Classical fear conditioning in the anxiety disorders: a meta-analysis

Fear conditioning represents the process by which a neutral stimulus comes to evoke fear following its repeated pairing with an aversive stimulus. Although fear conditioning has long been considered a central pathogenic mechanism in anxiety disorders, studies employing lab-based conditioning paradigms provide inconsistent support for this idea. A quantitative review of 20 such studies, representing fear-learning scores for 453 anxiety patients and 455 healthy controls, was conducted to verify the aggregated result of this literature and to assess the moderating influences of study characteristics. Results point to modest increases in both acquisition of fear learning and conditioned responding during extinction among anxiety patients. Importantly, these patient-control differences are not apparent when looking at discrimination studies alone and primarily emerge from studies employing simple, single-cue paradigms where only danger cues are presented and no inhibition of fear to safety cues is required.     

Spontaneous recovery from forward and backward blocking

This article demonstrates and analyzes spontaneous recovery of stimulus control following both forward and backward blocking in a conditioned suppression preparation with rats. Experiment 1 found, in first-order conditioning, robust forward blocking and an attenuation of it following a retention interval. Experiment 2 showed, in sensory preconditioning, recovery of responding following both forward and backward blocking. Also, the results of this experiment indicated that response recovery to the blocked stimulus cannot be explained by an impaired status of the blocking stimulus after a retention interval. Experiment 3, also in sensory preconditioning, suggested that spontaneous recovery following both forward and backward blocking in Experiment 2 was due to impaired associative activation of the blocking stimulus' representation during testing with the blocked stimulus. Although no contemporary model of associative learning can explain these results, a modification of R. R. Miller and L. D. Matzel's (1988) comparator hypothesis is proposed to do so.     

Evidence for a gene-environment interaction in predicting behavioral inhibition in middle childhood

Gene-environment interactions are presumed to shape human behavior during early development. However, no human research has demonstrated that such interactions lead to stable individual differences in fear responses. We tested this possibility by focusing on a polymorphism in the promoter region of the gene for the serotonin transporter (5-HTT). This polymorphism has been linked to many indices of serotonin activity. Specifically, we tested the hypothesis that an interaction between children's 5-HTT status and maternal reports of social support predicts inhibited behavior with unfamiliar peers in middle childhood. Results were consistent with this hypothesis: Children with the combination of the short 5-HTT allele and low social support had increased risk for behavioral inhibition in middle childhood.     

A comparison between elemental and compound training of cues in retrospective revaluation

Associative learning theories assume that cue interaction and, specifically, retrospective revaluation occur only when the target cue is previously trained in compound with the to-be-revalued cue. However, there are recent demonstrations of retrospective revaluation in the absence of compound training (e.g., Matute & Pine?o, 1998a, 1998b). Nevertheless, it seems reasonable to assume that cue interaction should be stronger when the cues are trained together than when they are trained apart. In two experiments with humans, we directly compared compound and elemental training of cues. The results showed that retrospective revaluation in the elemental condition can be as strong as and, sometimes, stronger than that in the compound condition. This suggests that within-compound associations are not necessary for retrospective revaluation to occur and that these effects can possibly be best understood in the framework of general interference theory.     

Electroencephalographic asymmetries in adolescents with major depression: influence of comorbidity with anxiety disorders

This study examined whether adolescents with major depressive disorder (MDD) display the abnormal electroencephalographic (EEG) alpha asymmetries found in depressed adults. Resting EEG was recorded in 25 right-handed female outpatients (19 with MDD, 11 of whom also had a current anxiety disorder; 6 with anxiety disorders only) and 10 non-ill controls. In contrast to the non-ill controls, adolescents having MDD but no anxiety disorder showed alpha asymmetry indicative of less activation over right than over left posterior sites. Within the MDD patient group, comorbid anxiety disorders reduced the posterior alpha asymmetry, supporting the potential importance of evaluating anxiety in studies of regional brain activation in adolescent MDD. These preliminary findings are similar to those from adult studies that suggest that MDD is associated with right parietotemporal hypoactivation.     

