Uncertainty increases neural indices of attention in obsessive-compulsive disorder

Reduced generalization of reward among individuals with subthreshold depression: Behavioral and EEG evidence

Altered stimulus generalization has been well-documented in anxiety disorders; however, there is a paucity of research investigating this phenomenon in the context of depression. Depression is characterized by impaired reward processing and heightened attention to negative stimuli. It is hypothesized that individuals with depression exhibit reduced generalization of reward stimuli and enhanced generalization of loss stimuli. Nevertheless, no study has examined this process and its underlying neural mechanisms. In the present study, we recruited 25 participants with subthreshold depression (SD group) and 24 age-matched healthy controls (HC group). Participants completed an acquisition task, in which they learned to associate three distinct pure tones (conditioned stimuli, CSs) with a reward, a loss, or no outcome. Subsequently, a generalization session was conducted, during which similar tones (generalization stimuli, GSs) were presented, and participants were required to classify them as a reward tone, a loss tone, or neither. The results revealed that the SD group exhibited reduced generalization errors in the early phase of generalization, suggesting a diminished ability to generalize reward-related stimuli. The event-related potential (ERP) results indicated that the SD group exhibited decreased generalization of positive valence to reward-related GSs and heightened generalization of negative valence to loss-related GSs, as reflected by the N1 and P2 components. However, the late positive potential (LPP) was not modulated by depression in reward generalization or loss generalization. These findings suggested that individuals with subthreshold depression may have a blunted or reduced ability to generalize reward stimuli, shedding light on potential treatment strategies targeting this particular process.

In the anticipation of threat: Neural regulatory activity indicated by delta-beta correlation and its relation to anxiety

The anticipation of oncoming threats is emotionally challenging and related to anxiety. The current study aimed to investigate the neural regulatory processes during the anticipatory preparations in stressful situations in relation to trait anxiety, especially in an uncertainty-related stressful situation. To this end, we measured within-subjects delta-beta amplitude-amplitude correlation (AAC) and phase-amplitude coupling (PAC) with electroencephalography using a well-defined stress-inducing paradigm in 28 high-trait-anxiety (HTA) and 29 low-trait-anxiety (LTA) college students. Specifically, a threat probability task was conducted, where participants anticipated the future stimuli under the uncertain (i.e., an average of 50% electric shocks), certain (i.e., 100% electric shocks) and no threat conditions, as well as a resting state task. Results showed a generally larger delta-beta AAC in the LTA group relative to the HTA group across conditions, supporting the hypothesis that delta-beta AAC reflects the efficiency of stress regulation and trait anxiety could compromise this adaptive regulatory activity. Furthermore, a larger delta-beta PAC was found under the uncertain threat condition relative to the no threat condition, indicating the sensitivity of delta-beta PAC in reflecting state anxiety. These findings indicate that while delta-beta AAC is more related to trait anxiety and could distinguish between high and low trait anxiety irrespective of conditions, delta-beta PAC is more related to state anxiety and is sensitive enough to detect the uncertainty-related anxious state.

Early visual perceptual processing is altered in obsessive-compulsive disorder

OBJECTIVE

Existing studies have shown changes in attention and emotion processing of disorder-relevant visual stimuli in those with obsessive compulsive disorder (OCD). However, early visual processing in OCD has not been assessed, as previous studies did not examine the entire time course of visual processing but instead assessed potential differences in pre-determined visual evoked potentials (VEPs). This study investigates the entire visual processing stream in OCD compared to healthy age-matched controls (HC) using emotionally-neutral visual stimuli and a data-driven rather than hypothesis-driven approach.

METHODS

35 HC and 26 participants with OCD underwent EEG recording while completing a modified Eriksen flanker task. Permutation-controlled t-tests were used to identify group differences in the data's full time course of visual evoked potentials. Baseline-corrected amplitudes at time points where the groups were significantly different were analyzed using ANCOVAs with BDI, BAI, and SNAP-inattentiveness scores included as covariates.

RESULTS

This analysis identified enhanced P1 amplitudes to two visual stimuli (the initial flanker and the stimulus), corresponding to time windows of 65-93 ms and 157-187 ms post-flanker presentation in the OCD group compared to controls. Group (OCD vs. HC) was the strongest predictor of VEP amplitude during both time windows, with no significant influences of any covariates.

CONCLUSIONS

This study showed an enhanced P1 component in people with OCD to neutral visual stimuli, potentially reflecting either inefficient or excessive early visual processing in this population. Additional inquiry is necessary to determine whether altered visual processing is associated with the sensory hypervigilance observed in those with OCD.

SIGNIFICANCE

This work identifies early visual processing alterations in OCD using neutral stimuli and a data-driven approach.

