Biomedical subjects

Raymond J Dolan

Publications and source records attributed to Raymond J Dolan.

At least 37 records · Page 2Linked to original sources

PubMed2006

Fear recognition ability predicts differences in social cognitive and neural functioning in men.

By testing the facial fear-recognition ability of 341 men in the general population, we show that 8.8% have deficits akin to those seen with acquired amygdala damage. Using psychological tests and functional magnetic resonance imaging (fMRI) we tested the hypothesis that poor fear recognition would predict deficits in other domains of social cognition and, in response to socially relevant stimuli, abnormal activation in brain regions that putatively reflect engagement of the "social brain." On tests of "theory of mind" ability, 25 "low fear scorers" (LFS) performed significantly worse than 25 age- and IQ-matched "normal (good) fear scorers" (NFS). In fMRI, we compared evoked activity during a gender judgement task to neutral faces portraying different head and eye gaze orientations in 12 NFS and 12 LFS subjects. Despite identical between-group accuracy in gender discrimination, LFS demonstrated significantly reduced activation in amygdala, fusiform gyrus, and anterior superior temporal cortices when viewing faces with direct versus averted gaze. In a functional connectivity analysis, NFS show enhanced connectivity between the amygdala and anterior temporal cortex in the context of direct gaze; this enhanced coupling is absent in LFS. We suggest that important individual differences in social cognitive skills are expressed within the healthy male population, which appear to have a basis in a compromised neural system that underpins social information processing.

Adult↗

PubMed2006

Neural correlates of self-distraction from anxiety and a process model of cognitive emotion regulation.

Cognitive strategies used in volitional emotion regulation include self-distraction and reappraisal (reinterpretation). There is debate as to what the psychological and neurobiological mechanisms underlying these strategies are. For example, it is unclear whether self-distraction and reappraisal, although distinct at a phenomenological level, are also mediated by distinct neural processes. This is partly because imaging studies on reappraisal and self-distraction have been performed in different emotional contexts and are difficult to compare. We have therefore investigated the neural correlates of self-distraction, as indexed by a thought suppression task, in an anticipatory anxiety paradigm previously employed by us to study reappraisal. Brain activity was measured by functional magnetic resonance imaging. We show that self-distraction recruits the left lateral prefrontal cortex. Based on a review of the existing data, we develop a process model of cognitive emotion regulation. The model posits that both self-distraction and reappraisal attenuate emotional reactions through replacement of emotional by neutral mental contents but achieve replacement in different ways. This is associated with a dependence of self-distraction on a left prefrontal production function, whereas reappraisal depends on a right prefrontal higher order monitoring process.

Acoustic Stimulation↗

PubMed2005

Cognitive functioning after medial frontal lobe damage including the anterior cingulate cortex: a preliminary investigation.

Two patients with medial frontal lobe damage involving the anterior cingulate cortex (ACC) performed a range of cognitive tasks, including tests of executive function and anterior attention. Both patients lesions extended beyond the ACC, therefore caution needs to be exerted in ascribing observed deficits to the ACC alone. Patient performance was compared with age and education matched healthy controls. Both patients showed intact intellectual, memory, and language abilities. No clear-cut abnormalities were noted in visuoperceptual functions. Speed of information processing was mildly reduced only in Patient 2 (bilateral ACC lesion). The patients demonstrated weak or impaired performance only on selective executive function tests. Performance on anterior attention tasks was satisfactory. We tentatively suggest that our findings are inconsistent with anterior attention theories of ACC function based on neuroimaging findings. We propose that the data may imply that the ACC does not have a central role in cognition. We speculate that our findings may be compatible with the view that the ACC integrates cognitive processing with autonomic functioning to guide behaviour.

Adult↗

PubMed2005

Emotional and autonomic consequences of spinal cord injury explored using functional brain imaging.

