Bruce N. Cuthbert

Emotion, attention, and the startle reflex.

This theoretical model of emotion is based on research using the startle-probe methodology. It explains inconsistencies in probe studies of attention and fear conditioning and provides a new approach to emotional perception, imagery, and memory. Emotions are organized biphasically, as appetitive or aversive (defensive). Reflexes with the same valence as an ongoing emotional state are augmented; mismatched reflexes are inhibited. Thus, the startle response (an aversive reflex) is enhanced during a fear state and is diminished in a pleasant emotional context. This affect-startle effect is not determined by general arousal, simple attention, or probe modality. The effect is found when affects are prompted by pictures or memory images, changes appropriately with aversive conditioning, and may be dependent on right-hemisphere processing. Implications for clinical, neurophysiological, and basic research in emotion are outlined.

Brain potentials in affective picture processing: covariation with autonomic arousal and affective report

Emotionally arousing picture stimuli evoked scalp-recorded event-related potentials. A late, slow positive voltage change was observed, which was significantly larger for affective than neutral stimuli. This positive shift began 200-300 ms after picture onset, reached its maximum amplitude approximately 1 s after picture onset, and was sustained for most of a 6-s picture presentation period. The positive increase was not related to local probability of content type, but was accentuated for pictures that prompted increased autonomic responses and reports of greater affective arousal (e.g. erotic or violent content). These results suggest that the late positive wave indicates a selective processing of emotional stimuli, reflecting the activation of motivational systems in the brain.

Toward the future of psychiatric diagnosis: the seven pillars of RDoC

BackgroundCurrent diagnostic systems for mental disorders rely upon presenting signs and symptoms, with the result that current definitions do not adequately reflect relevant neurobiological and behavioral systems - impeding not only research on etiology and pathophysiology but also the development of new treatments.DiscussionThe National Institute of Mental Health began the Research Domain Criteria (RDoC) project in 2009 to develop a research classification system for mental disorders based upon dimensions of neurobiology and observable behavior. RDoC supports research to explicate fundamental biobehavioral dimensions that cut across current heterogeneous disorder categories. We summarize the rationale, status and long-term goals of RDoC, outline challenges in developing a research classification system (such as construct validity and a suitable process for updating the framework) and discuss seven distinct differences in conception and emphasis from current psychiatric nosologies.SummaryFuture diagnostic systems cannot reflect ongoing advances in genetics, neuroscience and cognitive science until a literature organized around these disciplines is available to inform the revision efforts. The goal of the RDoC project is to provide a framework for research to transform the approach to the nosology of mental disorders.

Affective picture processing : the late positive potential is modulated by motivational relevance

Recent studies have shown that the late positive component of the event-related-potential (ERP) is enhanced for emotional pictures, presented in an oddball paradigm, evaluated as distant from an established affective context. In other research, with context-free, random presentation, affectively intense pictures (pleasant and unpleasant) prompted similar enhanced ERP late positivity (compared with the neutral picture response). In an effort to reconcile interpretations of the late positive potential (LPP), ERPs to randomly ordered pictures were assessed, but using the faster presentation rate, brief exposure (1.5 s), and distinct sequences of six pictures, as in studies using an oddball based on evaluative distance. Again, results showed larger LPPs to pleasant and unpleasant pictures, compared with neutral pictures. Furthermore, affective pictures of high arousal elicited larger LPPs than less affectively intense pictures. The data support the view that late positivity to affective pictures is modulated both by their intrinsic motivational significance and the evaluative context of picture presentation.

Emotion, motivation, and anxiety: brain mechanisms and psychophysiology

The organization of response systems in emotion is founded on two basic motive systems, appetitive and defensive. The subcortical and deep cortical structures that determine primary motivated behavior are similar across mammalian species. Animal research has illuminated these neural systems and defined their reflex outputs. Although motivated behavior is more complex and varied in humans, the simpler underlying response patterns persist in affective expression. These basic phenomena are elucidated here in the context of affective perception. Thus, the research examines human beings watching uniquely human stimuli--primarily picture media (but also words and sounds) that prompt emotional arousal--showing how the underlying motivational structure is apparent in the organization of visceral and behavioral responses, in the priming of simple reflexes, and in the reentrant processing of these symbolic representations in the sensory cortex. Implications of the work for understanding pathological emotional states are discussed, emphasizing research on psychopathy and the anxiety disorders.

