伤害性躯体感觉的中枢网络动态编码过程

痛觉是感受躯体所受伤害性刺激的保护性感觉;慢性痛则是耗费巨额医疗费用的顽固性疾病。近年来的研究表明,疼痛感知觉的形成是一个大规模的中枢网络编码过程,包括了感觉、情绪、认知等若干不同的维度,牵涉到脊髓、脑干、边缘系统、皮层等多个相关结构。慢性痛则是一种由神经网络编码异常所导致的中枢性疾患。上述编码过程的任何异常都可能导致慢性痛。认识痛觉的中枢网络编码机制,将促进人们对感觉与情绪形成过程的深入理解,并有助于寻求新的临床疼痛治疗措施     

Neurochemical mechanisms underlying amygdaloid modulation of aggressive behavior in the cat

Studies designed to determine the respective roles of substance P, excitatory amino acids, and enkephalins in amygdaloid modulation of defensive rage behavior in the cat are presented. The basic design of these studies involved three stages. In stage I, cannula electrodes for stimulation and drug infusion were implanted into medial hypothalamic or midbrain periaqueductal gray (PAG) sites from which defensive rage behavior could be elicited. Then, a stimulating electrode was implanted into a site within the medial, basal, or central nuclear complex from which modulation of the defensive rage response could be obtained. Amygdaloid modulation of defensive rage was determined in the following manner: it employed the paradigm of dual stimulation in which comparisons were made of response latencies between alternate trials of dual (i. e., amygdala = medial hypothalamus [or PAG]) and single stimulation of the hypothalamus or PAG alone. Thus, stage I established the baseline level ofmodulation (i. e., facilitation or suppression of defensive rage) in the predrug stimulation period. In stage II, a selective or nonselective receptor antagonist for a given transmitter system was administered either peripherally or intracerebrally at the defensive rage site, after which time the same dual stimulation paradigm was then repeated over the ensuing 180 min postinjection period in order to determine the effects of drug delivery upon amygdaloid modulation of defensive rage. Stage III of the study took place at the completion of the pharmacological testing phase. The retrograde axonal tracer, Fluoro-Gold, was microinjected into the defensive rage site within the medial hypothalamus or PAG, and following a 6-14 day survival period, animals were sacrificed and brains were processed for histological and immunocytochemical analyses for the neurotransmitters noted above. This procedure thus permitted identification of cells within the amygdala which were labeled retrogradely and which were also immunostained positively for substance P, excitatory amino acids, or enkephalin. For studies involving substance P, defensive rage was elicited from the medial hypothalamus and for studies examining the roles of excitatory amino acids and enkephalin, defensive rage was elicited from the PAG. In the first study, facilitation of hypothalamically elicited defensive rage was obtained with dual stimulation of the medial nucleus of the amygdala. In separate experiments, the selective NK₁ non-peptide antagonist, CP 96,345, was administered both peripherally as well as intracerebrally into the hypothalamic defensive rage sites in doses of 0.5-4.0 mg/kg (i. p.) and 0.5-2.5 nmol (i. c.). Following drug delivery, the facilitatory effects of medial amygdaloid stimulation were blocked in a dose- and time-dependent manner in which the effects were noted as early as 5 min postinjection. The maximum drug dose (4.0 mg/kg) employed for peripheral administration resulted in a 42% reduction in the facilitatory effects of the medical amygdala (P < 0.002). This drug, when microinjected directly into medial hypothalamic defensive rage sites at the maximum dose level of 2.5 nmol, resulted in an 84% reduction of the suppressive effects of amygdaloid stimulation (P < 0.5) at 5 min postinjection. In the next study, an N-methyl-D-aspartate (NMDA) antagonist, DL-α-amino-7-phosphonoheptanoic acid (AP-7), was administered either peripherally (0.1-1.0 mg/kg) or intracerebrally (0.2 and 2.0 nmol) into PAG defensive rage sites. Facilitation of defensive rage behavior, which was observed following dual stimulation of the basal amygdala and PAG, was significantly reduced by either route of drug administration in a dose- and time-dependent manner. At the maximum dose level of peripheral administration, AP-7 reduced amygdaloid facilitation of defensive rage by 63% (P < 0.001) for 60 min, postinjection. A smaller (i. e., 19%) but still significant (P < 0.05) reduction in facilitation was obtained following intracerebral administration of the drug. In a third study, the non-selective opioid receptor antagonist, naloxone (27.5 nmol), infused directly into PAG defensive rage sites, totally blocked the suppressive effects of central amygdaloid stimulation for a period of 30 min (P < 0.05) in a dose- and time-dependent manner. The anatomical phase of this study revealed the following relationships: 1) that large numbers of neurons projecting to the medial hypothalamus from the medial amygdala immunoreact positively for substance P; 2) that neurons projecting to the PAG from the basal complex of amygdala immunoreact positively for glutamate and aspartate; and 3) that neurons located within the central nucleus of the amygdala which project to the PAG immunoreact positively for met-enkephalin. Collectively, these observations provide new evidence which characterizes the likely neurotransmitters linked with specific amygdaloid pathways subserving the modulation of defensive rage behavior in the cat.     