In health, emotions are integrated with autonomic bodily responses. Emotional stimuli elicit changes in somatic (including autonomic) bodily states, which feedback to influence the expression of emotional feelings. In patients with spinal cord injury (SCI), this integration of emotion and bodily arousal is partially disrupted, impairing both efferent generation of sympathetic responses and afferent sensory feedback of visceral state via the spinal cord. A number of theoretical accounts of emotion predict emotional deficits in SCI patients, particularly at the level of emotional feelings, yet evidence for such a deficit is equivocal. We used functional MRI (fMRI) and a basic emotional learning paradigm to investigate the expression of emotion-related brain activity consequent upon SCI. We scanned seven SCI patients and seven healthy controls during an aversive fear conditioning task. Subjects viewed randomized presentations of four angry faces. One of the faces (CS + arm) was associated with delivery of electrical shock to the upper arm on 50% of trials. This shock was painful to all subjects. A face of the same gender acted as a 'safe' control stimulus (CS - arm). In both control subjects and SCI patients, painful cutaneous stimulation of the arm evoked enhanced activity within components of a central pain matrix, including dorsal anterior cingulate, right insula and medial temporal lobe. However, SCI patients differed from controls in conditioning-related brain activity. SCI patients showed a relative enhancement of activity within dorsal anterior cingulate, periaqueductal grey matter (PAG) and superior temporal gyrus. Conversely, SCI patients showed relative attenuation of activity in subgenual cingulate, ventromedial prefrontal and posterior cingulate cortices to threat of painful arm stimulation (CS + arm > CS - arm). Our findings provide evidence for differences in emotion-related brain activity in SCI patients. We suggest that the observed functional abnormalities including enhanced anterior cingulate and PAG reflect central sensitization of the pain matrix, while decreased subgenual cingulate activity may represent a substrate underlying affective vulnerability in SCI patients consequent upon perturbation of autonomic control and afferent visceral representation. Together these observations may account for motivational and affective sequelae of SCI in some individuals.

Anger↗

PubMed2005

Doing the right thing: a common neural circuit for appropriate violent or compassionate behavior.

Humans have a considerable facility to adapt their behavior in a manner that is appropriate to social or societal context. A failure of this ability can lead to social exclusion and is a feature of disorders such as psychopathy and disruptive behavior disorder. We investigated the neural basis of this ability using a customized video game played by 12 healthy participants in an fMRI scanner. Two conditions involved extreme examples of context-appropriate action: shooting an aggressive humanoid assailant or healing a passive wounded person. Two control conditions involved carefully matched stimuli paired with inappropriate actions: shooting the person or healing the assailant. Surprisingly, the same circuit, including the amygdala and ventromedial prefrontal cortex, was activated when participants acted in a context-appropriate manner, whether being compassionate towards an injured conspecific or aggressive towards a violent assailant. The findings indicate a common system that guides behavioral expression appropriate to social or societal context irrespective of its aggressive or compassionate nature.

Adolescent↗

PubMed2005

Contingency awareness in human aversive conditioning involves the middle frontal gyrus.

In contrast to the wealth of data describing the neural mechanisms underlying classical conditioning, we know remarkably little about the mechanisms involved in acquisition of explicit contingency awareness. Subjects variably acquire contingency awareness in classical conditioning paradigms, in which they are able to describe the temporal relationship between a conditioned cue and its outcome. Previous studies have implicated the hippocampus and prefrontal cortex in the acquisition of explicit knowledge, although their specific roles remain unclear. We used functional magnetic resonance imaging to track the trial-by-trial acquisition of explicit knowledge in a concurrent trace and delay conditioning paradigm. We show that activity in bilateral middle frontal gyrus and parahippocampal gyrus correlates with the accuracy of explicit contingency awareness on each trial. In contrast, amygdala activation correlates with conditioned responses indexed by skin conductance responses (SCRs). These results demonstrate that brain regions known to be involved in other aspects of learning and memory also play a specific role, reflecting on each trial the acquisition and representation of contingency awareness.

Adult↗

PubMed2005

Anterior cingulate activity during error and autonomic response.

The contribution of anterior cingulate cortex (ACC) to human cognition remains unclear. The rostral (rACC) and dorsal (dACC) ACC cortex are implicated in tasks that require increased response control due to emotional and cognitive interference, respectively. However, both rACC and dACC are activated by conditions that induce changes in visceral arousal, suggesting that ACC supports a generation of integrated bodily responses. To clarify the relationship between purely cognitive and psychophysiological accounts of ACC function, we scanned 15 subjects using functional magnetic resonance imaging while they performed numerical versions of the Stroop task. To index autonomic arousal, we simultaneously measured pupil diameter. Performance errors accounted for most of the variance in a pupil-derived measure of evoked autonomic arousal. In analysis of the functional imaging data, activity within a region spanning rACC and dACC predicted trial-by-trial variation in autonomic response magnitude and was enhanced during error trials, shown using conjunction analyses. Activity within other loci within rACC predicted evoked autonomic arousal and showed sensitivity to errors but did not meet criteria for both. These data highlight the role of ACC in psychophysiological aspects of error processing and suggest that an interface exists within ACC between cognitive and biobehavioral systems in the service of response adaptation.

