Testing the effects of end-goal during reach-to-grasp movements in Parkinson’s disease

Previous evidence suggests that hand shaping during reaching is modulated by the presence and the nature of the end-goal following object’s grasp. Here we test whether such modulation is maintained in Parkinson’s disease (PD). Six participants with PD and six healthy participants took part in the study. Participants were requested to reach towards a bottle filled with water, and then: (1) grasp it without performing any subsequent action; (2) grasp it and place it accurately on a target area; (3) grasp it and pour its contents within a container. The results showed that participants shaped their hand differently depending on the presence or absence of an action following object’s grasp. However, the request to perform an action after grasp determined a modulation of hand kinematics which was delayed for PD than for control participants. Further, whereas for control participants the nature of the end-goal determined a modulation of hand shaping, for PD patients such modulation was not evident. Data are discussed in terms of the role played by basal ganglia in implementing anticipatory mechanisms for the control of manipulative activities. We contend that in PD patients these mechanisms are not totally compromised, but their implementation depends on the action information that has to be anticipated.     

Examining HPA-axis functioning as a mediator of the relationship between depression and cognition across the adult lifespan

Altered HPA-axis functioning is a hypothesized mechanism for worsened cognition in depression. The current study examines the indirect effects of depression on processing speed, executive functioning, and memory as a function of the HPA-axis. 38 individuals with a depression diagnosis and 50 healthy controls (HCs) aged 18–86 underwent neuropsychological testing and at-home diurnal salivary cortisol collection. Depression was assessed via structured clinical interviews and rating scales. Cognitive composite scores were derived from factor analysis. Daytime cortisol exposure was estimated using area under the curve (AUC). Depression was associated with higher cortisol levels and slower processing speed . A significant suppression effect of AUC was present on the relationship between depression and processing speed. Limitations include the cross-sectional design and limited sample heterogeneity. Though poorly modulated HPA-axis is one proposed mechanism of cognitive alterations in depression, our results did not support this conclusion for processing speed. Alternative mechanisms should be considered to inform interventions to target cognitive alterations in depression.     

特里尔社会应激测验对儿童皮质醇分泌的影响

研究以32名小学儿童（平均年龄10.47岁,男生16人）为被试,采用唾液皮质醇为应激测验的客观指标、以被试主观紧张度为主观指标,考察特里尔社会应激测验对中国儿童皮质醇分泌的影响。结果表明：（1）社会应激测验任务引发儿童皮质醇浓度和主观紧张度的显著上升,任务后的恢复期皮质醇浓度和主观紧张度能够恢复到任务前的水平。（2）社会应激测验任务引发的男生皮质醇水平变化显著高于女生,但是引发的主观紧张度水平变化不存在显著性别差异。社会应激测验中文修订版能够有效引发儿童的压力应激变化,可以用其开展儿童社会应激的相关研究。     

The thalamus and basal ganglia: What is exactly where?: A reply to ‘Neuropsychological consequences of right thalamic injury: Case study and review,’ MJ Summers, Brain and Cognition 50 (2002)

The present paper re-analyzes anatomical and clinical data of a previous case report ([Summers, 2002]). In this case study, a patient with severe neuropsychological and behavioral impairments is described and it is claimed that these impairments are causally linked to an right thalamic lesion. A simple method how to perform a lesion analysis is introduced which shows that PD’s lesion was a striatocapsular hematoma, and not a thalamic bleeding. The results of this anatomical re-analysis challenge the original behavioral-lesion hypothesis and emphasize the importance to provide appropriate data on brain lesions and clinical findings in neuropsychological case reports.     

Personality traits and endocrine response as possible asymmetry factors of agonistic outcome in karate athletes

Individual variations of plasma levels of hormones testosterone (T) and cortisol (C), before (pre) and after (post) Kumite (real fight) and Kata (ritualized fight) were measured in male karate athletes and analyzed in relation with the agonistic outcome (i.e. winning or losing the fight) and personality trait measures. T and C increased only during Kumite contest and pre‐ and post‐competition C levels were higher in losers than winners. Losers showed higher levels of harm avoidance and anxiety as well as lower level of novelty seeking than winners. Importantly, novelty seeking negatively correlates with pre C and the higher the level of risk assessment, emotionality and insecurity indexes the higher the pre C level. In conclusion, personality traits might be an important factor asymmetry between athletes influencing both the probability of winning or losing an agonistic interaction and the different anticipatory endocrine response to the incipient fight. Aggr. Behav. 35:324–333, 2009. © 2009 Wiley‐Liss, Inc.     

