Poststimulation time interval-dependent effects of motor cortex anodal tDCS on reaction-time task performance

Anodal transcranial direct current stimulation (tDCS) induces long-term potentiation-like plasticity, which is associated with long-lasting effects on different cognitive, emotional, and motor performances. Specifically, tDCS applied over the motor cortex is considered to improve reaction time in simple and complex tasks. The timing of tDCS relative to task performance could determine the efficacy of tDCS to modulate performance. The aim of this study was to compare the effects of a single session of anodal tDCS (1.5 mA, for 15 min) applied over the left primary motor cortex (M1) versus sham stimulation on performance of a go/no-go simple reaction-time task carried out at three different time points after tDCS—namely, 0, 30, or 60 min after stimulation. Performance zero min after anodal tDCS was improved during the whole course of the task. Performance 30 min after anodal tDCS was improved only in the last block of the reaction-time task. Performance 60 min after anodal tDCS was not significantly different throughout the entire task. These findings suggest that the motor cortex excitability changes induced by tDCS can improve motor responses, and these effects critically depend on the time interval between stimulation and task performance.     

Intracellular calcium chelation and pharmacological SERCA inhibition of Ca2+ pump in the insular cortex differentially affect taste aversive memory formation and retrieval

Variation in intracellular calcium concentration regulates the induction of long-term synaptic plasticity and is associated with a variety of memory/retrieval and learning paradigms. Accordingly, impaired calcium mobilization from internal deposits affects synaptic plasticity and cognition in the aged brain. During taste memory formation several proteins are modulated directly or indirectly by calcium, and recent evidence suggests the importance of calcium buffering and the role of intracellular calcium deposits during cognitive processes. Thus, the main goal of this research was to study the consequence of hampering changes in cytoplasmic calcium and inhibiting SERCA activity by BAPTA-AM and thapsigargin treatments, respectively, in the insular cortex during different stages of taste memory formation. Using conditioned taste aversion (CTA), we found differential effects of BAPTA-AM and thapsigargin infusions before and after gustatory stimulation, as well as during taste aversive memory consolidation; BAPTA-AM, but not thapsigargin, attenuates acquisition and/or consolidation of CTA, but neither compound affects taste aversive memory retrieval. These results point to the importance of intracellular calcium dynamics in the insular cortex during different stages of taste aversive memory formation.     

An introduction to the 2011 National Multicultural Conference & Summit keynote addresses

This article provides and introduction to the 2011 National Multicultural Conference & Summit Keynote Addresses. The authors explain that they chose to focus on the tension and possibilities within multicultural psychology at the seventh biennial National Multicultural Conference & Summit (NMCS), which was held on January 27-28, 2011, at The Westin-Seattle Hotel. During the 2-day conference, nearly 900 attendees engaged with one another and heard from experts in the field as we focused on the theme, "Unification through Diversity: Bridging Psychological Science & Practice in the Public Interest. Two key sets of presentations are highlighted.     

Weighing the past and the future in decision making

Prior irreversible investments of money, time, or effort referred to as sunk costs frequently lead to decisions to continue a chosen course of action despite that this is irrational. With the aim of demonstrating that such escalation of commitment is a special case of a more general phenomenon, two experiments were carried out employing undergraduates as participants. Experiment 1 showed for fictitious personal and business investment scenarios that both prior losses and gains (sunk outcomes) affected choices to continue or discontinue the investment. In Experiment 2 the effect of sunk outcomes was reduced although not eliminated by a monetary bonus that in one condition depended on the future outcomes of the second gamble in two-stage gambles, in another condition on the future returns in personal investment scenarios. In support of a more inclusive theory subsuming escalation of commitment, the decisions were affected by both past and future outcomes and both gains and losses.     

