Language comprehension vs. language production: age effects on fMRI activation

Normal language acquisition is a process that unfolds with amazing speed primarily in the first years of life. However, the refinement of linguistic proficiency is an ongoing process, extending well into childhood and adolescence. An increase in lateralization and a more focussed productive language network have been suggested to be the neural correlates of this process. However, the processes underlying the refinement of language comprehension are less clear. Using a language comprehension (Beep Stories) and a language production (Vowel Identification) task in fMRI, we studied language representation and lateralization in 36 children, adolescents, and young adults (age 6-24 years). For the language comprehension network, we found a more focal activation with age in the bilateral superior temporal gyri. No significant increase of lateralization with age could be observed, so the neural basis of language comprehension as assessed with the Beep Stories task seems to be established in a bilateral network by late childhood. For the productive network, however, we could confirm an increase with age both in focus and lateralization. Only in the language comprehension task did verbal IQ correlate with lateralization, with higher verbal IQ being associated with more right-hemispheric involvement. In some subjects (24%), language comprehension and language production were lateralized to opposite hemispheres.     

Multi- and unisensory decoding of words and nonwords result in differential brain responses in dyslexic and nondyslexic adults

The present functional magnetic resonance imaging (fMRI) study was designed, in order to investigate the neural substrates involved in the audiovisual processing of disyllabic German words and pseudowords. Twelve dyslexic and 13 nondyslexic adults performed a lexical decision task while stimuli were presented unimodally (either aurally or visually) or bimodally (audiovisually simultaneously).The behavioral data collected during the experiment evidenced more accurate processing for bimodally than for unimodally presented stimuli irrespective of group. Words were processed faster than pseudowords. Notably, no group differences have been found for either accuracy or for reaction times. With respect to brain responses, nondyslexic compared to dyslexic adults elicited stronger hemodynamic responses in the leftward supramarginal gyrus (SMG), as well as in the right hemispheric superior temporal sulcus (STS). Furthermore, dyslexic compared to nondyslexic adults showed reduced responses to only aurally presented signals and enhanced hemodynamic responses to audiovisual, as well as visual stimulation in the right anterior insula.Our behavioral results evidence that the two groups easily identified the two-syllabic proper nouns that we provided them with. Our fMRI results indicate that dyslexics show less neuronal involvement of heteromodal and extrasylvian regions, namely, the STS, SMG, and insula when decoding phonological information. We posit that dyslexic adults evidence deficient functioning of word processing, which could possibly be attributed to deficits in phoneme to grapheme mapping. This problem may be caused by impaired audiovisual processing in multimodal areas.     

Individual differences in working memory capacity predict retrieval-induced forgetting

Selectively retrieving a subset of previously studied information enhances memory for the retrieved information but causes forgetting of related, nonretrieved information. Such retrieval-induced forgetting (RIF) has often been attributed to inhibitory executive-control processes that supposedly suppress the nonretrieved items' memory representation. Here, we examined the role of working memory capacity (WMC) in young adults' RIF. WMC was assessed by means of the operation span task. Results revealed a positive relationship between WMC and RIF, with high-WMC individuals showing more RIF than low-WMC individuals. In contrast, individuals showed enhanced memory for retrieved information regardless of WMC. The results are consistent with previous individual-differences work that suggests a close link between WMC and inhibitory efficiency. In particular, the finding supports the inhibitory executive-control account of RIF.     

Being present in more than one place at a time? Patterns of mental self-localization

Research in cognitive neuroscience and spatial presence suggests that human mental self-localization is tied to one place at a given point in time. In this study, we examined whether it is possible to feel localized at two distinct places at the same time. Participants (N = 30) were exposed to a virtual rollercoaster and they continuously judged to what extent they felt present in the immediate environment and in the mediated environment, respectively. The results show that participants distributed their self-localization to both environments, and the two values added up to closely 100% over time. In addition, even though the judgments are highly idiosyncratic, they were almost perfectly inversely related. This indicates that individuals can distribute their self over two distinct places. These findings provide important insights about understanding of the human self-localization.     

Placebo-mediated, Naloxone-sensitive suggestibility of short-term memory performance