中央执行负荷对成人估算策略运用的影响

随机选取128名大学生为被试, 运用选择/无选法研究范式, 考察了不同中央执行负荷对估算策略运用的影响。结果发现：(1)中央执行负荷不影响策略分布; (2)策略运用条件、中央执行负荷影响策略执行。主次一致任务, 负荷对策略执行反应时的影响随负荷强度增大而增大, 对策略执行精确度影响不大; 而对主次不一致任务, 低负荷对策略执行反应时及精确度影响都不明显; (3)策略运用条件、中央执行负荷影响策略选择。负荷强度对策略选择反应时起重要作用, 只有当次级任务负荷高时, 干扰作用才明显; (4)成人的策略选择适应性受负荷强度的影响。无负荷条件下个体策略适应性更好。     

Movement segmentation and visual perturbation increase developmental differences in motor control and learning

We examined the developmental differences in motor control and learning of a two‐segment movement. One hundred and five participants (53 female) were divided into three age groups (7–8 years, 9–10 years and 19–27 years). They performed a two‐segment movement task in four conditions (full vision, fully disturbed vision, disturbed vision in the first movement segment and disturbed vision in the second movement segment). The results for movement accuracy and overall movement time show that children, especially younger children, are more susceptible to visual perturbations than adults. The adults’ movement time in one of the movement segments could be increased by disturbing the vision of the other movement segment. The children's movement time for the second movement segment increased when their vision of the first movement segment was disturbed. Disturbing the vision of the first movement segment decreased the percentage of central control of the second movement in younger children, but not in the other two age groups. The children's normalized jerk was more easily increased by visual perturbations. The children showed greater improvement after practice in the conditions of partial vision disturbance. As the participants’ age increased, practice tended to improve their feedforward motor control rather than their feedback motor control. These results suggest that children's central movement control improves with age and practice. We discuss the theoretical implications and practical significance of the differential effects of visual perturbation and movement segmentation upon motor control and learning from a developmental viewpoint.     

高功能孤独症幼儿空间工作记忆的组块加工缺陷

孤独症谱系障碍者存在空间工作记忆加工缺陷,其具体受损环节尚不明确。组块是一种有效的策略性信息编码方式,是空间工作记忆的关键环节。高度结构化的刺激容易形成高水平组块,因此,刺激结构化程度对记忆效果的影响能够反映个体的组块加工能力。研究采用Sternberg空间工作记忆任务、Corsi空间广度任务,加入刺激结构化因素,考察高功能孤独症幼儿是否存在组块加工缺陷,并探讨组块加工是否直接影响到空间工作记忆容量。实验1采用Sternberg空间工作记忆任务,结果表明,ASD幼儿存在明显的组块加工缺陷。在易于组块的高结构化条件下,健康幼儿的记忆成绩明显较高,而ASD幼儿在高、低结构化条件下的记忆成绩并无显著差异。实验2采用Corsi空间广度任务,结果显示,不论高、低结构化条件,ASD幼儿的空间工作记忆容量均显著低于健康幼儿。但ASD幼儿由于存在组块加工缺陷,在高、低结构化条件下的记忆成绩差异较健康幼儿小。因此,ASD幼儿的组块能力一定程度上影响了空间工作记忆容量。此外,记忆存储器的异常可能也是ASD幼儿空间工作记忆容量不足的重要原因。研究表明,ASD幼儿的空间组块缺陷主要由于弱中央统合的认知风格,他们缺乏自上而下的组块加工动机,难以主动对刺激形成高水平组块编码,从而影响记忆效果。     

