The conditioning model of neurosis

Effects of transcranial direct current stimulation on neural activity and functional connectivity during fear extinction

Background/Objective

Anxiety disorders are highly prevalent and negatively impact daily functioning and quality of life. Transcranial direct current stimulation (tDCS) targeting the dorsolateral prefrontal cortex (dlPFC), especially in the right hemisphere impacts extinction learning; however, the underlying neural mechanisms are elusive. Therefore, we aimed to investigate the effects of cathodal tDCS stimulation to the right dlPFC on neural activity and connectivity patterns during delayed fear extinction in healthy participants.

Methods

We conducted a two-day fear conditioning and extinction procedure. On the first day, we collected fear-related self-reports, clinical questionnaires, and skin conductance responses during fear acquisition. On the second day, participants in the tDCS group (n = 16) received 20-min offline tDCS before fMRI and then completed the fear extinction session during fMRI. Participants in the control group (n = 18) skipped tDCS and directly underwent fMRI to complete the fear extinction procedure. Whole-brain searchlight classification and resting-state functional connectivity analyses were performed.

Results

Whole-brain searchlight classification during fear extinction showed higher classification accuracy of threat and safe cues in the left anterior dorsal and ventral insulae and hippocampus in the tDCS group than in the control group. Functional connectivity derived from the insula with the dlPFC, ventromedial prefrontal cortex, and inferior parietal lobule was increased after tDCS.

Conclusion

tDCS over the right dlPFC may function as a primer for information exchange among distally connected areas, thereby increasing stimulus discrimination. The current study did not include a sham group, and one participant of the control group was not randomized. Therefore, to address potential allocation bias, findings should be confirmed in the future with a fully randomized and sham controlled study.

Know thy SEFL: Fear sensitization and its relevance to stressor-related disorders

Extreme stress can cause long-lasting changes in affective behavior manifesting in conditions such as post-traumatic stress disorder (PTSD). Understanding the biological mechanisms that govern trauma-induced behavioral dysregulation requires reliable and rigorous pre-clinical models that recapitulate multiple facets of this complex disease. For decades, Pavlovian fear conditioning has been a dominant paradigm for studying the effects of trauma through an associative learning framework. However, severe stress also causes long-lasting nonassociative fear sensitization, which is often overlooked in Pavlovian fear conditioning studies. This paper synthesizes recent research on the stress-enhanced fear learning (SEFL) paradigm, a valuable rodent model that can dissociate associative and nonassociative effects of stress. We discuss evidence that the SEFL paradigm produces nonassociative fear sensitization that is distinguishable from Pavlovian fear conditioning. We also discuss key biological variables, such as age and sex, neural circuit mechanisms, and crucial gaps in knowledge. We argue that nonassociative fear sensitization deserves more attention within current PTSD models and that SEFL provides a valuable complement to Pavlovian conditioning research on trauma-related pathology.

A narrative review of psychological theories of post-traumatic stress disorder, voice hearing, and other psychotic symptoms

BACKGROUND

Most voice hearers report childhood trauma. Many voice hearers report comorbid post-traumatic stress symptoms and that the content of their voices (auditory verbal hallucinations) is directly (voices repeat phrases spoken by perpetrators) or indirectly (voice content and trauma is thematically similar) related to their trauma. The factors that maintain trauma-related voices are unknown, and there is limited research in this area. This study aimed to identify potential maintaining factors of trauma-related voices by reviewing models of post-traumatic stress disorder (PTSD) and positive symptoms of psychosis.

METHOD

Models of PTSD and positive symptoms were reviewed to identify potential factors that are unique and common to both sets of symptoms.

RESULTS

We reviewed 10 models of PTSD, 4 models of positive symptoms, and 2 trauma-informed models of voice hearing. One model provided a theoretical explanation of different types of trauma-related voices. Twenty-one factors were extracted from 16 theoretical models. No existing model incorporated all these factors.

DISCUSSION

Existing PTSD and positive symptom models present a range of common and unique factors. There may be value in extending existing integrative models to include a broader range of potential factors that could explain different pathways to, and expressions of, trauma-related voices. A future research agenda is presented to investigate how such an extension could lead to more complete individualized case formulations and targeted treatments.

