Error monitoring dysfunction across the illness course of schizophrenia

Response monitoring abnormalities have been reported in chronic schizophrenia patients, but it is unknown whether they predate the onset of psychosis, are present in early stages of illness, or are late-developing abnormalities associated with illness progression. Response-synchronized event-related potentials (ERP) recorded during a picture-word matching task yielded error-related negativity (ERN), correct-response negativity (CRN), and error positivity (Pe) from 84 schizophrenia patients (SZ), 48 clinical high risk patients (CHR), and their age-matched healthy controls (HC; n = 110 and 88, respectively). A sub-sample of 35 early illness schizophrenia patients (ESZ) was compared to 93 age-matched HC and the CHR patients (after statistically removing the effects of normal aging). Relative to HC, 1) SZ, ESZ, and CHR had smaller ERNs, and 2) SZ and ESZ had larger CRNs and smaller Pes. Within the SZ, longer illness duration was associated with larger CRNs but was unrelated to ERN or Pe. CHR and ESZ did not differ on ERN or CRN, although Pe was smaller in ESZ than CHR. These results indicate that while ERN, CRN, and Pe abnormalities are present early in the illness, only the ERN abnormality is evident prior to psychosis onset, and only the CRN abnormality appears to worsen progressively over the illness course. Brain regions subserving response monitoring may be compromised early in the illness and possibly during its clinical prodrome.     

The effects of anxiety upon attention allocation to affective stimuli

Pictures of emotionally aversive, neutral, and pleasant scenes were presented for 500 ms, followed by a probe presented in the same location (valid trials) or an alternate location (invalid trials) as the picture. Response-times to the probes were recorded in low (N=20) and high (N=27) trait anxious participants. Results revealed an overall negative cue validity effect of shorter reaction times (RTs) on invalid than valid trials, suggestive of an inhibition of return effect. Moreover, high trait anxious females showed a reduced negative cue validity effect for aversive pictures in comparison with neutral and pleasant pictures, suggestive of selective interference by the unpleasant material. By contrast, low trait anxious females showed an enhanced negative cue validity effect for aversive pictures relative to neutral and pleasant pictures, suggestive of attentional avoidance of the aversive content. The emotional content of picture cues did not significantly affect RTs in males, regardless of anxiety status. The results suggest that biased attention processes for aversive stimuli may contribute to the greater female propensity for anxiety disorders.     

Effects of task-relevant incentives on the electrophysiological correlates of error processing in major depressive disorder

Major depressive disorder (MDD) is associated with action-monitoring dysfunction—particularly, disrupted error processing. Whether such dysregulation is further modulated by task incentives is largely unknown. The goal of this study was to investigate possible dysfunctions in error processing in MDD as a function of varying task incentives and clinical profile. To this end, we recorded the error-related negativity (ERN) and error positivity (Pe) in 18 MDD participants and 18 healthy controls during a Stroop task that intermixed no-incentive and reward trials. Relative to controls, MDD participants showed (1) larger ERN irrespective of task incentives, and (2) reduced Pe during reward (but not no-incentive) trials. Moreover, among MDD participants, Pe amplitudes were negatively correlated with depression severity and clinical symptoms. The present findings highlight distinct effects of task incentives on electrophysiological components of error processing and are interpreted within current theories of action monitoring and incentive processing in depression.     

Conflicts as aversive signals

Theories of human action control deal with the question of how cognitive control is dynamically adjusted to task demands. The conflict monitoring theory of anterior cingulate (ACC) function suggests that the ACC monitors for response conflicts in the ongoing processing stream thereby triggering the mobilization of cognitive control. Alternatively, the outcome evaluation account of ACC function suggests that the ACC monitors for negative performance outcomes, an information that serves as an aversive learning signal for future action selection. Botvinick (2007) recently suggested that both theories might converge on the detection of aversive signals in general. Here, the authors provide first evidence that conflicts are registered as aversive signals. Congruent and incongruent Stroop color-words served as primes, and positive and negative stimuli as targets in an affective priming paradigm. Negative targets were evaluated faster after incongruent than after congruent Stroop primes, and positive targets were evaluated slower after incongruent than after congruent primes. The finding that conflicts are actually registered as aversive signals bridges the gap between competing theories of ACC function and has broad theoretical and behavioral implications as it makes the conflict monitoring theory applicable to a much wider range of situations and tasks.     

