Pupil response to negative emotional information in individuals at risk for depression

Pupillary response to cognitive control in depression-prone individuals

Revealing the pupillary correlates of depression-prone individuals is conducive to the early intervention and treatment of depression. This study recruited 31 depression-prone and 31 healthy individuals. They completed an emotional task-switching task combined with a go/no-go task, and task-evoked pupillary responses (TEPR) were recorded. Behavioral results showed no significant differences in behavioral performance in terms of cognitive flexibility and inhibition between the depression-prone group and the healthy control group. The pupillary results revealed that (1) the depression-prone group showed slightly lower TEPRs to positive stimuli than the healthy controls during cue presentation; (2) during target presentation, the depression-prone group did not show an effect of emotional valence on the pupillary response in the task-repeat trials; and (3) compared to the healthy controls, the depression-prone group showed significantly smaller TEPRs to negative no-go stimuli and had a longer latency of the second peak of pupil dilation in no-go trials. These results imply that depression-prone individuals may have slower neural responses in cognitive control tasks and emotion-specific weakened cognitive control than healthy individuals.

Are depressive symptoms linked to a reduced pupillary response to novel positive information?-An eye tracking proof-of-concept study

Introduction

Depressive symptoms have been linked to difficulties in revising established negative beliefs in response to novel positive information. Recent predictive processing accounts have suggested that this bias in belief updating may be related to a blunted processing of positive prediction errors at the neural level. In this proof-of-concept study, pupil dilation in response to unexpected positive emotional information was examined as a psychophysiological marker of an attenuated processing of positive prediction errors associated with depressive symptoms.

Methods

Participants (N = 34) completed a modified version of the emotional Bias Against Disconfirmatory Evidence (BADE) task in which scenarios initially suggest negative interpretations that are later either confirmed or disconfirmed by additional information. Pupil dilation in response to the confirmatory and disconfirmatory information was recorded.

Results

Behavioral results showed that depressive symptoms were related to difficulties in revising negative interpretations despite disconfirmatory positive information. The eye tracking results pointed to a reduced pupil response to unexpected positive information among people with elevated depressive symptoms.

Discussion

Altogether, the present study demonstrates that the adapted emotional BADE task can be appropriate for examining psychophysiological aspects such as changes in pupil size along with behavioral responses. Furthermore, the results suggest that depression may be characterized by deviations in both behavioral (i.e., reduced updating of negative beliefs) and psychophysiological (i.e., decreased pupil dilation) responses to unexpected positive information. Future work should focus on a larger sample including clinically depressed patients to further explore these findings.

Pupillary motility responses to affectively salient stimuli in individuals with depression or elevated risk of depression: A systematic review and meta-analysis

Elaborative affective processing is observed in depression, and pupillary reactivity, a continuous, sensitive, and reliable indicator of physiological arousal and neurocognitive processing, is increasingly utilized in studies of depression-related characteristics. As a first attempt to quantitively summarize existing evidence on depression-related pupillary reactivity alterations, this review and meta-analysis evaluated the direction, magnitude, and specificity of pupillary indices of affective processing towards positively, negatively, and neutrally-valenced stimuli among individuals diagnosed with depression or with elevated risk of depression. Studies on pupillary responses to affective stimuli in the target groups were identified in PsycINFO and PubMed databases. Twenty-two articles met inclusion criteria for the qualitative review and 16 for the quantitative review. Three-level frequentist and Bayesian models were applied to summarize pooled effects from baseline-controlled stimuli-induced average changes in pupillary responses. In general, compared to non-depressed individuals, individuals with depression or elevated risk of depression exhibited higher pupillary reactivity (d =0.15) towards negatively-valenced stimuli during affective processing. Pupillary motility towards negatively-valenced stimuli may be a promising trait-like marker for depression vulnerability.

Pupillary response in reward processing in adults with major depressive disorder in remission

OBJECTIVE

Major depressive disorder (MDD) is associated with impaired reward processing and reward learning. The literature is inconclusive regarding whether these impairments persist after remission. The current study examined reward processing during a probabilistic learning task in individuals in remission from MDD (n = 19) and never depressed healthy controls (n = 31) matched for age and sex. The outcome measures were pupil dilation (an indirect index of noradrenergic activity and arousal) and computational modeling parameters.