Teoria da Sensibilidade ao Reforçamento: Pressupostos, Procedimentos e Medidas

Resumo A Teoria da Sensibilidade ao Reforçamento (RST) é um modelo psicobiológico de personalidade derivado de estudos experimentais com humanos e não humanos. Na RST, duas dimensões de personalidade influenciam a reatividade ao ambiente: sensibilidade à recompensa (SR) e sensibilidade à punição (SP). O pressuposto central da teoria é de que há uma relação entre personalidade (SR e SP) e aprendizagem por condicionamento. O objetivo deste artigo é apresentar aos pesquisadores brasileiros a história, as hipóteses centrais e os procedimentos experimentais da RST e discutir as medidas utilizadas para testar os pressupostos da teoria. A RST é um modelo promissor para o estudo da personalidade dentro da psicologia experimental, psiquiatria e neurociências.

Triggers of Primary Headaches: Issues and Pathways Forward

The triggers of primary headaches have considerable significance for our understanding and management of headache and migraine. Triggers explain the variance in headaches - why they occur when they do. Trigger management is generally viewed as an important component of a comprehensive treatment approach for headaches. Historically, however, triggers have not had a prominent place in the headache literature. This situation began to change 20 to 30 years ago, and the pace of change has increased exponentially in recent times. Nevertheless, the field is beset with issues that have held it back from achieving more. This review will focus on elaborating those issues with the goal of suggesting ways forward. The first issue considered will be the definition of a trigger, and how specific triggers are labeled. Consideration will then be given to a classification system for triggers. The review will discuss next the evidence relating to whether self-reported triggers can, indeed, precipitate headaches, and how the capacity to elicit headaches may be acquired or extinguished. Attention will be given to the very important clinical issue of trigger management. Finally, the pathways forward will be proposed. Perhaps the most useful thing to accomplish at this point in time would be agreement on a definition of headache triggers, a list of triggers, and a classification system for triggers. This would greatly assist in comparing research on triggers from different research groups as well as eliminating some of the issues identified in this review. An authoritative body such as the American Headache Society or the International Headache Society, could establish a multidisciplinary committee that would complete these tasks. Consideration should also be given to incorporating triggers into the International Classification of Headache Disorders as an axis or via the use of codes, as this would raise the profile of triggers in assessment and management.

General personality dimensions, impairment and treatment response in obsessive-compulsive disorder

General personality dimensions are associated with clinical severity and treatment response in individuals with depression and many anxiety disorders, but little is known about these relationships in individuals with obsessive-compulsive disorder (OCD). Individuals in the current study included 705 adults with OCD who had participated in family and genetic studies of the disorder. Participants self-completed the Neuroticism, Extraversion, Openness Personality Inventory or Neuroticism, Extraversion, Openness Five-Factor Inventory-3. Relationships between personality scores, and subjective impairment and OCD treatment response, were evaluated. The odds of subjective impairment increased with (unit increase in) the neuroticism score (odds ratio, OR = 1.03; 95% CI = 1.01-1.04; p < 0.01) and decreased with extraversion scores (OR = 0.98; 95% CI = 0.96-0.99; p < 0.01). The odds of reporting a good response to serotonin/selective serotonin reuptake inhibitors (OR = 1.02; 95% CI = 1.01-1.04; p < 0.01) or cognitive behavioural therapy (OR = 1.03; 95% CI = 1.01-1.05; p < 0.01) increased with the extraversion score. The magnitude of these relationships did not change appreciably after adjusting for other clinical features related to one or more of the personality dimensions. The findings suggest that neuroticism and extraversion are associated with subjective impairment, and that extraversion is associated with self-reported treatment response, in individuals with OCD. © 2019 John Wiley & Sons, Ltd.

