Changes in the electroencephalographic spectrum in response to smoking cues in smokers and ex-smokers

Aims: To investigate the changes in the electroencephalographic (EEG) spectrum in smokers during exposure to a neutral and a smoking-related cue to determine whether these EEG changes are still present in ex-smokers after prolonged abstinence and to examine the relationship between the power in each spectral bandwidth and subjective craving. Methods: EEG frequencies in response to a smoking-related and a neutral cue were examined in 23 smokers and 21 ex-smokers, who quit smoking for 1.4 years on average. Additionally, self-report measures of cigarette craving and nicotine dependence were obtained. The spectral power of each bandwidth was computed, log-transformed, and analyzed using a within-subject design. Differences between EEG activity under neutral and smoking conditions were correlated with differences between pre- and postexperimental subjective craving. Results: Increases in reward craving (desire and intention to smoke) were associated with reduced theta activity, whereas increases in withdrawal craving (reduction of negative affect and withdrawal symptoms) were correlated with increases in both delta and higher alpha power. Furthermore, in smokers, but not in ex-smokers, a significant beta power increase was observed between the neutral condition and the smoking condition. Conclusion: Since the beta band is associated with arousal, attention, and alertness, it is suggested that the beta increase in response to the smoking cue might reflect an enhanced allocation of resources to smoking-related stimuli, i.e. a processing bias, which is an important feature of substance abuse. Since ex-smokers do not respond to the smoking cue with beta activity enhancement, we preliminarily conclude that smoking cues do not arouse ex-smokers or capture their attention as much as they do in smokers

* The late positive potential and explicit versus implicit processing of facial valence

* The late positive potential (LPP) depicts brain electrical activity during both automatic and controlled sustained attentional processing of emotional stimuli. We investigated in a sample of 18 healthy women how the LPP is modulated by facial expression during an explicit valence rating task and an implicit sex classification task. Midline LPP amplitudes were significantly larger for valence rating than for sex classification. During valence rating, faces with a positive valence resulted in larger LPP amplitudes at centrofrontal electrodes than faces with a negative valence. During sex classification, a similar valence effect was observed at midline parietal electrodes. This implicit LPP valence effect appears to depend on higher visual processing, as during an additional sex classification task with blurred faces no such implicit valence effect was found

Event-related potential responses to love-related facial stimuli

In event-related potential (ERPs) studies, emotional stimuli usually elicit an enhanced late positive potential (LPP), which is assumed to reflect motivated attention. However, whether a stimulus elicits emotional responses may depend on the individual's state, such as experiencing romantic love. It has been suggested that stimuli that are related to someone's beloved will elicit increased attention in that infatuated individual. In this study, participants who were in love viewed faces of their beloved, their friend, and of an unknown, beautiful person. The friend was included to control for familiarity, and the unknown person for perceived beauty. As expected, the LPP was larger in response to the face of the beloved than to the other two emotionally significant faces. Interpreting the LPP as reflecting motivated attention, this implies that romantic love is accompanied by increased attention for the face of one's beloved

Snake pictures draw more early attention than spider pictures in non-phobic women: Evidence from event-related brain potentials

Snakes were probably the first predators of mammals and may have been important agents of evolutionary changes in the primate visual system allowing rapid visual detection of fearful stimuli (Isbell, 2006). By means of early and late attention-related brain potentials, we examined the hypothesis that more early visual attention is automatically allocated to snakes than to spiders. To measure the early posterior negativity (EPN), 24 healthy, non-phobic women watched the random rapid serial presentation of 600 snake pictures, 600 spider pictures, and 600 bird pictures (three pictures per second). To measure the late positive potential (LPP), they also watched similar pictures (30 pictures per stimulus category) in a non-speeded presentation. The EPN amplitude was largest for snake pictures, intermediate for spider pictures and smallest for bird pictures. The LPP was significantly larger for both snake and spider pictures when compared to bird pictures. Interestingly, spider fear (as measured by a questionnaire) was associated with EPN amplitude for spider pictures, whereas snake fear was not associated with EPN amplitude for snake pictures. The results suggest that ancestral priorities modulate the early capture of visual attention and that early attention to snakes is more innate and independent of reported fear

Early Adolescent Friendship Selection Based on Externalizing Behavior: the Moderating Role of Pubertal Development. The SNARE Study

Abstract This study examined friendship (de-)selection processes in early adolescence. Pubertal development was examined as a potential moderator. It was expected that pubertal development would be associated with an increased tendency for adolescents to select their friends based on their similarities in externalizing behavior engagement (i.e., delinquency, alcohol use, and tobacco use). Data were used from the first three waves of the SNARE (Social Network Analysis of Risk behavior in Early adolescence) study (N = 1144; 50 % boys; M age = 12.7; SD = 0.47), including students who entered the first year of secondary school. The hypothesis was tested using Stochastic Actor-Based Modeling in SIENA. While taking the network structure into account, and controlling for peer influence effects, the results supported this hypothesis. Early adolescents with higher pubertal development were as likely as their peers to select friends based on similarity in externalizing behavior and especially likely to remain friends with peers who had a similar level of externalizing behavior, and thus break friendship ties with dissimilar friends in this respect. As early adolescents are actively engaged in reorganizing their social context, adolescents with a higher pubertal development are especially likely to lose friendships with peers who do not engage in externalizing behavior, thus losing an important source of adaptive social control (i.e., friends who do not engage in externalizing behavior)

