A role for Synapsin in associative learning: the Drosophila larva as a study case

Synapsins are evolutionarily conserved, highly abundant vesicular phosphoproteins in presynaptic terminals. They are thought to regulate the recruitment of synaptic vesicles from the reserve pool to the readily-releasable pool, in particular when vesicle release is to be maintained at high spiking rates. As regulation of transmitter release is a prerequisite for synaptic plasticity, we use the fruit fly Drosophila to ask whether Synapsin has a role in behavioral plasticity as well; in fruit flies, Synapsin is encoded by a single gene (syn). We tackled this question for associative olfactory learning in larval Drosophila by using the deletion mutant syn^97CS, which had been backcrossed to the Canton-S wild-type strain (CS) for 13 generations. We provide a molecular account of the genomic status of syn^97CS by PCR and show the absence of gene product on Western blots and nerve-muscle preparations. We found that olfactory associative learning in syn^97CS larvae is reduced to ~50% of wild-type CS levels; however, responsiveness to the to-be-associated stimuli and motor performance in untrained animals are normal. In addition, we introduce two novel behavioral control procedures to test stimulus responsiveness and motor performance after “sham training.” Wild-type CS and syn^97CS perform indistinguishably also in these tests. Thus, larval Drosophila can be used as a case study for a role of Synapsin in associative learning.     

The role of body image in the prevention of eating disorders

This article reviews theory and research pertaining to prevention of negative body image and eating disorders. Research derived from the social cognitive model (SCM) and non-specific vulnerability-stressor (NSVS) model indicates that sustained prevention effects for attitudes and behaviors are possible, but not easy to achieve or explain. These limitations are considered in the context of promising research derived from a third model, critical social perspectives (CSP). We conclude that (1) research on practice should aim beyond the examination of efficacy in order to clarify the active ingredients contributing to prevention; and (2) research informed by each of the divergent perspectives can be used to enrich theory and practice in the field of eating disorders prevention.     

Landmarks as beacons and associative cues: Their role in route learning

Relatively little is known about how people use the landmarks in their environment to learn routes. Landmarks are commonly regarded as associative cues--stimuli that enable recall of directional responses that lead closer to the navigator's goal. We contrast the function of landmark as associative cue with that of a beacon-a landmark near enough to a goal that moving toward it leads the navigator closer to his or her goal. In five experiments, participants learned a route through a simple desktop virtual environment. In the first three experiments, routes were learned better when their landmarks served as beacons than as associative cues. Two additional experiments showed that the acquired route knowledge depends on the function that landmarks serve during learning. Beacon-based route knowledge is less enduring and relatively less likely to involve knowledge of directions in the environment than is the route knowledge formed from landmarks that serve as associative cues.     

Using career development theories in the treatment of clients with eating disorders

Various types of psychotherapy have been used in treating clients with eating disorders - a debilitating and frustrating form of psychological illness which mainly occurs in females, especially female youth. However, little is known about the relevance of career counselling for this group of clients. This article attempts to incorporate theoretical concepts from vocational and career psychology into the helping process for clients with eating disorders. It illustrates the rationale and applicability of infusing career counselling concepts and strategies into the psychotherapy for individuals recovering from eating disorders. It also provides the implications for blending the career counselling and therapeutic interventions in the treatment process.     

The role of associative history in models of associative learning: A selective review and a hybrid model

Associative learning theories strive to capture the processes underlying and driving the change in strength of the associations between representations of stimuli that develop as a result of experience of the predictive relationships between those stimuli. Historically, formal models of associative learning have focused on two potential factors underlying associative change, namely processing of the conditioned stimulus (in terms of changes in associability) and processing of the unconditioned stimulus (in terms of changes in error). This review constitutes an analysis of the proper role of these two factors, specifically with regard to the way in which they are influenced by associative history (the prior training undergone by cues). A novel “hybrid” model of associative learning is proposed and is shown to provide a more satisfactory account of the effects of associative history on subsequent learning than any previous single-process theory.     

A method for the control of eating rate: A potential intervention in eating disorders

A method for the control of eating rate gave subjects feedback from a computer screen on how much and at what rate to eat during a meal. The method also allowed us to record the development of satiety during the meal. Linear eaters—that is, women selected for eating at an approximately constant rate—underate when challenged to eat at a lower rate and overate when challenged to eat at a higher rate, thereby modeling the eating behavior of patients with anorexia nervosa and binge eating disorder, respectively. In both cases, the women’s postmeal perception of satiety mimicked that of the respective patient group. The results provide support for the notion that linear eaters have the capacity to exhibit disordered eating.     