Effects of UCS Intensity and Duration of Exposure of Nonreinforced CS on Conditioned Electrodermal Responses: An Experimental Analysis of the Incubation Theory of Anxiety

Eysenck's incubation theory of fear or anxiety was examined in a human Pavlovian conditioning experiment with skin-conductance responses as the dependent variable. The conditioned stimuli (CSs) were fear-relevant slides (snakes and spiders) and the unconditioned stimuli (UCSs) were aversive tones. Different groups of subjects were presented two tone intensities during the acquisition phase and three durations of nonreinforced CS (extinction phase) in a delay differential conditioning paradigm. Resistance to extinction of conditioned skin-conductance responses (conditioned fear responses) exhibited was largest for high intensity of tone and short presentations of the nonreinforced CS (CS + presented alone). The result tends to support Eysenck's incubation theory of anxiety.

The uses of trauma in experiment: Traumatic stress and the history of experimental neurosis, c. 1925-1975

The article retraces the shifting conceptualizations of psychological trauma in experimental psychopathological research in the middle decades of the twentieth century in the United States. Among researchers studying so-called experimental neuroses in animal laboratories, trauma was an often-invoked category used to denote the clash of conflicting forces believed to lead to neurotic suffering. Experimental psychologists, however, soon grew skeptical of the traumatogenic model and ultimately came to reject neurosis as a disease entity. Both theoretical differences and practical circumstances, such as the technical challenge of stabilizing neurotic symptoms in rats, led to this demise. Yet, despite their reservations, experimental psychologists continued to employ traumatic stimuli to produce psychopathological syndromes. In the 1960s, a new understanding of trauma evolved, which emphasized the loss of control experienced by traumatized animal subjects. These shifting ideas about trauma, I argue, reflect both varying experimental cultures, epistemic norms as well as changing societal concerns.

Inhibited Personality Temperaments Translated Through Enhanced Avoidance and Associative Learning Increase Vulnerability for PTSD

Although many individuals who experience a trauma go on to develop post-traumatic stress disorder (PTSD), the rate of PTSD following trauma is only about 15-24%. There must be some pre-existing conditions that impart increased vulnerability to some individuals and not others. Diathesis models of PTSD theorize that pre-existing vulnerabilities interact with traumatic experiences to produce psychopathology. Recent work has indicated that personality factors such as behavioral inhibition (BI), harm avoidance (HA), and distressed (Type D) personality are vulnerability factors for the development of PTSD and anxiety disorders. These personality temperaments produce enhanced acquisition or maintenance of associations, especially avoidance, which is a criterion symptom of PTSD. In this review, we highlight the evidence for a relationship between these personality types and enhanced avoidance and associative learning, which may increase risk for the development of PTSD. First, we provide the evidence confirming a relationship among BI, HA, distressed (Type D) personality, and PTSD. Second, we present recent findings that BI is associated with enhanced avoidance learning in both humans and animal models. Third, we will review evidence that BI is also associated with enhanced eyeblink conditioning in both humans and animal models. Overall, data from both humans and animals suggest that these personality traits promote enhanced avoidance and associative learning, as well as slowing of extinction in some training protocols, which all support the learning diathesis model. These findings of enhanced learning in vulnerable individuals can be used to develop objective behavioral measures to pre-identify individuals who are more at risk for development of PTSD following traumatic events, allowing for early (possibly preventative) intervention, as well as suggesting possible therapies for PTSD targeted on remediating avoidance or associative learning. Future work should explore the neural substrates of enhanced avoidance and associative learning for behaviorally inhibited individuals in both the animal model and human participants.

Reconceptualising Exposure and Some Implications for Cognitive-Behavioural and Psychodynamic Practice

The concept of exposure is ubiquitous in the research and practice of clinical psychology, most notably in cognitive-behavioural models. Yet there remains confusion and ambiguity around how exposure in ‘exposure therapy’ is characterised. Current definitions are found to be inadequate, as each identifies certain features of the exposure process but omits others. As such, an elaborated model of exposure is presented, referred to here as the re-exposure-extinction learning process. This process involves a complex causal situation consisting of clinical features (the cause/causes, C), acting upon a person (the field, F), to bring about re-exposure to anxiety-provoking stimuli and then extinction learning, leading, over time, to therapeutic change (the effect/effects, E). Importantly, re-exposure and extinction learning are two processes distinct from the therapeutic procedures (i.e., techniques and methods) used to bring them about. Furthermore, these processes are not inherently tied to a particular model of therapy or clinical intervention. They are, therefore, logically independent of the procedures used to facilitate them. Considering this reconceptualisation, we propose that working in the transference, a cornerstone of psychodynamic psychotherapy, can be understood as a complementary and effective method of facilitating the re-exposure-extinction learning process. We argue that this is achieved through enabling a person to repeatedly re-evaluate their fearful expectations as they manifest in the unfolding dynamics of the therapeutic relationship. Finally, some clinical implications indicated by this elaborated model are explored.