数学学习困难初中生的中央执行系统特点

为揭示数学学习困难学生的认知过程加工特点,筛选上海111名初中生（男生46名,女生68名,平均年龄11.97岁）比较数学困难学生（55名）与数学优秀学生（56名）的中央执行系统的表现差异,通过反应停止任务和Flanker任务考察抑制能力以及注意控制能力。结果发现各种抑制和注意控制条件下,数困组学生的正确率低于数优组;在具有干扰的情况的成绩更能有效预测数学成绩;中央执行系统能力在初中总体具有上升发展趋势,数困生的发展具有波动性。因此,数学学习困难在中央执行系统中的缺损主要是对抗干扰的能力不足,而非简单的加工速度。     

工作记忆中央执行对儿童算术认知策略的影响

运用“双重任务”范式,以113名小学二年级儿童为被试,考察了儿童工作记忆的中央执行对算术认知策略表现的影响。结果表明:中央执行对儿童算术认知策略的选择产生了针对性的影响,集中表现在外部策略、支持性策略和猜测放弃策略上。中央执行干扰使策略执行的正确率下降、反应时增加。在简单加法任务上,中央执行影响了外部策略和支持性策略的选择频次;在复杂任务中,这种影响体现在外部策略和放弃策略上。无论是简单任务还是复杂任务,中央执行的干扰都造成了策略整体执行效果的下降。     

心理病理学网络理论、方法与挑战

对于精神障碍这一概念的理解, 传统DSM-ICD分类诊断系统和研究领域标准RDoC均基于潜变量视角, 认为精神障碍的症状由其潜在共同原因所致。这2种观点都忽略了症状间的相互作用。不同于分类和维度视角, Borsboom在2008年对精神障碍的概念化提出了的全新视角——心理病理学网络理论。此理论的核心观点是症状之间的动态因果关系构成了精神障碍。基于心理病理学网络理论的网络分析方法, 主要以结合EBIC的glasso算法估计症状间的偏相关网络, 并通过网络中节点中心性与网络连接性等指标, 来考查精神障碍症状的不同特性。近几年来, 研究者发现心理病理学网络分析方法在对症状间因果关系的推断、核心症状的识别和网络结构的可靠性与可重复性方面仍面临一些挑战。这些挑战为心理病理学网络理论与方法指明了未来可能的发展方向。     

The Learning of Programmed- and Feedback-Based Processes Controlling the Production of a Positioning Response in Two Dimensions

Two experiments were conducted to investigate the learning of the programmed- and feedback-based processes controlling the production of a slow, self-paced positioning response in two dimensions (direction and extent) in the horizontal plane. Both experiments had two phases: an acquisition phase of 60 trials with KR, followed by a KR withdrawal phase of 20 trials. In Experiment 1, one group (N=15) had visual feedback about the ongoing movement and the other group (N=15) did not. In Experiment 2, one group (N=15) practiced initiating the response in the criterion direction and moving the criterion extent, whereas, the other group (N=15) practiced initiating the response in the criterion direction and moving randomly varied extents. The results of Experiment 1 indicated that the learning of a programmed-based process is a gradually acquired freedom from visual feedback. Experiment 2 revealed that a programmed-based process can be learned independent of a feedback-based process.     

Central Nervous System Complications of Sickle Cell Disease in Children: An Overview

Complications involving the central nervous system are among the most devastating manifestations of sickle cell disease. Although overt stroke occurs in 1 in 10 children with Hemoglobin SS, “silent cerebral infarcts” are even more frequent. Both are associated with significant neuropsychological deficits. The end result of these effects on the CNS often is diminished school performance. The use of transcranial Doppler ultrasonography screening allows the identification of patients at high risk for clinical stroke as well as stroke prevention by chronic transfusion. However, definitive prophylaxis and treatment for most CNS complications of sickle cell disease have yet to be determined.