Adult↗

PubMed2005

Human neural learning depends on reward prediction errors in the blocking paradigm.

Learning occurs when an outcome deviates from expectation (prediction error). According to formal learning theory, the defining paradigm demonstrating the role of prediction errors in learning is the blocking test. Here, a novel stimulus is blocked from learning when it is associated with a fully predicted outcome, presumably because the occurrence of the outcome fails to produce a prediction error. We investigated the role of prediction errors in human reward-directed learning using a blocking paradigm and measured brain activation with functional magnetic resonance imaging. Participants showed blocking of behavioral learning with juice rewards as predicted by learning theory. The medial orbitofrontal cortex and the ventral putamen showed significantly lower responses to blocked, compared with nonblocked, reward-predicting stimuli. In reward-predicting control situations, deactivation in orbitofrontal cortex and ventral putamen occurred at the time of unpredicted reward omissions. Responses in discrete parts of orbitofrontal cortex correlated with the degree of behavioral learning during, and after, the learning phase. These data suggest that learning in primary reward structures in the human brain correlates with prediction errors in a manner that complies with principles of formal learning theory.

Adult↗

PubMed2005

Integrated neural representations of odor intensity and affective valence in human amygdala.

Arousal and valence are proposed to represent fundamental dimensions of emotion. The neural substrates for processing these aspects of stimuli are studied widely, with recent studies of chemosensory processing suggesting the amygdala processes intensity (a surrogate for arousal) rather than valence. However, these investigations have assumed that a valence effect in the amygdala is linear such that testing valence extremes is sufficient to infer responses across valence space. In this study, we tested an alternative hypothesis, namely that valence responses in the amygdala are nonlinear. Using event-related functional magnetic resonance imaging, we measured amygdala responses to high- and low-concentration variants of pleasant, neutral, and unpleasant odors. Our results demonstrate that the amygdala exhibits an intensity-by-valence interaction in olfactory processing. In other words, the effect of intensity on amygdala activity is not the same at all levels of valence. Specifically, the amygdala responds differentially to high (vs low)-intensity odor for pleasant and unpleasant smells but not for neutral smells. This implies that the amygdala codes neither intensity nor valence per se, but a combination that we suggest reflects the overall emotional value of a stimulus.

Adult↗

PubMed2005

Regret and its avoidance: a neuroimaging study of choice behavior.

Human decisions can be shaped by predictions of emotions that ensue after choosing advantageously or disadvantageously. Indeed, anticipating regret is a powerful predictor of future choices. We measured brain activity using functional magnetic resonance imaging (fMRI) while subjects selected between two gambles wherein regret was induced by providing information about the outcome of the unchosen gamble. Increasing regret enhanced activity in the medial orbitofrontal region, the anterior cingulate cortex and the hippocampus. Notably, across the experiment, subjects became increasingly regret-aversive, a cumulative effect reflected in enhanced activity within medial orbitofrontal cortex and amygdala. This pattern of activity reoccurred just before making a choice, suggesting that the same neural circuitry mediates direct experience of regret and its anticipation. These results demonstrate that medial orbitofrontal cortex modulates the gain of adaptive emotions in a manner that may provide a substrate for the influence of high-level emotions on decision making.

Adult↗

PubMed2005

Modulation of pain processing in hyperalgesia by cognitive demand.

The relationship between pain and cognitive function is of theoretical and clinical interest, exemplified by observations that attention-demanding activities reduce pain in chronically afflicted patients. Previous studies have concentrated on phasic pain, which bears little correspondence to clinical pain conditions. Indeed, phasic pain is often associated with differential or opposing effects to tonic pain in behavioral, lesion, and pharmacological studies. To address how cognitive engagement interacts with tonic pain, we assessed the influence of an attention-demanding cognitive task on pain-evoked neural responses in an experimental model of chronic pain, the capsaicin-induced heat hyperalgesia model. Using functional magnetic resonance imaging (fMRI), we show that activity in the orbitofrontal and medial prefrontal cortices, insula, and cerebellum correlates with the intensity of tonic pain. This pain-related activity in medial prefrontal cortex and cerebellum was modulated by the demand level of the cognitive task. Our findings highlight a role for these structures in the integration of motivational and cognitive functions associated with a physiological state of injury. Within the limitations of an experimental model of pain, we suggest that the findings are relevant to understanding both the neurobiology and pathophysiology of chronic pain and its amelioration by cognitive strategies.

