How are you feeling? Revisiting the quantification of emotional qualia.

Numerous emotion researchers have asked their study participants to attend to the distinct feelings of arousal and valence, and self-report and physiological data have supported the independence of the two. We examined whether this dissociation reflects introspection about distinct emotional qualia or the way in which valence is measured. With either valence (Experiment 1) or arousal (Experiment 2) as the primary focus, when valence was measured using a bipolar scale (ranging from negative to positive), it was largely dissociable from arousal. By contrast, when two separate unipolar scales of pleasant and unpleasant valence were used, their sum was equivalent to feelings of arousal and its autonomic correlates. The association (or dissociation) of valence and arousal was related to the estimation (or nonestimation) of mixed-valence experiences, which suggests that the distinction between valence and arousal may reflect less the nature of emotional experience and more how it is measured. These findings further encourage use of unipolar valence scales in psychological measurement.

An exploratory study of functional brain activation underlying response inhibition in major depressive disorder and borderline personality disorder.

Cognitive control is associated with impulsive and harmful behaviours, such as substance abuse and suicidal behaviours, as well as major depressive disorder (MDD) and borderline personality disorder (BPD). The association between MDD and BPD is partially explained by shared pathological personality traits, which may be underpinned by aspects of cognitive control, such as response inhibition. The neural basis of response inhibition in MDD and BPD is not fully understood and could illuminate factors that differentiate between the disorders and that underlie individual differences in cross-cutting pathological traits. In this study, we sought to explore the neural correlates of response inhibition in MDD and BPD, as well as the pathological personality trait domains contained in the ICD-11 personality disorder model. We measured functional brain activity underlying response inhibition on a Go/No-Go task using functional magnetic resonance imaging in 55 female participants recruited into three groups: MDD without comorbid BPD (n = 16), MDD and comorbid BPD (n = 18), and controls with neither disorder (n = 21). Whereas response-inhibition-related activation was observed bilaterally in frontoparietal cognitive control regions across groups, there were no group differences in activation or significant associations between activation in regions-of-interest and pathological personality traits. The findings highlight potential shared neurobiological substrates across diagnoses and suggest that the associations between individual differences in neural activation and pathological personality traits may be small in magnitude. Sufficiently powered studies are needed to elucidate the associations between the functional neural correlates of response inhibition and pathological personality trait domains.

The transdiagnostic relationship of cumulative lifetime stress with memory, the hippocampus, and personality psychopathology.

Stress has a detrimental impact on memory, the hippocampus, and psychological health. Psychopathology research on stress has centered mainly on psychiatric diagnoses rather than symptom dimensions, and less attention has been given to the neurobiological factors through which stress might be translated into psychopathology. The present work investigates the transdiagnostic relationship of cumulative stress with episodic memory and the hippocampus (both structure and function) and explores the extent to which stress mediates the relationship between personality psychopathology and hippocampal size and activation. Cumulative lifetime stress was assessed in a sample of females recruited to vary in stress exposure and severity of personality psychopathology. Fifty-six participants completed subjective and objective tests of episodic memory, a T2-weighted high-resolution magnetic resonance imaging (MRI) scan of the medial-temporal lobe, and functional MRI (fMRI) scanning during a learning and recognition memory task. Higher cumulative stress was significantly related to memory complaints (but not episodic memory performance), lower bilateral hippocampal volume, and greater encoding-related hippocampal activation during the presentation of novel stimuli. Furthermore, cumulative stress significantly mediated the relationship between personality psychopathology and both hippocampal volume and activation, whereas alternative mediation models were not supported. The findings suggest that structural and functional activation differences in the hippocampus observed in case-control studies of psychiatric diagnoses may share cumulative stress as a common factor, which may mediate broadly reported relationships between psychopathology and hippocampal structure and function.

Stressed, sick, and sad: Neuroendoimmune pathways between subjective lifetime stress and depression.

Disruptions in stress-sensitive biological systems, notably the immune system and hypothalamic-pituitary-adrenal axis, are strongly implicated in depression, and disturbances in these neuroendoimmune systems could reflect potential pathways through which experiences of stress are translated into depression. To characterize the links between stress and depression, the present study investigated whether neuroendoimmune activity mediates the relationship between perceived stress and depressive symptoms in 59 medically healthy adult females with varying levels of depression. Consistent with hypotheses, both greater perceived stress and higher concentrations of the proinflammatory immune marker, interleukin-6 (IL-6), were associated with greater depressive symptoms. Although neuroendoimmune activity did not significantly mediate the relationship between lifetime perceived stress and depressive symptoms, when considered together, elevated concentrations of IL-6 and lower free cortisol mediated the relationship between severity of childhood stress and current depressive symptoms. These findings shed light on how early life stress may be translated into adulthood depression.

Spending one's time: the hedonic principle in ad libitum viewing of pictures.

The hedonic principle maintains that humans strive to maximize pleasant feelings and avoid unpleasant feelings. Surprisingly, and contrary to hedonic logic, previous experiments have demonstrated a relationship between picture viewing time and arousal (activation) but not with valence (pleasure vs. displeasure), suggesting that arousal rather than the hedonic principle accounts for how individuals choose to spend their time. In 2 experiments we investigated the arousal and hedonic principles underlying viewing time behavior while controlling for familiarity with stimuli, picture complexity, and demand characteristics. Under ad libitum conditions of picture viewing, we found strong relationships between viewing time, valence, and facial corrugator electomyographic (EMG) activity with familiar but not novel pictures. Viewing time of novel stimuli was largely associated with arousal and visual complexity. We conclude that only after initial information about the stimulus is gathered, where we choose to spend our time is guided by the hedonic principle.