Developments of a water-maze procedure for studying spatial learning in the rat

Developments of an open-field water-maze procedure in which rats learn to escape from opaque water onto a hidden platform are described. These include a procedure (A) for automatically tracking the spatial location of a hooded rat without the use of attached light-emitting diodes; (B) for studying different aspects of spatial memory (e.g. working memory); and (C) for studying non-spatial discrimination learning. The speed with which rats learn these tasks suggests that they may lend themselves to a variety of behavioural investigations, including pharmacological work and studies of cerebral function.

The Fear-Avoidance Model of Musculoskeletal Pain: Current State of Scientific Evidence

Research studies focusing on the fear-avoidance model have expanded considerably since the review by Vlaeyen and Linton (Vlaeyen J. W. S. & Linton, S. J. (2000). Fear-avoidance and its consequences in chronic musculoskeletal pain: a state of the art. Pain, 85(3), 317--332). The fear-avoidance model is a cognitive-behavioral account that explains why a minority of acute low back pain sufferers develop a chronic pain problem. This paper reviews the current state of scientific evidence for the individual components of the model: pain severity, pain catastrophizing, attention to pain, escape/avoidance behavior, disability, disuse, and vulnerabilities. Furthermore, support for the contribution of pain-related fear in the inception of low back pain, the development of chronic low back pain from an acute episode, and the maintenance of enduring pain, will be highlighted. Finally, available evidence on recent clinical applications is provided, and unresolved issues that need further exploration are discussed.

Addiction motivation reformulated: an affective processing model of negative reinforcement

This article offers a reformulation of the negative reinforcement model of drug addiction and proposes that the escape and avoidance of negative affect is the prepotent motive for addictive drug use. The authors posit that negative affect is the motivational core of the withdrawal syndrome and argue that, through repeated cycles of drug use and withdrawal, addicted organisms learn to detect interoceptive cues of negative affect preconsciously. Thus, the motivational basis of much drug use is opaque and tends not to reflect cognitive control. When either stressors or abstinence causes negative affect to grow and enter consciousness, increasing negative affect biases information processing in ways that promote renewed drug administration. After explicating their model, the authors address previous critiques of negative reinforcement models in light of their reformulation and review predictions generated by their model.

Binge eating as escape from self-awareness

This article proposes that binge eating is motivated by a desire to escape from self-awareness. Binge eaters suffer from high standards and expectations, especially an acute sensitivity to the difficult (perceived) demands of others. When they fall short of these standards, they develop an aversive pattern of high self-awareness, characterized by unflattering views of self and concern over how they are perceived by others. These aversive self-perceptions are accompanied by emotional distress, which often includes anxiety and depression. To escape from this unpleasant state, binge eaters attempt the cognitive response of narrowing attention to the immediate stimulus environment and avoiding broadly meaningful thought. This narrowing of attention disengages normal inhibitions against eating and fosters an uncritical acceptance of irrational beliefs and thoughts. The escape model is capable of integrating much of the available evidence about binge eating.

Protective and damaging effects of mediators of stress. Elaborating and testing the concepts of allostasis and allostatic load

Stress is a condition of human existence and a factor in the expression of disease. A broader view of stress is that it is not just the dramatic stressful events that exact their toll but rather the many events of daily life that elevate activities of physiological systems to cause some measure of wear and tear. We call this wear and tear "allostatic load," and it reflects not only the impact of life experiences but also of genetic load; individual habits reflecting items such as diet, exercise, and substance abuse; and developmental experiences that set life-long patterns of behavior and physiological reactivity (see McEwen). Hormones associated with stress and allostatic load protect the body in the short run and promote adaptation, but in the long run allostatic load causes changes in the body that lead to disease. This will be illustrated for the immune system and brain. Among the most potent of stressors are those arising from competitive interactions between animals of the same species, leading to the formation of dominance hierarchies. Psychosocial stress of this type not only impairs cognitive function of lower ranking animals, but it can also promote disease (e.g. atherosclerosis) among those vying for the dominant position. Social ordering in human society is also associated with gradients of disease, with an increasing frequency of mortality and morbidity as one descends the scale of socioeconomic status that reflects both income and education. Although the causes of these gradients of health are very complex, they are likely to reflect, with increasing frequency at the lower end of the scale, the cumulative burden of coping with limited resources and negative life events and the allostatic load that this burden places on the physiological systems involved in coping and adaptation.