Adult↗

PubMed2005

Noradrenergic modulation of emotion-induced forgetting and remembering.

We used a free-recall paradigm to establish a behavioral index of the retrograde and anterograde interference of emotion with episodic memory encoding. In two experiments involving 78 subjects, we show that negatively valenced items elicit retrograde amnesia, whereas positively valenced items elicit retrograde hypermnesia. These data indicate item valence is critical in determining retrograde amnesia and retrograde hypermnesia. In contrast, we show that item arousal induces an anterograde amnesic effect, consistent with the idea that a valence-evoked arousal mechanism compromises anterograde episodic encoding. Randomized double-blind administration of the beta-adrenoceptor antagonist propranolol compared with the selective norepinephrine (NE) reuptake-inhibitor reboxetine, and placebo, demonstrated that the magnitude of this emotional amnesia and hypermnesia can be upregulated and downregulated as a function of emotional arousal and central NE signaling. We conclude that a differential processing of emotional arousal and valence influences how the brain remembers and forgets.

Adrenergic Uptake Inhibitors↗

PubMed2005

Information theory, novelty and hippocampal responses: unpredicted or unpredictable?

Shannon's information theory provides a principled framework for the quantitative analysis of brain responses during the encoding and representation of event streams. In particular, entropy measures the expected uncertainty of events in a given context. This contextual uncertainty or unpredictability may, itself, be important for balancing [bottom-up] sensory information and [top-down] prior expectations during perceptual synthesis. Using event-related functional magnetic resonance imaging (fMRI), we found that the anterior hippocampus is sensitive to the entropy of a visual stimulus stream. In contrast, activity in an extensive bilateral cortico-thalamic network was dictated by the surprise or information associated with each particular stimulus. In short, we show that the probabilistic structure or context in which events occur is an important predictor of hippocampal activity.

Adult↗

PubMed2005

Dissociating intentional learning from relative novelty responses in the medial temporal lobe.

The establishment of a role for medial temporal lobe (MTL) structures in episodic memory has led to an investigative focus on the specific contributions and interactions between constituent MTL regions, including the hippocampus and surrounding medial temporal cortices. By dissociating an intentional stimulus-category learning condition from a passive viewing condition, we demonstrate, using fMRI, that novelty- and familiarity-driven responses in human anterior and posterior hippocampus, respectively, only occur during intentional learning. With increasing familiarity of stimulus-category associations, there is a shift in neuronal responses from anterior to posterior hippocampal regions. This anterior/posterior response gradient may reflect a weighting of functional hippocampal architecture related to encoding of novel and retrieval of familiar information. By contrast, perirhinal cortex is engaged by novel stimuli irrespective of task, highlighting this region as a component of a generic familiarity discrimination system. By introducing distinct stimulus types, we further demonstrate that these MTL responses are independent of stimulus complexity. Different patterns of activity for intentional learning vs. passive viewing indicate that intentional encoding/retrieval of stimulus-category associations and automatic novelty/familiarity assessment of stimuli are processed in anatomically dissociable neuronal ensembles within the MTL memory system.

Adult↗

PubMed2005

Neurophysiological correlates of increased verbal working memory in high-dissociative participants: a functional MRI study.

