Barnaby D. Dunn

Early Detection and Differential Diagnosis of Alzheimer’s Disease and Depression with Neuropsychological Tasks

The development of novel treatments for Alzheimer’s disease (AD), aimed at ameliorating symptoms and modifying disease processes, increases the need for early diagnosis. Neuropsychological deficits such as poor episodic memory are a consistent feature of early-in-the-course AD, but they overlap with the cognitive impairments in other disorders such as depression, making differential diagnosis difficult. Computerised and traditional tests of memory, attention and executive function were given to four subject groups: mild AD (n = 26); questionable dementia (QD; n = 43); major depression (n = 37) and healthy controls (n = 39). A visuo-spatial associative learning test accurately distinguished AD from depressed/control subjects and revealed an apparent sub-group of QD patients who performed like AD patients. QD patients’ performance correlated with the degree of subsequent global cognitive decline. Elements of contextual and cued recall may account for the task’s sensitivity and specificity for AD.

Listening to Your Heart How Interoception Shapes Emotion Experience and Intuitive Decision Making

Theories proposing that how one thinks and feels is influenced by feedback from the body remain controversial. A central but untested prediction of many of these proposals is that how well individuals can perceive subtle bodily changes (interoception) determines the strength of the relationship between bodily reactions and cognitive-affective processing. In Study 1, we demonstrated that the more accurately participants could track their heartbeat, the stronger the observed link between their heart rate reactions and their subjective arousal (but not valence) ratings of emotional images. In Study 2, we found that increasing interoception ability either helped or hindered adaptive intuitive decision making, depending on whether the anticipatory bodily signals generated favored advantageous or disadvantageous choices. These findings identify both the generation and the perception of bodily responses as pivotal sources of variability in emotion experience and intuition, and offer strong supporting evidence for bodily feedback theories, suggesting that cognitive-affective processing does in significant part relate to “following the heart.”

The role of interoception in addiction: a critical review.

Interoception refers to a collection of processes by which the state of the body is transmitted back to the brain, giving rise to awareness of the internal milieu, and motivating behavioural responses to homeostatically regulate internal state. Recent work has begun to explore the relevance of this construct to drug addiction: drugs of abuse and drug-related stimuli induce pronounced peripheral changes, and damage to a brain region known to support interoception (the insula) disrupts nicotine dependence. This article critically reviews existing accounts of addiction that suggest impaired interoception contributes to drug abuse. Conceptually, we argue that existing addiction interoception models could be usefully extended by considering (i) the multiple components of the bodily feedback system (signal, perception, and appraisal) and (ii) how individual differences in these three components impact on cognitive-affective processing in addiction. Empirically, whilst no studies have examined direct behavioural measures of interoception in addicted populations, several indirect lines of experimental work that pertain to this altered interoception hypothesis are presented. Clinical implications are discussed.

The consequences of effortful emotion regulation when processing distressing material: A comparison of suppression and acceptance

The present study investigated the consequences of different forms of emotion regulation. Eighty nine healthy participants viewed a distressing video of the aftermath of road traffic accidents under either suppression (of both felt and expressed affect), acceptance, or no-regulation control instructions and the immediate and longer-term consequences on emotion, mood, and memory were examined. Suppression (relative to control) led to reduced subjective experience of fear when viewing the video, but did not alter electrodermal (EDA) or heart rate (HR) response. Subsequently, suppression led to a less marked subjective emotional reaction to positive but not negative emotional images, reduced free recall memory of the video, and a greater likelihood of experiencing zero intrusions of the videos content. Acceptance (relative to control) had no impact when viewing the video, was associated with a less marked increase in EDA activity in the 5 min period immediately after viewing the video, a more marked HR deceleration and EDA response to both positive and negative images, and elevated negative affect at one week follow-up. These findings suggest, contrary to the current clinical zeitgeist, that emotion suppression can successfully lead to an ongoing down-regulation of emotion and memory, whereas acceptance may elevate subsequent emotionality.

Can you feel the beat? Interoceptive awareness is an interactive function of anxiety- and depression-specific symptom dimensions.

Delineating the differential effects of anxiety versus depression on patterns of information processing has proved challenging. The tripartite model of mood disorders (Clark & Watson, 1991) suggests that one way forward is to adopt a dimensional rather than categorical approach, making it possible to explore the main and interaction effects of depression- and anxiety-specific symptoms on a given cognitive-affective process. Here we examined how the interplay of anxiety-specific arousal and depression-specific anhedonia symptoms in the same individuals relate to interoceptive (bodily) awareness. 113 participants with varying levels of mood disorder symptoms completed a heartbeat perception task to assess interoceptive accuracy. Superior interoception was associated with anxiety-specific arousal symptoms, and this relationship held when controlling for depression-specific anhedonia symptoms and shared general distress symptoms. This main effect was qualified by an interaction between anhedonia and arousal. As anhedonia symptoms increased in severity, the relationship between arousal and interoceptive accuracy became less strong. These results further validate the tripartite framework, help clarify the mixed existing literature on interoception in mood disorders, and suggest that considering the unique and interactive effects of different symptom dimensions is a useful strategy to help identify the cognitive-affective profiles associated with anxiety and depression.