Intolerance of uncertainty and neural measures of anticipation and reactivity for affective stimuli

Intolerance of uncertainty (IU) is a transdiagnostic construct referring to the aversive interpretation of contexts characterized by uncertainty. Indeed, there is a growing body of research examining individual differences in IU and how these are associated with emotional anticipation and reactivity during periods of certainty and uncertainty, however, how these associations are reflected via neurophysiological indices remain understudied and poorly understood. The present study examined the relationship between self-reported IU and neurophysiological measures of emotional anticipation and reactivity, namely stimulus preceding negativity (SPN) and late positive potential (LPP), and self-report measures of emotional experiences. These measures were captured during an S1-S2 picture viewing tasks in which participants were presented with cues (S1) that either indicated the affective valence of upcoming picture (S2) or provided no information about the valence. Findings here provide evidence for significant associations between SPN amplitude and IU scores during uncertain and certain-positive cueing conditions, and significant associations between LPP amplitude and IU scores during both certain- and uncertain-negative picture viewing conditions that appear driven by prospective IU sub-scores. These positive associations between IU and SPN amplitude are suggestive of heightened emotional anticipation following S1 cues, while positive associations between IU and LPP are suggestive of heightened emotional reactivity following S2 images. These findings are discussed in detail relative to existing IU literature, and potential implications of these findings.

When the approaching threat is uncertain: Dynamics of defensive motivation and attention in trait anxiety

Uncertainty of threat has been linked to anxiety, but little is known about how neurophysiological responses change as uncertain threats approach and whether trait anxiety modulates these changes. The current study was designed to explore aspects of the dynamics of defensive motivation (startle reflex elicited by acoustic startle probes), attention (probe N100 component of event-related potentials elicited by acoustic startle probes), and autonomic nervous system activity (heart rate) when the approaching threat was certain or uncertain in a variant of the threat probability task. Behavioral results showed that high-trait anxious individuals reported higher levels of anxiety than low-trait anxious individuals only under the uncertain threat condition. Electromyographic data showed that high-trait anxious individuals tended to produce a more pronounced startle reflex, especially when the uncertain threat was proximal. This pattern was not observed in low-trait anxious individuals. By examining early attention engagement through probe N100, we observed a similar pattern in relation to defensive motivation. Moreover, under the uncertain threat condition, high-trait anxious individuals yielded a greater deceleration of heart rate than low-trait anxious individuals. These results indicate a distinct modulation effect of trait anxiety in the dynamics of defensive motivation, attention, and the autonomic nervous system during the anticipation of uncertain threats.

Impaired differential learning of fear versus safety signs in obsessive-compulsive disorder

Pavlovian learning mechanisms are of great importance both for models of psychiatric disorders and treatment approaches, but understudied in obsessive-compulsive disorder (OCD). Using an established Pavlovian fear conditioning and reversal procedure, we studied skin conductance responses in 41 patients with OCD and in 32 matched healthy control participants. Within both groups, fear acquisition and reversal effects were evident. When comparing groups, patients showed impaired differential learning of threatening and safe stimuli, consistent with previous research. In contrast to prior findings, differential learning impairments were restricted to fear acquisition, and not observed in the reversal stage of the experiment. As previous and present fear reversal experiments in OCD differed in the use of color coding to facilitate stimulus discrimination, the studies converge to suggest that differential learning of threatening versus safe stimuli is impaired in OCD, but manifests itself differently depending on the difficulty of the association to be learned. When supported by the addition of color, patients with OCD previously appeared to acquire an association early but failed to reverse it according to changed contingencies. In absence of such color coding of stimuli, our data suggest that patients with OCD already show differential learning impairments during fear acquisition, which may relate to findings of altered coping with uncertainty previously observed in OCD. Impaired differential learning of threatening versus safe stimuli should be studied further in OCD, in order to determine whether impairments in differential learning predict treatment outcomes in patients, and whether they are etiologically relevant for OCD.

Tactile P300 to unpredictable electric shocks: Association with anxiety symptoms, intolerance of uncertainty, and neuroticism

The no, predictable, and unpredictable threat (NPU-threat) task is an experimental paradigm that delineates the anticipation of predictable vs. unpredictable threat. The current literature suggests that heightened defensive motivation in anticipation of unpredictable threat is associated with anxiety disorders and increased symptoms. Few investigations have examined whether a heightened response to actual threat is also associated with anxiety-related phenomenology. The present study examined the relationship between the tactile P300 to shock delivery during the NPU-threat task and individual differences in anxiety symptoms, intolerance of uncertainty, and neuroticism. Overall, the tactile P300 was enhanced in response to unpredictable shocks relative to predictable shocks. Greater tactile P300 enhancement to unpredictable shocks was associated with greater anxiety symptoms, intolerance of uncertainty, and neuroticism. The present study suggests that temporal unpredictability enhances attentional engagement to threat, which is greater in individuals characterized by narrow and broad anxiety constructs.