Testing the Snake-Detection hypothesis: Larger early posterior negativity in humans to pictures of snakes than to pictures of other reptiles, spiders and slugs

According to the snake detection hypothesis (Isbell, 2006), fear specifically of snakes may have pushed evolutionary changes in the primate visual system allowing pre-attentional visual detection of fearful stimuli. A previous study demonstrated that snake pictures, when compared to spiders or bird pictures, draw more early attention as reflected by larger early posterior negativity (EPN). Here we report two studies that further tested the snake detection hypothesis. In Study 1, we tested whether the enlarged EPN is specific for snakes or also generalizes to other reptiles. Twenty-four healthy, non-phobic women watched the random rapid serial presentation of snake, crocodile, and turtle pictures. The EPN was scored as the mean activity at occipital electrodes (PO3, O1, Oz, PO4, O2) in the 225–300 ms time window after picture onset. The EPN was significantly larger for snake pictures than for pictures of the other reptiles. In Study 2, we tested whether disgust plays a role in the modulation of the EPN and whether preferential processing of snakes also can be found in men. 12 men and 12 women watched snake, spider, and slug pictures. Both men and women exhibited the largest EPN amplitudes to snake pictures, intermediate amplitudes to spider pictures and the smallest amplitudes to slug pictures. Disgust ratings were not associated with EPN amplitudes. The results replicate previous findings and suggest that ancestral priorities modulate the early capture of visual attention

Fractures in pituitary adenoma patients from the Dutch National Registry of Growth Hormone Treatment in Adults

Purpose: The effects of growth hormone (GH) replacement therapy on fracture risk in adult GH deficient (GHD) patients with different etiologies of pituitary GHD are not well known, due to limited data. The aim of this study was to investigate characteristics and fracture occurrence at start of (baseline) and during long-term GH replacement therapy in GHD adults previously treated for Cushing’s disease (CD) or acromegaly, compared to patients with previous nonfunctioning pituitary adenoma (NFPA). Methods: From the Dutch National Registry of Growth Hormone Treatment in Adults, a nationwide surveillance study in severe GHD adults, all patients using ≥30 days of GH replacement therapy with previous NFPA (n = 783), CD (n = 180) and acromegaly (n = 65) were selected. Patient characteristics, fractures and potential influencing factors were investigated. Results: At baseline, patients with previous CD were younger, more often female and had more often a history of osteopenia or osteoporosis, whereas patients with previous acromegaly had more often received cranial radiotherapy and a longer duration between treatment of their pituitary tumor and start of adult GH replacement therapy. During follow-up, a fracture occurred in 3.8 % (n = 39) of all patients. Compared to patients with previous NFPA, only patients with previous acromegaly had an increased fracture risk after 6 years of GH replacement therapy. Conclusions: During GH replacement therapy, an increased fracture risk was observed in severe GHD adult patients previously treated for acromegaly, but not in those previously treated for CD, compared to severe GHD adult patients using GH replacement therapy because of previous NFPA. Further studies are needed to confirm these findings and to elucidate potential underlying mechanisms

Comparison of RBE values of high- LET α-particles for the induction of DNA-DSBs, chromosome aberrations and cell reproductive death

<p>Abstract</p> <p>Background</p> <p>Various types of radiation effects in mammalian cells have been studied with the aim to predict the radiosensitivity of tumours and normal tissues, e.g. DNA double strand breaks (DSB), chromosome aberrations and cell reproductive inactivation. However, variation in correlations with clinical results has reduced general application. An additional type of information is required for the increasing application of high-LET radiation in cancer therapy: the Relative Biological Effectiveness (RBE) for effects in tumours and normal tissues. Relevant information on RBE values might be derived from studies on cells in culture.</p> <p>Methods</p> <p>To evaluate relationships between DNA-DSB, chromosome aberrations and the clinically most relevant effect of cell reproductive death, for ionizing radiations of different LET, dose-effect relationships were determined for the induction of these effects in cultured SW-1573 cells irradiated with gamma-rays from a Cs-137 source or with α-particles from an Am-241 source. RBE values were derived for these effects. Ionizing radiation induced foci (IRIF) of DNA repair related proteins, indicative of DSB, were assessed by counting gamma-H2AX foci. Chromosome aberration frequencies were determined by scoring fragments and translocations using premature chromosome condensation. Cell survival was measured by colony formation assay. Analysis of dose-effect relations was based on the linear-quadratic model.</p> <p>Results</p> <p>Our results show that, although both investigated radiation types induce similar numbers of IRIF per absorbed dose, only a small fraction of the DSB induced by the low-LET gamma-rays result in chromosome rearrangements and cell reproductive death, while this fraction is considerably enhanced for the high-LET alpha-radiation. Calculated RBE values derived for the linear components of dose-effect relations for gamma-H2AX foci, cell reproductive death, chromosome fragments and colour junctions are 1.0 ± 0.3, 14.7 ± 5.1, 15.3 ± 5.9 and 13.3 ± 6.0 respectively.</p> <p>Conclusions</p> <p>These results indicate that RBE values for IRIF (DNA-DSB) induction provide little valid information on other biologically-relevant end points in cells exposed to high-LET radiations. Furthermore, the RBE values for the induction of the two types of chromosome aberrations are similar to those established for cell reproductive death. This suggests that assays of these aberrations might yield relevant information on the biological effectiveness in high-LET radiotherapy.</p