Event-related functional magnetic resonance imaging of response inhibition in obsessive-compulsive disorder.
ABSTRACT Obsessive-compulsive disorder (OCD) has been hypothesized to involve inhibitory control dysfunction related to abnormal frontal-striatal-thalamic-cortical (FSTC) circuitry.
We examined the neural substrates of response inhibition in adults with OCD using functional magnetic resonance imaging (fMRI) and a go/no-go task. Participants consisted of 12 adults with OCD and 14 healthy comparison subjects.
During response inhibition, healthy adults showed predominantly right-hemisphere activation including the right inferior frontal gyrus, whereas the patient group showed a more diffuse, bilateral pattern of activation. Furthermore, the OCD group demonstrated less activation than the comparison group in several right-hemisphere regions during response inhibition, including inferior and medial frontal gyri. Symptom severity was inversely correlated with activation in right orbitofrontal and anterior cingulate gyri and positively correlated with thalamic and posterior cortical activations. Neither depressed mood nor medication status could account for the results.
These findings indicate that adults with OCD demonstrate underactivation of FSTC circuitry during response inhibition. Results suggest that the thalamus and related circuitry may play a role in the expression or intensity of OCD symptoms, whereas right frontal subregions may be involved in the suppression of symptoms.
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ABSTRACT: Over the past 20 years, motor response inhibition and interference control have received considerable scientific effort and attention, due to their important role in behavior and the development of neuropsychiatric disorders. Results of neuroimaging studies indicate that motor response inhibition and interference control are dependent on cortical-striatal-thalamic-cortical (CSTC) circuits. Structural and functional abnormalities within the CSTC circuits have been reported for many neuropsychiatric disorders, including obsessive-compulsive disorder (OCD) and related disorders, such as attention-deficit hyperactivity disorder, Tourette's syndrome, and trichotillomania. These disorders also share impairments in motor response inhibition and interference control, which may underlie some of their behavioral and cognitive symptoms. Results of task-related neuroimaging studies on inhibitory functions in these disorders show that impaired task performance is related to altered recruitment of the CSTC circuits. Previous research has shown that inhibitory performance is dependent upon dopamine, noradrenaline, and serotonin signaling, neurotransmitters that have been implicated in the pathophysiology of these disorders. In this narrative review, we discuss the common and disorder-specific pathophysiological mechanisms of inhibition-related dysfunction in OCD and related disorders.Frontiers in Human Neuroscience 06/2014; 8:419. · 2.90 Impact Factor
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ABSTRACT: Obsessive-compulsive disorder (OCD) is an anxiety disorder characterized by repeated thoughts and behaviors. Inhibitory deficits are presumably related to the onset and maintenance of this disorder. The present study investigated whether obsessive-compulsive (OC) symptoms are related to enhanced response tendencies in reaction to external stimuli. Our goal was to search for direct evidence of an early response preparation process by examining the event-related potential (ERP) component of the readiness potential (RP). An enhanced response tendency might underlie inhibitory deficits in OCD. Response to novel stimuli was studied using a dishabituation paradigm in which a small number of schematic faces (angry or neutral) were presented. An analog sample of healthy subjects was divided into groups of high and low OC levels and high and low trait anxiety levels. The high OC group presented with a greater RP slope gradient that was enhanced under negative valence, compared to the low OC group. No such effect was found in the high versus low trait anxiety groups or in behavioral reaction times (ms). Results support the hypothesis that a stronger readiness for action might characterize subjects with OC symptoms, especially in the presence of threatening stimuli. This finding, specific to OC symptoms and not to anxiety symptoms, may underlie habitual and embodiment tendencies in OCD. This study suggests that early stages of motor preparation might be important to the etiology and maintenance of OC symptoms.Psychiatry Research Neuroimaging 11/2014; · 2.83 Impact Factor
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