MSCT对左肾静脉走行规律的显示及对胡桃夹综合征诊断的启示

目的应用多层螺旋CT(MSCT)及后处理技术研究正常左肾静脉(left renal vein,LRV)、肠系膜上动脉(su-perior mesenteric artery,SMA)与腹主动脉(abdominal aorta,AA)夹角的解剖形态学规律,探讨MSCT诊断"胡桃夹"综合征(nutcracker syndrome,NCS)的临床应用价值。方法采用64层MSCT,前瞻性观察220例正常者的SMA与AA的夹角大小,LRV夹角处、近肾门段最宽处的内径(前后径)及相应水平的截面积,以明确LRV的走行特征及正常人SMA与AA夹角的大小对LRV形态的影响,并计算出正常人SMA与AA夹角的范围、LRV受压前后的内径、截面积的参考范围以及体重指数与夹角的关系。图像后处理技术包括MPR、MIP。另有3例临床已证实NCS的病例作为分析参考。结果 220例正常SMA与AA的夹角的大小为(56.67±18.27)°,肾门段LRV前后径(DD)为(9.91±2.23)mm,截面积(SAD)为(119.81±43.03)mm2;夹角段LRV前后径(DN)为(6.50±2.31)mm,截面积(SAN)为(86.47±41.27)mm2;并计算DD/DN,SAD/SAN。220例正常人中体重指数(body mass index,BMI,Kg/m2)与SMA与AA间的夹角不具有明显的相关性,但是有一定的正相关联系。结论正常人LRV于SMA夹角处呈所谓轻度受压征象(移行型或夹角小于50°)是一种普遍存在的正常现象。NCS是一个以临床症状为前提的综合诊断,不能单纯依靠CT表现确诊NCS,但CT表现可提示患NCS的可能性大小。当LRV呈未受压型或移行型,SMA夹角大于50°,截面积缩小在Ⅱ°以下,可排除NCS的可能;LRV呈漏斗型,夹角小于50°,截面积缩小达Ⅱ°以上者,高度可疑NCS,应结合临床症状进一步检查确诊。     

M-mode magnetic resonance imaging: a new modality for assessing cardiac function

Summary. Magnetic resonance imaging (MRI) studies of the heart have been used for some years, but there are few tools available to quantify cardiac motion. A method has been developed that creates an M-mode MRI image, analogous to the one used in echocardiography, to display motion along a line as a function of time. The M-mode image is created from MRI images acquired with an ordinary gradient echo cine sequence. In a cinematographic display of the images, a cursor line can be positioned in order to determine the orientation of the measurement. A resampling algorithm then calculates the appearance of the M-mode image along the cursor line. The MRI method has been compared to echocardiographic M-mode in a phantom study and by measuring mitral and tricuspid annulus motion in 20 normal subjects. The phantom study showed no significant differences between MRI and echocardiographic M-mode measurements (difference mm). The annulus motion exhibits a similar pattern using both methods and the measured amplitudes are in close agreement. M-mode MRI provides similar information to echocardiography, but the cursor line can be placed arbitrarily within the image plane and the method is thus not limited to certain acoustic windows. This makes M-mode MRI a promising technique for assessing cardiac motion.     

Anterior cingulate activity during error and autonomic response

The contribution of anterior cingulate cortex (ACC) to human cognition remains unclear. The rostral (rACC) and dorsal (dACC) ACC cortex are implicated in tasks that require increased response control due to emotional and cognitive interference, respectively. However, both rACC and dACC are activated by conditions that induce changes in visceral arousal, suggesting that ACC supports a generation of integrated bodily responses. To clarify the relationship between purely cognitive and psychophysiological accounts of ACC function, we scanned 15 subjects using functional magnetic resonance imaging while they performed numerical versions of the Stroop task. To index autonomic arousal, we simultaneously measured pupil diameter. Performance errors accounted for most of the variance in a pupil-derived measure of evoked autonomic arousal. In analysis of the functional imaging data, activity within a region spanning rACC and dACC predicted trial-by-trial variation in autonomic response magnitude and was enhanced during error trials, shown using conjunction analyses. Activity within other loci within rACC predicted evoked autonomic arousal and showed sensitivity to errors but did not meet criteria for both. These data highlight the role of ACC in psychophysiological aspects of error processing and suggest that an interface exists within ACC between cognitive and biobehavioral systems in the service of response adaptation.     