Neuromodulation Strategies in Post-Traumatic Stress Disorder: From Preclinical Models to Clinical Applications

Post-traumatic stress disorder (PTSD) is an often debilitating disease with a lifetime prevalence rate between 5⁻8%. In war veterans, these numbers are even higher, reaching approximately 10% to 25%. Although most patients benefit from the use of medications and psychotherapy, approximately 20% to 30% do not have an adequate response to conventional treatments. Neuromodulation strategies have been investigated for various psychiatric disorders with promising results, and may represent an important treatment option for individuals with difficult-to-treat forms of PTSD. We review the relevant neurocircuitry and preclinical stimulation studies in models of fear and anxiety, as well as clinical data on the use of transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation (rTMS), and deep brain stimulation (DBS) for the treatment of PTSD.

A conditioning model of delusion

"Delusions" are beliefs that are false and persistent. It is suggested here that these characteristics can emerge from interplays between two fundamental learning processes: (1) the allocation of attentional resources among stimuli; and (2) the effects of feedback on learning. The former of these has been operationalized in the learned irrelevance and latent inhibition paradigms; the latter in studies of the effects of persistence-training. Normally, the attentional process functions to constrain persistence-training effects so that only valid associations acquire persistence. But when persistence-training is less influenced in this way, its mechanisms can interact with a noisy environment to gradually insulate maladaptive associations from disconfirming feedback. When unchecked, these dynamics likely lead to a systematic distortion of beliefs that can become increasingly persistent regardless of their validity. Delusions are therefore predicted to tend to arise whenever the balance of (1) is weakened in favour of (2), whether by experimental manipulation, trait-related factors, cultural causes or evolutionary history. Existing evidence is consistent with the model and further implications are discussed.

Posttraumatic Stress Disorder: Perspectives for the Use of Deep Brain Stimulation

OBJECTIVES

Deep Brain Stimulation (DBS) has been either approved or is currently under investigation for a number of psychiatric disorders.

MATERIALS AND METHODS

We review clinical and preclinical concepts as well as the neurocircuitry that may be of relevance for the implementation of DBS in posttraumatic stress disorder (PTSD).

RESULTS

PTSD is a chronic and debilitating illness associated with dysfunction in well-established neural circuits, including the amygdala and prefrontal cortex. Although most patients often improve with medications and/or psychotherapy, approximately 20-30% are considered to be refractory to conventional treatments. In other psychiatric disorders, DBS has been investigated in treatment-refractory patients. To date, preclinical work suggests that stimulation at high frequency delivered at particular timeframes to different targets, including the amygdala, ventral striatum, hippocampus, and prefrontal cortex may improve fear extinction and anxiety-like behavior in rodents. In the only clinical report published so far, a patient implanted with electrodes in the amygdala has shown striking improvements in PTSD symptoms.

CONCLUSIONS

Neuroimaging, preclinical, and preliminary clinical data suggest that the use of DBS for the treatment of PTSD may be practical but the field requires further investigation.

Can Transcranial Direct Current Stimulation Augment Extinction of Conditioned Fear?

BACKGROUND

Exposure-based therapy parallels extinction learning of conditioned fear. Prior research points to the ventromedial prefrontal cortex as a potential site for the consolidation of extinction learning and subsequent retention of extinction memory.

OBJECTIVE/HYPOTHESIS

The present study aimed to evaluate whether the application of non-invasive transcranial direct current stimulation (tDCS) during extinction learning enhances late extinction and early recall in human participants.

