Attention network functioning in children with anxiety disorders, attention-deficit/hyperactivity disorder and non-clinical anxiety.

BACKGROUND: Research with adults suggests that anxiety is associated with poor control of executive attention. However, in children, it is unclear (a) whether anxiety disorders and non-clinical anxiety are associated with deficits in executive attention, (b) whether such deficits are specific to anxiety versus other psychiatric disorders, and (c) whether there is heterogeneity among anxiety disorders (in particular, specific phobia versus other anxiety disorders). METHOD: We examined executive attention in 860 children classified into three groups: anxiety disorders (n = 67), attention-deficit/hyperactivity disorder (ADHD; n = 67) and no psychiatric disorder (n = 726). Anxiety disorders were subdivided into: anxiety disorders excluding specific phobia (n = 43) and specific phobia (n = 21). The Attention Network Task was used to assess executive attention, alerting and orienting. RESULTS: Findings indicated heterogeneity among anxiety disorders, as children with anxiety disorders (excluding specific phobia) showed impaired executive attention, compared with disorder-free children, whereas children with specific phobia showed no executive attention deficit. Among disorder-free children, executive attention was less efficient in those with high, relative to low, levels of anxiety. There were no anxiety-related deficits in orienting or alerting. Children with ADHD not only had poorer executive attention than disorder-free children, but also higher orienting scores, less accurate responses and more variable response times. CONCLUSIONS: Impaired executive attention in children (reflected by difficulty inhibiting processing of task-irrelevant information) was not fully explained by general psychopathology, but instead showed specific associations with anxiety disorders (other than specific phobia) and ADHD, as well as with high levels of anxiety symptoms in disorder-free children.

Biased attention to threat in paediatric anxiety disorders (generalized anxiety disorder, social phobia, specific phobia, separation anxiety disorder) as a function of 'distress' versus 'fear' diagnostic categorization.

BACKGROUND: Structural models of emotional disorders propose that anxiety disorders can be classified into fear and distress disorders. Sources of evidence for this distinction come from genetic, self-report and neurophysiological data from adults. The present study examined whether this distinction relates to cognitive processes, indexed by attention bias towards threat, which is thought to cause and maintain anxiety disorders. METHOD: Diagnostic and attention bias data were analysed from 435 children between 5 and 13 years of age; 158 had principal fear disorder (specific phobia, social phobia or separation anxiety disorder), 75 had principal distress disorder (generalized anxiety disorder, GAD) and 202 had no psychiatric disorder. Anxious children were a clinic-based treatment-seeking sample. Attention bias was assessed on a visual-probe task with angry, neutral and happy faces. RESULTS: Compared to healthy controls, children with principal distress disorder (GAD) showed a significant bias towards threat relative to neutral faces whereas children with principal fear disorder showed an attention bias away from threat relative to neutral faces. Overall, children displayed an attention bias towards happy faces, irrespective of diagnostic group. CONCLUSIONS: Our findings support the distinction between fear and distress disorders, and extend empirically derived structural models of emotional disorders to threat processing in childhood, when many anxiety disorders begin and predict lifetime impairment.

Threat bias in attention orienting: evidence of specificity in a large community-based study.

BACKGROUND: Preliminary research implicates threat-related attention biases in paediatric anxiety disorders. However, major questions exist concerning diagnostic specificity, effects of symptom-severity levels, and threat-stimulus exposure durations in attention paradigms. This study examines these issues in a large, community school-based sample. Method A total of 2046 children (ages 6-12 years) were assessed using the Development and Well Being Assessment (DAWBA), Childhood Behavior Checklist (CBCL) and dot-probe tasks. Children were classified based on presence or absence of 'fear-related' disorders, 'distress-related' disorders, and behavioural disorders. Two dot-probe tasks, which differed in stimulus exposure, assessed attention biases for happy-face and threat-face cues. The main analysis included 1774 children. RESULTS: For attention bias scores, a three-way interaction emerged among face-cue emotional valence, diagnostic group, and internalizing symptom severity (F = 2.87, p < 0.05). This interaction reflected different associations between internalizing symptom severity and threat-related attention bias across diagnostic groups. In children with no diagnosis (n = 1411, mean difference = 11.03, s.e. = 3.47, df = 1, p < 0.001) and those with distress-related disorders (n = 66, mean difference = 10.63, s.e. = 5.24, df = 1, p < 0.05), high internalizing symptoms predicted vigilance towards threat. However, in children with fear-related disorders (n = 86, mean difference = -11.90, s.e. = 5.94, df = 1, p < 0.05), high internalizing symptoms predicted an opposite tendency, manifesting as greater bias away from threat. These associations did not emerge in the behaviour-disorder group (n = 211). CONCLUSIONS: The association between internalizing symptoms and biased orienting varies with the nature of developmental psychopathology. Both the form and severity of psychopathology moderates threat-related attention biases in children.

