Neural correlates of response reversal: considering acquisition.
ABSTRACT Previous work on response reversal has typically used a single pair of stimuli that serially reverse. This conflation of acquisition and reversal processes has prevented an examination of the functional role of neural systems implicated in response reversal during acquisition despite the relevance of such data in evaluating accounts of response reversal. In the current study, participants encountered 16 independent reversing stimulus pairs in the context of a probabilistic response reversal paradigm. Functional regions of interest identified as involved in response reversal through a contrast used in the previous literature (punished errors made in the reversal phase versus rewarded correct responses), were interrogated across conditions. Consistent with suggestions that middle frontal cortex codes reward, this region showed significantly greater responses to rewarded rather than punished trials irrespective of accuracy or learning phase (acquisition or reversal). Consistent with the suggestion that this coding of the expectation of reinforcement is acquired via input from the amygdala, we observed significant positive connectivity between activity within the amygdala and a region of rostral anterior cingulate cortex highly proximal to this region of middle frontal/mesial prefrontal cortex. In contrast, inferior frontal cortex, anterior cingulate cortex and caudate showed greater responses to punished errors than to the rewarded correct responses. These three regions also showed significant activation to rewarded errors during acquisition, in contrast to positions suggesting that inferior frontal cortex represents punishment or suppresses previously rewarded responses. Moreover, a connectivity analysis with an anterior cingulate cortex seed revealed highly significant positive connectivity among them. The implications of these data for recent accounts of response reversal and of response reversal impairments in specific neuropsychiatric populations are discussed.
- SourceAvailable from: Derek G V Mitchell[Show abstract] [Hide abstract]
ABSTRACT: Top-down attentional control is necessary to ensure successful task performance in the presence of distracters. Lateral prefrontal cortex, parietal cortex and anterior cingulate cortex have been previously implicated in top-down attentional control. However, it is unclear whether these regions are engaged independent of distracter type or whether, as has been suggested for anterior cingulate cortex, different regions provide attentional control over emotional versus other forms of salient distracter. In the current task, subjects viewed targets that were preceded by distracters that varied in both emotionality and visibility. We found that behaviorally, the presence of preceding distracters significantly interfered with target judgment. At the neural level, increases in the emotional and visual saliency of distracters were both associated with increased activity in proximal regions of prefrontal, parietal and cingulate cortex. Moreover, a conjunction analysis indicated considerable overlap in the regions of prefrontal, parietal cortex and anterior cingulate cortex responding to distracters of increased emotionality and visibility.NeuroImage 12/2007; 38(3):631-9. DOI:10.1016/j.neuroimage.2007.07.051 · 6.13 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Across a range of mammalian species, early developmental variations in fear-related behaviors constrain patterns of anxious behavior throughout life. Individual differences in anxiety among rodents and non-human primates have been shown to reflect early-life influences of genes and the environment on brain circuitry. However, in humans, the manner in which genes and the environment developmentally shape individual differences in anxiety and associated brain circuitry remains poorly specified. The current review presents a conceptual framework that facilitates clinical research examining developmental influences on brain circuitry and anxiety. Research using threat-exposure paradigms might most directly integrate basic and clinical perspectives on pediatric anxiety.Journal of Child Psychology and Psychiatry 08/2007; 48(7):631-48. DOI:10.1111/j.1469-7610.2007.01751.x · 5.67 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: The processing of the emotional signals of others is fundamental for normal socialization and interaction. Reduced responsiveness to the expressions of sadness and fear has been implicated in the development of psychopathy (Blair, 1995). The current study investigates the ability of boys with psychopathic tendencies to process auditory affect information. Boys with psychopathic tendencies and a comparison group, as defined by the Antisocial Process Screening Device (APSD: Frick & Hare, 2001), were presented with neutral words spoken with intonations conveying happiness, disgust, anger, sadness and fear and were asked to identify the emotion of the speaker based on prosody. The boys with psychopathic tendencies presented with a selective impairment for the recognition of fearful vocal affect. These results are interpreted with reference to amygdala dysfunction and components of the Integrated Emotion Systems model.Journal of Child Psychology and Psychiatry 03/2005; 46(3):327-36. DOI:10.1111/j.1469-7610.2004.00356.x · 5.67 Impact Factor