Solving the puzzle of deliberate self-harm: The experiential avoidance model

Despite increasing attention to the phenomenon of deliberate self-harm (DSH), the literature currently lacks a unifying, evidence-based, theoretical framework within which to understand the factors that control this behavior. The purpose of the present paper is to outline such a framework-the Experiential Avoidance Model (EAM) of DSH. The EAM poses that DSH is primarily maintained by negative reinforcement in the form of escape from, or avoidance of, unwanted emotional experiences. Literature on factors that may lead to experiential avoidance is reviewed, along with the mounting empirical evidence that DSH functions to help the individual escape from unwanted emotional experiences. The EAM integrates a variety of research on emotions, experiential avoidance, and DSH within a clinically useful framework that sparks novel research directions.

Simulating dynamical features of escape panic

One of the most disastrous forms of collective human behaviour is the kind of crowd stampede induced by panic, often leading to fatalities as people are crushed or trampled. Sometimes this behaviour is triggered in life-threatening situations such as fires in crowded buildings; at other times, stampedes can arise during the rush for seats or seemingly without cause. Although engineers are finding ways to alleviate the scale of such disasters, their frequency seems to be increasing with the number and size of mass events. But systematic studies of panic behaviour and quantitative theories capable of predicting such crowd dynamics are rare. Here we use a model of pedestrian behaviour to investigate the mechanisms of (and preconditions for) panic and jamming by uncoordinated motion in crowds. Our simulations suggest practical ways to prevent dangerous crowd pressures. Moreover, we find an optimal strategy for escape from a smoke-filled room, involving a mixture of individualistic behaviour and collective 'herding' instinct.

When fear is near: threat imminence elicits prefrontal-periaqueductal gray shifts in humans

Humans, like other animals, alter their behavior depending on whether a threat is close or distant. We investigated spatial imminence of threat by developing an active avoidance paradigm in which volunteers were pursued through a maze by a virtual predator endowed with an ability to chase, capture, and inflict pain. Using functional magnetic resonance imaging, we found that as the virtual predator grew closer, brain activity shifted from the ventromedial prefrontal cortex to the periaqueductal gray. This shift showed maximal expression when a high degree of pain was anticipated. Moreover, imminence-driven periaqueductal gray activity correlated with increased subjective degree of dread and decreased confidence of escape. Our findings cast light on the neural dynamics of threat anticipation and have implications for the neurobiology of human anxiety-related disorders.

Fear in animals: a meta-analysis and review of risk assessment

The amount of risk animals perceive in a given circumstance (i.e. their degree of 'fear') is a difficult motivational state to study. While many studies have used flight initiation distance as a proxy for fearfulness and examined the factors influencing the decision to flee, there is no general understanding of the relative importance of these factors. By identifying factors with large effect sizes, we can determine whether anti-predator strategies reduce fear, and we gain a unique perspective on the coevolution of predator and anti-predator behaviour. Based on an extensive review and formal meta-analysis, we found that predator traits that were associated with greater risk (speed, size, directness of approach), increased prey distance to refuge and experience with predators consistently amplified the perception of risk (in terms of flight initiation distance). While fish tolerated closer approach when in larger schools, other taxa had greater flight initiation distances when in larger groups. The presence of armoured and cryptic morphologies decreased perception of risk, but body temperature in lizards had no robust effect on flight initiation distance. We find that selection generally acts on prey to be sensitive to predator behaviour, as well as on prey to modify their behaviour and morphology.

Analgesia from electrical stimulation in the brainstem of the rat

Stimulation at several mesencephalic and diencephalic sites abolished responsiveness to intense pain in rats while leaving responsiveness to other sensory modes relatively unaffected. The peripheral field of analgesia was usually restricted to one-half or to one quadrant of the body, and painful stimuli applied outside this field elicited a normal reaction. Analgesia outlasted stimulation by up to 5 minutes. Most electrode placements that produced analgesia also supported self-stimulation. One placement supported self-stimulation only in the presence of pain.

