Gabriel S. Dichter

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The aim of this study was to investigate reward circuitry responses in autism during reward anticipation and outcomes for monetary and social rewards. During monetary anticipation, participants with autism spectrum disorders (ASDs) showed hypoactivation in right nucleus accumbens and hyperactivation in right hippocampus, whereas during monetary outcomes,(More)
The purpose of the present investigation was to evaluate reward processing in unipolar major depressive disorder (MDD). Specifically, we investigated whether adults with MDD demonstrated hyporesponsivity in striatal brain regions and/or hyperresponsivity in cortical brain regions involved in conflict monitoring using a Wheel of Fortune task designed to(More)
Social interaction deficits and restricted repetitive behaviors and interests that characterize autism spectrum disorders (ASDs) may both reflect aberrant functioning of brain reward circuits. However, no neuroimaging study to date has investigated the integrity of reward circuits using an incentive delay paradigm in individuals with ASDs. In the present(More)
BACKGROUND Recent studies have suggested that the social and cognitive impairments in autism are associated with neural processing deficits in specific brain regions. However, these studies have primarily focused on neural systems responsible for face processing and social behaviors. Although repetitive, stereotyped behaviors are a hallmark of autism,(More)
In two experimental sessions, we assessed early- and late-onset acoustic startle eyeblink modulation and subjective ratings of emotional pictures by nondepressed participants and by unipolar depressed participants. Depressed participants were assessed before and after treatment with the antidepressant medication Bupropion SR. Both depressed and nondepressed(More)
We tested the prediction that resting frontal brain asymmetry would be a marker of vulnerability for depression among adolescents. Baseline electroencephalographic (EEG) activity was recorded from 12 to 14-year-old adolescents whose mothers had a history of depression (high risk group) and whose mothers were lifetime-free of axis I psychopathology (low risk(More)
Previous studies have demonstrated the ability of the [11C]raclopride positron emission tomography (PET) technique to measure behaviorally induced changes in endogenous dopamine transmission in humans. However, these studies have lacked well matched sensorimotor control conditions, making it difficult to know what sensory, cognitive, or motor features(More)
Although affective modulation of the startle reflex is a highly replicable effect, the majority of studies have administered startle probes during exposure to affective stimuli. To examine more comprehensively the temporal course of startle potentiation, we assessed blink modulation before, during and immediately after exposure to positive, negative and(More)
Autism spectrum disorders are characterized by cognitive control deficits as well as impairments in social interactions. However, the brain mechanisms mediating the interactive effects of these deficits have not been addressed. We employed event-related functional magnetic resonance imaging (fMRI) to examine the effects of processing directional information(More)
Though the functional neural correlates of impaired cognitive control and social dysfunction in autism spectrum disorders (ASD) have been delineated, brain regions implicated in poor cognitive control of social information is a novel area of autism research. We recently reported in a non-clinical sample that detection of 'social oddball' targets activated a(More)