Mental models in propositional reasoning and working memory's central executive

We examine the role of working memory's central executive in the mental model explanation of propositional reasoning by using two working memory measures: the classical “reading span” test by Daneman and Carpenter (1980 Daneman, M. and Carpenter, P. A. 1980. Individual differences in working memory and reading. Journal of Verbal Learning and Verbal Behavior, 19: 450–466. [Crossref] , [Google Scholar]) and a new measure. This new “reasoning span” measure requires individuals to solve very simple anaphora problems, and store and remember the word solution in a growing series of inferential problems. We present one experiment in which we check the involvement of the central executive in conditional and disjunctive inference tasks and compare predictions of the new reasoning span test with those of the classical reading span test. The results of the experiment confirm that reasoning responses, which according to mental model theory require high cognitive work, are predicted by working memory measures. Results also show that some reasoning responses are probably obtained by means of superficial biases or strategies that do not load working memory. The reasoning span test, which involves the central executive to a greater degree, predicts reasoning performance better than the reading span test. The significance and possibilities of the new measure in studying reasoning are discussed.     

Emotion Comprehension: The Impact of Nonverbal Intelligence

A substantial body of research has established that emotion understanding develops throughout early childhood and has identified three hierarchical developmental phases: external, mental, and reflexive. The authors analyzed nonverbal intelligence and its effect on children's improvement of emotion understanding and hypothesized that cognitive level is a consistent predictor of emotion comprehension. In all, 366 children (182 girls, 184 boys) between the ages of 3 and 10 years were tested using the Test of Emotion Comprehension and the Coloured Progressive Matrices. The data obtained by using the path analysis model revealed that nonverbal intelligence was statistically associated with the ability to recognize emotions in the 3 developmental phases. The use of this model showed the significant effect that cognitive aspect plays on the reflexive phase. The authors aim to contribute to the debate about the influence of cognitive factors on emotion understanding.     

Performance of an Adapted Version of the Timed Up-and-Go Test in People with Cognitive Impairments

In clinical practice, older people with cognitive impairment may have difficulties to understand the instructions of the Timed Up-and-Go (TUGT) test and present a bad performance. The purpose of this study was to identify differences in the TUGT performance, in an adapted version, between older adults with preserved cognition (PC), mild cognitive impairment (MCI) and Alzheimer's disease (AD), and to identify the association between the adapted TUGT performance and cognition among groups. A cross-sectional study was conducted with 118 community-dwelling older adults divided in three groups: PC (n?=?40), MCI (n?=?40) and AD (n?=?38). The evaluation was composed by the adapted TUGT and cognitive assessment (Addenbrooke's Cognitive Examination and Frontal Assessment Battery). Only the cadence of TUGT presented significant difference between groups, specifically between AD versus MCI and PC groups. The main correlations were found between time of TUGT with fluency domain and global cognitive function, especially in the AD Group. The findings contribute to the understanding of how cognition interferes on functional mobility in older people with MCI and AD. The adapted TUGT is easy to perform in clinical practice and can be useful when assessing mobility in people with cognitive impairment.     

Temperament and negative semantic priming in children 7 to 12 years old

The present research assessed whether children with high and low scores on temperament traits differed in their ability to inhibit irrelevant task information in a lexical decision task. Children from 7 to 12 years old were classified based on temperament dimensions measured using a version of the Temperament in Middle Childhood Questionnaire. The participants were instructed to either attend to (and remember) or to ignore a masked prime word followed by a central probe target on which they made a lexical decision. The results revealed several notable outcomes. First of all, recognition memory was better for attended than ignored words, providing further evidence that attention instructions influenced the processing of the primes.

Secondly, although no negative priming effect was obtained in the “ignore” condition, 43% of children showed this effect. Thirdly, children scoring high on Inhibitory Control and Impulsivity showed ignored negative priming, whereas children scoring high on Inhibitory Control and low on Impulsivity ignored facilitation. Data are discussed within the framework of negative priming as a complex phenomenon that involves the interaction of different factors such as age, type of task, and certain temperament traits.