Emotional arousal and activation of the visual cortex: An fMRI analysis

Functional activity in the visual cortex was assessed using functional magnetic resonance imaging technology while participants viewed a series of pleasant, neutral, or unpleasant pictures. Coronal images at four different locations in the occipital cortex were acquired during each of eight 12-s picture presentation periods (on) and 12-s interpicture interval (off). The extent of functional activation was larger in the right than the left hemisphere and larger in the occipital than in the occipitoparietal regions during processing of all picture contents compared with the interpicture intervals. More importantly, functional activity was significantly greater in all sampled brain regions when processing emotional (pleasant or unpleasant) pictures than when processing neutral stimuli. In Experiment 2, a hypothesis that these differences were an artifact of differential eye movements was ruled out. Whereas both emotional and neutral pictures produced activity centered on the calcarine fissure (Area 17), only emotional pictures also produced sizable clusters bilaterally in the occipital gyrus, in the right fusiform gyrus, and in the right inferior and superior parietal lobules.

Developing constructs for psychopathology research: Research domain criteria.

There exists a divide between findings from integrative neuroscience and clinical research focused on mechanisms of psychopathology. Specifically, a clear correspondence does not emerge between clusters of complex clinical symptoms and dysregulated neurobiological systems, with many apparent redundancies. For instance, many mental disorders involve multiple disruptions in putative mechanistic factors (e.g., excessive fear, deficient impulse control), and different disrupted mechanisms appear to play major roles in many disorders. The Research Domain Criteria (RDoC) framework is a heuristic to facilitate the incorporation of behavioral neuroscience in the study of psychopathology. Such integration might be achieved by shifting the central research focus of the field away from clinical description to more squarely examine aberrant mechanisms. RDoC first aims to identify reliable and valid psychological and biological mechanisms and their disruptions, with an eventual goal of understanding how anomalies in these mechanisms drive psychiatric symptoms. This approach will require new methods to ascertain samples, relying on hypothesized psychopathological mechanisms to define experimental groups instead of traditional diagnostic categories. RDoC, by design, uncouples research efforts from clinically familiar categories to focus directly on fundamental mechanisms of psychopathology. RDoC proposes a matrix of domains and levels of analyses and invites the field to test and refine the framework. If RDoC is successful, the domains will ultimately relate to familiar psychopathologies in ways that promote new knowledge regarding etiology and more efficient development of new preventive and treatment interventions.

Emotion in the criminal psychopath : fear image processing

We tested the hypothesis that the response mobilization that normally accompanies imagery of emotional situations is deficient in psychopaths. Cardiac, electrodermal, and facial muscle responses of 54 prisoners, assigned to low- and high-psychopathy groups using R. D. Hares (1991) Psychopathy Checklist--Revised, were recorded while subjects imagined fearful and neutral scenes in a cued sentence-processing task. Groups did not differ on self-ratings of fearfulness, imagery ability, or imagery experience. Low-psychopathy subjects showed larger physiological reactions during fearful imagery than high-psychopathy subjects. Extreme scores on the antisocial behavior factor of psychopathy predicted imagery response deficits. Results are consistent with the idea that semantic and emotional processes are dissociated in psychopaths.

Brain processes in emotional perception: Motivated attention

Brain potentials and blink reflexes were recorded while participants viewed emotional pictures organised into content categories that varied in motivational significance. Event‐related potentials at picture onset showed the largest late positive potentials to erotic scenes and to scenes of threat and mutilation, suggesting heightened attention to contents that are presumed to strongly activate appetitive and defensive motivational systems. Erotic content also showed the greatest sustained attention over the viewing interval as measured by the inhibition of the P3 component of the event‐related potential to the late interval startle probe. Among pleasant contents, probe P3 amplitude was inversely related to reported arousal; however, P3 was similarly inhibited across all unpleasant contents. Replicating previous findings, greatest modulation of the startle reflex occurred when participants viewed pictures depicting threat, violent death, and erotica. Overall, the data were seen as consistent with a motivated attention model of emotional perception.

Emotion, novelty, and the startle reflex: habituation in humans.

Previous research with both animal and human subjects has shown that startle reflex magnitude is potentiated in an aversive stimulus context, relative to responses elicited in a neutral or appetitive context. In the present experiment, the same pleasant, unpleasant, and neutral picture stimuli were repeatedly presented to human subjects. Startle reflex habituation was assessed in each stimulus context and was compared with the habituation patterns of heart rate, electrodermal, and facial corrugator muscle responses. All systems showed initial differentiation among affective picture contents and general habituation over trials. The startle reflex alone, however, continued to differentiate among pleasant, neutral, and unpleasant pictures throughout the presentation series. These results suggest that (a) the startle probe reflex is relatively uninfluenced by stimulus novelty, (b) the startle modulatory circuit (identified with amygdala-reticular connections in animals) varies systematically with affective valence, and (c) the modulatory influence is less subject to habituation than is the obligatory startle pathway or responses in other somatic and autonomic systems.