Central command neurons of the sympathetic nervous system: basis of the fight-or-flight response

During stress, the activity of the sympathetic nervous system is changed in a global fashion, leading to an increase in cardiovascular function and a release of adrenal catecholamines. This response is thought to be regulated by a common set of brain neurons that provide a dual input to the sympathetic preganglionic neurons regulating cardiac and adrenal medullary functions. By using a double-virus transneuronal labeling technique, the existence of such a set of central autonomic neurons in the hypothalamus and brainstem was demonstrated. These neurons innervate both of the sympathetic outflow systems and likely function in circumstances where parallel sympathetic processing occurs, such as in the fight-or-flight response.

The role of defeat and entrapment (arrested flight) in depression: an exploration of an evolutionary view

BACKGROUND

The social rank theory of psychopathology suggests that with the evolution of social hierarchies various psychobiological mechanisms became attuned to the success or failure in conflict situations. Specifically, subordinates and those who have lost status are at greater risk of pathology than winners and those of higher status. In this theory concepts of defeat and entrapment are seen to be of special relevance to the study of depression. We outline the role of defeat and entrapment within the social rank theory of depression.

METHODS

New self-report measures of entrapment and defeat were developed and used to test predictions of the social rank theory of depression. Both a sample of students and depressed patients were assessed with these new scales and other social rank measures (e.g. social comparison and submissive behaviour).

RESULTS

The entrapment and defeat measures were found to have good psychometric properties and significantly correlated with depression. They were also strongly associated with other rank variables. Defeat maintained a strong association with depression even after controlling for hopelessness (r = 0.62), whereas the relationship between hopelessness and depression was substantially reduced when controlling for defeat. Entrapment and defeat added substantially to the explained variance of depression after controlling for the other social rank variables.

CONCLUSIONS

Defeat and entrapment appear to be promising variables for the study of depression. These variables may also help to develop linkages between human and animal models of psychopathology.

Uncontrollability and unpredictability in post-traumatic stress disorder: an animal model

The disturbances observed in animals subjected to unpredictable and uncontrollable aversive events resemble post-traumatic stress disorder (PTSD) symptoms and thus may constitute an animal model of this disorder. It is argued that the similarity between animals' symptoms and those of trauma victims may reflect common etiological factors. Relevant experiments in which animals exhibit generalized fear and arousal, discrete fear of a conditioned stimulus (CS), analgesia, and avoidance are reviewed with the view that these manifestations may be analogous to the PTSD symptom clusters of persistent arousal, reexperiencing, numbing, and avoidance, respectively. Finally, animal paradigms are suggested to test the validity of the model and specific hypotheses are derived from the animal literature regarding trauma variables that are predictive of particular PTSD symptom clusters.

Family enhancement of cognitive style in anxious and aggressive children

Previous research has shown that anxious adults provide more threat interpretations of ambiguous stimuli than other clinic and nonclinic persons. We were interested in investigating if the same bias occurs in anxious children and how family processes impact on these children's interpretations of ambiguity. Anxious, oppositional, and nonclinical children and their parents were asked separately to interpret and provide plans of action to ambiguous scenarios. Afterwards, each family was asked to discuss two of these situations as a family and for the child to provide a final response. The results showed that anxious and oppositional children were both more likely to interpret ambiguous scenarios in a threatening manner. However, the two clinic groups differed in that the anxious children predominantly chose avoidant solutions whereas the oppositional children chose aggressive solutions. After family discussions, both the anxious children's avoidant plans of action and the oppositional children's aggressive plans increased. Thus, this study provides the first evidence of family enhancement of avoidant and aggressive responses in children. These results support a model of anxiety that emphasizes the development of an anxious cognitive style in the context of anxiety-supporting family processes.

