Adult mice maintained on a high-fat diet exhibit object location memory deficits and reduced hippocampal SIRT1 gene expression

Mounting evidence has established that diet-induced obesity (DIO) is associated with deficits in hippocampus-dependent memory. The bulk of research studies dealing with this topic have utilized rats fed a high-fat diet as an experimental model. To date, there has been a paucity of research studies that have established whether the memory deficits exhibited in DIO rats can be recapitulated in mice. Moreover, the majority of experiments that have evaluated memory performance in rodent models of DIO have utilized memory tests that are essentially aversive in nature (i.e., Morris water maze). The current study sought to fill an empirical void by determining if mice maintained on a high-fat diet exhibit deficits in two non-aversive memory paradigms: novel object recognition (NOR) and object location memory (OLM). Here we report that mice fed a high-fat diet over 23 weeks exhibit intact NOR, albeit a marked impairment in hippocampus-dependent OLM. We also determined the existence of corresponding aberrations in gene expression within the hippocampus of DIO mice. DIO mice exhibited significant reductions in both SIRT1 and PP1 mRNA within the hippocampus. Our data suggest that mice maintained on a high-fat diet present with impaired hippocampus-dependent spatial memory and a corresponding alteration in the expression of genes that have been implicated in memory consolidation.     

There’s an App for that: The Uses and Gratifications of Online Social Networks for Gay Men

This essay is an exploratory study of the uses and gratifications of social networking applications and sites widely utilized by gay men. Based on findings from six different focus groups and intercept interviews with gay and bisexual men, this essay explores the motivations and perceived benefits of social networking sites that allow for the creation of a virtual community of sexual minorities. This paper also considers these technological developments as part of a larger history of gay men communicating with other gay men within a culture where talk about homosexuality is closely policed and often restricted. Through a uses and gratifications approach, this essay discusses the needs and motivations that bring gay men online to social network sites, how they manage multiple identities online and the resulting gratifications of their online activity.     

Diagnosis of ADHD in Adults: What Is the Appropriate DSM-5 Symptom Threshold for Hyperactivity-Impulsivity?

Objective: To empirically identify the appropriate symptom threshold for hyperactivity-impulsivity for diagnosis of ADHD in adults. Method: Participants were 88 adults (M [SD] age = 41.69 [11.78] years, 66% female, 16% minority) meeting formal DSM-IV criteria for ADHD combined or predominantly inattentive subtypes based on a structured diagnostic interview keyed to DSM-IV (Conners' Adult ADHD Diagnostic Interview for DSM-IV [CAADID]). All participants also completed the Conners' Adult ADHD Rating Scale (CAARS), which was normed on the general adult population and includes subscales for DSM-IV inattentive and DSM-IV hyperactive-impulsive symptoms. A T-score threshold of 65 (at least 1.5 SD above population mean) on the CAARS DSM-IV hyperactive-impulsive dimension was used to identify participants with empirically elevated symptom severity. Results: Of 88 participating adults, 48 (55%) had a T-score of at least 65 (1.5 SD) on the CAARS DSM-IV Hyperactive-Impulsive scale. Of these, only 25 (52%) met the DSM-IV cutoff of six hyperactive-impulsive symptoms on the CAADID. Thus, approximately half of those who reported empirically elevated hyperactive-impulsive complaints on the CAARS did not concurrently meet the six-symptom DSM-IV cutoff on the CAADID. An alternative cutoff of four hyperactive-impulsive symptoms on the CAADID captured 39 (81%) cases identified by the CAARS. Conclusion: In adults, mandating at least six hyperactive-impulsive symptoms excludes a significant percentage (almost half) of adults who are at least 1.5 SD above the population mean on a dimensional measure of hyperactivity-impulsivity. These data provide a compelling basis for lowering the symptom threshold of hyperactivity-impulsivity for adults in the DSM-5.     

Variables associated with the nature of sexual abuse to minors

This study analyzes the prevalence and characteristics of childhood and adolescence sexual abuse suffered by a sample of university students, as well as the variables associated with the nature of abuse. Participants anonymously completed the Questionnaire on Child Sexual Abuse, in order to obtain information about experience of sexual abuse. Of a total of 2,375 students, 289 (12.2%) declared having suffered sexual abuse before the age of 18. The invasiveness, continuity, and severity of abuse was related to the location where the abuse took place (the more severe cases were committed in the homes of the victim and perpetrator) and to the circumstances of abuse (relationships with partners/at a party or while caring for a child predicted more severe abuse). The age of the victim (preschool) and an intrafamilial relationship between victim and perpetrator were also related to more invasive, continuous, and severe sexual abuse. The knowledge of characteristics of perpetrator and victim and the context in which sexual abuse occurs can help to better comprehend the nature and correlates of sexual abuse. The results of the present study may contribute to the design of programs for the prevention of sexual abuse to minors.     

Active music classes in infancy enhance musical, communicative and social development

Previous studies suggest that musical training in children can positively affect various aspects of development. However, it remains unknown as to how early in development musical experience can have an effect, the nature of any such effects, and whether different types of music experience affect development differently. We found that random assignment to 6 months of active participatory musical experience beginning at 6 months of age accelerates acquisition of culture-specific knowledge of Western tonality in comparison to a similar amount of passive exposure to music. Furthermore, infants assigned to the active musical experience showed superior development of prelinguistic communicative gestures and social behaviour compared to infants assigned to the passive musical experience. These results indicate that (1) infants can engage in meaningful musical training when appropriate pedagogical approaches are used, (2) active musical participation in infancy enhances culture-specific musical acquisition, and (3) active musical participation in infancy impacts social and communication development.     

Hippocampal sequences link past, present, and future

Disrupting the reactivation of hippocampal neurons during sleep impairs memory consolidation in rats. However, the functional importance of reactivation during awake states is unknown. An experiment in which awake reactivation was disrupted suggests that this phenomenon could adaptively guide behavior by linking previous learning with the current state of the world.     

Exploring the ability to identify visual search differences when observing drivers’ eye movements

How can we improve learner drivers’ visual skills? Much research has demonstrated that learner drivers have an impoverished spread of search during driving and that this is partly due to lack of knowledge of where and when to look, rather than simply an issue of cognitive load. Several training interventions have tried to improve scanning in these drivers with limited success. We propose that exposing drivers to examples of good and bad scanning behaviour may prove to be a useful tool in training visual search. The success of this approach, however, requires drivers to be able to distinguish between examples of good and bad scanning. To this end, two studies were undertaken where video clips of simulated driving with an overlaid eye movement trace were presented to participants who had to judge whether the eye movements were that of a learner driver or a driving instructor. Overall, participants found this discrimination task very difficult. However, the findings suggested that novice and learner drivers were able to correctly classify those eye movement traces of other learner drivers better than chance. It was also demonstrated that the ability to distinguish between the eye movements of learner drivers and driving instructors improved as the number of objective differences between the two groups increased across specific scenarios (as determined by frame-by-frame analysis using a priori categories). The results suggest that, under certain situations, drivers can extract information about the appropriateness of a particular scanning strategy just by watching a video of the eye movement trace. The implications for training interventions are discussed.