Acute stress impairs frontocingulate activation during error monitoring in remitted depression

Trait- and state-like co-activation pattern dynamics in current and remitted major depressive disorder

BACKGROUND

Distinguishing between trait- and state-like neural alternations in major depressive disorder (MDD) may advance our understanding of this recurring disorder. We aimed to investigate dynamic functional connectivity alternations in unmedicated individuals with current or past MDD using co-activation pattern analyses.

METHODS

Resting-state functional magnetic resonance imaging data were acquired from individuals with first-episode current MDD (cMDD, n = 50), remitted MDD (rMDD, n = 44), and healthy controls (HCs, n = 64). Using a data-driven consensus clustering technique, four whole-brain states of spatial co-activation were identified and associated metrics (dominance, entries, transition frequency) were analyzed with respect to clinical characteristics.

RESULTS

Relative to rMDD and HC, cMDD showed increased dominance and entries of state 1 (primarily involving default mode network (DMN)), and decreased dominance of state 4 (mostly involving frontal-parietal network (FPN)). Among cMDD, state 1 entries correlated positively with trait rumination. Conversely, relative to cMDD and HC, individuals with rMDD were characterized by increased state 4 entries. Relative to HC, both MDD groups showed increased state 4-to-1 (FPN to DMN) transition frequency but reduction in state 3 (spanning visual attention, somatosensory, limbic networks), with the former metric specifically related to trait rumination.

LIMITATIONS

Further confirmation with longitudinal studies are required.

CONCLUSIONS

Regardless of symptoms, MDD was characterized by increased FPN-to-DMN transitions and reduced dominance of a hybrid network. State-related effect emerged in regions critically implicated in repetitive introspection and cognitive control. Asymptomatic individuals with past MDD were uniquely linked to increased FPN entries. Our findings identify trait-like brain network dynamics that might increase vulnerability to future MDD.

Electrophysiological evidence of mal-adaptation to error in remitted depression

Identifying risk markers for major depressive disorder (MDD) that persist into remission is key to address MDD's high rate of recurrence. Central to MDD recurrence are the disorder's negative information processing biases, such as heightened responses to errors, which may subsequently impair abilities to monitor performance and adjust behaviors based on environmental demands. However, little is known regarding the neurophysiological correlates of post-error adaptation in depression. The current study investigated event-related potentials (ERPs) and behavioral performance following errors from a flanker task in 58 participants with remitted MDD (rMDD) and 118 healthy controls (HC). Specifically, using trial-level data, we tested: (a) the impact of errors on response-locked ERPs of the current and post-error trials (error-related negativity [ERN] and correct response negativity [CRN]) and (b) longer-term adaptation to errors (ERN/CRN) over the course of the task. Compared to HC, rMDD participants showed a larger ERN to the current trial and smaller habituation in ERN over time. On trials immediately following errors, rMDD participants showed slower reaction times that were predicted by the previous-trial ERN amplitude but comparable accuracy to HC, suggesting a deficient ability to disengage from errors and/or a compensatory effort to mitigate accuracy decrements. Critically, this pattern of responding: (a) was concurrently associated with greater levels of anhedonia symptoms, more severe MDD history, and interpersonal impairment (but lower impairment in life activities) and (b) predicted more anhedonia symptoms at one-year follow-up. Collectively, a hyperactive performance monitoring system may be a useful risk marker for future MDD recurrence.

Now or Later? Stress-Induced Increase and Decrease in Choice Impulsivity Are Both Associated with Elevated Affective and Endocrine Responses

Exposure to acute stress elicit physiological and psychological responses that can impact decision-making, often expressed as an increased tendency to act in an impulsive manner following stress. Delay discounting (DD) task has emerged as a reliable measure of impulsive behavior in the form of choice impulsivity (CI). Interestingly, studies that examined the effect of acute stress on DD performance reported mixed results. To address this, we conducted a within-subject examination of the impact of acute stress on CI, focusing on individual differences in response patterns. One hundred and fifty healthy female participants completed the DD task twice, before and after undergoing an acute laboratory stress induction procedure. Saliva samples and self-report mood and affect measures were collected at four time points throughout the session. Fifty-nine matched healthy control participants completed only the DD task twice, with no stress in between. Results indicate that the acute stress procedure elicited the expected effects of increased cortisol release and increased negative mood and affect, at the group level. With respect to DD, stress indeed increased CI at the group level, yet participants differed in the magnitude and direction of this effect. Interestingly, regression analysis revealed quadratic relations between stress-induced changes in CI and cortisol release. Indeed, dividing the sample into three sub-groups based on the impact of stress on CI revealed that, compared to participants that exhibited no substantial change in their CI following stress, participants that exhibited either stress-induced increase or decrease in their CI also exhibited more stress-induced cortisol release, as well as more negative affect. Taken together, these findings suggest that elevated physiological and psychological responses to stress are associated with either increased or decreased choice impulsivity, thus depicting quadratic relations between stress and impulsivity.

A Lifespan Model of Interference Resolution and Inhibitory Control: Risk for Depression and Changes with Illness Progression

The cognitive processes involved in inhibitory control accuracy (IC) and interference resolution speed (IR) or broadly - inhibition - are discussed in this review, and both are described within the context of a lifespan model of mood disorders. Inhibitory control (IC) is a binary outcome (success or no for response selection and inhibition of unwanted responses) for any given event that is influenced to an extent by IR. IR refers to the process of inhibition, which can be manipulated by task design in earlier and later stages through use of distractors and timing, and manipulation of individual differences in response proclivity. We describe the development of these two processes across the lifespan, noting factors that influence this development (e.g., environment, adversity and stress) as well as inherent difficulties in assessing IC/IR prior to adulthood (e.g., cross-informant reports). We use mood disorders as an illustrative example of how this multidimensional construct can be informative to state, trait, vulnerability and neuroprogression of disease. We present aggregated data across numerous studies and methodologies to examine the lifelong development and degradation of this subconstruct of executive function, particularly in mood disorders. We highlight the challenges in identifying and measuring IC/IR in late life, including specificity to complex, comorbid disease processes. Finally, we discuss some potential avenues for treatment and accommodation of these difficulties across the lifespan, including newer treatments using cognitive remediation training and neuromodulation.