Dysfunction of sensory oscillations in Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a highly prevalent developmental disability characterized by deficits in social communication and interaction, restricted interests, and repetitive behaviors. Recently, anomalous sensory and perceptual function has gained an increased level of recognition as an important feature of ASD. A specific impairment in the ability to integrate information across brain networks has been proposed to contribute to these disruptions. A crucial mechanism for these integrative processes is the rhythmic synchronization of neuronal excitability across neural populations; collectively known as oscillations. In ASD there is believed to be a deficit in the ability to efficiently couple functional neural networks using these oscillations. This review discusses evidence for disruptions in oscillatory synchronization in ASD, and how disturbance of this neural mechanism contributes to alterations in sensory and perceptual function. The review also frames oscillatory data from the perspective of prevailing neurobiologically-inspired theories of ASD.     

Deciphering phonemes from syllables in blood oxygenation level‐dependent signals in human superior temporal gyrus

Linguistic units such as phonemes and syllables are important for speech perception. How the brain encodes these units is not well understood. Many neuroimaging studies have found distinct representations of consonant–vowel syllables that shared one phoneme and differed in the other phoneme (e.g. /ba/ and /da/), but it is unclear whether this discrimination ability is due to the neural coding of phonemes or syllables. We combined functional magnetic resonance imaging with multivariate pattern analysis to explore this question. Subjects listened to nine Mandarin syllables in a consonant–vowel form. We successfully decoded phonemes from the syllables based on the blood oxygenation level‐dependent signals in the superior temporal gyrus (STG). Specifically, a classifier trained on the cortical patterns elicited by a set of syllables, which contained two phonemes, could distinguish the cortical patterns elicited by other syllables that contained the two phonemes. The results indicated that phonemes have unique representations in the STG. In addition, there was a categorical effect, i.e. the cortical patterns of consonants were similar, and so were the cortical patterns of vowels. Further analysis showed that phonemes exhibited stronger encoding specificity in the mid‐STG than in the anterior STG.     

慢性失眠症患者无意识与有意识信息加工特点

目的:探讨慢性失眠症患者大脑无意识与有意识信息加工特点。方法:对慢性失眠症患者(失眠组,36例)以及年龄、性别、教育年限相匹配健康志愿者(正常组,36例)进行失配性负波(MMN)和事件相关电位P300检测;应用匹兹堡睡眠质量指数量表(PSQI)对失眠组患者进行评估。结果:与正常组比较,失眠组MMN及P300波幅明显降低,P300潜伏期延迟(P0.01或P0.05)。线性回归分析显示PSQI评分与P300潜伏期、波幅显著相关(P0.01或P0.05)。结论:慢性失眠症患者无意识信息加工过程中的干扰信息过滤能力、有意识信息加工过程中的注意力集中与资源调动能力均减弱;有意识信息加工异常反映疾病严重程度。     

高功能孤独症儿童汉语普通话语言感知能力障碍的初步研究

目的研究简化版的汉语普通话噪音下听觉测验(MHINT)在高功能孤独症儿童群体中的适用性。观察高功能孤独症儿童对汉语普通话语音感知能力是否存在障碍。方法对18例高功能孤独症儿童及18例正常儿童(年龄、性别匹配)分别应用原始版和简化版MHINT测试其语言感知能力,分析两种测试方法的一致性,比较两组儿童的测验结果是否存在统计学差异。结果 1)简化版MHINT测试数据与原版MHINT的一致性检验结果为:孤独症组儿童(安静条件r=0.931,P=0.001;噪音条件r=0.869,P=0.018);对照组儿童(安静条件r=0.911,P=0.001;噪音条件r=0.858,P=0.003),两种测试材料的一致性较好。2)应用两种测试材料的实验结果均为安静条件下,组间差异无统计学意义;而噪音条件下孤独症组儿童测试成绩显著低于正常儿童,且组间差异有统计学意义。结论简化版MHINT测试与原版的一致度较好,可以用于测试高功能孤独症儿童言语感知能力;与正常儿童对比,高功能孤独症儿童在噪音下对汉语普通话语言信息的分辨能力降低,可能存在语言感知功能障碍。