Obese adults have visual attention bias for food cue images: evidence for altered reward system function.

BACKGROUND: The major aim of this study was to investigate whether the motivational salience of food cues (as reflected by their attention-grabbing properties) differs between obese and normal-weight subjects in a manner consistent with altered reward system function in obesity. METHODOLOGY/PRINCIPAL FINDINGS: A total of 18 obese and 18 normal-weight, otherwise healthy, adult women between the ages of 18 and 35 participated in an eye-tracking paradigm in combination with a visual probe task. Eye movements and reaction time to food and non-food images were recorded during both fasted and fed conditions in a counterbalanced design. Eating behavior and hunger level were assessed by self-report measures. Obese individuals had higher scores than normal-weight individuals on self-report measures of responsiveness to external food cues and vulnerability to disruptions in control of eating behavior. Both obese and normal-weight individuals demonstrated increased gaze duration for food compared to non-food images in the fasted condition. In the fed condition, however, despite reduced hunger in both groups, obese individuals maintained the increased attention to food images, whereas normal-weight individuals had similar gaze duration for food and non-food images. Additionally, obese individuals had preferential orienting toward food images at the onset of each image. Obese and normal-weight individuals did not differ in reaction time measures in the fasted or fed condition. CONCLUSIONS/SIGNIFICANCE: Food cue incentive salience is elevated equally in normal-weight and obese individuals during fasting. Obese individuals retain incentive salience for food cues despite feeding and decreased self-report of hunger. Sensitization to food cues in the environment and their dysregulation in obese individuals may play a role in the development and/or maintenance of obesity.

Do the affective properties of smoking-related cues influence attentional and approach biases in cigarette smokers?

Research indicates that drug-related cues elicit attention and approach biases in drug users. However, attentional biases are not unique to addiction (e.g., they are also found for emotional information). This study examined whether attentional and approach biases in cigarette smokers are mediated by the motivational salience of cues (relevance to drug-taking), rather than by their affective properties (subjective liking of the cues). Cues included pleasant and unpleasant smoking-related pictures. Attentional biases, approach tendencies and subjective evaluation of the cues were assessed on visual probe, stimulus-response compatibility and rating tasks, respectively. Compared with non-smokers, smokers showed a greater attentional bias for both pleasant and unpleasant smoking-related cues presented for 2000 ms, but not for 200 ms. Smokers showed a greater approach bias for unpleasant cues, although the groups did not differ significantly in approach bias for pleasant smoking-related cues. Smokers rated both pleasant and unpleasant smoking pictures more positively than did non-smokers. Results suggest that a bias to maintain attention on smoking-related cues in young adult smokers is primarily a function of drug-relevance, rather than affective properties, of the cues. In contrast, approach tendencies and pleasantness judgements were influenced by drug use, drug-relevance and the affective properties of the cues.

Proteomics in zebrafish exposed to endocrine disrupting chemicals.

Embryonic zebrafish were examined for changes in protein expression following exposure to sublethal concentrations of 17beta-estradiol (E2) and the estrogen mimic 4-nonylphenol (4-NP). Protein Expression Signatures were derived from embryo homogenates by two-dimensional electrophoresis and digital imaging. In both experiments approximately 30% of the proteins sampled were specific to either E2 or 4-NP and about 33% were common to the control, 4-NP and E2. However, of the proteins induced by either E2 or 4-NP, 28% were common to both chemicals at 1 ppm but only 7% were common to both at 0.1 ppm. While there are many proteins that respond specifically to each chemical, relatively few are common to the two chemicals suggesting that the response pathways of the two chemicals are distinct.

Attentional orienting towards smoking-related stimuli.

According to incentive salience theory, conditioned stimuli (CS+) associated with drug reinforcement acquire the capacity to elicit a conditioned attentional orienting response, which controls drug-seeking and drug-taking behaviour. We sought evidence for this proposal by measuring visual attentional orienting towards smoking pictures presented briefly in the periphery of the visual field, versus control pictures likewise presented, in smokers versus non-smokers. In each trial, smokers and non-smokers responded manually to a dot probe stimulus that appeared in a location previously occupied by either a smoking picture or a control picture. Attentional bias scores were calculated by subtracting the median reaction time (RT) in the former condition from the median RT in the latter condition. In two experiments, light-smokers (smokers of fewer than 20 cigarettes/day) produced a mean bias score that was significantly greater than that of heavy-smokers (smokers of 20 or more cigarettes/day) and non-smokers. In addition, when smokers from the two experiments were pooled, a significant quadratic relationship was found between cigarettes/day and the attentional bias for the smoking stimuli. These findings are consistent with incentive salience theories and dual-process theories of addiction.