METHODS

Forty-four healthy volunteers completed a 2-day Pavlovian fear conditioning, extinction, and recall paradigm while skin conductance activity was continuously measured. Twenty-six participants received 2 mA anodal tDCS over EEG coordinate AF3 during extinction of a first conditioned stimulus. The remaining 18 participants received similar tDCS during extinction of a second conditioned stimulus. Sham stimulation was applied for the balance of extinction trials in both groups. Normalized skin conductance changes were analyzed using linear mixed models to evaluate effects of tDCS over late extinction and early recall trials.

RESULTS

We observed a significant interaction between timing of tDCS during extinction blocks and changes in skin conductance reactivity over late extinction trials. These data indicate that tDCS was associated with accelerated late extinction learning of a second conditioned stimulus after tDCS was combined with extinction learning of a previous conditioned stimulus. No significant effects of tDCS timing were observed on early extinction recall.

CONCLUSIONS

Results could be explained by an anxiolytic aftereffect of tDCS and extend previous studies on tDCS-induced modulation of fear and threat related learning processes. These findings support further exploration of the clinical use of tDCS.

D-Cycloserine acts via increasing the GluN1 protein expressions in the frontal cortex and decreases the avoidance and risk assessment behaviors in a rat traumatic stress model

D-cycloserine (DCS), an FDA approved anti-tuberculosis drug has extensively been studied for its cognitive enhancer effects in psychiatric disorders. DCS may enhance the effects of fear extinction trainings in animals during exposure therapy and hence we investigated the effects of DCS on distinct behavioral parameters in a predator odor stress model and tested the optimal duration for repeated daily administrations of the agent. Cat fur odor blocks were used to produce stress and avoidance and risk assessment behavioral parameters were used where DCS or saline were used as treatments in adjunct to extinction trainings. We observed that DCS facilitated extinction training by providing further extinction of avoidance responses, risk assessment behaviors and increased the contact with the cue in a setting where DCS was administered before extinction trainings for 3 days without producing a significant tolerance. In amygdala and hippocampus, GluN1 protein expressions decreased 72h after the fear conditioning in the traumatic stress group suggesting a possible down-regulation of NMDARs. We observed that extinction learning increased GluN1 proteins both in the amygdaloid complex and the dorsal hippocampus of the rats receiving extinction training or extinction training with DCS. Our findings also indicate that DCS with extinction training increased GluN1 protein levels in the frontal cortex. We may suggest that action of DCS relies on enhancement of the consolidation of fear extinction in the frontal cortex.

Enhancing cognitive-behavioural therapy for recurrent headache: design of a randomised controlled trial

Background

We have argued against the traditional approach of counselling avoidance of all triggers of headaches and migraine. Problems with this approach include the impossibility of avoiding all triggers and the high costs associated with trying to do so, and that avoidance could lead to reduced tolerance for the triggers. We have developed an alternative approach called Learning to Cope with Triggers (LCT) that encourages avoidance of triggers that are detrimental to health and wellbeing, but uses exposure to other triggers to desensitise headache sufferers to the triggers. This approach has been shown to be more effective than advising avoidance of all triggers. Trigger management is only one component of a comprehensive treatment program and the current study is designed to evaluate a new approach to treating headaches in which LCT has been integrated into an established cognitive-behavioural therapy (CBT) package (LCT/CBT).

Methods/Design

A target sample of 120 adult participants who suffer from migraine or tension-type headache, at least six days per month, and have done so for at least 12 months will be recruited. Participants will be randomly assigned to one of three groups: LCT/CBT; Avoid/CBT (CBT combined with instructions to avoid all triggers); and waiting-list control. Measures will include: daily diaries for recording headaches, triggers and medication consumption; headache disability and quality of life; trigger avoidance; locus of control and self-efficacy; and coping strategies. Treatment will involve 12 60-minute sessions scheduled weekly. Assessment will be completed before and after treatment, and at 4 and 12 month follow-up. The data will be analysed to determine which approach is most effective, and predictors of response to treatment.

Discussion

Migraine and tension-type headache are common and can be disabling. CBT has been demonstrated to be an efficacious treatment for both disorders. However, there is room for improvement. This study aims to increase the efficacy of behavioural approaches and identify factors predictive of a positive response.

Trial registration

Australian and New Zealand Clinical Trials Registry ACTRN12614000435684.