Chronic worry and the temporal dynamics of emotional processing

Worriers avoid upsetting thoughts yet also demonstrate vigilance for aversive emotional information. Potentially, these processes coexist but are separated in time. Individuals scoring high on a measure of chronic uncontrollable worry were compared to low scorers during valence categorization of emotional stimuli with interleaved Stroop color word trials to monitor extended effects of emotional processing. High worriers were especially fast and accurate in judging the valence of emotional words compared to low worriers. Worriers also had smaller pupil diameters following personally relevant negative emotional stimuli compared to low worriers. Correlations with self-report scales indicated associations between the worrier pupil response profile and symptoms of chronic worry and depression. The combined behavioral and physiological data support theories of emotional vigilance followed by avoidance in worriers.     

Error-related electrocortical responses in 10-year-old children and young adults

Recent anatomical and electrophysiological evidence suggests that the anterior cingulate cortex (ACC) is relatively late to mature. This brain region appears to be critical for monitoring, evaluating, and adjusting ongoing behaviors. This monitoring elicits characteristic ERP components including the error-related negativity (ERN), error positivity (Pe) and correct-related negativity (CRN), with the ERN clearly relating to activation of the ACC; however, little attention has been paid to the examination of these ERP components in children. The present study examined developmental differences in the ERN, Pe, and CRN in normal 10-year-old children and young adults in a standard visual flanker task. We found that children had smaller ERNs than adults, with no between-group differences on the Pe, and some ambiguity concerning the CRN. Results provide electrophysiological support either for late maturation of the ACC or late involvement of the ACC in response monitoring. Results also suggest that there is some functional independence of response-monitoring ERP components. Error-related ERPs may be a useful tool in studying the development of this brain region and its role in behavior in normal and atypical development.     

Enhanced memory for emotional pictures: A product of increased attention to affective stimuli?

The current experiment addressed the question, is enhanced memory for emotional pictures due to increased attention to affective stimuli? Participants viewed pairs of pictures (emotional-neutral or neutral-neutral) whilst their eye movements were recorded; participants had to decide which picture out of each pair they preferred. There was increased attention to positive pictures and decreased attention to negative images during picture viewing. Despite this, when a recognition test was given 1 week later, memory enhancements were found for negative pictures only. Moreover, although there was a general correlation between total inspection time and memory performance, this reliability was clear only for neutral pictures, and not for emotional images. The results suggest that memory advantages for emotional pictures can occur without increased attention to such images.     

Escape conditioning and goal punishment: Effects of acquisition trials,initial punishment trials,and CS extent

In the first of three experiments in which albino rats were given spaced shockescape trials in a straight runway, groups of 6 animals were given 6 or 24 trials followed by extinction, with or without goal-box punishment. Punishment facilitated behavior after 24 trials but did not significantly affect it after 6. Both punishment and 24 trials led to more “abrupt” extinction. In the second experiment, 6 groups of 6 animals received 6, 12, or 24 trials followed by 54 extinction trials with or without goal punishment on the first 18. All punished groups ran self-punitively, and acquisition trials effects were apparent during and after punishment. In the third experiment, buzzer extent, or duration, was manipulated, and longer extents produced stronger self-punitive effects. The results of all three experiments were interpreted in the context of presumed directive effects of aversive and conditioned aversive stimuli.     