From the lexicon to expectations about kinds: a role for associative learning

In the novel noun generalization task, 2 1/2-year-old children display generalized expectations about how solid and nonsolid things are named, extending names for never-before-encountered solids by shape and for never-before-encountered nonsolids by material. This distinction between solids and nonsolids has been interpreted in terms of an ontological distinction between objects and substances. Nine simulations and behavioral experiments tested the hypothesis that these expectations arise from the correlations characterizing early learned noun categories. In the simulation studies, connectionist networks were trained on noun vocabularies modeled after those of children. These networks formed generalized expectations about solids and nonsolids that match children's performances in the novel noun generalization task in the very different languages of English and Japanese. The simulations also generate new predictions supported by new experiments with children. Implications are discussed in terms of children's development of distinctions between kinds of categories and in terms of the nature of this knowledge.     

Using group therapy to foster the psychosexual development of patients with eating disorders

When eating-disordered patients participate in long-term eating-dis-order groups, they move through phases of group development that parallel phases of psychosexual development. In the trust (oral) phase, members have an opportunity to experience a positive symbiosis, a suitable holding environment, and optimal frustration. In the control (anal) phase, members learn to identify and express anger constructively. In the intimacy (oedipal) phase, members learn to compete and be intimate. Individual and group movement is facilitated by the group leader being able to identify stages of group development and being able to utilize phase-related techniques.Many thanks to Anne Alonso, Ph.D., Robert Dies, Ph.D., and Geraldine Alpert, Ph.D., for their critiques of the first draft of this paper.     

Domain effects in lexical development: learning words for foods and toys

We investigated 3-year-olds’ and adults’ use of domain cues in learning words for solid and nonsolid material entities. In Experiments 1 and 2, participants heard a novel neutral noun (e.g., “my X”) for a standard solid or nonsolid entity described as either a toy or a food. They then were asked to extend the word to one of two other entities. Both options matched the standard in solidity; but one differed from it in an object-relevant property (shape) and the other in a substance-relevant property (color, texture, or smell). Both children and adults were more likely to select the same-shaped entity if the standard was (1) solid than if it was nonsolid, and (2) described as a toy than if it was described as a food. Their interpretations of novel words for material entities were thus affected not only by perceptual information (about solidity) but also by conceptual information (about domain). In Experiment 3, the novel noun was presented in a syntactic context that suggested the solid entity should be interpreted as an object (e.g., “an X”) and that the nonsolid entity should be interpreted as a substance (e.g., “some X”). For adults, these changes largely eliminated the effect of the entity’s domain (toy, food) on interpretation. We interpret these findings in terms of the proposal that domain cues, like solidity cues, furnish information about whether an entity’s structure should be thought of as arbitrary or nonarbitrary and, hence, about whether a word should be interpreted as naming an object or a substance construal.     

Selective visual attention for ugly and beautiful body parts in eating disorders

Body image disturbance is characteristic of eating disorders, and current treatments use body exposure to reduce bad body feelings. There is however little known about the cognitive effects of body exposure. In the present study, eye movement registration (electroculography) as a direct index of selective visual attention was used while eating symptomatic and normal control participants were exposed to digitalized pictures of their own body and control bodies. The data showed a decreased focus on their own 'beautiful' body parts in the high symptomatic participants, whereas inspection of their own 'ugly' body parts was given priority. In the normal control group a self-serving cognitive bias was found: they focused more on their own 'beautiful' body parts and less on their own 'ugly' body parts. When viewing other bodies the pattern was reversed: high symptom participants allocated their attention to the beautiful parts of other bodies, whereas normal controls concentrated on the ugly parts of the other bodies. From the present findings the hypothesis follows that a change in the processing of information might be needed for body exposure to be successful.     

Sociological factors in the development of eating disorders.

In recent years, anorexia and bulimia nervosa, whether combined into a single clinical picture or considered as distinct syndromes, have reached epidemic proportions among adolescents. Professionals in the educational and physical and mental health care fields need to be aware of the influence of social pressures on teenagers' perceptions of body image and appearance. This article reviews the sociocultural, socioeconomic, and sex-related factors which contribute to the development of eating disorders. It is recommended that professionals help adolescents resist societal pressure to conform to unrealistic standards of appearance, and provide guidance on nutrition, realistic body ideals, and achievement of self-esteem, self-efficacy, interpersonal relations and coping skills.     