Developmental shifts in fMRI activations during visuospatial relational reasoning

To investigate maturational plasticity of fluid cognition systems, functional brain imaging was undertaken in healthy 8-19 year old participants while completing visuospatial relational reasoning problems similar to Raven's matrices and current elementary grade math textbooks. Analyses revealed that visuospatial relational reasoning across this developmental age range recruited activations in the superior parietal cortices most prominently, the dorsolateral prefrontal, occipital-temporal, and premotor/supplementary cortices, the basal ganglia, and insula. There were comparable activity volumes in left and right hemispheres for nearly all of these regions. Regression analyses indicated increasing activity predominantly in the superior parietal lobes with developmental age. In contrast, multiple anterior neural systems showed significantly less activity with age, including dorsolateral and ventrolateral prefrontal, paracentral, and insula cortices bilaterally, basal ganglia, and particularly large clusters in the midline anterior cingulate/medial frontal cortex, left middle cingulate/supplementary motor cortex, left insula-putamen, and left caudate. Findings suggest that neuromaturational changes associated with visuospatial relational reasoning shift from a more widespread fronto-cingulate-striatal pattern in childhood to predominant parieto-frontal activation pattern in late adolescence.     

Multiple memory stores and operant conditioning: a rationale for memory's complexity

Why does the brain contain more than one memory system? Genetic algorithms can play a role in elucidating this question. Here, model animals were constructed containing a dorsal striatal layer that controlled actions, and a ventral striatal layer that controlled a dopaminergic learning signal. Both layers could gain access to three modeled memory stores, but such access was penalized as energy expenditure. Model animals were then selected on their fitness in simulated operant conditioning tasks. Results suggest that having access to multiple memory stores and their representations is important in learning to regulate dopamine release, as well as in contextual discrimination. For simple operant conditioning, as well as stimulus discrimination, hippocampal compound representations turned out to suffice, a counterintuitive result given findings that hippocampal lesions tend not to affect performance in such tasks. We argue that there is in fact evidence to support a role for compound representations and the hippocampus in even the simplest conditioning tasks.     

Biological correlates of social support and pressure at work in managers

The aim was to explore the patterns of correlations between psychosocial stress indices and neuroendocrinological factors in managers. Fifty-eight male managers in three Swedish companies constituted the sample. They answered two questionnaires with 17 selected stress indices and also an organizational test. The indices have been analyzed by means of computations of age adjusted partial correlations with nine different variables analyzed in fasting blood samples. The serum concentrations of lipids were the variables most strongly correlated with psychosocial factors. Neither smoking nor physical activity changed the correlations significantly. Good social support at work and in private life was consistently associated with low adverse serum lipids and corresponding lipoproteins. On the other hand, some indices of social support were associated with indices of high arousal levels. This may indicate a possible psychophysiological “load effect” of some aspects of social support in managers. The analyses of corporate culture measured as “Rules of the Game” indicated that “bureaucracy” was significantly associated with high LDL-cholesterol and low HDL-cholesterol. Managers have special conditions and therefore the patterns of associations between psychosocial conditions and coping strategies on one hand and endocrine-biochemical state on the other hand may be different, from those of other groups. To what extent such differences are due to individual characteristics or environmental factors needs to be further investigated. According to the results, however, good social support is in general health promoting also to managers, at least with regard to serum lipids. Bureaucracy, on the other hand, seems to be dangerous to the health of managers.     

Psychological and Neuroendocrine Reactivity to Ostracism

This study used the ostracism detection theory to investigate how ostracism impacts individuals in two ways: (1) immediate poststressor needs, mood, ruminative thoughts, and desire to affiliate, and (2) short‐term affective and cortisol reactivity. A total of 58 college students were randomly assigned to the inclusion or ostracism conditions of Cyberball, a virtual ball‐tossing game. Immediately following the experimental manipulation, ostracized participants reported more thwarted psychological need states, more negative mood, and fewer positive ruminative thoughts, relative to their included counterparts. Ostracized participants reported a greater interest in affiliating with others in online or in‐person settings. In the short‐term, ostracized males reported more hostility than included males, although the scores were within expected norms for most males. There was no relation between Cyberball condition and gender across time for depression, anxiety, or positive affect. Approximately 20 min after the onset of the stressor, women in the luteal phase and women taking oral contraceptives in the ostracized group displayed higher cortisol than their counterparts in the included group. Relative to baseline, however, cortisol did not reliably increase after the onset of the stressor. Ostracized females taking oral contraceptives showed the greatest decline in cortisol, compared to included oral contraceptive users. Overall, results suggest that most of the negative effects of ostracism are immediate and limited to psychological, not neuroendocrine, responses.     

应激影响脑老化的相关学说与机制

应激是机体受到各种内外环境因素刺激时的适应性反应,当反应持续时间过久或长期处于激活状态,则会对机体产生不良影响。目前认为,老化与糖皮质激素的过量分泌所致大脑相关区域的损伤相关,这些区域不仅参与认知与情绪,而且与下丘脑-垂体-肾上腺轴控制的其他活动相关。除此之外,皮质醇基础水平的差异性、皮质醇在脑内的可用性、糖皮质激素受体的失衡及大脑本身的易损性、回弹性等都是应激影响脑老化的参与因素。本文将对应激所致正常或非正常老化过程的相关影响机制与学说进行综述。