Equating context conditioning in Pavlovian incubation of US signal value

The present study replicated the finding by Goddard (2013), that when a single food pellet unconditioned stimulus (US) signaled the delivery of three additional pellets, responding after the single US was significantly greater on a delayed, compared to an early, test. Importantly, the present study equated context conditioning by delivering the identical number of food pellets in both conditioning and testing and showed that responding was significantly reduced in control subjects that had received unpaired single food-triple food presentations. Implications for theories of conditioning are considered.

Learning models of PTSD: Theoretical accounts and psychobiological evidence

Learning abnormalities have long been centrally implicated in posttraumatic psychopathology. Indeed, of all anxiety disorders, PTSD may be most clearly attributable to discrete, aversive learning events. In PTSD, such learning is acquired during the traumatic encounter and is expressed as both conditioned fear to stimuli associated with the event and more general over-reactivity-or failure to adapt-to intense, novel, or fear-related stimuli. The relatively straightforward link between PTSD and these basic, evolutionarily old, learning processes of conditioning, sensitization, and habituation affords models of PTSD comprised of fundamental, experimentally tractable mechanisms of learning that have been well characterized across a variety of mammalian species including humans. Though such learning mechanisms have featured prominently in explanatory models of psychological maladjustment to trauma for at least 90years, much of the empirical testing of these models has occurred only in the past two decades. The current review delineates the variety of theories forming this longstanding tradition of learning-based models of PTSD, details empirical evidence for such models, attempts an integrative account of results from this literature, and specifies limitations of, and future directions for, studies testing learning models of PTSD.

Trauma Revaluation, Conditioning, and Anxiety Disorders

This paper describes a two-component conditioning model of anxiety disorders whose two main components are an associative process and a process which determines the evaluation of the unconditioned stimulus (UCS). It is argued that the inclusion of UCS revaluation processes enables conditioning models to explain a variety of anxiety-related phenomena that hitherto had been difficult to explain solely in associative terms. In particular, (a) experiments are described which suggest that incubation of the conditioned response (CR) can be explained in terms of processes contributing to UCS inflation, (b) the experimental evidence on UCS revaluation is assessed in relation to cognitive processes that might lead to trauma revaluation within specific anxiety disorders, and (c) the role of personality factors in effecting UCS and trauma revaluation is discussed.

From Pavlov to PTSD: the extinction of conditioned fear in rodents, humans, and anxiety disorders

Nearly 100 years ago, Ivan Pavlov demonstrated that dogs could learn to use a neutral cue to predict a biologically relevant event: after repeated predictive pairings, Pavlov's dogs were conditioned to anticipate food at the sound of a bell, which caused them to salivate. Like sustenance, danger is biologically relevant, and neutral cues can take on great salience when they predict a threat to survival. In anxiety disorders such as posttraumatic stress disorder (PTSD), this type of conditioned fear fails to extinguish, and reminders of traumatic events can cause pathological conditioned fear responses for decades after danger has passed. In this review, we use fear conditioning and extinction studies to draw a direct line from Pavlov to PTSD and other anxiety disorders. We explain how rodent studies have informed neuroimaging studies of healthy humans and humans with PTSD. We describe several genes that have been linked to both PTSD and fear conditioning and extinction and explain how abnormalities in fear conditioning or extinction may reflect a general biomarker of anxiety disorders. Finally, we explore drug and neuromodulation treatments that may enhance therapeutic extinction in anxiety disorders.

Incubation of fear

While fear and anxiety can grow over time in anxiety disorders, most efforts to model this phenomenon with fear conditioning in rodents cause fear that remains stable or decreases across weeks or months. Here, we describe several methods to induce conditioned fear that grows over the course of 1 month and is sustained for at least 2 months using an extended fear conditioning approach. These methods include a very reliable standard method that causes multiple fear measures to increase over months, as well as alternative methods.