METHOD

Participants completed two versions (facial/nonfacial feedback) of probabilistic reward learning task with changing contingencies. Pupil dilation was measured with a corneal reflection eye tracker. The hypotheses and analysis plan were preregistered.

RESULT

Healthy controls had larger pupil dilation following losses than gains (p <.001), whereas no significant difference between outcomes was found in individuals with a history of MDD, resulting in an interaction between group and outcome (β = 0.81, SE = 0.34, t = 2.37, p = .018). The rMDD group also achieved lower mean score at the last trial (t[46.77] = 2.12, p = .040) as well as a smaller proportion of correct choices (t[46.70] = 2.09, p = .041) compared with healthy controls.

CONCLUSION

Impaired reward processing may persist after remission from MDD and could constitute a latent risk factor for relapse. Measuring pupil dilation in a reward learning task is a promising method for identifying reward processing abnormalities linked to MDD. The task is simple and noninvasive, which makes it feasible for clinical research.

Publication guidelines and recommendations for pupillary measurement in psychophysiological studies

A variety of psychological and physical phenomena elicit variations in the diameter of pupil of the eye. Changes in pupil size are mediated by the relative activation of the sphincter pupillae muscle (decrease pupil diameter) and the dilator pupillae muscle (increase pupil diameter), innervated by the parasympathetic and sympathetic branches, respectively, of the autonomic nervous system. The current guidelines are intended to inform and guide psychophysiological research involving pupil measurement by (1) summarizing important aspects concerning the physiology of the pupil, (2) providing methodological and data-analytic guidelines and recommendations, and (3) briefly reviewing psychological phenomena that modulate pupillary reactivity. Because of the increased ease and tractability of pupil measurement, the goal of these guidelines is to promote accurate recording, analysis, and reporting of pupillary data in psychophysiological research.

Multifactorial prediction of depression diagnosis and symptom dimensions

While depression is a leading cause of disability, prior investigations of depression have been limited by studying correlates in isolation. A data-driven approach was applied to identify out-of-sample predictors of current depression from adults (N = 217) sampled on a continuum of no depression to clinical levels. The current study used elastic net regularized regression and predictors from sociodemographic, self-report, polygenic scores, resting electroencephalography, pupillometry, actigraphy, and cognitive tasks to classify individuals into currently depressed (MDE), psychiatric control (PC), and no current psychopathology (NP) groups, as well as predicting symptom severity and lifetime MDE. Cross-validated models explained 20.6% of the out-of-fold deviance for the classification of MDEs versus PC, 33.2% of the deviance for MDE versus NP, but -0.6% of the deviance between PC and NP. Additionally, predictors accounted for 25.7% of the out-of-fold variance in anhedonia severity, 65.7% of the variance in depression severity, and 12.9% of the deviance in lifetime depression (yes/no). Self-referent processing, anhedonia, and psychosocial functioning emerged as important differentiators of MDE and PC groups. Findings highlight the advantages of using psychiatric control groups to isolate factors specific to depression.

Eyeing ambiguity: Pupillary reactivity during early automatic interpretations in major depressive disorder

Automatic interpretation biases (AIB) are theorized to be a risk factor for depression. However, documenting AIB in depressed persons has been challenging and the source (affective vs cognitive) of AIB remains unclear. We conducted a psychophysiological investigation of AIB in a sample of 25 clinical interview assessed individuals experiencing a current major depressive episode and 28 never-depressed control individuals. Participants completed the Word Sentence Association Paradigm for Depression while their pupil size was recorded. Repeated measures ANOVAs were used to examine behavioral response data and multilevel modeling was used to examine pupillary reactivity (change from trial baseline). Compared to controls, the depressed group was both more likely to endorse negative AIB (p = .001, d = 1.01) and less likely to endorse benign AIB (p = .011, d = 0.72). Further, the depressed group exhibited significantly increased pupil size while processing negative words when they endorsed a negative interpretation compared with controls (ps = .010-.037, ds = 0.69-0.87), but did not differ during other AIB trial types. Within group comparisons revealed greater differentiation between interpretations in the healthy control group in both reaction time and pupillary reactivity AIB measures. This depression-related pupillary reactivity pattern fits with an emotional salience-based explanation better than a cognitive effort-based hypothesis of negative AIB, while pupillary reactivity pattern within the control group is consistent with a benign bias. People with depression lack benign AIB and may be more emotionally engaged during negative AIB than healthy controls.