Electroencephalographic Correlates of Obsessive-Compulsive Disorder

This chapter reviews EEG research in Obsessive-Compulsive Disorder (OCD), focusing on Event-Related Potentials (ERPs) such as the Contingent Negative Variation, N2, Error-Related Negativity, the feedback Error-Related Negativity and the Readiness Potential and their neural bases. The functional significance, utility and correlation of these ERPs with OCD symptoms will be discussed, alongside novel theories for integrating the research findings. I will consider hypotheses including goal-directed behaviour, overreliance on habits, dissociations between action and knowledge, and excessive intolerance of uncertainty in the context of EEG studies, thus providing a comprehensive framework of the electroencephalographic literature concerning OCD.

Cue Valence Influences the Effects of Cue Uncertainty on ERP Responses to Emotional Events

Individuals often predict consequences, particularly emotional consequences, according to emotional or non-emotional signals conveyed by environmental cues (i.e., emotional and non-emotional cues, respectively). Some of these cues signify the consequences with certainty (i.e., certain cues), whereas others do not (i.e., uncertain cues). Several event-related potential (ERP) studies regarding non-emotional cues have suggested that the effects of cue uncertainty on attention to emotional events occur in both perception and evaluation processes. However, due to the limitations of previous studies, it is unclear what the effects of cue uncertainty would be in an emotional cue condition. Moreover, it is uncertain whether the effects of cue uncertainty are affected by cue valence (i.e., emotional and non-emotional cues). To address these questions, we asked participants to view cues and then to view emotional (positive or negative) pictures. The cues either did or did not indicate the emotional content of the picture. In the emotional cue condition, happy and fearful faces were used as certain cues indicating upcoming positive and negative pictures, respectively, and neutral faces were used as uncertain cues. In the non-emotional cue condition, scrambled faces outlined in red and blue indicated upcoming positive and negative pictures, respectively, and scrambled faces outlined in green served as uncertain cues. The results showed that for negative pictures, ERP responses in a time range between 60 and 1,000 ms were shifted to a more negative direction in a certain condition than in the uncertain condition when the cues were emotional. However, the effect was the reverse for positive pictures. This effect of cue uncertainty was similar in the non-emotional cue—negative condition. In contrast, there was no effect of cue uncertainty in the non-emotional cue—positive condition. Therefore, the findings indicate that cue uncertainty modulates attention toward emotional events when the events are signified by emotional cues. The findings may also suggest that cue valence modulates the effects of cue uncertainty on attention to emotional events.

Cued for risk: Evidence for an incentive sensitization framework to explain the interplay between stress and anxiety, substance abuse, and reward uncertainty in disordered gambling behavior

Gambling disorder is an impairing condition confounded by psychiatric co-morbidity, particularly with substance use and anxiety disorders. Yet, our knowledge of the mechanisms that cause these disorders to coalesce remains limited. The Incentive Sensitization Theory suggests that sensitization of neural "wanting" pathways, which attribute incentive salience to rewards and their cues, is responsible for the excessive desire for drugs and cue-triggered craving. The resulting hyper-reactivity of the "wanting' system is believed to heavily influence compulsive drug use and relapse. Notably, evidence for sensitization of the mesolimbic dopamine pathway has been seen across gambling and substance use, as well as anxiety and stress-related pathology, with stress playing a major role in relapse. Together, this evidence highlights a phenomenon known as cross-sensitization, whereby sensitization to stress, drugs, or gambling behaviors enhance the sensitivity and dopaminergic response to any of those stimuli. Here, we review the literature on how cue attraction and reward uncertainty may underlie gambling pathology, and examine how this framework may advance our understanding of co-mordidity with substance-use disorders (e.g., alcohol, nicotine) and anxiety disorders. We argue that reward uncertainty, as seen in slot machines and games of chance, increases dopaminergic activity in the mesolimbic pathway and enhances the incentive value of reward cues. We propose that incentive sensitization by reward uncertainty may interact with and predispose individuals to drug abuse and stress, creating a mechanism through which co-mordidity of these disorders may emerge.