How chimpanzees (<Emphasis Type="Italic">Pan troglodytes</Emphasis>) perform in a modified emotional Stroop task

The emotional Stroop task is an experimental paradigm developed to study the relationship between emotion and cognition. Human participants required to identify the color of words typically respond more slowly to negative than to neutral words (emotional Stroop effect). Here we investigated whether chimpanzees (Pan troglodytes) would show a comparable effect. Using a touch screen, eight chimpanzees were trained to choose between two simultaneously presented stimuli based on color (two identical images with differently colored frames). In Experiment 1, the images within the color frames were shapes that were either of the same color as the surrounding frame or of the alternative color. Subjects made fewer errors and responded faster when shapes were of the same color as the frame surrounding them than when they were not, evidencing that embedded images affected target selection. Experiment 2, a modified version of the emotional Stroop task, presented subjects with four different categories of novel images: three categories of pictures of humans (veterinarian, caretaker, and stranger), and control stimuli showing a white square. Because visits by the veterinarian that include anaesthetization can be stressful for subjects, we expected impaired performance in trials presenting images of the veterinarian. For the first session, we found correct responses to be indeed slower in trials of this category. This effect was more pronounced for subjects whose last anaesthetization experience was more recent, indicating that emotional valence caused the slowdown. We propose our modified emotional Stroop task as a simple method to explore which emotional stimuli affect cognitive performance in nonhuman primates.     

Error-related psychophysiology and negative affect

The error-related negativity (ERN/Ne) and error positivity (Pe) have been associated with error detection and response monitoring. More recently, heart rate (HR) and skin conductance (SC) have also been shown to be sensitive to the internal detection of errors. An enhanced ERN has consistently been observed in anxious subjects and there is some suggestion that the ERN is related to general negative affective experience (NA). The ERN has been source localized to the anterior cingulate cortex-a structure implicated in the regulation of affective, response selection, and autonomic resources. Thus, the findings that autonomic measures and affective distress are related to response monitoring are consistent with anterior cingulate cortex function. In the present experiment, we sought to evaluate more comprehensively the relationship between self-reported negative affect and error-related physiology in a between-groups design. Results indicate that high NA was associated with significantly greater ERN and error-related SCR, and smaller Pe. These results are discussed in terms of anterior cingulate cortex function, psychopathology, and response monitoring.     

Implicit and explicit emotional behavior and mindfulness

The objective of this study was to examine whether the “step back and watch” attitude of mindfulness manifests in less emotional behavior. We hypothesized that the “acceptance” facet of mindfulness, but not the “presence” facet, is negatively associated with the magnitude of emotional behavior in four tests, i.e., (1) rating of words, (2) rating of aversive and neutral pictures, and (3) evaluative conditioning (EC). Additionally, we hypothesized that (4) the acceptance facet is associated with increased reaction time (RT) in an emotional Stroop test, and that the presence facet is associated with decreased RT and lower error rate. The sample consisted of N = 247 non-clinical adults and was tested in a cross-sectional study. The results provide partial evidence that the acceptance facet of mindfulness may be associated with less aversive reactions towards aversive stimuli. Future studies should substantiate these findings but also determine their clinical relevance.     

Trait emotions and affective modulation of the startle eyeblink: on the unique relationship of trait anger

We examined relationships among individual differences in trait emotions and the emotion-modulated startle-eyeblink response. In particular, we examined the extent to which trait anger, which is negative in valence, would be associated with a pattern of approach motivation in startle eyeblink responses to appetitive stimuli. Self-reported trait emotions were compared with emotion-modulated startle eyeblink responses to auditory probes during appetitive, aversive, and neutral pictures. Results revealed that trait anger, enjoyment, and surprise were each associated with greater blink inhibition to appetitive pictures, indicating an approach motivational response. No other trait emotions were associated with startle eyeblink responses to appetitive or aversive pictures. These results support the idea that trait anger, although experienced as a negative emotion, is associated with an approach-related motivational response to appetitive stimuli at basic, reflexive levels of processing.     

