Clayton Eccard - Academia.edu (original) (raw)
Papers by Clayton Eccard
Neuroimage, 2000
Seven healthy adult subjects were scanned while performing a hanker task (1). Subjects were instr... more Seven healthy adult subjects were scanned while performing a hanker task (1). Subjects were instructed to press the left key if the center stimulus (>) was pointing left and the right key if the center stimulus was pointing right. Compatible and incompatible flankers were presented on either side of the target stimulus (e.g., >>> > >>>). The predictive value of the flankers was manipulated by block such that predictive blocks consisted of 70% compatible and 30% incompatible flankers, and nonpredictive blocks consisted of 30% compatible and 70% incompatible flankers. The behavioral results showed that during the predictive condition subjects had more difficulty on incompatible trials than during the nonpredictive condition (514 msec and 91% accuracy vs. 505 msec and 96%, CCIICCII cclIcc1l
Proceedings of The National Academy of Sciences, 2000
Two different attentional networks have been associated with visuospatial attention and conflict ... more Two different attentional networks have been associated with visuospatial attention and conflict resolution. In most situations either one of the two networks is active or both are increased in activity together. By using functional magnetic resonance imaging and a flanker task, we show conditions in which one network (anterior attention system) is increased in activity whereas the other (visuospatial attention system) is reduced, showing that attentional conflict and selection are separate aspects of attention. Further, we distinguish between neural systems involved in different forms of conflict. Specifically, we dissociate patterns of activity in the basal ganglia and insula cortex during simple violations in expectancies (i.e., sudden changes in the frequency of an event) from patterns of activity in the anterior attention system specifically correlated with response conflict as evidenced by longer response latencies and more errors. These data provide a systems-level approach in understanding integrated attentional networks.
Biological Psychiatry, 1999
Background: This investigation examined the relationship between trauma, psychiatric symptoms and... more Background: This investigation examined the relationship between trauma, psychiatric symptoms and urinary free cortisol (UFC) and catecholamine (epinephrine [EPI], norepinephrine [NE], dopamine [DA]) excretion in prepubertal children with posttraumatic stress disorder (PTSD) secondary to past child maltreatment experiences (n ϭ 18), compared to non-traumatized children with overanxious disorder (OAD) (n ϭ 10) and healthy controls (n ϭ 24).
Archives of General Psychiatry, 2001
Background: Alterations in amygdala function have been implicated in the pathophysiological chara... more Background: Alterations in amygdala function have been implicated in the pathophysiological characteristics of adult anxiety and depressive disorders. Studies with healthy adults and children, as well as with adults who have amygdala lesions, have found facial expressions of emotion to be useful probes of amygdala activity. Our study examined the amygdala response to fearful and neutral facial expressions in healthy, anxious, and depressed children. We hypothesized that children with anxiety and depression may show atypical amygdala responses to emotional stimuli.
Biological Psychiatry, 2001
Background: The amygdala plays a central role in the human response to affective or emotionally c... more Background: The amygdala plays a central role in the human response to affective or emotionally charged stimuli, particularly fear-producing stimuli. We examined the specificity of the amygdala response to facial expressions in adults and children.Methods: Six adults and 12 children were scanned in a 1.5-T scanner during passive viewing of fearful and neutral faces using an EPI BOLD sequence. All scans were registered to a reference brain, and analyses of variance were conducted on the pooled data to examine interactions with age and gender.Results: Overall, we observed predominantly left amygdala and substantia innominata activity during the presentation of nonmasked fearful faces relative to fixation, and a decrease in activation in these regions with repeated exposure to the faces. Adults showed increased left amygdala activity for fearful faces relative to neutral faces. This pattern was not observed in the children who showed greater amygdala activity with neutral faces than with fearful faces. For the children, there was an interaction of gender and condition whereby boys but not girls showed less activity with repeated exposure to the fearful faces.Conclusions: This is the first study to examine developmental differences in the amygdala response to facial expressions using functional magnetic resonance imaging.
Proceedings of The National Academy of Sciences, 2000
Two different attentional networks have been associated with visuospatial attention and conflict ... more Two different attentional networks have been associated with visuospatial attention and conflict resolution. In most situations either one of the two networks is active or both are increased in activity together. By using functional magnetic resonance imaging and a flanker task, we show conditions in which one network (anterior attention system) is increased in activity whereas the other (visuospatial attention system) is reduced, showing that attentional conflict and selection are separate aspects of attention. Further, we distinguish between neural systems involved in different forms of conflict. Specifically, we dissociate patterns of activity in the basal ganglia and insula cortex during simple violations in expectancies (i.e., sudden changes in the frequency of an event) from patterns of activity in the anterior attention system specifically correlated with response conflict as evidenced by longer response latencies and more errors. These data provide a systems-level approach in understanding integrated attentional networks.