Neural substrates of individual differences in human fear learning: evidence from concurrent fMRI, fear-potentiated startle, and US-expectancy data

To provide insight into individual differences in fear learning, we examined the emotional and cognitive expressions of discriminative fear conditioning in direct relation to its neural substrates. Contrary to previous behavioral–neural (fMRI) research on fear learning—in which the emotional expression of fear was generally indexed by skin conductance—we used fear-potentiated startle, a more reliable and specific index of fear. While we obtained concurrent fear-potentiated startle, neuroimaging (fMRI), and US-expectancy data, healthy participants underwent a fear-conditioning paradigm in which one of two conditioned stimuli (CS⁺ but not CS^–) was paired with a shock (unconditioned stimulus [US]). Fear learning was evident from the differential expressions of fear (CS⁺ > CS^–) at both the behavioral level (startle potentiation and US expectancy) and the neural level (in amygdala, anterior cingulate cortex, hippocampus, and insula). We examined individual differences in discriminative fear conditioning by classifying participants (as conditionable vs. unconditionable) according to whether they showed successful differential startle potentiation. This revealed that the individual differences in the emotional expression of discriminative fear learning (startle potentiation) were reflected in differential amygdala activation, regardless of the cognitive expression of fear learning (CS–US contingency or hippocampal activation). Our study provides the first evidence for the potential of examining startle potentiation in concurrent fMRI research on fear learning.

Well that changes everything! The genesis of memory bias for threat with implications for delayed onset in anxiety disorders

BACKGROUND AND OBJECTIVES

A number of aetiological pathways have been proposed in the development of anxiety disorders, including those associated with stressful triggering situations. Life events can provide new meaning to past situations, potentially leading to the delayed onset of a disorder. Whether or not a disorder will emerge is theoretically related to one's appraisal and memory of prior events, and memory biases are proposed to exist for threat-related information in association with anxiety. Given that new events may change the meaning of past experiences, threatening information may change one's memory for once-neutral events.

METHODS

The current study aimed to examine the effect of threatening information on memory for previously encoded (neutral) stimuli. Undergraduate participants (n = 81) interacted with 30 neutral objects (displayed in two boxes) and completed a recall memory test for these objects. They were then randomly assigned to receive either new threatening or new neutral information about half (one box) of the already-learned objects; a second recall test was then administered.

RESULTS

Individuals given threatening information showed a greater proportion of memory for items that were manipulated to total items recalled than did individuals given new non-threatening information.

LIMITATIONS

A nonclinical sample reported relatively low ratings of disgust and anxiety. Additionally, the time between the two memory tests was brief, likely differing from the actual occurrence of delayed onset disorders.

CONCLUSIONS

Results showed the genesis of a memory bias for threat in the presumed absence of an attentional bias, and are discussed in terms of the delayed onset of anxiety disorders.

Theoretical implications of the neurotic paradox as a problem in behavior theory: An experimental resolution

Why do human phobias last for months or years when such behavior should undergo extinction? This failure of extinction or persistence of self-defeating behavior of human disorders was labeled by Mowrer as the neurotic paradox. The paradox is cited by an ever-increasing number of critics who challenge any laboratory-based learning model of human psychopathology. Laboratory research, of course, omits essential requirements in the analysis of behavior, and the principles derived from such analyses must be combined in order to explain complex human behavaior. Validation for a behavioral model can thus be achieved if (a) basic principles inferred from observation of humans treated with a laboratory-derived extinction procedure (e.g., implosive therapy) are combined with (b) principles examined in laboratory research that are combined to generate unique predictions that correspond to known features of human phobic behavior. The latter evidence is briefly reviewed in research demonstrating sustained responding over one thousand consecutive active avoidance responses with complete avoidance of the "phobic" CS for an initial single shock trial. Differential reinforcement for responses to early sequential stimuli depends on minimal work requirement, and reinforcement by timeout from avoidance. This combination of factors effectively precludes extinction to main conditioned aversive stimuli for nonhumans, as it does for human phobias. Support for a laboratory model of human phobia is thereby attained.

Aspects of psychodynamic neuropsychiatry II: psychical locality and biology: toward the neurobiology of psychotherapy

Throughout his career, Freud believed that psychiatry in general and psychoanalysis in particular would one day be rooted in anatomical/biological ground. He felt confidant that such ground would replace the psychological understanding on which he had been forced to base most of his clinical theory and practice. He felt confidant that one day psychotherapy would be more "scientific." This article seeks to demonstrate that this day is arriving. A clinical case is presented where assessment and formulation are largely based on neurobiology, where treatment was conducted less in accord with psychodynamic theory than neurodynamic data of anatomy and biology.

