Clock drawing performance and brain morphology in mild cognitive impairment and Alzheimer's disease

The Clock Drawing Test (CDT) is a widely used instrument in the neuropsychological assessment of Alzheimer's disease (AD). As CDT performance necessitates several cognitive functions (e.g., visuospatial and constructional abilities, executive functioning), an interaction of multiple brain regions is likely. Fifty-one subjects with mild cognitive impairment, 23 with AD and 15 healthy controls underwent high-resolution magnetic resonance imaging. Optimized voxel-based morphometry (VBM) was performed to investigate the putative association between CDT performance and gray matter (GM) density throughout the entire brain. In the first step of analysis (p<.001, uncorrected), VBM revealed a reduced GM density in numerous cortical (temporal lobe, frontal lobe, parietal lobe, cerebellum) and subcortical (thalamus, basal ganglia) brain regions to be associated with poorer CDT performance. When corrected for multiple comparisons (p<.01), the associations remained significant predominantly in the left temporal and--less pronounced--the right temporal lobe. VBM demonstrated CDT performance to depend on the integrity of widely distributed cortical and subcortical areas in both brain hemispheres with accentuation in the left-sided temporal lobe region.     

The role of animacy in the real time comprehension of Mandarin Chinese: Evidence from auditory event-related brain potentials

Two auditory ERP studies examined the role of animacy in sentence comprehension in Mandarin Chinese by comparing active and passive sentences in simple verb-final (Experiment 1) and relative clause constructions (Experiment 2). In addition to the voice manipulation (which modulated the assignment of actor and undergoer roles to the arguments), both arguments were either animate or inanimate. This allowed us to examine the interplay of animacy with thematic interpretation. In Experiment 1, we observed no effect of animacy at NP1, but N400 effects for inanimate actor arguments in second position. This result mirrors previous findings in German, thus suggesting that an initial undergoer universally leads to the prediction of an ideal (animate) actor. We also observed an N400 effect for passive sentences with an inanimate initial (undergoer) argument. We attribute this effect to a language-specific property of the passive construction in Chinese, namely that the first argument is negatively affected by the event described (i.e. bears an experiencer role). Experiment 2 showed that both of these effects can also be observed in sentence constructions of another type, in which the critical information sources become available in a different order. These findings provide the first demonstration that the N400 is not only sensitive to general (universal) aspects of thematic processing (i.e. "who is acting on whom") but also to the interaction between thematic interpretation and language-specific pragmatic principles.     

Response selection and response execution in task switching: evidence from a go-signal paradigm

The present study used a go/no-go signal delay (GSD) to explore the role of response-related processes in task switching. A go/no-go signal was presented at either 100 ms or 1,500 ms after the stimulus. Participants were encouraged to use the GSD for response selection and preparation. The data indicate that the opportunity to select and prepare a response (i.e., long GSD) resulted in a substantial reduction of task-shift costs (Experiment 1) and n-2 task-repetition costs (i.e., backward inhibition; Experiment 2) in the current trial. These results suggest that interference from the preceding trial can be resolved during response selection and preparation. Furthermore, the shift costs and the n-2 repetition costs after no-go trials with long GSD (i.e., response selection but no execution) were markedly smaller than after go trials. These findings suggest that the interference that gives rise to shift costs and n-2 repetition costs is related not solely to response selection but also to response execution. Thus, the present study demonstrates dissociable contributions of response selection and response execution to interference effects in task switching.     

Posttraumatische Belastungssymptome als Spätfolge von Kindheiten im Zweiten Weltkrieg

Psychological late-life sequelae of war childhood have rarely been examined. The study evaluated posttraumatic symptoms and current psychopathology in a sample of former German war children of which 10.8% reported significant posttraumatic symptoms indicating a possible posttraumatic stress disorder (PTSD). The presence of PTSD symptoms was significantly associated with current psychopathological distress, even 6 decades after World War II. Our data underline the urgent need for research in this field. Clinical implications for a psychotherapeutic approach are discussed.     

Schlusswort

Ohne Zusammenfassung     

Mutual friends’ social support and self-disclosure in face-to-face and instant messenger communication

In the present study, we investigated long-term effects of self-disclosure on social support in face-to-face and instant messenger (IM) communication between mutual friends. Using a representative sample of 583 German IM users, we explored whether self-disclosure and positive experiences with regard to social support would dynamically interact in the form of a reinforcing spiral across three measurement occasions. If mutual friends self-disclose today, will they receive more social support 6 months later? In turn, will this affect their willingness to self-disclose another 6 months later? We further analyzed spill-over effects from face-to-face to IM communication and vice versa. We found that self-disclosure predicted social support and vice versa in IM communication, but not in face-to-face communication. In light of these results, the impact of IM communication on how individuals maneuver friendships through the interplay between self-disclosure and social support are discussed.     