Neuroimage, 2000
Seven healthy adult subjects were scanned while performing a hanker task (1). Subjects were instr... more Seven healthy adult subjects were scanned while performing a hanker task (1). Subjects were instructed to press the left key if the center stimulus (>) was pointing left and the right key if the center stimulus was pointing right. Compatible and incompatible flankers were presented on either side of the target stimulus (e.g., >>> > >>>). The predictive value of the flankers was manipulated by block such that predictive blocks consisted of 70% compatible and 30% incompatible flankers, and nonpredictive blocks consisted of 30% compatible and 70% incompatible flankers. The behavioral results showed that during the predictive condition subjects had more difficulty on incompatible trials than during the nonpredictive condition (514 msec and 91% accuracy vs. 505 msec and 96%, CCIICCII cclIcc1l
Proceedings of The National Academy of Sciences, 2000
Two different attentional networks have been associated with visuospatial attention and conflict ... more Two different attentional networks have been associated with visuospatial attention and conflict resolution. In most situations either one of the two networks is active or both are increased in activity together. By using functional magnetic resonance imaging and a flanker task, we show conditions in which one network (anterior attention system) is increased in activity whereas the other (visuospatial attention system) is reduced, showing that attentional conflict and selection are separate aspects of attention. Further, we distinguish between neural systems involved in different forms of conflict. Specifically, we dissociate patterns of activity in the basal ganglia and insula cortex during simple violations in expectancies (i.e., sudden changes in the frequency of an event) from patterns of activity in the anterior attention system specifically correlated with response conflict as evidenced by longer response latencies and more errors. These data provide a systems-level approach in understanding integrated attentional networks.
Biological Psychiatry, 1999
Background: This investigation examined the relationship between trauma, psychiatric symptoms and... more Background: This investigation examined the relationship between trauma, psychiatric symptoms and urinary free cortisol (UFC) and catecholamine (epinephrine [EPI], norepinephrine [NE], dopamine [DA]) excretion in prepubertal children with posttraumatic stress disorder (PTSD) secondary to past child maltreatment experiences (n ϭ 18), compared to non-traumatized children with overanxious disorder (OAD) (n ϭ 10) and healthy controls (n ϭ 24).
Archives of General Psychiatry, 2001
Background: Alterations in amygdala function have been implicated in the pathophysiological chara... more Background: Alterations in amygdala function have been implicated in the pathophysiological characteristics of adult anxiety and depressive disorders. Studies with healthy adults and children, as well as with adults who have amygdala lesions, have found facial expressions of emotion to be useful probes of amygdala activity. Our study examined the amygdala response to fearful and neutral facial expressions in healthy, anxious, and depressed children. We hypothesized that children with anxiety and depression may show atypical amygdala responses to emotional stimuli.
Biological Psychiatry, 2001
Background: The amygdala plays a central role in the human response to affective or emotionally c... more Background: The amygdala plays a central role in the human response to affective or emotionally charged stimuli, particularly fear-producing stimuli. We examined the specificity of the amygdala response to facial expressions in adults and children.Methods: Six adults and 12 children were scanned in a 1.5-T scanner during passive viewing of fearful and neutral faces using an EPI BOLD sequence. All scans were registered to a reference brain, and analyses of variance were conducted on the pooled data to examine interactions with age and gender.Results: Overall, we observed predominantly left amygdala and substantia innominata activity during the presentation of nonmasked fearful faces relative to fixation, and a decrease in activation in these regions with repeated exposure to the faces. Adults showed increased left amygdala activity for fearful faces relative to neutral faces. This pattern was not observed in the children who showed greater amygdala activity with neutral faces than with fearful faces. For the children, there was an interaction of gender and condition whereby boys but not girls showed less activity with repeated exposure to the fearful faces.Conclusions: This is the first study to examine developmental differences in the amygdala response to facial expressions using functional magnetic resonance imaging.
Proceedings of The National Academy of Sciences, 2000
Two different attentional networks have been associated with visuospatial attention and conflict ... more Two different attentional networks have been associated with visuospatial attention and conflict resolution. In most situations either one of the two networks is active or both are increased in activity together. By using functional magnetic resonance imaging and a flanker task, we show conditions in which one network (anterior attention system) is increased in activity whereas the other (visuospatial attention system) is reduced, showing that attentional conflict and selection are separate aspects of attention. Further, we distinguish between neural systems involved in different forms of conflict. Specifically, we dissociate patterns of activity in the basal ganglia and insula cortex during simple violations in expectancies (i.e., sudden changes in the frequency of an event) from patterns of activity in the anterior attention system specifically correlated with response conflict as evidenced by longer response latencies and more errors. These data provide a systems-level approach in understanding integrated attentional networks.