Interoception, contemplative practice, and health.

Interoception can be broadly defined as the sense of signals originating within the body. As such, interoception is critical for our sense of embodiment, motivation, and well-being. And yet, despite its importance, interoception remains poorly understood within modern science. This paper reviews interdisciplinary perspectives on interoception, with the goal of presenting a unified perspective from diverse fields such as neuroscience, clinical practice, and contemplative studies. It is hoped that this integrative effort will advance our understanding of how interoception determines well-being, and identify the central challenges to such understanding. To this end, we introduce an expanded taxonomy of interoceptive processes, arguing that many of these processes can be understood through an emerging predictive coding model for mind–body integration. The model, which describes the tension between expected and felt body sensation, parallels contemplative theories, and implicates interoception in a variety of affective and psychosomatic disorders. We conclude that maladaptive construal of bodily sensations may lie at the heart of many contemporary maladies, and that contemplative practices may attenuate these interpretative biases, restoring a person’s sense of presence and agency in the world.

Categorical and dimensional reports of experienced affect to emotion-inducing pictures in depression

Self-reported affect to positive and negative emotional pictures was contrasted in people with major depressive disorder (MDD) and never-depressed control participants (n = 25 in each group). The results revealed significant differences in response to positive images (reduced arousal, less pleasant valence, decreased happiness, increased sadness) in MDD but no clear group differences in response to negative stimuli. Extending earlier findings of reduced responsiveness to positive, but not negative, stimuli in MDD (D. M. Sloan, M. E. Strauss, S. W. Quirk, & M. Satajovik, 1997; D. M. Sloan, M. E. Strauss, & K. L. Wisner, 2001), the data indicate that blunted response to positive stimuli is found when both categorical and dimensional ratings are elicited. Further, the data replicate earlier findings of elevated sadness reports to positive stimuli (J. Rottenberg, K. L. Kasch, J. J. Gross, & I. H. Gotlib, 2002), which may reflect broader difficulties in regulating emotions in MDD.

Reduced Autobiographical Memory Specificity and Posttraumatic Stress: Exploring the Contributions of Impaired Executive Control and Affect Regulation

Reduced specificity of autobiographical memories retrieved to word cues on the Autobiographical Memory Test (AMT) is associated with increased posttraumatic stress in traumatized samples. Theoretical debates concerning the dominant influences on this effect have focused on affect regulation, whereby specific personal information is avoided more by those experiencing greater distress, versus compromised executive control, whereby increased distress is associated with an inability to set aside inappropriately general responses on the AMT. The present study compared these 2 views in a correlational design using a reversed version of the AMT (the AMT-R) for which trauma-exposed participants (N=36) had to generate general memories from the past and avoid specific memories. An emphasis on the role of affect regulation would predict that distress would be associated with reduced specificity (as in the standard AMT), whereas emphasis on the role of executive control would predict that this relationship would be reversed. The data supported the affect regulation account, with greater posttraumatic stress being associated with reduced memory specificity.

Affective Neuroscience: Past, Present, and Future

The discipline of affective neuroscience is concerned with the underlying neural substrates of emotion and mood. This review presents an historical overview of the pioneering work in affective neuroscience of James and Lange, Cannon and Bard, and Hess, Papez, and MacLean before summarizing the current state of research on the brain regions identified by these seminal researchers. We also discuss the more recent strides made in the field of affective neuroscience. A final section considers different hypothetical organizations of affective neuroanatomy and highlights future directions for the discipline.

Seeing the bigger picture: Training in perspective broadening reduces self-reported affect and psychophysiological response to distressing films and autobiographical memories.

Appraising negative experiences in ways that reduce associated distress is a key component of successful emotion regulation. In 4 studies, the authors examined the effects of systematically practicing appraisal skills using a computer-mediated cognitive bias modification (CBM) methodology. In Studies 1-3, healthy participants practiced applying appraisal themes linked to the idea of seeing the bigger picture to a series of distressing training films, either during each film (Study 1) or immediately after each film (Studies 2 and 3). Control participants watched the same films with no appraisal instructions. Participants who practiced appraisal, compared with controls, exhibited reduced levels of self-reported negative emotional (Studies 1-3) and electrodermal (Study 1) responses to a final test film that all participants were instructed to appraise. In Study 4, a comparable effect of appraisal practice was found using distressing autobiographical memories for participants with higher levels of negative affect. Appraisal practice also led to reduced intrusion and avoidance of the target memories in the week poststudy, compared with prestudy levels, and relative to the no-practice controls. The findings are discussed in terms of the broader literature on CBM.