Emotional arousal elicited by irrelevant stimuli affects event-related potentials (ERPs) during response inhibition

Previous event-related potential (ERP) studies using the Go/Nogo task have indicated that response inhibition is influenced by the arousal elicited by emotional stimuli, when those stimuli are relevant to response selection of Go and Nogo trials. Due to stimulus and task design issues, however, it is uncertain whether response inhibition is affected by emotional valence or arousal, when emotional stimuli are irrelevant to response selection. Therefore, the present study aimed to re-investigate this issue by circumventing limitations of previous research. To address this issue, thirty-one young adults (16 females and 15 males) were required to make motor responses to frequently-presented faces of one sex (Go trials) and to inhibit responses to less-frequently presented faces of the opposite sex (Nogo trials). Crucially, the faces were superimposed onto positive, negative and neutral pictures. The pictures were presented in a randomized order. The arousal values between positive and negative pictures were highly matched. Results showed that Nogo faces elicited smaller N2 but larger P3a amplitudes, when the faces were associated with positive and negative pictures as compared to neutral pictures. These findings suggest that response inhibition is influenced by emotional arousal, when emotional stimuli are irrelevant to response selection. Additionally, for Go faces, results showed smaller N2 but larger P3a amplitudes within negative pictures as compared to neutral and positive pictures, suggesting a role of emotional valence elicited by irrelevant stimuli on response execution.

Neuro-hemodynamic endophenotypes of emotional interference in OCD: fMRI study using emotion counting stroop task

BACKGROUND

We sought to examine the endophenotype pattern of neuro-hemodynamic substrates of emotion counting Stroop (ecStroop) paradigm in patients with OCD, their unaffected siblings [first degree relatives-FDR] and healthy controls (HC).

METHODS

OCD patients (medication naïve)[N = 16], their unaffected siblings(FDR)[N = 16] and HC [N = 24] were compared using an established ecStroop paradigm in a 3-Tesla fMRI. The relative BOLD signals corresponding to the three types of conditions (neural words-N, words with negative emotional salience-E and words with salience for OCD-O) were examined in the apriori hypothesized brain regions.

RESULTS

Both in O minus N contrast and O minus E contrast, the groups demonstrated significant differential activation of right insula (BA 13). The post-hoc analyses showed in patients and FDRs relative to HC the following: significant hyperactivation of insula in O minus E contrast; significant hyperactivation of right insula and right DLPFC (BA 9) in O minus N contrast.

CONCLUSIONS

The neuro-hemodynamic responses corresponding to the obsessive words in insula and DLPFC could be potential endophenotypes. "Threat relatedness" might thus have a vulnerability meaning in the pathogenesis and neurobiological basis of OCD.

Anticipation of Uncertain Threat Modulates Subsequent Affective Responses and Covariation Bias

Uncertainty contributes to stress and anxiety-like behaviors by impairing the ability of participants to objectively estimate threat. Our study used the cue-picture paradigm in conjunction with the event-related potential (ERP) technique to explore the temporal dynamics of anticipation for and response to uncertain threat in healthy individuals. This task used two types of cue. While ‘certain’ cues precisely forecasted the valence of the subsequent pictures (negative or neutral), the valence of pictures following ‘uncertain’ cues was not predictable. ERP data showed that, during anticipation, uncertain cues elicited similar Stimulus-Preceding Negativity (SPN) to certain-negative cues, while both of them elicited larger SPN than certain-neutral cues. During affective processing, uncertainty enlarged the mean amplitude of late positive potential (LPP) for both negative and neutral pictures. Behavioral data showed that participants reported more negative mood ratings of uncertain-neutral pictures relative to certain-neutral pictures and overestimated the probability of negative pictures following uncertain cues. Importantly, the enlarged anticipatory activity evoked by uncertain cues relative to that evoked by certain-neutral cues positively modulated the more negative mood ratings of uncertain-neutral pictures relative to certain-neutral pictures. Further, this more negative mood ratings and the general arousal anticipation during anticipatory stage contributed to the covariation bias. These results can provide a novel insight into understanding the neural mechanism and pathological basis of anxiety.

Differential effects of uncertainty on LPP responses to emotional events during explicit and implicit anticipation

Previous studies have investigated whether uncertainty influences neural responses to emotional events. The findings of such studies, particularly with respect to event-related potentials (ERPs), have been controversial due to several factors, such as the stimuli that serve as cues and the emotional content of the events. However, it is still unknown whether the effects of uncertainty on ERP responses to emotional events are influenced by anticipation patterns (e.g., explicit or implicit anticipation). To address this issue, participants in the present study were presented with anticipatory cues and then emotional (negative and neutral) pictures. The cues either did or did not signify the emotional content of the upcoming picture. In the inter-stimulus intervals between cues and pictures, participants were asked to estimate the expected probability of the occurrence of a specific emotional category of the subsequent picture based on a scale in the explicit anticipation condition, while in the implicit condition, participants were asked to indicate, using a number on a scale, which color was different from the others. The results revealed that in the explicit condition, uncertainty increased late positive potential (LPP) responses, particularly for negative pictures, whereas LPP responses were larger for certain negative pictures than for uncertain negative pictures in the implicit condition. The findings in the present study suggest that the anticipation pattern influences the effects of uncertainty when evaluation of negative events.