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.     

Olfactory blocking and odorant similarity in the honeybee

Blocking occurs when previous training with a stimulus A reduces (blocks) subsequent learning about a stimulus B, when A and B are trained in compound. The question of whether blocking exists in olfactory conditioning of proboscis extension reflex (PER) in honeybees is under debate. The last published accounts on blocking in honeybees state that blocking occurs when odors A and B are similar (the "similarity hypothesis"). We have tested this hypothesis using four odors (1-octanol, 1-nonanol, eugenol, and limonene) chosen on the basis of their chemical and physiological similarity (experiment 1). We established a generalization matrix that measured perceptual similarity. Bees in the "block group" were first trained with an odor A and, in the second phase, with the mixture AB. Bees in the "novel group" (control group) were first trained with an odor N and, in the second phase, with the mixture AB. After conditioning, bees in both groups were tested for their response to B. We assayed all 24 possible combinations for the four odors standing for A, B, and N. We found blocking in four cases, augmentation in two cases, and no difference in 18 cases; odor similarity could not account for these results. We also repeated the experiments with those six odor combinations that gave rise to the similarity hypothesis (experiment 2: 1-hexanol, 1-octanol, geraniol) and found augmentation in one and no effect in five cases. Thus, blocking is not a consistent phenomenon, nor does it depend on odor similarity.     

Adolescents with high mental toughness adapt better to perceived stress: A longitudinal study with Swiss vocational students

A mindset of mental toughness enables an individual to cope successfully with the pressures and demands of life. This 10-month study prospectively examined the association between mental toughness and stress resilience in 865 students (M = 17.86 years, 42.7% girls) from two vocational schools. Within each school, separate cluster analyses identified groups with different profiles of risk (assessed with perceived stress) and adaptation (operationalized with depressive symptoms and life satisfaction). Four clusters emerged characterizing students with well-adjusted (low risk, good adaptation), maladjusted (elevated risk, bad adaptation), deteriorated (low initial risk, worsening adaptation) and resilient profiles (elevated initial risk, improving adaptation). The latter two clusters reported similar levels of mental toughness at baseline, but resilient adolescents scored significantly higher on mental toughness at follow-up. After controlling for possible confounds, baseline toughness levels predicted depressive symptoms and life satisfaction over time. This study shows that mental toughness operates as a stress resilience resource. Mental toughness is, therefore a topic of interest for health specialists working with adolescent populations.     

Development of a telephone-based intervention for support persons to help smokers quit

This study represents the first step toward systematic behavioral treatment development and pilot testing of a novel approach to smoking cessation that utilizes adults interested in helping someone to stop smoking (i.e., support persons) as the agent of change. The counselor manual for a telephone-based intervention for support persons was developed based on a previous clinic-based intervention. Social cognitive theory served as the conceptual basis for the intervention. Ten adult non-smoking females completed the treatment protocol, consisting of six 20 - 30-min sessions and written materials. The support person was the sole recipient of the professional intervention. Feedback was obtained from 8 of the 10 participants and all 4 telephone counselors 1 week post-treatment (week 10). Results indicate that the telephone-based intervention was feasible and acceptable to participants. The intervention was refined based on participant and counselor feedback and will be subsequently tested in a randomized pilot trial.     

Attributions of Blame in Sexual Assault to Perpetrators and Victims of Both Genders1

Previous research found that men attribute more blame to rape victims than do women; men also attribute less blame to perpetrators. In rape situations with a male perpetrator and a female victim, the roles of perpetrator and victim are confounded with gender category. To determine whether men are more lenient toward perpetrators or toward other males, the present study examined attributions of blame in scenarios that varied the gender category of both perpetrator and victim. Results showed that men's and women's attributions of blame to perpetrators were based on the role that was enacted, rather than gender per se: Men attributed less blame to perpetrators than did women, regardless of the perpetrator's gender category, indicating that men were more lenient toward perpetrators than were women. In addition, when the victim was female, the perpetrator was blamed more and the victim was blamed less than when the victim was male.     

Self-Prophecy Effects and Voter Turnout: An Experimental Replication

Psychological research has found that being asked to predict one's future actions can bring about subsequent behavior consistent with the prediction but different from what would have occurred had no prediction been made. In a 1987 study, Greenwald, Carnot, Beach, and Young induced an increase in voting behavior by means of such a "self-prophecy" effect: Undergraduates who were asked to predict whether they would vote in an upcoming election were substantially more likely to go to the polls than those who had not been asked for a prediction. This paper reports on a replication of the Greenwald study conducted among a larger group of respondents more representative of the American electorate. No evidence was found that self-prophecy effects increase voter turnout.     

Distribution and Correlates of Self-Reported Crimes of Trust

This study examines the distribution and correlates of a special class of property crimes, crimes of trust, using longitudinal and cross sectional self-report data from a national sample. We begin by defining crimes of trust and consider their conceptual relationship to "conventional" property crimes, which we here characterize as crimes of stealth, and to white collar crimes, which are defined in terms of the social status of the perpetrators. Crimes of trust are here defined as property crimes that typically involve deliberate contact with the victim or, where there is more than one victim, with at least one or more victims, in which there is typically more of a focus on concealing the fact that a crime has been committed than on concealing the identity of the perpetrator (as is the case in crimes of stealth), without regard to the socioeconomic status of the perpetrator (thus including but not limited to white collar crimes). The focus here is on crimes of trust committed by individuals (as opposed to corporate crime). We first examine their distribution by sociodemographic characteristics, then examine the correlation of crimes of trust with other types of illegal behavior, using data from the National Youth Survey Family Study, including (1) longitudinal self-report data from a nationally representative panel of individuals who were 11-18 years old in 1976-77 and who were followed through early middle age (ages 36-44) in 2002-2003, plus (2) cross-sectional data on these individuals plus their parents, spouses, and children age 11 and older in 2002-2003 (total age range 11-88). The results suggest that crimes of trust have a different age-crime curve from conventional crimes, and that they are not as strongly correlated with problem substance use, gender, and other socioeconomic indicators as conventional crimes.     

Generalizability of career orientations: A comparative study in Switzerland and Great Britain

This study examined the generalizability of types of career orientation. Exploratory latent class analyses were used to examine whether structurally the same career orientations can be found across a large sample of Swiss German (N=737), Swiss French (N=319), and British (N=1,002) employees. The finding showed that the generalizability of career orientations was not supported across the two countries and not even between the German‐ and French‐speaking parts of Switzerland. At least four career orientations were found in all samples. Country‐specific inspection of these four career orientations showed that they differed in terms of their combinations of specific components (boundaryless, protean, advancement, and time orientation). Mixtures of types of career orientations exist and make it difficult to identify fully the same type of career orientation across different cultural contexts. Explanations for differences in career orientation are discussed focusing on the cultural and economic context of Switzerland and Great Britain. Implications for organizational career management practices as well as theory of the career orientation concept are discussed.