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Ronald E. Dahl
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Journal Articles
Publisher: Journals Gateway
Journal of Cognitive Neuroscience (2016) 28 (2): 199–209.
Published: 01 February 2016
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The onset of adolescence is associated with an increase in the behavioral tendency to explore and seek novel experiences. However, this exploration has rarely been quantified, and its neural correlates during this period remain unclear. Previously, activity within specific regions of the rostrolateral PFC (rlPFC) in adults has been shown to correlate with the tendency for exploration. Here we investigate a recently developed task to assess individual differences in strategic exploration, defined as the degree to which the relative uncertainty of rewards directs responding toward less well-evaluated choices, in 62 girls aged 11–13 years from whom resting state fMRI data were obtained in a separate session. Behaviorally, this task divided our participants into groups of explorers ( n = 41) and nonexplorers ( n = 21). When seed ROIs within the rlPFC were used to interrogate resting state fMRI data, we identified a lateralized connection between the rlPFC and posterior putamen/insula whose strength differentiated explorers from nonexplorers. On the basis of Granger causality analyses, the preponderant direction of influence may proceed from posterior to anterior. Together, these data provide initial evidence concerning the neural basis of exploratory tendencies at the onset of adolescence.
Journal Articles
Publisher: Journals Gateway
Journal of Cognitive Neuroscience (1997) 9 (6): 835–847.
Published: 01 November 1997
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This study examines important developmental differences in patterns of activation in the prefrontal cortex during performance of a Go-No-Go paradigm using functional magnetic resonance imaging (fMRI). Eighteen subjects (9 children and 9 adults) were scanned using gradient echo, echo planar imaging during performance of a response inhibition task. The results suggest four general findings. First, the location of activation in the prefrontal cortex was not different between children and adults, which is similar to our earlier pediatric fMRI results of prefrontal activation during a working memory task (Casey et al., 1995). Second, the volume of activation was significantly greater for children relative to adults. These differences in volume of activation were observed predominantly in the dorsal and lateral prefrontal cortices. Third, although inhibitory processes have typically been associated with more ventral or orbital frontal regions, the current study revealed activation that was distributed across both dorsolateral and orbitofrontal cortices. Finally, consistent with animal and human lesion studies, activity in orbital frontal and anterior cingulate cortices correlated with behavioral performance (i.e., number of false alarms). These results further demonstrate the utility of this methodology in studying pediatric populations.