Microspectrophotometric analysis of intact chromatophores of the Japanese medaka, Oryzias latipes.

To investigate the possible photoprotective role of chromatophores in fish, the absorbances of four types of intact chromatophores in adult and larval Japanese medaka were analyzed using microspectrophotometric techniques. The absorbance spectrum of each chromatophore class was obtained from 300 to 550 nm. The absorbance spectra of intact leucophores, melanophores and xanthophores were very similar to the published absorbance spectra of the isolated pure pigments contained in each chromatophore type, pteridines, melanin and carotenoids or pteridines, respectively. Based on these absorbance spectra, leucophores and melanophores should provide the most ultraviolet (UV) photoprotection to fish since the compounds they contain, pteridines and melanin, correspondingly, have strong absorbances in the UV region of the spectrum. Xanthophores containing carotenoids are not likely to provide much protection to fish from UV-induced damage since carotenoids have low absorbances in the UV range. Xanthophores containing colored pteridines, however, may provide somewhat greater UV protection to fish, since pteridines absorb more light than carotenoids in the UV portion of the spectrum. The relative frequency, coverage and thickness of these two types of xanthophores should determine how much protection xanthophores as a chromatophore type would provide against UV-induced damage.

Attentional bias for drug cues in opiate dependence.

BACKGROUND: In a number of theories of compulsive drug use conditioned responses to stimuli associated with drug taking play a pivotal role. For example, according to incentive-sensitization theory (Robinson & Berridge, 1993), drug-related stimuli selectively capture attention, and the neural mechanisms underlying this attentional bias play a key role in the development and maintenance of drug dependence, and in relapse. However, there has been little work that assesses attentional biases in addiction. METHODS: We used a pictorial probe detection task to investigate whether there is an attentional bias to stimuli associated with drug use in opiate dependence. Stimuli presented included pairs of drug-related and matched neutral pictures. Methadone-maintained opiate addicts (N = 16) were compared with age-matched controls (N = 16). RESULTS: A mixed design analysis of variance of response times to probes revealed a significant three-way interaction of group x drug picture location x probe location. Opiate addicts had relatively faster reaction times to probes that replaced drug pictures rather than neutral pictures, consistent with the predicted attentional bias to drug-related stimuli. CONCLUSIONS: These results support the idea that an attentional bias for drug-related stimuli occurs in opiate dependence. This is consistent with the concept of a central role for such salient stimuli in compulsive drug use.

Biases in eye movements to threatening facial expressions in generalized anxiety disorder and depressive disorder.

The study investigated biases in selective attention to emotional face stimuli in generalized anxiety disorder (GAD) and depressive disorder, using a modified probe detection task. There were 4 face types: threatening, sad, happy, and neutral. Measures of attentional bias included (a) the direction and latency of the initial eye movement in response to the faces and (b) manual reaction time (RT) to probes replacing the face stimuli 1,000 ms after their onset. Results showed that individuals with GAD (without depressive disorder) were more likely to look first toward threat faces rather than neutral faces compared with normal controls and those with depressive disorder. They also shifted their gaze more quickly toward threat faces, rather than away from them, relative to the other two groups. There were no significant findings from the manual RT data. Implications of the results for recent theories of clinical anxiety and depression are discussed.

Protein expression signatures identified in Mytilus edulis exposed to PCBs, copper and salinity stress.

Applied to environmental toxicology, proteome analysis may be used to isolate chemical-specific protein expression signatures (PES). In this project specific PES were isolated in mussels, Mytilus edulis, from the Baltic Sea subjected in the laboratory to treatment with copper (70 ppb), Aroclor 1248 (1 ppb), and to lowered salinity. Four mussels in each treatment group were acclimated in the laboratory for 24 h before beginning the 7-day exposure. Whole body tissue was homogenized and separated using two-dimensional gel electrophoresis. The protein gels were scanned to TIFF files and compared using MELANIE II 2D gel analysis software (BioRad). Protein expression signatures including proteins induced and repressed by exposure were isolated for each treatment group. The specificity of PES due to environmental changes shows promise in bioindication, toxicity testing and in helping identify possible toxicity mechanisms.

Protein expression signatures and lysosomal stability in Mytilus edulis exposed to graded copper concentrations.