A review of existing measures of attentional biases in body image and eating disorders research

Cognitive theories emphasise the important role of attentional biases in the development and maintenance of body image issues and eating pathology. A wealth of research has been conducted to examine attentional biases toward body‐related information among individuals with eating pathology. However, there is considerable variability in the methods that have been used to measure attention and, importantly, these methods tap into different attentional processes. Given the multifaceted nature of attention, it is important for researchers to select the right tools to test their hypotheses. This review critically evaluates the attentional measures that have been used in previous research, primarily the modified Stroop task, dot probe task, visual search task, and eyetracking. The strengths and limitations of each measure will be discussed in order to provide a guide for researchers to further investigate the attentional mechanisms underlying body image issues and eating disorders. Overall, we recommend that researchers use a combination of eyetracking technology and specific reaction‐time measures that target the specific attentional mechanism of interest.     

Learning to fear outgroups: An associative learning explanation for the development and reduction of intergroup anxiety

Pavlovian conditioning is a form of associative learning shown to contribute to the development and reduction of clinical anxiety and fear, and more recently, intergroup anxiety and fear. The current review provides a synthesis of the literature on associative learning of fear toward outgroups. Findings are reviewed that outline how fear toward the outgroup, relative to the ingroup, can be preferentially learnt and is resistant to extinction‐based techniques. Novel future research directions for intergroup anxiety are then identified based upon previous research on clinical anxiety. It is proposed that processes known to enhance the extinction of specific phobia should be investigated with social stimuli. Specifically, it is argued that exploring cognitive factors during extinction and conducting extinction in multiple contexts may provide new avenues to pursue intergroup harmony through reduced intergroup anxiety. The review concludes by suggesting innovative research designs are needed to validate an associative learning account of fear toward outgroups outside of experimental settings.     

Gender role typing,the superwoman ideal,and the potential for eating disorders

The interactive effects of gender role typing and adherence to a superwoman ideal (desiring to excel in many diverse roles) on the potential for disordered eating were examined among a nonclinical sample of women. Results indicated that both masculine and feminine gender-typed women who strongly adhered to a superwoman ideal were at greater risk for eating disorders than androgynous superwomen. In contrast, androgynous superwomen had relatively low potential for disordered eating and appeared comparable to women who, regardless of gender typing, rejected the superwoman ideal. Women undifferentiated with regard to gender type, whether superwomen or not, also had reduced potential for disordered eating. Findings are discussed with regard to gender role socialization and expectations, and the implications for mediating the potential for eating disorders are considered.     

Multidimensional body image comparisons among patients with eating disorders,body dysmorphic disorder,and clinical controls: A multisite study

Body image disturbance is considered a core characteristic of eating disorders and body dysmorphic disorder (BDD), however its definition has been unclear within the literature. This study examined the multidimensional nature of body image functioning among individuals with either anorexia nervosa (AN; n = 35), bulimia nervosa (BN; n = 26), or BDD (n = 56), relative to female (n = 34) and male (n = 36) psychiatric controls. Participants were recruited from 10 treatment centers in the United States and England and completed psychometrically validated and standardized self-report measures of body image. Overall, the AN, BN, and BDD groups were characterized by significantly elevated disturbances in most body image dimensions relative to their gender-matched clinical controls. There was variability, however, in the comparisons among the three groups of interest, including foci of body dissatisfaction and body image coping patterns. On omnibus indices of body image disturbance and body image quality of life, patients with BDD reported more body image impairment than those with eating disorders. Although AN, BN, and BDD are characterized by body image disturbances, similar and partially distinctive cognitive, behavioral, and emotional elements of body image functioning exist among these groups. The study's empirical and clinical implications are considered.     

Predictors for relapse and chronicity in eating disorders: A review of follow-up studies

Abstract: Eating disorders have been known to be intractable. Yet, their long-term consequences have received relatively little attention in the literature. In this paper, the outcome and follow-up studies of anorexia nervosa and bulimia are reviewed and the current knowledge of the predictors and correlates of relapse and chronicity in each disorder is summarized. Based on the problems and limitations of the extant studies, suggestions for future research are offered, especially from a developmental perspective, to understand better the mechanisms underlying long-term prognosis and relapse.