Attention training normalises combat-related post-traumatic stress disorder effects on emotional Stroop performance using lexically matched word lists

We examined two groups of combat veterans, one with post-traumatic stress disorder (PTSD) (n?=?27) and another without PTSD (n?=?16), using an emotional Stroop task (EST) with word lists matched across a series of lexical variables (e.g. length, frequency, neighbourhood size, etc.). Participants with PTSD exhibited a strong EST effect (longer colour-naming latencies for combat-relevant words as compared to neutral words). Veterans without PTSD produced no such effect, t?p?>?.37. Participants with PTSD then completed eight sessions of attention training (Attention Control Training or Attention Bias Modification Training) with a dot-probe task utilising threatening and neutral faces. After training, participants—especially those undergoing Attention Control Training—no longer produced longer colour-naming latencies for combat-related words as compared to other words, indicating normalised attention allocation processes after treatment.     

Simulating the Acquisition of Verb Inflection in Typically Developing Children and Children With Developmental Language Disorder in English and Spanish

Children with developmental language disorder (DLD) have significant deficits in language ability that cannot be attributed to neurological damage, hearing impairment, or intellectual disability. The symptoms displayed by children with DLD differ across languages. In English, DLD is often marked by severe difficulties acquiring verb inflection. Such difficulties are less apparent in languages with rich verb morphology like Spanish and Italian. Here we show how these differential profiles can be understood in terms of an interaction between properties of the input language, and the child's ability to learn predictive relations between linguistic elements that are separated within a sentence. We apply a simple associative learning model to sequential English and Spanish stimuli and show how the model's ability to associate cues occurring earlier in time with later outcomes affects the acquisition of verb inflection in English more than in Spanish. We relate this to the high frequency of the English bare form (which acts as a default) and the English process of question formation, which means that (unlike in Spanish) bare forms frequently occur in third-person singular contexts. Finally, we hypothesize that the pro-drop nature of Spanish makes it easier to associate person and number cues with the verb inflection than in English. Since the factors that conspire to make English verb inflection particularly challenging for learners with weak sequential learning abilities are much reduced or absent in Spanish, this provides an explanation for why learning Spanish verb inflection is relatively unaffected in children with DLD.     

Rejection sensitivity and disruption of attention by social threat cues

Two studies tested the hypothesis that Rejection Sensitivity (RS) increases vulnerability to disruption of attention by social threat cues, as would be consistent with prior evidence that it motivates individuals to prioritize detecting and managing potential rejection at a cost to other personal and interpersonal goals. In Study 1, RS predicted disruption of ongoing goal-directed attention by social threat but not negative words in an Emotional Stroop task. In Study 2, RS predicted attentional avoidance of threatening but not pleasant faces in a Visual Probe task. Threat-avoidant attention was also associated with features of borderline personality disorder. This research extends understanding of processes by which RS contributes to a self-perpetuating cycle of interpersonal problems and distress.     

Impact of Behavioral Inhibition and Parenting Style on Internalizing and Externalizing Problems from Early Childhood through Adolescence

Behavioral inhibition (BI) is characterized by a pattern of extreme social reticence, risk for internalizing behavior problems, and possible protection against externalizing behavior problems. Parenting style may also contribute to these associations between BI and behavior problems (BP). A sample of 113 children was assessed for BI in the laboratory at 14 and 24 months of age, self-report of maternal parenting style at 7 years of age, and maternal report of child internalizing and externalizing BP at 4, 7, and 15 years. Internalizing problems at age 4 were greatest among behaviorally inhibited children who also were exposed to permissive parenting. Furthermore, greater authoritative parenting was associated with less of an increase in internalizing behavior problems over time and greater authoritarian parenting was associated with a steeper decline in externalizing problems. Results highlight the importance of considering child and environmental factors in longitudinal patterns of BP across childhood and adolescence.