Protein expression and lysosomal stability were observed in Mytilus edulis exposed to 0, 20, 40, 60, and 80 ppb copper sulfate for 24 h in a static exposure system. Haemolymph was removed from each mussel and analyzed for lysosomal damage using the Neutral Red retention assay expressed as the ratio of lysosomal size to cell area, the lysosomal destabilization ratio. Gill tissue from the same individuals was dissected, homogenized and the proteins extracted and then separated using two-dimensional gel electrophoresis. Two-dimensional protein maps from each concentration were analyzed using MELANIE II 2D gel analysis software (Biorad). Lysosomal damage increased with each dosage, with LDRs ranging from 0.18 +/- 0.01 at 0 ppb copper sulfate to 0.32 +/- 0.11 at 80 ppb copper sulfate. Orthogonal comparisons showed that the control, 20 and 40 ppb classes together differed significantly (P < 0.05) from the 60 and 80 ppb classes together. Specific protein expression signatures were identified at each dosage.

Attentional bias for emotional faces in generalized anxiety disorder.

OBJECTIVES: Recent cognitive theories propose that attentional biases cause or maintain anxiety disorders. This study had several aims: (i) to investigate such biases in generalized anxiety disorder (GAD) using naturalistic, ecologically valid stimuli, namely, emotional facial expressions; (ii) to test the emotionality hypothesis by examining biases for happy as well as threat faces; and (iii) to assess the time course of the attentional bias. DESIGN: The dependent variable was an index of attentional bias derived from manual RTs to probe stimuli. There were four independent variables: one between-subjects variable of group (2: GAD, control), and three within-subjects variables: Type of emotional face (2: threat, happy), Stimulus duration (2: 500 ms, 1250 ms) and Half of task (2: first, second). METHOD: Attentional bias was assessed with a dot probe task. The stimuli comprised photographs of threatening, happy and neutral faces, presented using two exposure durations: 500 ms and 1250 ms. RESULTS: Anxious patients showed greater vigilance for threatening faces relative to neutral faces, compared with normal controls. This effect did not significantly vary as a function of stimulus duration. Anxious patients also showed enhanced vigilance for happy faces, but this was only significant in the second half of the task. CONCLUSIONS: The study confirmed not only that GAD patients show a bias in selective attention to threat, relative to controls, but also that this bias operates for naturalistic, non-verbal stimuli. As the attentional biases for threat and happy faces appeared to develop over a different time frame, different underlying mechanisms may be responsible.

Some methodological issues in assessing attentional biases for threatening faces in anxiety: a replication study using a modified version of the probe detection task.

Various versions of the probe detection task have been developed to assess attentional biases in anxiety and there is debate about their relative merits in terms of reliability and sensitivity to such biases. The present study used a pictorial version of the probe detection task to examine attentional biases for emotional facial expressions. The main aims were (1) to see if our previous finding of greater vigilance for threatening faces in high than low trait anxiety could be replicated [Bradley, B. P., Mogg, K., Falla, S. J., & Hamilton, L. R. (1998). Attentional bias for threatening facial expressions in anxiety: manipulation of stimulus duration. Cognition and Emotion, in press] and (2) to examine whether the same pattern of results and a similar effect size, would be obtained using a 'probe position' task (i.e. where is the probe?), rather than the 'probe classification' task (i.e. what is the type of the probe?) used by Bradley et al. (1998). The probe position task produced similar results to those obtained from the probe classification task, so providing further evidence of an anxiety-related attentional bias for threatening faces. Results also indicated that, for non-clinical participants, the probe position task yielded faster overall RTs, fewer errors and a similar effect size, compared with the probe classification task. Implications for the assessment of attentional biases in non-clinical and clinical samples are discussed.

A cognitive-motivational analysis of anxiety.

Evidence of preattentive and attentional biases in anxiety is evaluated from a cognitive-motivational perspective. According to this analysis, vulnerability to anxiety stems mainly from a lower threshold for appraising threat, rather than a bias in the direction of attention deployment. Thus, relatively innocuous stimuli are evaluated as having higher subjective threat value by high than low trait anxious individuals, and it is further assumed that everyone orients to stimuli that are judged to be significantly threatening. This account is contrasted with other recent cognitive models of anxiety, and implications for the etiology, maintenance and treatment of anxiety disorders are discussed.

Selective attention to food-related stimuli in hunger: are attentional biases specific to emotional and psychopathological states, or are they also found in normal drive states?

