Acute stress or systemic insulin injection increases flunitrazepam sensitive-GABAA receptor density in synaptosomes of chick forebrain: Modulation by systemic epinephrine

Interactions between acute stress and systemic insulin and epinephrine on GABAA receptor density in the forebrain were studied. Here, 10 day-old chicks were intraperitoneally injected with insulin, epinephrine or vehicle and then immediately stressed by partial water immersion for 15 min and killed by decapitation. Non-stressed controls were similarly injected, then returned to their rearing boxes for 15 min and then killed. Forebrains were dissected and GABAA receptor density was measured ex vivo in synaptosomes by 3[H]-flunitrazepam binding assay. In non-stressed chicks, insulin at 1.25, 2.50 and 5.00 IU/kg of body weight (non-hypoglycemic doses) increased Bmax by 33, 53 and 44% compared to saline, respectively. A similar increase of 41% was observed in receptor density after stress. However, the insulin effect was not additive to the stress-induced increase suggesting that both effects occur through similar mechanisms. In contrast, epinephrine, at 0.25 and 0.5 mg/kg did not induce any changes in Bmax in non-stressed chicks. Nevertheless, after stress these doses increased the receptor density by about 13 and 27%, respectively. Similarly, the same epinephrine doses co-administered with insulin (2.50 IU/kg), increased the receptor density by about 20% compared to insulin alone. These results suggest that systemic epinephrine, perhaps by evoking central norepinephrine release, modulates the increase in forebrain GABAA receptor binding induced by both insulin and stress.     

The role of dark‐side of motivation and intention to continue in exercise: A self‐determination theory approach

Motivation plays an important role when it comes to regular physical exercise. Hence, low levels of intentions to continue exercising in the future may ultimately lead to higher rates of exercise dropout. The first objective of the present research was to test a theoretical model considering the dark side of motivational determinants on intentions towards exercising in the future. The second objective consisted in comparing groups with different characteristics, as a way to identify individuals with weaker intention, which is believed to be an indicator of a higher dropout risk. In total, 544 (294 female; 250 male) gym exercisers aged between 18 and 58 years (M = 35.00; SD = 11.57) partook in the present research. Participants were engaged in fitness group classes (n = 273) or in cardio/resistance workouts (n = 271), and their exercise experience ranged from 3 to 120 months (M = 47.41; SD = 7.54). Results showed that the measurement and the structural model had an excellent fit. In addition, the structural model was invariant between gender, fitness activities, and exercise experience. Each group displayed different explained variance in intention to continue exercising. Overall, male, young adults and more experienced exercisers had stronger intentions towards exercising. Fitness instructors should be aware of their own thwarting behaviors, especially when interacting with female, young and less experienced exercisers, since they have weaker intentions to exercise in the future, possibly representing an increased risk of withdrawal.     

Validation of the Basic Psychological Needs in Exercise Scale in a Portuguese sample

In line with self-determination theory (SDT: Deci & Ryan, 1985, 2002) the satisfaction of the basic psychological needs for autonomy, competence, and relatedness has been identified as an important predictor of behavior and optimal functioning in various contexts including exercise. The lack of a valid and reliable instrument to assess the extent to which these needs are fulfilled among Portuguese exercise participants limits the evaluation of causal links proposed by SDT in the Portuguese exercise context. The aim of the present study was to translate into Portuguese and validate the Basic Psychological Needs in Exercise Scale (BPNES: Vlachopoulos & Michailidou, 2006). Using data from 522 exercise participants the findings provided evidence of strong internal consistency of the translated BPNES subscales while confirmatory factor analysis supported a good fit of the correlated 3-factor model to the data. The present findings support the use of the translated into Portuguese BPNES to assess the extent of basic psychological need fulfilment among Portuguese exercise participants.     

Cross-cultural invariance of the basic psychological needs in exercise scale and need satisfaction latent mean differences among Greek,Spanish, Portuguese and Turkish samples

ObjectivesThe present study examined the extent to which scores from the Basic Psychological Needs in Exercise Scale are measurement invariant across Greek, Spanish, Portuguese, and Turkish samples of exercise participants.DesignA cross-sectional design wherein responses were analyzed from 504 Greek participants, 518 Spanish participants, 989 Portuguese participants, and 686 Turkish participants.MethodsData on exercise participants' need satisfaction were collected using the Basic Psychological Needs in Exercise Scale (Vlachopoulos & Michailidou, 2006) after back translation for the languages involved in the study.ResultsMulti-sample confirmatory factor analyses showed that BPNES scores were largely invariant at the configural, metric, and strong invariance levels, but not at the strict invariance level for Spanish, Portuguese, and Turkish samples compared to the Greek sample. Portuguese participants reported higher levels of satisfaction for all three needs compared to Greek participants, while for Spanish participants this was the case only for competence and relatedness. Turkish participants did not differ from Greek participants.ConclusionsThe present findings support valid cross-cultural comparisons at the latent variance/covariance level and the latent/observed mean level of the constructs of autonomy, competence, and relatedness using the BPNES.     

The effects of age and emotional valence on recognition memory: An ex‐Gaussian components analysis

The aim of this work was to study the effects of valence and age on visual image recognition memory. The International Affective Picture System (IAPS) battery was used, and response time data were analyzed using analysis of variance, as well as an ex‐Gaussian fit method. Older participants were slower and more variable in their reaction times. Response times were longer for negative valence pictures, however this was statistically significant only for young participants. This suggests that negative emotional valence has a strong effect on recognition memory in young but not in old participants. The τ parameter, often related to attention in the literature, was smaller for young than old participants in an ex‐Gaussian fit. Differences on the τ parameter might suggest poorer attentional performance in old participants.     

Initial validation of the Portuguese version of the Interpersonal Behavior Questionnaire (IBQ & IBQ-Self) in the context of exercise: Measurement invariance and latent mean differences

Current Psychology - The aim of the present research is to examine the factor structure of the Interpersonal Behavior Questionnaire (IBQ), and the Interpersonal Behavior Questionnaire Self...