The Effects of Cognitive Training on Brain Network Activity and Connectivity in Aging and Neurodegenerative Diseases: a Systematic Review

Neuropsychology Review - Cognitive training (CT) is an increasingly popular, non-pharmacological intervention for improving cognitive functioning in neurodegenerative diseases and healthy aging....     

Suggestions to Improve the Comprehensibility of Current Definitions of Scientific Authorship for International Authors

Science and Engineering Ethics - Much has been said about the need for improving the current definitions of scientific authorship, but an aspect that is often overlooked is how to formulate and...     

Effect of atropine or atenolol on cardiovascular responses to novelty stress in freely-moving rats

Cardiac hemodynamic mechanisms involved in cardiovascular responses to stress were studied in conscious, freely-moving female spontaneously hypertensive rats exposed for 15 min to an open-field. When pretreated with saline, the rats displayed a rapid rise in blood pressure, heart rate, aortic dP/dt and locomotor activity. In rats pretreated with 0.5 mg/kg of methylatropine, the tachycardia was slightly, but significantly reduced. In rats pretreated with 1 mg/kg of atenolol, the tachycardis and rise in dP/dt were markedly reduced. These data suggest that the cardiac responses to stress include predominantly cardiac sympathetic activation and a minor component of vagal withdrawal.     

Blocking is sensitive to causal structure in 4-year-old and 8-year-old children

In a contingency learning task, 4-year-old and 8-year-old children had to predict the outcome displayed on the back of a card on the basis of cues presented on the front. The task was embedded in either a causal or a merely predictive scenario. Within this task, either a forward blocking or a backward blocking procedure was implemented. Blocking occurred in the causal but not in the predictive scenario. Moreover, blocking was affected by the scenario to the same extent in both age groups. The pattern of results was similar for forward and backward blocking. These results suggest that even young children are sensitive to the causal structure of a contingency learning task and that the occurrence of blocking in such a task defies an explanation in terms of associative learning theory.     

Semisupervised category learning facilitates the development of automaticity

In the human category of learning, learning is studied in a supervised, an unsupervised, or a semisupervised way. The rare human semisupervised category of learning studies all focus on early learning. However, the impact of the semisupervised category learning late in learning, when automaticity develops, is unknown. Therefore, in Experiment 1, all participants were first trained on the information-integration category structure for 2 days until they reached an expert level. Afterwards, half of the participants learned in a supervised way and the other half in a semisupervised way over two successive days. Both groups received an equal number of feedback trials. Finally, all participants took part in a test day where they were asked to respond as quickly as possible. Participants were significantly faster on this test in the semisupervised group than in the supervised group. This difference was not found on day 2, implying that the no-feedback trials in the semisupervised condition facilitated automaticity. Experiment 2 was designed to test whether the higher number of trials in the semisupervised condition of Experiment 1 caused the faster response times. We therefore created an almost supervised condition where participants almost always received feedback (95%) and an almost unsupervised condition where participants almost never received feedback (5%). All conditions now contained an equal number of trials to the semisupervised condition of Experiment 1. The results show that receiving feedback almost always or almost never led to slower response times than the semisupervised condition of Experiment 1. This confirms the advantage of semisupervised learning late in learning.     

The effects of prior knowledge and text structure on comprehension processes during reading of scientific texts

The aim of the present study was to investigate the effects of prior knowledge and text structure on cognitive processes during comprehension of scientific texts. To investigate the processes online, we used a think-aloud methodology in Experiment 1 and a reading time methodology in Experiment 2. In both experiments, we obtained offline comprehension measures and measures of individual differences in working memory and need for cognition. Across the two experiments, the results indicated that readers adjust their processing as a function of the interaction between prior knowledge and text structure. In particular, adjustments in theactual processes that take place during reading were observed for readers who had erroneous prior knowledge,but only when they read a text that was structured to explicitly refute this prior knowledge. Furthermore, the results showed that readers' memory for the text was affected by differences in their prior knowledge, independently of text structure. These findings contribute to our understanding of the relation between different factorsthat are associated with comprehension of scientific texts and have implications for theories of comprehension and conceptual change.     

Dissociating affective evaluation and social cognitive processes in the ventral medial prefrontal cortex

In recent studies, various regions of the ventral medial prefrontal cortex (vmPFC) have been implicated in at least two potentially different mental functions: reasoning about the minds of other people (social cognition) and processing reward related information (affective evaluation). In this study, we test whether the activation in a specific area of the vmPFC, the para-anterior cingulate cortex (PACC), correlates with the reward value of stimuli in general or is specifically associated with social cognition. Participants performed a time estimation task with trial-to-trial feedback in which reward and social context were manipulated separately. Reward was manipulated by giving either positive or negative feedback in the form of small squirts of fluid delivered orally. Social context was manipulated by instructing participants that positive and negative feedback was determined by another person or a computer. The data demonstrate a main effect of feedback, but not social context, in the PACC, suggesting that this area of the vmPFC serves a general function in evaluating and/or representing reward value. In addition, activity in a more anterior subregion of the vmPFC demonstrated reward-related sensitivity only in the social context. Another area that showed a similar interaction was the subgenual cingulate, but this region was only sensitive to negative feedback in the social condition. These findings suggest that, within the vmPFC, the PACC subserves primarily an affective function, whereas in other regions social context can modulate affective responses.     

Spider fear and covariation bias in children and adolescents

Covariation bias can be defined as phobic people's tendency to overestimate the association between fear-relevant stimuli and negative outcomes. The current article presents two studies that examined this type of cognitive bias in children and adolescents aged 8-16 years. Study 1 was concerned with a thought experiment during which youths (N=150) were asked to imagine that they participated in an experiment during which they had to view a series of pictures showing spiders, guns, and flowers, that were occasionally followed by a negative outcome (i.e., a mild electric shock). Participants were asked to estimate the relation between each type of picture and the negative outcome. The results indicated that youths with higher levels of spider fear displayed a specific tendency to relate spider pictures to a negative outcome. In Study 2, youths (N=220) actually participated in a computer game during which they were confronted with pictures of spiders, guns, and flowers, each of which was equally often followed by a negative (i.e., losing candy), positive (i.e., winning candy), or neutral outcome. After the game, participants had to estimate the relation between each type of picture and various outcomes. It was found that youths with higher levels of spider fear estimated more negative and less positive outcomes in relation to spider pictures. Taken together, these findings provide support for a fear-related covariation bias in youths. Further developmental analyses indicated that this type of cognitive bias seems to be more consistently present among adolescents than among children.     

Feeling guilty as a source of information about threat and performance

OCD patients experience increased feelings of guilt, threat and uncertainty about harm prevention. As to the relation between these phenomena, it was hypothesised that the experience of guilt acts as "information" that increases the sense of threat and decreases the sense that preventive action is effective. We tested whether state guilt is used as information about risk and prevention effects and whether people high in trait guilt do so more than others. Participants high and low in trait guilt were included. Three types of affect were experimentally induced: guilt, anxiety and a neutral affect. Then, participants estimated the likelihood and severity of a negative outcome, and the dissatisfaction with preventive performances in two OCD relevant scenarios. Relative to low-trait guilt participants, people high in trait guilt had higher ratings of risk after induction of state guilt. With regards to dissatisfaction with preventive performance, there was only a trend for high-trait guilt participants to respond stronger to state guilt. The results suggest that people with a general inclination to feel guilty use temporary feelings of guilt as information about the threat content of a situation and do so even if the source of state guilt is unrelated to the situation. Implications for the understanding of OCD are discussed.