Pupil Dilation during Reward Anticipation Is Correlated to Depressive Symptom Load in Patients with Major Depressive Disorder

Depression is a debilitating disorder with high prevalence and socioeconomic cost, but the brain-physiological processes that are altered during depressive states are not well understood. Here, we build on recent findings in macaques that indicate a direct causal relationship between pupil dilation and anterior cingulate cortex mediated arousal during anticipation of reward. We translated these findings to human subjects with concomitant pupillometry/fMRI in a sample of unmedicated participants diagnosed with major depression and healthy controls. We could show that the upregulation and maintenance of arousal in anticipation of reward was disrupted in patients in a symptom-load dependent manner. We could further show that the failure to maintain reward anticipatory arousal showed state-marker properties, as it tracked the load and impact of depressive symptoms independent of prior diagnosis status. Further, group differences of anticipatory arousal and continuous correlations with symptom load were not traceable only at the level of pupillometric responses, but were mirrored also at the neural level within salience network hubs. The upregulation and maintenance of arousal during reward anticipation is a novel translational and well-traceable process that could prove a promising gateway to a physiologically informed patient stratification and targeted interventions.

Increased neural and pupillary reactivity to emotional faces in adolescents with current and remitted major depressive disorder

This study combined multiple levels of analysis to examine whether disrupted neural and pupillary reactivity to emotional faces serves as a state- or trait-like marker of adolescent major depressive disorder (MDD). The study examined differences in pupil dilation and the event-related potential (ERP) late positive potential (LPP) component to emotional faces before and after a negative mood induction between 71 adolescents (age 11–18 years) with (i) a current diagnosis of MDD, (ii) a past episode of MDD currently in full remission and (iii) no lifetime history of any Axis I disorder. Relative to healthy control (HC) youth, adolescents with current or remitted MDD exhibited an enhanced LPP and pupillary response to all emotional facial expressions (fearful, happy and sad). This difference in reactivity between remitted depressed and HC adolescents persisted following the negative mood induction. Results also revealed that LPP and pupillary responses to emotional faces were significantly related, but only among the currently depressed adolescents. This study suggests that increased physiological and neural activation in response to social-emotional stimuli may not only characterize currently depressed adolescents, but also remains following MDD remission, potentially serving as a mechanism of risk for future depression relapse.

Pupil Size Coupling to Cortical States Protects the Stability of Deep Sleep via Parasympathetic Modulation

During wakefulness, pupil diameter can reflect changes in attention, vigilance, and cortical states. How pupil size relates to cortical activity during sleep, however, remains unknown. Pupillometry during natural sleep is inherently challenging since the eyelids are usually closed. Here, we present a novel head-fixed sleep paradigm in combination with infrared back-illumination pupillometry (iBip) allowing robust tracking of pupil diameter in sleeping mice. We found that pupil size can be used as a reliable indicator of sleep states and that cortical activity becomes tightly coupled to pupil size fluctuations during non-rapid eye movement (NREM) sleep. Pharmacological blocking experiments indicate that the observed pupil size changes during sleep are mediated via the parasympathetic system. We furthermore found that constrictions of the pupil during NREM episodes might play a protective role for stability of sleep depth. These findings reveal a fundamental relationship between cortical activity and pupil size, which has so far been hidden behind closed eyelids.

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Infrared back-illumination allows accurate pupillometry in sleeping mice

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Brain activity and pupil diameter are tightly coupled during sleep

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The parasympathetic system is the main driver of pupillary changes during NREM sleep

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Pupillary constrictions might have a protective function to stabilize deep sleep

Increased pupil dilation to angry faces predicts interpersonal stress generation in offspring of depressed mothers

BACKGROUND

Interpersonal stress generation is one mechanism hypothesized to increase risk for the intergenerational transmission of depression. Although there is some evidence of stress generation in offspring of depressed mothers, specific predictors of stress generation in these youth remain unknown. The goal of this study was to examine a peripheral measure of cognitive-affective reactivity (i.e. pupil dilation) to emotional interpersonal stimuli as a predictor of stress generation in offspring of depressed mothers.