Noradrenergic enhancement of reconsolidation in the amygdala impairs extinction of conditioned fear in rats--a possible mechanism for the persistence of traumatic memories in PTSD

BACKGROUND

Posttraumatic stress disorder (PTSD) is associated with enhanced noradrenergic activity. Animal and human studies demonstrate that noradrenergic stimulation augments consolidation of fear learning. Retrieval of well-established memories by presenting a learned fear cue triggers reconsolidation processes during which memories may be updated, weakened, or strengthened. We previously reported that noradrenergic blockade in the rat amygdala impairs reconsolidation of fear memories. Here we investigated the effects of noradrenergic enhancement on reconsolidation of learned fear.

METHODS

Using auditory fear conditioning in rats, we tested the effects of postretrieval intraamygdala infusion of the β-adrenergic receptor agonist isoproterenol or the antagonist propranolol on conditioned fear in the amygdala.

RESULTS

A single intraamygdala infusion of isoproterenol following a retrieval of a well-consolidated memory enhanced fear memory elicited by the learned fear stimulus and impaired extinction of this memory 48 hr later. Intraamygdala infusion of the β-adrenergic receptor antagonist propranolol following a consecutive retrieval trial blocked the enhancing effects of isoproterenol on fear memory.

CONCLUSIONS

Postretrieval β-adrenergic stimulation in the amygdala enhances reconsolidation of fear memories, making them resistant to extinction. Noradrenergic augmentation during retrieval of fear memories may thus contribute to persistence and severity of traumatic memories. Reconsolidation may be a useful tool in understanding the pathology of PTSD and may thus help in developing new and in modifying existing treatments of traumatic memories.

Behavioral management of migraine headache triggers: learning to cope with triggers

The literature on migraine triggers is reviewed, including the most common triggers, interactions between triggers, the research evidence related to the capacity of self-reported triggers to precipitate headaches, and the neurobiologic pathways by which triggers induce migraine attacks. An argument is developed against the standard advice to avoid migraine triggers as the best way of preventing attacks, based on conceptual and practical criticisms, and consideration of cognate literatures on chronic pain, stress, and anxiety. A small number of studies suggest that exposure to headache triggers has the same effect as exposure to anxiety-eliciting stimuli, with short exposure associated with increased pain response and prolonged exposure associated with decreased pain response. On the basis of this literature, "learning to cope with triggers" is advocated, where controlled exposure and approach/confront strategies are used to manage migraine triggers, except in cases where such an approach would probably be inappropriate.

The phylogeny and ontogeny of behavior

Responses are strengthened by consequences having to do with the survival of individuals and species. With respect to the provenance of behavior, we know more about ontogenic than phylogenic contingencies. The contingencies responsible for unlearned behavior acted long ago. This remoteness affects our scientific methods, both experimental and conceptual. Until we have identified he variables responsible for an event, we tend to invent causes. Explanatory entities such as “instincts,” “drives,” and “traits” still survive. Unable to show how organisms can behave effectively under complex circumstances, we endow them with special abilities permitting them to do so.

Behavior exhibited by most members of a species is often accepted as inherited if all members were not likely to have been exposed to relevant ontogenic contingencies. When contingencies are not obvious, it is perhaps unwise to call any behavior either inherited or acquired, as the examples of churring in honey guides and following in imprinted ducklings show. Nor can the relative importance of phylogenic and ontogenic contingencies be argued from instances in which unlearned or learned behavior intrudes or dominates. Intrusions occur in both directions.

Behavior influenced by its consequences seems directed toward the future, but only past effects are relevant. The mere fact that behavior is adaptive does not indicate whether phylogenic or ontogenic processes have been responsible for it. Examples include the several possible provenances of imitation, aggression, and communication. The generality of such concepts limits their usefulness. A more specific analysis is needed if we are to deal effectively with the two kinds of contingencies and their products.