Aversive and appetitive electrodermal classical conditioning using pictures as stimuli

The principal goal of this study was to verify whether it was possible to obtain both aversive and appetitive electrodermal classical conditioning, using pictures as conditioned stimuli (CS), and unconditioned stimuli (US). Additionally, we tried to verify whether, as a consequence of such conditioning, diminution of the unconditioned response (UR) was observed. With this aim, IAPS (?International Affective Picture System?) pictures were selected as stimuli. A picture showing a burnt face was used as the aversive US (USav), and a picture showing a scene with erotic content was used as the appetitive US (USap). As the aversive CS (CSav), and appetitive CS (CSap), two images with intermediate values of valence and arousal showing male faces were selected. In the experimental group, 10 CSav/USav and 10 CSap/USap trials were presented. In the control group 10 CSav, CSap, USav, and USap trials were presented in pseudorandom order. Skin conductance response (SCR) elicited by both the CSs and the USs was scored. Results showed aversive conditioning, but neither appetitive conditioning nor UR diminution. Problems to obtain conditioning using pictures as stimuli and possible options to overcome them in future research are discussed.     

Insular activity during passive viewing of aversive stimuli reflects individual differences in state negative affect

People differ with regard to how they perceive, experience, and express negative affect. While trait negative affect reflects a stable, sustained personality trait, state negative affect represents a stimulus limited and temporally acute emotion. So far, little is known about the neural systems mediating the relationship between negative affect and acute emotion processing. To address this issue we investigated in a healthy female sample how individual differences in state negative affect are reflected in changes in blood oxygen level-dependent responses during passive viewing of emotional stimuli. To assess autonomic arousal we simultaneously recorded changes in skin conductance level. At the psychophysiological level we found increased skin conductance level in response to aversive relative to neutral pictures. However, there was no association of state negative affect with skin conductance level. At the neural level we found that high state negative affect was associated with increased left insular activity during passive viewing of aversive stimuli. The insula has been implicated in interoceptive processes and in the integration of sensory, visceral, and affective information thus contributing to subjective emotional experience. Greater recruitment of the insula in response to aversive relative to neutral stimuli in subjects with high state negative affect may represent increased processing of salient aversive stimuli.     

Working memory load reduces the late positive potential and this effect is attenuated with increasing anxiety

Emotion regulation decreases the processing of arousing stimuli, as indexed by the late positive potential (LPP), an electrocortical component that varies in amplitude with emotional arousal. Emotion regulation increases activity in the prefrontal areas associated with cognitive control, including the dosolateral prefrontal cortex (DLPFC). The present study manipulated working memory load, known to activate the DLPFC, and recorded the LPP elicited by aversive and neutral IAPS pictures presented during the retention interval. The LPP was larger on low-load compared to high-load trials, and on trials with aversive compared to neutral pictures. These LPP data suggest that emotional content and working memory load have opposing effects on attention to distracting stimuli. State anxiety was associated with reduced modulation of the LPP by working memory load. Results are discussed in terms of competition for attention between emotion and cognition and suggest a relationship between DLPFC activation and the allocation of attentional resources to distracting visual stimuli–a relationship that may be disrupted with increasing anxiety.     

Cognitive avoidance,positive affect,and gender as predictors of the processing of aversive information

The study investigated the influence of cognitive avoidance, positive affect, and gender on the evaluation of and memory for threat-related information varying in degrees of aversiveness and ambiguity. Stimulus material consisted of threatening, nonthreatening, and ambiguous pictures. First, valence ratings of the stimuli were collected. This phase was followed by a first memory test. A second memory test was administered three days later. Memory for aversive information was influenced by cognitive avoidance, positive affect, and gender. Avoiders exhibited a comparatively good memory for aversive information in the first (immediate) test and a very poor memory in the delayed testing. A similar pattern was obtained for individuals high in positive affect. Compared to men, women gave more negative ratings to aversive and ambiguous pictures and had a better memory for ambiguous information in the immediate test. Results are discussed within the framework of the repressive discontinuity hypothesis proposed by Hock and Krohne [Hock, M., Krohne, H. W. (2004). Coping with threat and memory for ambiguous information: Testing the repressive discontinuity hypothesis. Emotion, 4, 65–86].     