Physiological studies of placebo-mediated suggestion have been recently performed beyond their traditional clinical context of pain and analgesia. Various neurotransmitter systems and immunological modulators have been used in successful placebo suggestions, including Dopamine, Cholecystokinin and, most extensively, opioids. We adhered to an established conceptual framework of placebo research and used the μ-opioid-antagonist Naloxone to test the applicability of this framework within a cognitive domain (e.g. memory) in healthy volunteers. Healthy men (n=62, age 29, SD=9) were required to perform a task-battery, including standardized and custom-designed memory tasks, to test short-term recall and delayed recognition. Tasks were performed twice, before and after intravenous injection of either NaCl (0.9%) or Naloxone (both 0.15 mg/kg), in a double-blind setting. While one group was given neutral information (S-), the other was told that it might receive a drug with suspected memory-boosting properties (S+). Objective and subjective indexes of memory performance and salivary cortisol (as a stress marker) were recorded during both runs and differences between groups were assessed. Short-term memory recall, but not delayed recognition, was objectively increased after placebo-mediated suggestion in the NaCl-group. Naloxone specifically blocked the suggestion effect without interfering with memory performance. These results were not affected when changes in salivary cortisol levels were considered. No reaction time changes, recorded to uncover unspecific attentional impairment, were seen. Placebo-mediated suggestion produced a training-independent, objective and Naloxone-sensitive increase in memory performance. These results indicate an opioid-mediated placebo effect within a circumscribed cognitive domain in healthy volunteers.     

Fruitful plans: adding targeted mental imagery to implementation intentions increases fruit consumption

Forming implementation intentions ('If I encounter situation X, then I will perform behaviour Y!') increases the probability of carrying out goals. This study tested the hypothesis that mental imagery targeting key elements of implementation intentions further increases goal achievement. The residents of a student residence were assigned the goal of consuming extra portions of fruit every day for 7 days and randomly assigned to one of four conditions: control (active rehearsal), implementation intentions, goal intention mental imagery or mental imagery targeted to the implementation intentions. Among low fruit consumers, but not high fruit consumers, fruit consumption at follow-up was higher in the targeted mental imagery group than in the other group, with the lowest fruit consumption in the control group. The findings suggest that it may be beneficial to use targeted mental imagery when forming implementation intentions.     

Negative post-event processing and decreased self-appraisals of performance following social stress in childhood social anxiety: an experimental study

Cognitive models of social phobia (SP) assume that following social evaluative stress, individuals with SP engage into dysfunctional post-event processing (PEP), a detailed negative review of the past event. While previous research has already shown, that children with high levels of social fears suffer from more frequent negative PEP, it remains unclear how stable PEP is across time in this age group and whether it leads to degraded self-appraisals of performance. Therefore in the present study we exposed a group of high (HSA) and low socially anxious children (LSA; both n = 20), aged 10–12 years, to a social evaluative situation and assessed negative and positive PEP as well as self-rated performance at 2.5 h and one week after the task. Our results revealed that HSA children reported more negative PEP than LSA children, independent of levels of depression. Moreover, negative PEP was related to measures of social anxiety and performance ratings within the tasks. Only the performance ratings in HSA children worsened over the course of the following week and were related to more negative PEP. Thus, these results speak for the high clinical relevance dysfunctional PEP may have for the maintenance of social fears already in childhood.     

The magic cup: great apes and domestic dogs (Canis familiaris) individuate objects according to their properties

Despite current interest in dog (Canis familiaris) cognition, very little is known about how dogs represent objects and how they compare with other species, such as the great apes. Therefore, we investigated how dogs and great apes (chimpanzees [Pan troglodytes], bonobos [Pan paniscus], orangutans [Pongo pygmaeus], gorillas [Gorilla gorilla]) individuate objects in a classical violation of expectation paradigm. We used a container (magic cup) with a double bottom that allowed us to change the type of food that subjects had seen being placed in the container. Using a 2 × 2 design, we varied whether subjects received a generally preferred food and whether the food was substituted (surprise trials) or not (baseline trials). Apes showed increased begging and looking behaviors and dogs showed increased smelling behavior. Both species stayed near the experimenter more frequently in the surprise trials compared with baseline trials. Both species reacted to positive (i.e., good food substituted for bad food) and negative (i.e., bad food substituted for good food) surprises. These results suggest that apes and dogs were able to individuate objects according to their properties or type in comparable ways. In addition, we looked for frustration and elation effects, but subjects' behaviors were not influenced by the food they saw and which they received in previous trials.     

Intrapersonal and interpersonal risk factors for peer victimization in immigrant youth in Finland

This study (a) compared native Finns and immigrant children with respect to different forms of peer victimization and (b) tested whether intrapersonal (e.g., depression) and interpersonal (e.g., peer rejection) sample was drawn from the first phase of a large intervention evaluation project, KiVa, in Finland, composed of 4,957 native Finns (51% girls), 146 first-generation immigrants (48% girls), and 310 second-generation immigrants (53% girls) 9 to 12 years of age. The concurrent data included self- and peer reports collected via Internet-based questionnaires. Compared with native youth, first- and second-generation immigrants were more often targets of both peer- and self-reported victimization. Both immigrant groups experienced higher levels of physical, racist, and sexual victimization than natives. Furthermore, second-generation immigrants reported higher levels of property damage, threats, and cybervictimization than native Finns. Significant indirect effects were found between immigrant status and victimization. Interpersonal but not intrapersonal risk factors helped to explain these associations.