METHOD

The study included 129 mothers and their offspring (ages 8-15) recruited from the community who participated at two time points separated by 6 months. Youth's average pupil dilation to emotional faces (angry, happy, sad) as well as maternal lifetime history of major depressive disorder were assessed at baseline. In addition, both time points included assessments of youth's levels of self-generated (dependent) and independent episodic life stress in the preceding 6 months.

RESULTS

Youth's pupil dilation to angry, but not sad or happy, faces predicted prospective increases in dependent interpersonal stress across the follow-up. This effect was only observed in offspring of depressed mothers and was not seen in offspring of never-depressed mothers.

CONCLUSIONS

This study highlights a potential risk factor (heightened reactivity to facial displays of anger) that may identify which offspring of depressed mothers are at greatest risk for interpersonal stress generation.

Pupillary response to emotional stimuli as a risk factor for depressive symptoms following a natural disaster: The 2011 Binghamton flood

Understanding pathways of risk following a natural disaster may help create next-generation targeted interventions. The current study examined if a biomarker of cognitive-affective response (pupil dilation) could identify which individuals are at greatest risk for depression following disaster-related stress. Fifty-one women completed a computer-based task assessing pupillary response to facial expressions of emotion and reported their depressive symptoms before the 2011 Binghamton flood. Following the flood, women were assessed for objective levels of flood-related stress and again reported their depressive symptoms. Supporting the proposed diathesis-stress model, decreased pupil dilation to emotional expressions predicted a significant increase in post-flood depressive symptoms, but only among women who experienced higher levels of flood-related stress. Findings suggest that reduced cognitive-affective response to emotional stimuli (measured via pupillary response) can increase risk for depression in the context of high levels of objective life stress.

As Far as the Eye Can See: Relationship between Psychopathic Traits and Pupil Response to Affective Stimuli

Psychopathic individuals show a range of affective processing deficits, typically associated with the interpersonal/affective component of psychopathy. However, previous research has been inconsistent as to whether psychopathy, within both offender and community populations, is associated with deficient autonomic responses to the simple presentation of affective stimuli. Changes in pupil diameter occur in response to emotionally arousing stimuli and can be used as an objective indicator of physiological reactivity to emotion. This study used pupillometry to explore whether psychopathic traits within a community sample were associated with hypo-responsivity to the affective content of stimuli. Pupil activity was recorded for 102 adult (52 female) community participants in response to affective (both negative and positive affect) and affectively neutral stimuli, that included images of scenes, static facial expressions, dynamic facial expressions and sound-clips. Psychopathic traits were measured using the Triarchic Psychopathy Measure. Pupil diameter was larger in response to negative stimuli, but comparable pupil size was demonstrated across pleasant and neutral stimuli. A linear relationship between subjective arousal and pupil diameter was found in response to sound-clips, but was not evident in response to scenes. Contrary to predictions, psychopathy was unrelated to emotional modulation of pupil diameter across all stimuli. The findings were the same when participant gender was considered. This suggests that psychopathy within a community sample is not associated with autonomic hypo-responsivity to affective stimuli, and this effect is discussed in relation to later defensive/appetitive mobilisation deficits.

