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Adaptive functioning is thought to reflect a balance between approach and avoidance neural systems with imbalances often producing pathological forms of avoidance. Yet little evidence is available in healthy adults demonstrating a balance between approach and avoidance neural systems and modulation in avoidance neurocircuitry by vulnerability factors for(More)
The effects of auditory statements describing a personal worry on brain activation as measured by functional magnetic resonance imaging were examined in patients with generalized anxiety disorder (GAD) before and after anxiety reduction with citalopram. Six patients were imaged while listening to verbal descriptions of a personal worry or a neutral(More)
BACKGROUND Neuroimaging technology has afforded advances in our understanding of normal and pathological brain function and development in children and adolescents. However, noncompliance involving the inability to remain in the magnetic resonance imaging (MRI) scanner to complete tasks is one common and significant problem. Task noncompliance is an(More)
Rats responded under progressive-ratio schedules for sweetened milk reinforcers; each session ended when responding ceased for 10 min. Experiment 1 varied the concentration of milk and the duration of postreinforcement timeouts. Postreinforcement pausing increased as a positively accelerated function of the size of the ratio, and the rate of increase was(More)
Avoidance of threatening or unpleasant events is usually an adaptive behavioural strategy. Sometimes, however, avoidance can become chronic and lead to impaired daily functioning. Excessive threat-avoidance is a central diagnostic feature of anxiety disorders, yet little is known about whether avoidance acquired in the absence of a direct history of(More)
Symbolic generalization of avoidance may underlie the aetiology and maintenance of anxiety disorders. The aim of the present study was to demonstrate inferred threat-avoidance and safety (non-avoidance) behaviours that occur in the presence of stimuli indirectly related to learned threat and safety cues. A laboratory experiment was conducted involving two(More)
Proton magnetic resonance spectroscopic imaging was performed to compare brain metabolism in patients with obsessive-compulsive OCD. Evaluation was done on responders and non-responders to pharmacotherapy and on healthy controls. The results showed significantly lower NAA/Cr ratios in the right basal ganglia in non-responders than in responders or in(More)
Results of numerous human imaging studies and nonhuman neurophysiological studies on "reward" highlight a role for frontal, striatal, and thalamic regions in operant learning. By integrating operant and functional neuroimaging methodologies, the present investigation examined brain activation to two types of discriminative stimuli correlated with different(More)
Successful adaption requires learning to respond appropriately to cues associated with response-reinforcer contingencies. In this investigation, we used functional magnetic resonance imaging to characterize changes in frontal and limbic activation associated with learning under a positive reinforcement contingency. Imaging analyses identified linear and(More)
Many forms of human psychopathology are characterized by sustained negative emotional responses to threat and chronic behavioral avoidance, implicating avoidance as a potential transdiagnostic factor. Evidence from both nonhuman neurophysiological and human neuroimaging studies suggests a distributed frontal-limbic-striatal brain network supports avoidance.(More)