Structural Brain Alterations in Obsessive-Compulsive Disorder

Compulsivity is associated with alterations in the structure and the function of parallel and interacting brain circuits involved in emotional processing (involving both the reward and the fear circuits), cognitive control, and motor functioning. These brain circuits develop during the pre-natal period and early childhood under strong genetic and environmental influences. In this review we bring together literature on cognitive, emotional, and behavioral processes in compulsivity, based mainly on studies in patients with obsessive-compulsive disorder and addiction. Disease symptoms normally change over time. Goal-directed behaviors, in response to reward or anxiety, often become more habitual over time. During the course of compulsive disorders the mental processes and repetitive behaviors themselves contribute to the neuroplastic changes in the involved circuits, mainly in case of chronicity. On the other hand, successful treatment is able to normalize altered circuit functioning or to induce compensatory mechanisms. We conclude that insight in the neurobiological characteristics of the individual symptom profile and disease course, including the potential targets for neuroplasticity is an unmet need to advance the field.

Emotion regulation by means of cognitive reappraisal has been widely studied with functional magnetic resonance imaging (fMRI). To date, several meta-analyses of studies using cognitive reappraisal tasks in healthy volunteers have been carried out, but no meta-analyses have yet been performed on the fMRI data of clinical populations with identified alterations in emotion regulation capacity. We provide a comprehensive meta-analysis of cognitive reappraisal fMRI studies in populations of patients with mood or anxiety disorders, yielding a pooled sample of 247 patients and 262 controls from thirteen independent studies. As a distinguishing feature of this meta-analysis, original statistical brain maps were obtained from six of these studies. Our primary results demonstrated that patients with mood and anxiety disorders recruited the regulatory fronto-parietal network involved in cognitive reappraisal to a lesser extent in comparison to healthy controls. Conversely, they presented increased activation in regions that may be associated with the emotional experience (i.e., insula, cerebellum, precentral and inferior occipital gyri) and in regions whose activation may be the consequence of compensatory mechanisms (i.e., supramarginal gyri and superior parietal lobule). Moreover, activations in the left ventrolateral prefrontal cortex and the left superior temporal gyrus were associated with reinterpretation emotion regulation strategies, whereas medial frontal and parietal activations were associated with the deployment of distancing strategies. The regions revealed by this meta-analysis conform to a pattern of dysfunctional brain activation during cognitive reappraisal common to mood and anxiety disorders. As such, this neural pattern may reflect a transdiagnostic feature of these disorders.

The notion of a “default mode of brain function” has taken on certain relevance in human neuroimaging studies and in relation to a network of lateral parietal and midline cortical regions that show prominent activity fluctuations during passive imaging states, such as rest. In this study, we perform three fMRI experiments that demonstrate consistency and specialization in the default mode network. Correlated activity fluctuations of default mode network regions are identified during ( i ) eyes-closed spontaneous rest, ( ii ) activation by moral dilemma, and ( iii ) deactivation by Stroop task performance. Across these imaging states, striking uniformity is shown in the basic anatomy of the default mode network, but with both tasks clearly and differentially modulating this activity compared with spontaneous fluctuations of the network at rest. Against rest, moral dilemma is further shown to evoke regionally specific activity increases of hypothesized functional relevance. Mapping spontaneous and task-related brain activity will help to constrain the meaning of the default mode network. These findings are discussed in relation to recent debate on the topic of default modes of brain function.