The Role of Leisure Interest and Engagement for Subjective Well-Being

During the last decades, the association between leisure engagement and subjective well-being (SWB) has been examined. Yet, the role of the interest in specific leisure activities for SWB has been neglected. Thus, we examined whether the pure leisure engagement or the opportunity to realize the longing to pursue a leisure activity is linked to well-being. A sample of 402 participants completed an online survey about interests and the frequency of engagement in diverse leisure activities as well as physical, cognitive, and affective well-being. The study revealed that leisure engagement showed stronger associations with all aspects of well-being than leisure interest per se. More specifically, interest and engagement in social activities and sports showed robust associations with different facets of well-being. Furthermore, a high individual fit between leisure interest and engagement across diverse activities incrementally predicted SWB beyond leisure engagement per se. Analyses of nonlinear associations indicated that too much leisure engagement was associated with lower levels of SWB, but high interest in leisure activities buffered this effect. Thus, the intrinsic motivation to leisure activities may play an important role for well-being in addition to the sheer leisure engagement.     

Risk seeking for losses modulates the functional connectivity of the default mode and left frontoparietal networks in young males

Value-based decision making (VBDM) is a principle that states that humans and other species adapt their behavior according to the dynamic subjective values of the chosen or unchosen options. The neural bases of this process have been extensively investigated using task-based fMRI and lesion studies. However, the growing field of resting-state functional connectivity (RSFC) may shed light on the organization and function of brain connections across different decision-making domains. With this aim, we used independent component analysis to study the brain network dynamics in a large cohort of young males (N = 145) and the relationship of these dynamics with VBDM. Participants completed a battery of behavioral tests that evaluated delay aversion, risk seeking for losses, risk aversion for gains, and loss aversion, followed by an RSFC scan session. We identified a set of large-scale brain networks and conducted our analysis only on the default mode network (DMN) and networks comprising cognitive control, appetitive-driven, and reward-processing regions. Higher risk seeking for losses was associated with increased connectivity between medial temporal regions, frontal regions, and the DMN. Higher risk seeking for losses was also associated with increased coupling between the left frontoparietal network and occipital cortices. These associations illustrate the participation of brain regions involved in prospective thinking, affective decision making, and visual processing in participants who are greater risk-seekers, and they demonstrate the sensitivity of RSFC to detect brain connectivity differences associated with distinct VBDM parameters.     

Selective inactivation of adenosine A(2A) receptors in striatal neurons enhances working memory and reversal learning

The adenosine A(2A) receptor (A(2A)R) is highly enriched in the striatum where it is uniquely positioned to integrate dopaminergic, glutamatergic, and other signals to modulate cognition. Although previous studies support the hypothesis that A(2A)R inactivation can be pro-cognitive, analyses of A(2A)R's effects on cognitive functions have been restricted to a small subset of cognitive domains. Furthermore, the relative contribution of A(2A)Rs in distinct brain regions remains largely unknown. Here, we studied the regulation of multiple memory processes by brain region-specific populations of A(2A)Rs. Specifically, we evaluated the cognitive impacts of conditional A(2A)R deletion restricted to either the entire forebrain (i.e., cerebral cortex, hippocampus, and striatum, fb-A(2A)R KO) or to striatum alone (st-A(2A)R KO) in recognition memory, working memory, reference memory, and reversal learning. This comprehensive, comparative analysis showed for the first time that depletion of A(2A)R-dependent signaling in either the entire forebrain or striatum alone is associated with two specific phenotypes indicative of cognitive flexibility-enhanced working memory and enhanced reversal learning. These selective pro-cognitive phenotypes seemed largely attributed to inactivation of striatal A(2A)Rs as they were captured by A(2A)R deletion restricted to striatal neurons. Neither spatial reference memory acquisition nor spatial recognition memory were grossly affected, and no evidence for compensatory changes in striatal or cortical D(1), D(2), or A(1) receptor expression was found. This study provides the first direct demonstration that targeting striatal A(2A)Rs may be an effective, novel strategy to facilitate cognitive flexibility under normal and pathologic conditions.