BACKGROUND: Dissociation, defined as a disruption in usually integrated mental functions, is found not only in DSM-IV dissociative disorders, but also in post-traumatic stress disorder and eating disorders. Dissociative phenomena are also common in the general population, and may reflect a constitutionally determined cognitive style rather than a pathological trait acquired through experiencing adverse life events. In pathological dissociation, evidence has been presented for episodic memory dysfunction. In contrast, in high-dissociative subjects increased performance has been found for episodic memory and dual task performance. These findings have been linked to changes in working memory capacity. METHOD: In the present study, the authors sought to extend these findings by using functional magnetic resonance imaging during performance of two parametric working memory tasks. We tested 21 healthy low- and high-dissociative participants. RESULTS: High-dissociative participants performed slightly better during both tasks. Imaging data showed that both groups activated similar networks for both tasks, i.e. (bilateral) dorsolateral (DL) and ventrolateral prefrontal cortex (PFC), parietal cortex, and supplementary motor area. Group x task interactions were found in the high-dissociative group in L DLPFC and L parietal cortex; in the low-dissociative group in R fusiform gyrus. The differences in the high-dissociative group were independent from performance differences, implying that high-dissociative subjects generally recruit this network to a greater extent. CONCLUSIONS: These results confirm earlier findings using a verbal WM task in high-dissociative participants, and are compatible with the conceptualization of non-pathological dissociation as an information-processing style, characterized by distinct attentional and mnemonic abilities.

Adult↗

PubMed2005

Changes in brain activity following sacral neuromodulation for urinary retention.

PURPOSE: Sacral nerve stimulation (neuromodulation) can restore bladder sensation and the ability to void in women with urinary retention due to sphincter overactivity (Fowler's syndrome). Modulation of central afferent activity is considered critical to this therapeutic effect but the neural mechanisms are poorly understood. Therefore, we undertook a functional brain imaging study to determine how neuromodulation acts on brain centers involved in the representation and control of bladder function. MATERIALS AND METHODS: Eight patients with Fowler's syndrome and 8 healthy controls underwent brain imaging with positron emission tomography to identify regions of brain activity relating to the perception of bladder fullness and their modulation by sacral nerve stimulation. RESULTS: In healthy controls bladder fullness enhanced activity in brainstem (midbrain) and limbic cortical regions. Women with urinary retention showed no significant brainstem activity but did show enhanced limbic cortical activity when the bladder was full in the absence of neuromodulation. Neuromodulation restored a normal pattern of midbrain activity and decreased cortical activity in this group. CONCLUSIONS: Our study provides novel neuroimaging evidence for the existence of abnormal interaction between brainstem and cortical centers in women with urinary retention. Furthermore, we have been able to show evidence that the therapeutic effect of sacral neuromodulation is achieved through restoration of activity associated with brainstem autoregulation and attenuation of cingulate activity.

Adult↗

PubMed2005

Anxiety reduction through detachment: subjective, physiological, and neural effects.

The ability to volitionally regulate emotions helps to adapt behavior to changing environmental demands and can alleviate subjective distress. We show that a cognitive strategy of detachment attenuates subjective and physiological measures of anticipatory anxiety for pain and reduces reactivity to receipt of pain itself. Using functional magnetic resonance imaging, we locate the potential site and source of this modulation of anticipatory anxiety in the medial prefrontal/anterior cingulate and anterolateral prefrontal cortex, respectively.

Adaptation, Psychological↗

PubMed2005

Selective attention modulates neural substrates of repetition priming and "implicit" visual memory: suppressions and enhancements revealed by FMRI.

Attention can enhance processing for relevant information and suppress this for ignored stimuli. However, some residual processing may still arise without attention. Here we presented overlapping outline objects at study, with subjects attending to those in one color but not the other. Attended objects were subsequently recognized on a surprise memory test, whereas there was complete amnesia for ignored items on such direct explicit testing; yet reliable behavioral priming effects were found on indirect testing. Event-related fMRI examined neural responses to previously attended or ignored objects, now shown alone in the same or mirror-reversed orientation as before, intermixed with new items. Repetition-related decreases in fMRI responses for objects previously attended and repeated in the same orientation were found in the right posterior fusiform, lateral occipital, and left inferior frontal cortex. More anterior fusiform regions also showed some repetition decreases for ignored objects, irrespective of orientation. View-specific repetition decreases were found in the striate cortex, particularly for previously attended items. In addition, previously ignored objects produced some fMRI response increases in the bilateral lingual gyri, relative to new objects. Selective attention at exposure can thus produce several distinct long-term effects on processing of stimuli repeated later, with neural response suppression stronger for previously attended objects, and some response enhancement for previously ignored objects, with these effects arising in different brain areas. Although repetition decreases may relate to positive priming phenomena, the repetition increases for ignored objects shown here for the first time might relate to processes that can produce "negative priming" in some behavioral studies. These results reveal quantitative and qualitative differences between neural substrates of long-term repetition effects for attended versus unattended objects.

Adult↗