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Functional magnetic resonance imaging (fMRI) of the human brain was used to study whether the amygdala is activated in response to emotional stimuli, even in the absence of explicit knowledge that such stimuli were presented. Pictures of human faces bearing fearful or happy expressions were presented to 10 normal, healthy subjects by using a backward(More)
BACKGROUND Extinction of conditioned fear is thought to form a new safety memory that is expressed in the context in which the extinction learning took place. Rodent studies implicate the ventromedial prefrontal cortex (vmPFC) and hippocampus in extinction recall and its modulation by context, respectively. The aim of the present study is to investigate the(More)
We measured amygdala activity in human volunteers during rapid visual presentations of fearful, happy, and neutral faces using functional magnetic resonance imaging (fMRI). The first experiment involved a fixed order of conditions both within and across runs, while the second one used a fully counterbalanced order in addition to a low level baseline of(More)
There is at present limited understanding of the neurobiological basis of the different processes underlying emotion perception. We have aimed to identify potential neural correlates of three processes suggested by appraisalist theories as important for emotion perception: 1) the identification of the emotional significance of a stimulus; 2) the production(More)
We used positron emission tomography (PET) to examine the role of the hippocampal formation in implicit and explicit memory. Human volunteers studied a list of familiar words, and then they either provided the first word that came to mind in response to three-letter cues (implicit memory) or tried to recall studied words in response to the same cues(More)
To date, there has been little investigation of the neurobiological basis of emotion processing abnormalities in psychiatric populations. We have previously discussed two neural systems: 1) a ventral system, including the amygdala, insula, ventral striatum, ventral anterior cingulate gyrus, and prefrontal cortex, for identification of the emotional(More)
The anterior cingulate cortex has been activated by color Stroop tasks, supporting the hypothesis that it is recruited to mediate response selection or allocate attentional resources when confronted with competing information-processing streams. The current study used the newly developed "Counting Stroop" to identify the mediating neural substrate of(More)
BACKGROUND A clinical characteristic of posttraumatic stress disorder (PTSD) is persistently elevated fear responses to stimuli associated with the traumatic event. The objective herein is to determine whether extinction of fear responses is impaired in PTSD and whether such impairment is related to dysfunctional activation of brain regions known to be(More)
BACKGROUND The anterior cingulate cognitive division (ACcd) plays a central role in attentional processing by: 1) modulating stimulus selection (i.e., focusing attention) and/or 2) mediating response selection. We hypothesized that ACcd dysfunction might therefore contribute to producing core features of attention-deficit/hyperactivity disorder (ADHD),(More)
BACKGROUND The emotional counting Stroop (ecStroop) functional magnetic resonance imaging (fMRI) activation paradigm was designed to recruit the anterior cingulate affective division (ACad). METHODS Nine normal, healthy male and female subjects (mean age 24.2 years) reported via button press the number of neutral and negative words that appeared on a(More)