Dichotic listening with forced attention in patients with temporal lobe epilepsy: significance of left hemisphere cognitive dysfunction

Fifty right-handed patients with focal temporal lobe epilepsy were administered a dichotic listening test with consonant-vowel syllables under non-forced, forced right and forced left attention conditions, and a neuropsychological test battery. Dichotic listening performance was compared in subgroups with and without left hemisphere cognitive dysfunction, measured by the test battery, and in subgroups with left and right temporal epileptic focus. Left hemisphere cognitive dysfunction led to more correct responses to left ear stimuli in all three attention conditions, and fewer correct responses to right ear stimuli in the non-forced attention condition. This was probably caused by basic left hemisphere perceptual dysfunction. Dichotic listening was less affected by a left-sided epileptic focus than by left hemisphere cognitive dysfunction. General cognitive functioning influenced dichotic listening performance stronger in forced than in non-forced attention conditions. Larger cerebral networks were probably involved in the forced attention conditions due to the emphasis on conscious effort.     

Connectivity among semantic associates: an fMRI study of semantic priming

Semantic priming refers to a reduction in the reaction time to identify or make a judgment about a stimulus that has been immediately preceded by a semantically related word or picture and is thought to result from a partial overlap in the semantic associates of the two words. A semantic priming lexical decision task using spoken words was presented in event-related fMRI and behavioral paradigms. Word pairs varied in terms of semantic relatedness and the connectivity between associates. Thirteen right-handed subjects underwent fMRI imaging and 10 additional subjects were tested in a behavioral version of the semantic priming task. It was hypothesized priming would be greatest, reaction time fastest, and cortical activation reduced the most for related word pairs of high connectivity, followed by related word pairs of low connectivity, and then by unrelated word pairs. Behavioral and fMRI results confirmed these predictions. fMRI activity located primarily in bilateral posterior superior and middle temporal regions showed modulation by connectivity and relatedness. The results suggest that these regions are involved in semantic processing.     

EDITORIAL

The aim of the present study was to evaluate the usefulness of Barkley’s (1997a) model of inhibition and executive functioning in describing the deficits associated with Attention Deficit Hyperactivity Disorder (ADHD). Besides group differences, the present study addressed the question of independent effects of inhibition and the other executive functions in discriminating between children with ADHD and controls and how well, in terms of sensitivity and specificity, these measures can classify the children into the correct group. The results showed that children with ADHD differed significantly from controls with regard to measures of inhibition as well as all other executive function measures, except repetition of hand movements. In logistic regression models, three different measures tapping inhibition, working memory and emotion regulation were shown to be significant independent predictors of group membership. The sensitivity for these three variables as a set was 76.2, the specificity was 90.5, with a total of 86% of the sample correctly classified. When excluding the parental rating of emotion regulation, the overall classification rate decreased some, but was still relatively high in comparison with previous studies within this area of research.     

Extracorporeal Membrane Oxygenation versus Conventional Treatment: Neurodevelopmental and Social Outcomes at 24 Months

The purpose of this prospective, controlled study was to compare neurodevelopmental and social outcomes at 2 years of age for children treated with extracorporeal membrane oxygenation (ECMO; n = 25) to those of children with severe respiratory illness treated with conventional methods (CT; n = 16) and to matched, healthy full-term (FT; n = 29) children. Mothers' parenting attitudes and children's mental, motor, language, exploratory play, and social competence skills were assessed. A retrospective chart review was also undertaken to further describe the groups with respect to the results of neuroimaging, audiologic, and neuromotor examinations. The FT group had significantly higher mental, motor, and language scores as compared to the ECMO and CT groups. Groups did not differ on measures of behavior, social competence, exploratory play skills, or parental attitudes. Specifically for the ECMO group, there was a trend toward language being more problematic than other areas of development. In general, the data demonstrate that severe respiratory complications, regardless of type of treatment, place children at increased risk for neurodevelopmental difficulties.     

