No abstract

Alzheimer's disease (AD) manifests with memory loss and spatial disorientation. AD pathology starts in the entorhinal cortex, making it likely that local neural correlates of spatial navigation, particularly grid cells, are impaired. Grid-cell-like representations in humans can be measured using functional magnetic resonance imaging. We found that young adults at genetic risk for AD (APOE-ε4 carriers) exhibit reduced grid-cell-like representations and altered navigational behavior in a virtual arena. Both changes were associated with impaired spatial memory performance. Reduced grid-cell-like representations were also related to increased hippocampal activity, potentially reflecting compensatory mechanisms that prevent overt spatial memory impairment in APOE-ε4 carriers. Our results provide evidence of behaviorally relevant entorhinal dysfunction in humans at genetic risk for AD, decades before potential disease onset.

BackgroundMounting evidence shows that smartphone usage heavily disrupts our work life and social activities. Moreover, it is possible that overuse could resemble addictive tendencies. A key contributing factor to smartphone overuse seems to be usage of the messaging application WhatsApp. Although WhatsApp is one of the most commonly used communication applications on smartphones, research in this area is scarce. Given the huge societal debate on the impact of smartphone usage on our daily lives, the present study undertook a large-scale investigation in order to provide numbers on smartphone usage generally—and use of WhatsApp in particular, with the aim of providing a basis for a scientific debate.MethodsIn a large sample of N = 2,418 users, we recorded WhatsApp behaviour over a 4 week period.ResultsOur data show that use of WhatsApp accounted for 19.83% (= 32.11 min) of all smartphone behaviour (compare: Facebook only 9.38% = 15.19 min). The mean of general daily smartphone usage was 161.95 min. Females used WhatsApp for significantly longer periods of time than males and younger age was associated with longer duration of WhatsApp use. While the personality trait Extraversion was positively associated with daily WhatsApp use, Conscientiousness showed an inverse correlation with the length of daily WhatsApp use.ConclusionsThe numbers on smartphone usage in the present study show that the smartphone dominates our daily life. In particular WhatsApp is a driving force, here. Given the length of daily smartphone and WhatsApp usage, more studies need to be conducted to better understand smartphone usage.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-015-1280-z) contains supplementary material, which is available to authorized users.

Memory consolidation transforms initially labile memory traces into more stable representations. One putative mechanism for consolidation is the reactivation of memory traces after their initial encoding during subsequent sleep or waking state. However, it is still unknown whether consolidation of individual memory contents relies on reactivation of stimulus-specific neural representations in humans. Investigating stimulus-specific representations in humans is particularly difficult, but potentially feasible using multivariate pattern classification analysis (MVPA). Here, we show in healthy human participants that stimulus-specific activation patterns can indeed be identified with MVPA, that these patterns reoccur spontaneously during postlearning resting periods and sleep, and that the frequency of reactivation predicts subsequent memory for individual items. We conducted a paired-associate learning task with items and spatial positions and extracted stimulus-specific activity patterns by MVPA in a simultaneous electroencephalography and functional magnetic resonance imaging (fMRI) study. As a first step, we investigated the amount of fMRI volumes during rest that resembled either one of the items shown before or one of the items shown as a control after the resting period. Reactivations during both awake resting state and sleep predicted subsequent memory. These data are first evidence that spontaneous reactivation of stimulus-specific activity patterns during resting state can be investigated using MVPA. They show that reactivation occurs in humans and is behaviorally relevant for stabilizing memory traces against interference. They move beyond previous studies because replay was investigated on the level of individual stimuli and because reactivations were not evoked by sensory cues but occurred spontaneously.

Aims: The present theoretical paper introduces the smartphone technology as a challenge for diagnostics in the study of Internet use disorders and reflects on the term “smartphone addiction.”Methods: Such a reflection is carried out against the background of a literature review and the inclusion of Gaming Disorder in ICD-11.Results: We believe that it is necessary to divide research on Internet use disorder (IUD) into a mobile and non-mobile IUD branch. This is important because certain applications such as the messenger application WhatsApp have originally been developed for smartphones and enfold their power and attractiveness mainly on mobile devices.Discussion and conclusions: Going beyond the argumentation for distinguishing between mobile and non-mobile IUD, it is of high relevance for scientists to better describe and understand what persons are actually (over-)using. This is stressed by a number of examples, explicitly targeting not only the diverse contents used in the online world, but also the exact behavior on each platform. Among others, it matters if a person is more of an active producer of content or passive consumer of social media.

The advent of the smartphone has dramatically altered how we communicate, navigate, work and entertain ourselves. While the advantages of this new technology are clear, constant use may also bring negative consequences, such as a loss of productivity due to interruptions in work life. A link between smartphone overuse and loss of productivity has often been hypothesized, but empirical evidence on this question is scarce. The present study addressed this question by collecting self-report data from N = 262 participants, assessing private and work-related smartphone use, smartphone addiction and self-rated productivity. Our results indicate a moderate relationship between smartphone addiction and a self-reported decrease in productivity due to spending time on the smartphone during work, as well as with the number of work hours lost to smartphone use. Smartphone addiction was also related to a greater amount of leisure time spent on the smartphone and was strongly related to a negative impact of smartphone use on daily non-work related activities. These data support the idea that tendencies towards smartphone addiction and overt checking of the smartphone could result in less productivity both in the workplace and at home. Results are discussed in relation to productivity and technostress.

In general, it is of importance to distinguish between generalized and specific Internet addiction.

Empathy is an important human ability associated with successful social interaction. It is currently unclear how to optimally measure individual differences in empathic processing. Although the Big Five model of personality is an effective model to explain individual differences in human experience and behavior, its relation to measures of empathy is currently not well understood. Therefore, the present study was designed to investigate the relationship between the Big Five personality concept and two commonly used measures for empathy [Empathy Quotient (EQ), Interpersonal Reactivity Index (IRI)] in four samples from China, Germany, Spain, and the United States of America. This approach was designed to advance the way the Big Five personality model can be used to measure empathy. We found evidence of medium effect sizes for associations between personality and empathy, with agreeableness and conscientiousness as the most important predictors of affective and cognitive empathy (measured by the respective IRI subscales) as well as for a one-dimensional empathy score (measured by the EQ). Empathy in a fictional context was most closely related to openness to experience while personal distress was first of all related to neuroticism. In terms of culture, we did not observe any distinct pattern concerning cultural differences. These results support the cross-cultural applicability of the EQ and the IRI and indicate structurally similar associations between personality and empathy across cultures.