Antipredator defensive behaviors in a visible burrow system

Analyzed defensive behaviors in a seminatural setting through videorecordings of groups of 4 male and 4 female rats. Before cat exposure dominant males showed more offensive behavior, eating, drinking, and use of the open area than subordinates. Presentation of a cat in the open area produced changes in four subpatterns of defense over a 24-hr period: withdrawal; immobility and movement constraint; risk assessment; and suppression of nondefensive behaviors. All Ss showed pronounced and consistent changes in each of these patterns, but dominant males alone showed increased risk assessment-related corner runs. These results provide an extensive description of rat defensive behaviors in a seminatural and relatively unstructured situation and suggest that the anxiety process is initially associated with withdrawal and movement arrest, giving way to a crucial and long-lasting risk-assessment stage that provides information leading to either further defensiveness or a return to nondefensive behaviors. This analysis suggests new models for the study of anxiety.

Inescapable versus escapable shock modulates long-term potentiation in the rat hippocampus

A group of rats was trained to escape low-intensity shock in a shuttle-box test, while another group of yoked controls could not escape but was exposed to the same amount and regime of shock. After 1 week of training, long-term potentiation (LTP) was measured in vitro in hippocampal slices. Exposure to uncontrollable shock massively impaired LTP relative to exposure to the same amount and regime of controllable shock. These results provide evidence that controllability modulates plasticity at the cellular-neuronal level.

Antecedents of adherence to medical recommendations: results from the Medical Outcomes Study

A longitudinal study of patients with chronic medical diseases (hypertension, diabetes, heart disease) was conducted to identify antecedents of adherence to medical recommendations. Data are from 1198 patients in three health-care provision systems in Los Angeles, Chicago, and Boston. Nonadherence at the beginning of the study was the strongest predictor of nonadherence 2 years later. Other significant predictors varied by type of adherence outcome. Patients who were younger and who relied upon avoidant coping strategies tended to be less likely to follow their doctor's specific recommendations. Patients who were distressed about their health, used avoidant coping strategies, or who reported worse physical and role functioning were less likely to adhere in general. Patient satisfaction with two features of care (interpersonal quality and financial aspects) was positively related to adherence in some models, but satisfaction with the technical quality of care was negatively associated with adherence to specific recommendations among heart disease patients. Social support contributed to specific adherence among diabetic patients. Implications of the study for medical care providers are discussed.

Twenty-two kHz alarm cries to presentation of a predator, by laboratory rats living in visible burrow systems

When a cat was presented to groups of 3 male and 2 female laboratory rats in the open area of a visible burrow system, the rats retreated to the burrow system and showed high levels of 18-24 kHz ultrasonic cries during the cat presentation and for 30 min following removal of the cat. Latency to make ultrasonic vocalizations, durations of these vocalizations, and duration in the burrow systems were all strikingly and reliably different during and after cat exposure in comparison to similar periods with a control (stuffed cat toy) stimulus. However, when individual rats were exposed to a cat in an open area of similar size, ultrasonic cry production was minimal. Also rats exposed individually to a cat in an apparatus providing an escape chamber similarly showed no ultrasonic cries, indicating that concealment per se is not a sufficient condition for their appearance. These results suggest that the production of ultrasonic vocalizations during and after exposure to a predator is greatly facilitated by the presence of familiar conspecifics, and may serve as alarm cries. While the alarm cry hypothesis also suggests a possible function for 18-24 kHz ultrasounds in the context of copulation and intraspecies aggression, the sonographic and functional relationships among the cries emitted in these different situations remain to be analyzed.

Test anxiety and the hierarchical model of approach and avoidance achievement motivation

This research was designed to incorporate the test anxiety (TA) construct into the hierarchical model of approach and avoidance achievement motivation. Hypotheses regarding state and trait TA were tested in 2 studies, and the results provided strong support for the predictions. State TA (specifically, worry) was documented as a mediator of the negative relationship between performance-avoidance goals and exam performance. The positive relationship between performance-approach goals and exam performance was shown to be independent of TA processes. A series of analyses documented the conceptual and functional convergence of trait TA and fear of failure (FOF), and further validation of the proposed integration was obtained by testing trait TA/FOF and state TA together in the same model. Mastery goals were positively and performance-avoidance goals negatively related to long-term retention.