Using the Research Domain Criteria Framework to Explore Associations Between MMPI-2-RF Constructs and Physiological Variables Assessed by Eye-Tracker Technology

The National Institute of Mental Health has proposed a paradigm shift in the conceptualization of psychopathology, abandoning the traditional categorical model in favor of one based on hierarchically organized dimensional constructs (Insel et al., 2010 ). One explicit goal of this initiative, the Research Domain Criteria (RDoC) project, is to facilitate the incorporation of newly available neurobiologic variables into research on psychopathology. The Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF; Ben-Porath & Tellegen, 2008/2011 ) represents a similar paradigm shift, also adopting a hierarchical arrangement of dimensional constructs. This study examined associations between MMPI-2-RF measures of psychopathology and eye-movement metrics. Participants were college students (n = 270) who completed the MMPI-2-RF and then viewed a sequence of 30-s video clips. Results show a pattern of positive correlations between pupil size and emotional/internalizing dysfunction scales when viewing video eliciting negative emotional reactions, reflecting greater arousability in individuals with higher scores on these measures. In contrast, when viewing stimuli depicting angry, threatening material, a clear pattern of negative correlations was found between pupil size and behavioral/externalizing trait measures. These data add to the construct validity of the MMPI-2-RF and support the use of the RDoC matrix as a framework for research on psychopathology.

Pupillary reactivity to negative stimuli prospectively predicts recurrence of major depressive disorder in women

There is a large body of research supporting the association between disrupted physiological reactivity to negative stimuli and depression. The present study aimed to examine whether physiological reactivity to emotional stimuli, assessed via pupil dilation, served as a biological marker of risk for depression recurrence among individuals who are known to be at a higher risk due to having previous history of depression. Participants were 57 women with a history of major depressive disorder (MDD). Pupil dilation to angry, happy, sad, and neutral faces was recorded. Participants' diagnoses and symptoms were assessed 24 months after the initial assessment. We found that women's pupillary reactivity to negative (sad or angry faces) but not positive stimuli prospectively predicted MDD recurrence. Additionally, we found that both hyper- and hypopupillary reactivity to angry faces predicted risk for MDD recurrence. These findings suggest that disrupted physiological response to negative stimuli indexed via pupillary dilation could serve as a physiological marker of MDD risk, thus presenting clinicians with a convenient and inexpensive method to predict which of the at-risk women are more likely to experience depression recurrence.

Integrating NIMH Research Domain Criteria (RDoC) into Depression Research

The NIMH Research Domain Criteria (RDoC) initiative grew out of the agency's goal to develop "new ways of classifying mental disorders based on behavioral dimensions and neurobiological measures" (NIMH, 2008). In this article, we review how depression research can be meaningfully conducted within an RDoC framework, with a particular focus on the negative valence systems construct of Loss. New efforts to understand depression within the context of RDoC must seek an integrative understanding of the disorder across multiple units of analysis from genes to neural circuits to behavior. In addition, the constructs or processes must be understood within the context of specific environmental and developmental influences. Key concepts are discussed and we end by highlighting research on rumination as a prime example of research that is consistent with RDoC.

Pupillary motility: bringing neuroscience to the psychiatry clinic of the future

Modern pupillometry has expanded the study and utility of pupil responses in many new domains, including psychiatry, particularly for understanding aspects of cognitive and emotional information processing. Here, we review the applications of pupillometry in psychiatry for understanding patients' information processing styles, predicting treatment, and augmenting function. In the past year pupillometry has been shown to be useful in specifying cognitive/affective occurrences during experimental tasks and informing clinical diagnoses. Such studies demonstrate the potential of pupillary motility to be used in clinical psychiatry much as it has been in neurology for the past century.

Gaze-fixation and pupil dilation in the processing of emotional faces: the role of rumination

Sustained attentional processing of negative information plays a significant role in the development and maintenance of depression. The present study examines the relationships between rumination, a relevant factor in information processing in depression, and the attentional mechanisms activated in individuals with different levels of depression severity when attending to emotional information (i.e., sad, angry and happy faces). Behavioural and physiological indicators of sustained processing were assessed in 126 participants (39 dysphoric and 87 non-dysphoric) using eye-tracking technology. Pupil dilation and total time attending to negative faces were correlated with a global ruminative style in the total sample once depression severity was controlled. Furthermore, in dysphoric participants the brooding component of rumination was specifically associated with the total time attending to sad faces. Finally, bootstrapping analyses showed that the relationships between global rumination and pupil diameter to emotional faces were accounted by total time attending to emotional faces, specifically for participants reporting lower levels of depression severity. The results support the idea that sustained processing of negative information is associated with a higher ruminative style and indicate differential associations between these factors at different levels of depressive symptomatology.