Impaired directed forgetting in abstinent heroin addicts

Drug-related memories persist long into abstinence and are potent elicitors of drug craving and relapse. We report two experiments examining whether heroin-dependent individuals are impaired in intentionally suppressing drug-related memories. Experiment 1 adopted the Item paradigm where addicts and healthy controls were presented with a list of words each followed by a remember or forget cue. Experiment 2 adopted the List paradigm where they studied one list of items and were then split into a remember group and a forget group. Both groups studied a second list, except that the forget group was told to forget the first list. Compared with controls, addicts showed a reduced directed forgetting effect in the Item method and a total absence of one measure of directed forgetting in the List method (List 2 benefits). Results indicate that heroin addicts are impaired in directed forgetting and that the deficits are likely associated with memory encoding as opposed to retrieval. Possible problems include reduced ability in actively suppressing/stopping encoding of irrelevant information into memory or inability in changing/resetting encoding strategies. In neither experiment did the addicts show any differential directed forgetting effects between drug-related words and neutral words, indicating the generic nature of their intentional forgetting deficits

Altered Gray Matter Volume and White Matter Integrity in College Students with Mobile Phone Dependence

Mobile phone dependence (MPD) is a behavioral addiction that has become an increasing public mental health issue. While previous research has explored some of the factors that may predict MPD, the underlying neural mechanisms of MPD have not been investigated yet. The current study aimed to explore the microstructural variations associated with MPD as measured with functional Magnetic Resonance Imaging (fMRI). Gray matter volume (GMV) and white matter (WM) integrity [four indices: fractional anisotropy (FA); mean diffusivity (MD); axial diffusivity (AD); and radial diffusivity (RD)] were calculated via voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) analysis, respectively. Sixty-eight college students (42 female) were enrolled and separated into two groups [MPD group, N = 34; control group (CG), N = 34] based on Mobile Phone Addiction Index (MPAI) scale score. Trait impulsivity was also measured using the Barratt Impulsiveness Scale (BIS-11). In light of underlying trait impulsivity, results revealed decreased GMV in the MPD group relative to controls in regions such as the right superior frontal gyrus (sFG), right inferior frontal gyrus (iFG), and bilateral thalamus (Thal). In the MPD group, GMV in the above mentioned regions was negatively correlated with scores on the MPAI. Results also showed significantly less FA and AD measures of WM integrity in the MPD group relative to controls in bilateral hippocampal cingulum bundle fibers (CgH). Additionally, in the MPD group, FA of the CgH was also negatively correlated with scores on the MPAI. These findings provide the first morphological evidence of altered brain structure with mobile phone overuse, and may help to better understand the neural mechanisms of MPD in relation to other behavioral and substance addiction disorders

Rating scores (A) and reaction times (B) over types of stimuli (low, medium, and high romance levels).

<p>Significance bars and asterisks designate the significance of rating and reaction time for the gender by stimulus type interactions. *, p<0.05.</p

Gender Differences in Perception of Romance in Chinese College Students

<div><p>Women often complain that their partners are not romantic enough. This raises the question: how romance is recognized and evaluated in a love relationship? However, there has been essentially no empirical research bearing on this issue. The present set of studies examined possible gender differences in perceptions of romance and the associated neural mechanisms in Chinese college students. In Study 1, 303 participants (198 women, 105 men) were administrated a questionnaire consisting of 60 sentences and required to rate the romance level of each sentence. Results showed higher rating scores in males than females for low romance items, but not for high or medium romance items. In Study 2, 69 participants (37 women, 32 men) were recruited to judge the degree of romance in sentences presented on a computer screen one by one. Compared with females, males again showed higher scores and responded more slowly only to low romance items. In Study 3, 36 participants (18 women, 18 men) currently in love with someone were scanned with functional MRI while they did the romance judgment task from Study 2. Compared with females, greater brain activation was found for males in the frontal lobe, precentral gyrus, precuneus and parahippocampal gyrus for low romance items. The results provide the first piece of evidence for gender differences in romance perception, suggesting enhanced cognitive processing in males when evaluating the degree of romance in romantic scenes.</p></div

Areas of activation for low romance level (Male>Female).

<p>Areas of activation for low romance level (Male>Female).</p

Ratings of romance degree across three stimulus levels in males and females.

<p>Males rated significantly higher than females for Low romantic stimuli.</p

Areas of activation sensitive to sex differences (male>female).

<p><i>x,y,z</i>, Talairach coordinates (Talairach and Tournoux, 1988) of the peak voxel of the activated cluster. <i>t</i> max, <i>t</i> value of the maximally activated voxel within the cluster.</p

The time course of experimental paradigm in Study 2.

<p>The time course of experimental paradigm in Study 2.</p

Data_Sheet_1_Phenotypic heterogeneity unveils a negative correlation between antibiotic resistance and quorum sensing in Pseudomonas aeruginosa clinical isolates.PDF

Colonization of Pseudomonas aeruginosa in the lung environments frequently leads to the enrichment of strains displaying enhanced antibiotic resistance and reduced production of quorum-sensing (QS) controlled products. However, the relationship between the emergence of QS deficient variants and antibiotic resistance remains less understood. In this study, 67 P. aeruginosa strains were isolated from the lungs of 14 patients with chronic obstructive pulmonary disease, followed by determining their genetic relationship, QS-related phenotypes and resistance to commonly used antibiotics. The integrity of P. aeruginosa QS system was checked by DNA sequencing. The relationship between the QS system and antibiotic resistance was then assessed by correlation analyses. The function of the LasR protein and bacterial virulence were evaluated through homology modeling and nematode-infection assay. The influence of antibiotic on the development of extracellular protease production ability of P. aeruginosa was tested by an evolutionary experiment. The results showed that P. aeruginosa clinical strains displayed abundant diversity in phenotype and genotype. The production of extracellular proteases was significantly negatively correlated with antibiotic resistance. The strains with enhanced antibiotic resistance also showed a notable overlap with the mutation of lasR gene, which is the core regulatory gene of P. aeruginosa QS system. Molecular docking and Caenorhabditis elegans infection assays further suggested that P. aeruginosa with impaired LasR protein could also have varying pathogenicity. Moreover, in vitro evolution experiments demonstrated that antibiotic-mediated selective pressure, particularly from Levofloxacin contributed to the emergence of extracellular protease-negative strains. Therefore, this study provides evidence for the connection of P. aeruginosa QS system and antibiotic resistance, and holds significance for developing targeted strategies to address antibiotic resistance and improving the management of antibiotic-resistant infections in chronic respiratory diseases.</p