The Association Between Experimentally Induced Stress, Performance Monitoring, and Response Inhibition: An Event-Related Potential (ERP) Analysis

Psychological stress is increasingly associated with alterations in performance and affect. Yet, the relationship between experimentally induced psychological stress and neural indices of performance monitoring and error processing, as well as response inhibition, are unclear. Using scalp-recorded event-related potentials (ERPs), we tested the relationship between experimental stress, using the Trier Social Stress Test (TSST), and the error-related negativity (ERN), error positivity (Pe), and N2 ERP components. A final sample of 71 undergraduate students were randomly assigned to go through the TSST (n = 36; 18 female) or a brief mindfulness relaxation exercise (n = 35; 16 female) immediately followed by a go/no-go task while electroencephalogram (EEG) data were collected. Salivary cortisol, heart rate, and blood pressure confirmed increased physiological stress in the TSST group relative to control. Reaction times, accuracy, and post-error slowing did not differ by stress group. Two-group (TSST, control) by 2-trial type (correct, incorrect for ERN/Pe; go correct, no-go correct for N2) repeated measures ANOVAs for the ERN, Pe, and N2 showed the expected main effects of trial type; neither the ERN nor the N2 ERP components showed interactions with the stress manipulation. In contrast, the Pe component showed a significant Group by Trial interaction, with reduced Pe amplitude following the stress condition relative to control. Pe amplitude did not, however, correlate with cortisol reactivity. Findings suggest a reduction in Pe amplitude following experimental stress that may be associated with reduced error awareness or attention to errors following the TSST. Given the variability in the extant literature on the relationship between experimentally induced stress and neurophysiological reflections of performance monitoring, we provide another point of data and conclude that better understanding of moderating variables is needed followed by high-powered replication studies to get at the nuance that is not yet understood in the relationship between induced stress and performance monitoring/response inhibition processes.

Temporal dynamic modulation of acute stress on error processing in healthy males

Error processing is critical for adaptive behaviors. Acute stress has been found to influence error processing. However, the neural dynamic correlates underlying this modulation remain elusive. To address this issue, we recruited 39 healthy male participants, who performed a two-session task before and after an acute stress test while their behavioral and EEG data were recorded. The participants were randomly exposed to either a stress condition (Maastricht Acute Stress Test) or a control condition. The stress test consisted of several hand immersion tasks (ice-cold water, 2°C) and mental arithmetic tasks. A color-word Stroop task was used to investigate the stress effect on error responses. Based on the level of stress-induced cortisol, the participants in the stress group were further classified as low (N = 13) or high (N = 13) cortisol responders. The results indicated that only in the high cortisol responders, the error-related negativity (ERN) amplitude was reduced after acute stress. In addition, the ∆ERN in the high cortisol responders was significantly smaller than that in the low cortisol responders. These results suggest that acute stress impairs error detection. However, the error positivity amplitudes increased in the stress group compared to the control group, indicating that acute stress leads to greater error assessment. Taken together, these results suggest that acute stress impairs error detection, which is modulated by individuals' response level following acute stress, and leads to more emotional and/or motivational responses to the error signal once the error is consciously realized.

Neuronal dynamics enable the functional differentiation of resting state networks in the human brain

Intrinsic brain activity is organized in spatial-temporal patterns, called resting-state networks (RSNs), exhibiting specific structural-functional architecture. These networks presumably reflect complex neurophysiological processes and have a central role in distinct perceptual and cognitive functions. In this work, we propose an innovative approach for characterizing RSNs according to their underlying neural oscillations. We investigated specific electrophysiological properties, including spectral features, fractal dimension, and entropy, associated with eight core RSNs derived from high-density electroencephalography (EEG) source-reconstructed signals. Specifically, we found higher synchronization of the gamma-band activity and higher fractal dimension values in perceptual (PNs) compared with higher cognitive (HCNs) networks. The inspection of this underlying rapid activity becomes of utmost importance for assessing possible alterations related to specific brain disorders. The disruption of the coordinated activity of RSNs may result in altered behavioral and perceptual states. Thus, this approach could potentially be used for the early detection and treatment of neurological disorders.

Opioid modulation of cognitive impairment in depression

The failure of traditional antidepressant medications to adequately target cognitive impairment is associated with poor treatment response, increased risk of relapse, and greater lifetime disability. Opioid receptor antagonists are currently under development as novel therapeutics for major depressive disorder (MDD) and other stress-related illnesses. Although it is known that dysregulation of the endogenous opioid system is observed in patients diagnosed with MDD, the impact of opioidergic neurotransmission on cognitive impairment has not been systematically evaluated. Here we review the literature indicating that opioid manipulations can alter cognitive functions in humans. Furthermore, we detail the preclinical studies that demonstrate the ability of mu-opioid receptor and kappa-opioid receptor ligands to modulate several cognitive processes. Specifically, this review focuses on domains within higher order cognitive processing, including attention and executive functioning, which can differentiate cognitive processes influenced by motivational state.