Previous work has indicated that anxiety disorders and eating disorders are associated with selective processing of stimuli relevant to patients' concerns (e.g. Mathews and MacLeod, 1994; Annual Review of Psychology, 45, 25-50; Channon et al., 1988; British Journal of Clinical Psychology, 27, 259-260). A dot probe task was used to investigate whether attentional biases are also a feature of a normal drive state. Specifically, we examined whether hunger is associated with biases in selective attention and in pre-attentive processes for food-relevant stimuli. Subjects with high levels of hunger showed a greater attentional bias for food-related words presented in a suprathreshold exposure condition (words shown for 500 msec), in comparison with those with low hunger. There was no evidence in the present study of a hunger-related bias in pre-attentive processes (i.e. when words were shown for 14 msec and masked). Results suggest that a non-emotional motivational state, such as hunger, is associated with a bias in certain aspects of information processing, such as selective attention, for stimuli that are relevant to the motivational state. Findings are discussed in relation to recent research into emotion-related cognitive biases.

Attentional biases for negative information in induced and naturally occurring dysphoria.

Two studies investigated the relationship between attentional biases for negative information and dysphoria--both induced (Study 1) and naturally occurring (Study 2). In a modified dot probe task a series of word pairs was presented, and Ss responded to probes that replaced one of the words in each pair. The stimuli included depression-related, anxiety-related and neutral words. To examine the time course of the attentional biases, there were three exposure durations of the word pairs: 14 ms (+ 186 ms mask); 500 ms and 1000 ms. In Study 1, the depressed mood induction procedure was associated with greater vigilance for depression-related words at 500 ms, with a similar trend at 1000 ms. In Study 2, measures of depressed mood and vulnerability correlated positively with vigilance for negative words in the 1000 ms condition. There was no evidence from either study that depressed mood was associated with a pre-conscious bias for negative words (i.e. in the 14 ms masked exposure condition). However, this pre-conscious bias was associated with high trait anxiety in Study 2, consistent with previous research. The results are discussed in relation to theoretical and empirical work on cognitive biases in clinical and non-clinical anxiety and depression.

Time course of attentional bias for threat information in non-clinical anxiety.

A modified version of the probe detection task was used to investigate the effect of stimulus exposure duration on attentional bias for threat stimuli in a non-clinical sample of subjects. Stimulus duration was manipulated in order to examine different components of the anxiety-related attentional bias, i.e. initial orienting versus maintenance of attention to threat. Word pairs were presented on a computer screen for 100, 500 or 1,500 msec, and immediately after the termination of the display of each pair, a dot probe appeared in the position of one of the words. Higher levels of state anxiety were associated with faster response latencies for probes that replaced threat words, rather than neutral words (i.e. attentional vigilance for threat). This bias was not significantly affected by the exposure duration of the word stimuli. Thus, the attentional bias for threat does not appear to vary significantly over this range (100-1,500 msec) in non-clinical anxiety; it is recommended that the time course of the attentional bias be investigated further in clinical anxiety.

Implicit memory bias in clinical and non-clinical depression.

Implicit memory for depression-relevant information was examined in non-clinical subjects with high versus low levels of dysphoria (Experiment 1), and in subjects who met DSM-III-R diagnostic criteria for depression versus normal controls (Experiment 2). The implicit memory test was a primed lexical decision task, with depression-relevant and neutral words, and suprathreshold and subthreshold primes. In Experiment 1, dysphoric subjects showed greater subthreshold priming of depression words than non-dysphoric subjects. In Experiment 2, clinically depressed individuals showed greater subthreshold and suprathreshold priming of depression words than normal non-depressed controls. The results confirmed those from previous studies using the primed lexical decision task to investigate implicit memory for negative information in depression (Bradley, Mogg & Williams, 1994, Behaviour Research and Therapy, 32, 65-78; Bradley, Mogg & Williams, 1995, Behaviour Research and Therapy, 33, 755-770). Implications for recent cognitive models of depression are discussed.

A follow-up study of cognitive bias in generalized anxiety disorder.

Patients with generalized anxiety disorder (GAD) without concurrent depression (n = 11) and normal controls (n = 17) were tested twice, about 2 months apart, on a modified Stroop colour-naming task, which presented anxiety-related, depression-related and neutral words in masked and unmasked exposure conditions. GAD patients received cognitive behaviour therapy in the test-retest interval, and were also retested at follow-up, about 20 months after initial testing. GAD patients showed interference in colour-naming negative words across both masked and unmasked conditions before treatment, but not post-treatment, compared with controls. Reduced interference effects of masked threat words over time correlated with reduced ratings of anxious thoughts at post-treatment, and at follow-up, in GAD patients. Thus, the preconscious bias for threat information in GAD appears to vary over time in association with changes in anxious thoughts and worries.