TNF-α和PGP9.5在椎体后缘离断症软骨终板的表达及意义

目的:观察TNF-α、PGP 9.5在椎体后缘离断症软骨终板中的表达、分布,探讨其与椎体后缘离断发生、发展的关系。方法:选取手术治疗的12例椎体后缘离断症患者的病椎软骨终板与4例椎体骨折伤椎软骨终板作对照研究。病椎标本包括离断缘及远离离断缘软骨终板组织。切片行TNF-α和PGP 9.5免疫组织化学染色,应用病理图像分析系统测量光密度值(OD值),观测其在椎体软骨终板的表达与分布。结果:骨折椎体的软骨终板内未见TNF-α和PGP 9.5免疫组化阳性染色。椎体离断缘软骨终板组织中,TNF-α和PGP 9.5表达均高于远离离断缘的软骨终板组织(P﹤0.05)。结论:TNF-α和PGP 9.5在椎体后缘离断症的软骨终板中均有表达,终板不同区域其表达存在差异性,局部高表达与椎体后缘离断有密切关系。     

Sequelae of a left-sided parietal stroke: Posterior alien hand syndrome

Posterior alien hand syndrome is a new addition to a poorly understood group of movement disorders. Historically, anatomical lesions causing uncontrolled limb movement and a feeling of foreignness were found to be located in the corpus callosum or frontal lobe. Recent case reports, however, demonstrate the typical symptoms of alien hand syndrome with lesions located in the parietal/occipital lobes. Disturbance of normal function in these regions tends to produce less complex motor activity, such as hand levitation, along with a sensory component characterized by feeling of estrangement. We discuss a patient who presented with unusual symptoms following an outpatient procedure and was found to have posterior alien hand syndrome.     

Site-Dependent Effects of tDCS Uncover Dissociations in the Communication Network Underlying the Processing of Visual Search

BackgroundThe right posterior parietal cortex (rPPC) and the right frontal eye field (rFEF) form part of a network of brain areas involved in orienting spatial attention. Previous studies using transcranial magnetic stimulation (TMS) have demonstrated that both areas are critically involved in the processing of conjunction visual search tasks, since stimulation of these sites disrupts performance.ObjectiveThis study investigated the effects of long term neuronal modulation to rPPC and rFEF using transcranial direct current stimulation (tDCS) with the aim of uncovering sharing of these resources in the processing of conjunction visual search tasks.MethodsParticipants completed four blocks of conjunction search trials over the course of 45 min. Following the first block they received 15 min of either cathodal or anodal stimulation to rPPC or rFEF, or sham stimulation.ResultsA significant interaction between block and stimulation condition was found, indicating that tDCS caused different effects according to the site (rPPC or rFEF) and type of stimulation (cathodal, anodal, or sham). Practice resulted in a significant reduction in reaction time across the four blocks in all conditions except when cathodal tDCS was applied to rPPC.ConclusionsThe effects of cathodal tDCS over rPPC are subtler than those seen with TMS, and no effect of tDCS was evident at rFEF. This suggests that rFEF has a more transient role than rPPC in the processing of conjunction visual search and is robust to longer-term methods of neuro-disruption. Our results may be explained within the framework of functional connectivity between these, and other, areas.     

Age-related changes to the neural correlates of social evaluation

Recent work suggests the existence of a specialized neural system underlying social processing that may be relatively spared with age, unlike pervasive aging-related decline occurring in many cognitive domains. We investigated how neural mechanisms underlying social evaluation are engaged with age, and how age-related changes to socioemotional goals affect recruitment of regions within this network. In a functional MRI study, 15 young and 15 older adults formed behavior-based impressions of individuals. They also responded to a prompt that was interpersonally meaningful, social but interpersonally irrelevant, or non-social. Both age groups engaged regions implicated in mentalizing and impression formation when making social relative to non-social evaluations, including dorsal and ventral medial prefrontal cortices, precuneus, and temporoparietal junction. Older adults had increased activation over young in right temporal pole when making social relative to non-social evaluations, suggesting reliance on past experiences when evaluating others. Young adults had greater activation than old in posterior cingulate gyrus when making interpersonally irrelevant, compared to interpersonally meaningful, evaluations, potentially reflecting enhanced valuation of this information. The findings demonstrate the age-related preservation of the neural correlates underlying social evaluation, and suggest that functioning in these regions might be mediated by age-related changes in socioemotional goals.