The “simulation” of the facial expression of emotions in case of short and long stimulus duration. The effect of pre-motor cortex inhibition by rTMS

Embodied cognition model states that the “simulation process” is necessary to the recognition of emotional significance of face. The present research explored the contribution of frontal motor brain components (i.e. mainly premotor area) to embodied cognition by using rTMS stimulation, to produce a temporary disruption of this specific cortical site. Secondly, short and long stimulus duration conditions were included to verify the contribution of the “simulation process” in response to overt and covert emotional stimulus comprehension. Nineteen subjects were asked to detect emotion/no emotion (anger, fear, happiness, neutral) in these two experimental conditions, by using a backward masking procedure. Five-second rTMS (1 Hz) was delivered before the stimulus onset. False alarms (Fa) and RTs increased and Hits decreased when frontal premotor brain activity was disrupted, specifically in response to anger and fear, for both long and shortduration condition. Thus, the present results highlight the main role of the frontal motor system for emotion facial expression processing.     

Executive functioning profiles in elite volleyball athletes: Preliminary results by a sport-specific task switching protocol

Executive functions (EF) are crucial for the athletes’ success, and they are even more essential in open skill sports (e.g. volleyball and football). In these sports, due to continuously changing conditions, goal-directed behaviours need to be repeatedly adjusted and corrected. One of the most important EF is the ability to continuously switch between two different tasks being required in a random sequence. We used a task-switching protocol in elite volleyball athletes, usually playing different roles, with the aim of evaluating if each role is characterized by specific switching abilities. On the basis of the specific competences requested by the game, thirty-six elite volleyball athletes were assigned to three groups: Strikers, Defenders and Mixed. Each player completed a customized sport-specific task-switching paradigm. Data evidenced that each role has specific characteristics. In Reaction Times, the Strikers were the fastest to answer to stimuli, while the Defender group provided a worse performance, particularly when defensive actions, that probably require more cognitive elaboration, had to be processed. Different effects emerged by the Errors. In fact, the Mixed group, which was the one with more expertise, appeared to be more accurate in the responses.Although preliminary, these results showed a minimal degree of cognitive flexibility for highly specialized Strikers and a maximum level for Mixed, allowing thus to highlight specific profiles of athletes. Data observed indicate the possibility to develop a test assessing the executive domain during the recruitment in a team, revealing a useful tool for choosing the most suitable role.     

左右半球在语篇理解中的协同作用

通过2例一侧颞叶损伤患者研究了一侧颞叶损伤及两侧半球的协同作用对语篇理解的影响,并探讨了发生此种影响的可能机制。结果表明一侧颞叶的损伤将导致患者语篇水平的理解障碍及语言推理能力的下降;提示语篇理解需双侧半球的协同作用,而推理能力下降可能是引发语篇理解障碍的原因之一。     

前瞻记忆的神经机制：来自临床研究的证据

前瞻记忆是指对预定事件或行为的记忆。本文总结了前瞻记忆脑机制相关的文献,介绍了前额皮层、丘脑,内侧颞叶等脑区域在前瞻记忆中的作用,并通过分析注意缺陷多动障碍儿童、老年痴呆症患者、酒精依赖症和内侧颞叶癫痫患者前瞻记忆的表现,从临床角度深入探讨了前瞻记忆神经机制的问题。证据表明,前额皮层参与前瞻记忆的编码、提取和监控过程,与意向保持也有密切的关系;丘脑与意向的执行有关,并且与前额叶互动在前瞻记忆监控中起着重要的作用;内侧颞叶与编码来源的提取和意向的激活都有密切的关系。研究认为前额皮层在前瞻记忆加工过程中起着核心的作用,同时与丘脑、内侧颞叶等区域相互作用,共同成为前瞻记忆编码、保持、提取、执行的神经基础。     

Neural substrates of cognitive skill learning in Parkinson's disease

While cognitive skill learning is normally acquired implicitly through frontostriatal circuitry in healthy individuals, neuroimaging studies suggest that patients with Parkinson's disease (PD) do so by activating alternate, intact brain areas associated with explicit memory processing. To further test this hypothesis, 10 patients with PD and 12 healthy controls were tested on a modified, learning version of the Tower of London task while undergoing positron emission tomography at four different time points over the course of learning. Despite having less accurate problem solving abilities than controls, PD patients were able to acquire the skill learning task. However, as compared to controls, they maintained higher levels of cerebral blood flow activity in the dorsolateral prefrontal cortex and hippocampus and showed an increase in activity in the frontopolar cortex and posterior cingulate over the course of learning. These findings reflect a shift to the explicit memory system in PD patients, enabling them to learn this cognitive skill, which is normally acquired by control subjects using implicit learning strategies and frontostriatal circuitry.