Sex differences in the time course of emotion

Conventional wisdom holds that women are more "emotional" than men. However, research evidence suggests that sex differences in emotion are considerably more complex. The authors tested hypotheses about sex differences in the engagement of the approach and avoidance motivational systems thought to underpin emotional responses. The authors measured reported emotional experience and startle response magnitude both during the presentation and after the offset of emotional stimuli that engage these motivational systems to assess whether men and women differ in their patterns of immediate response to emotional stimuli and in their patterns of recovery from these responses. Our findings indicated that women were more experientially reactive to negative, but not positive, emotional pictures compared to men, and that women scored higher than men on measure of aversive motivational system sensitivity. Although both men and women exhibited potentiation of the startle response during the presentation of negative pictures relative to neutral pictures, only women continued to show this relative potentiation during the recovery period, indicating that women were continuing to engage the aversive motivational system after the offset of negative emotional pictures.     

Cognitive Bias in Spider-Phobic Children: Comparison of a Pictorial and a Linguistic Spider Stroop

The relation between spider fear in children and cognitive processing bias toward threatening information was examined. It was investigated whether spider fear in children is related to a cognitive bias for threatening pictures and words. Pictorial and linguistic Stroop stimuli were administered to 28 spider phobic and 30 control children aged 8–12. Spider-phobic children showed a moderate bias for threatening words. Surprisingly, no bias was found for spider pictures, while the spider-phobic children judged the pictures as more aversive. Moreover, in a recent similar study in adults (Kindt & Brosschot, 1997), a strong relation between spider phobia and bias toward threat words and pictures was found. Several explanations are given to account for this divergence.     

Attention control: Relationships between self-report and behavioural measures,and symptoms of anxiety and depression

Previous research has demonstrated differences in processing between fear-relevant stimuli, such as snakes and spiders, and non-fear-relevant stimuli. The current research examined whether non-fear-relevant animal stimuli, such as dogs, birds and fish, were processed like fear-relevant stimuli following aversive learning. Pictures of a priori fear-relevant animals, snakes and spiders, were evaluated as negative in affective priming and ratings and were preferentially attended to in a visual search task. Pictures of dogs, birds and fish that had been trained as CS+ in an aversive conditioning design were evaluated more negatively and facilitated dot probe detection relative to CS? pictures. The current studies demonstrated that stimuli viewed as positive prior to aversive learning were negative and were preferentially attended to after a brief learning episode. We propose that aversive learning may provide a mechanism for the acquisition of stimulus fear relevance.     

The locus of the emotional Stroop effect: A study with the PRP paradigm

Stimuli that are clearly positive or negative (hence valence-laden stimuli) have the potential to interrupt unrelated task processing. A typical example is the emotional Stroop effect (ESE) in which responding to a certain task feature (e.g., color) is delayed by the presentation of task-irrelevant valent stimuli (e.g., negative pictures) compared to valence-neutral stimuli. Here we scrutinize which processes are slowed down by irrelevant but valent stimulation. In Experiment 1, participants performed in a Psychological Refractory Period (PRP) experiment with tone discrimination as Task 1 and color discrimination as Task 2. Importantly, colors in Task 2 were accompanied by valent or neutral pictures. Valent pictures delayed responding in Task 2 (thus an ESE) and this delay was additive to the time interval between tasks. In Experiment 2, task order was reversed and the ESE in Task 1 fully propagated to the Task 2 tone discrimination. These results imply that irrelevant valence-laden stimulation delays capacity-limited processes, and we suggest that this is a late perceptual process acting on stimulus categorization.