语言功能偏侧化及其与利手、功能连接的关系

对大脑语言功能偏侧化的探索起始于早期对脑损伤病人的研究。现代脑影像学研究发现, 语言功能偏侧化涉及额叶、颞叶、扣带回、梭状回和辅助运动区等脑区。语言偏侧化与利手和静息态功能连接之间的关系表现为：右利手的语言优势位于左半球, 而左利手的则分布在左半球、右半球或两个半球; 语言功能偏侧化与利手系数、静息态半球内功能连接之间具有正相关关系, 与半球间功能连接呈负相关, 并且语言功能偏侧化与静息态功能连接之间的关系在左右利手个体之间存在差异。总之, 大脑语言功能偏侧化、利手和静息态功能连接三者之间存在相互影响, 基于脑连接和遗传机制的研究将有望揭示出其底层的神经生理机制。     

身体活动对情绪的影响及其脑机制

身体活动不仅有助于提高人的生理机能, 还具有改善心境、调节情绪的功能。有规律的身体活动不仅能够增强个体的积极情绪, 提升幸福感和自尊感, 也可以缓解消极情绪、矫治情绪障碍。关于身体活动对情绪影响的脑神经机制, 研究者先后提出神经递质假说、大脑可塑性假说、前额叶偏侧化假说和双模型假说。进一步的研究需要控制运动强度对身体活动情绪效益的影响, 比较不同类型身体活动的情绪调节效果, 同时考察基因、神经生长及社会互动等因素对情绪的交互作用。     

声调的脑机能偏侧化研究

语言的机能偏侧化研究是神经心理学研究的主要任务之一,以往研究对象大多是非声调语言。汉语 是声调语言,其脑机能偏侧化有许多特点,对正常人的声调偏侧化研究结论不一,对语言障碍病人 的声调偏侧化研究大多认为两半球均势。我们通过对三例纯词哑患者的语言分析,左半球损伤对声 调的影响很小,其原因可能由于声调既是一种语言学信号,又有音乐的特点,具有两重性,对其控 制两半球皮层均有作用。     

字词认知N170成分及其发展

字词认知早期的N170成分是第一个对语言材料敏感的成分.最近对字词认知N170成分的研究主要集中在探讨其敏感性、偏侧化以及此成分的发展变化.大量研究认为字词N170成分的敏感性与正字法加工有关,但也有一些研究认为其受语音、语义调制.对于此成分的偏侧化研究结果较一致认为是左侧化.最近的发展研究对N170成分进行探讨,取得了一些成果.在剖析现有研究基础上,本文认为应对字词认知N170成分的偏侧化、功能分离等问题进行深入研究.     

“右好左坏”和“左好右坏”——利手与左右空间情感效价的关联性

人们会将“右”和“左”与积极或消极的事物相关联,这称为左右空间的情感效价.以具身认知理论和躯体特异性假设为基础的研究发现,右利手会将右侧空间与积极事物相关联,而左利手则会将左侧空间与积极事物相关连;左右空间情感效价是由利手与非利手的运动经验塑造的;利手与非利手运动经验的改变则会反转左右空间情感效价;趋近动机脑功能偏侧化与利手是一致的.未来的研究应进一步澄清利手运动与趋近动机在神经机制上的关联性,并探索文化因素与身体经验如何共同塑造左右空间情感效价.     

MAOA基因rs6323多态性与同伴关系对男青少年早期抑郁的影响

以683名男青少年为被试(初次测评时M = 13.35岁; SD = 0.51), 综合运用传统回归分析和新兴显著性区域检验, 考察了MAOA基因rs6323多态性与同伴关系对青少年早期抑郁的交互作用及其表现形式。结果表明：当同伴接纳水平较低时, G等位基因携带者的抑郁水平表现出高于T等位基因携带者的趋势, 当同伴接纳水平较高时, G型基因携带者的抑郁水平显著低于T等位基因携带者; 同伴接纳可以显著预测G等位基因携带者的抑郁, 但对T等位基因携带者的抑郁无显著预测作用; rs6323多态性与同伴拒绝的交互作用亦不显著。研究结果提示, 同伴关系对MAOA基因与男青少年早期抑郁的关联起调节作用, 且其作用形式部分支持不同易感性模型观点。     

婴儿对语音和非语音的感知:认知和神经机制

婴儿听觉感知能力的发展对于他们未来的语言学习和社会化都具有重要意义。过去大量的研究主要关注语音感知方面,只有较少的研究将非语音感知纳入考虑之中,但了解非语音感知的特征和机制将有助于增加研究者对听觉加工以及儿童发育的认识。该文分别介绍了婴儿语音感知中的三种偏好——对语音、“婴儿语”和母语的偏好,并尝试着将非语音分为音乐、人类的非言语发声、环境声音三类进行阐述。通过对比这两大类声音的感知得到婴儿可能存在语音感知的左脑偏侧化和音乐感知的右脑偏侧化现象,但这也尚存争议,目前有特定领域模型、特定线索模型和脑网络模型三种理论对偏侧化现象的认知机制进行解释。     

语言对知觉的影响—— 来自颜色范畴知觉研究的证据

介绍了近年来语言和颜色范畴知觉关系研究的新进展, 特别是颜色范畴知觉效应的偏侧化、婴幼儿颜色范畴知觉的特点等。同时指出了今后需要进一步研究的问题, 如颜色范畴知觉效应偏侧化与语言的关系、右脑语言优势者颜色范畴知觉的特点、颜色加工脑区和语言加工脑区之间的关系以及婴幼儿颜色范畴知觉特点的追踪研究等。     

利手与内隐左右空间情感效价关系的眼动研究

为探明手动作流畅性和情感材料呈现空间在不同利手者左右空间情感偏好中的关系,本研究将情绪Stroop范式和眼动测量相结合,通过反应速度和眼动数据将动作流畅性和空间情感注意偏向相分离,并考察其交互作用。结果发现右利手个体的反应速度存在优势手效应,不同利手者在使用左手时表现出对优势手同侧空间的内隐情感偏好,表明右利手个体的反应速度存在优势手流畅性的主导作用,手动作流畅性和内隐空间情感偏好的作用可以分离。     

语言表征的神经生物学理论

神经科学家F．Pulvermüller根据Hebb的“细胞群集”学说和相关性学习原理构建的“语言表征的神经生物学理论”首次试图基于皮层功能网络来解释语音、词汇和句法在大脑皮层的表征机制,不仅能较好地描述语言活动中经典语言脑区与其它参与活动脑区的相互关系,也对语言加工的大脑功能偏侧化与整合现象作了合适的说明。本文介绍了这一理论的主要观点和研究资料,并提出了一些尚需进一步研究的问题。     

An investigation of immune system disorder as a "marker" for anomalous dominance

Geschwind and Galaburda (1987) proposed that immune disorder (ID) susceptibility, along with left handedness and familial sinistrality (FS), is a "marker" for anomalous dominance. The theory predicts lesser left lateralization for language processes, lessened left hemisphere abilities, and enhanced right hemisphere abilities. We assessed language laterality (dichotic consonant vowel task) and performances on spatial and verbal tasks. Subjects were 128 college students. The factors of handedness, sex, FS, and immune disorder history (negative or positive) were perfectly counterbalanced. Left-handers were significantly less lateralized for language and scored lower than right-handers on the spatial tasks. Females scored lower on mental rotation than males, but performed comparably to males on the spatial relations task. The only effect of ID was by way of interaction with FS on both spatial tasks--subjects who were either negative or positive on both FS and ID status factors scored significantly higher than subjects negative for one but positive for the other factor. A speculative explanatory model for this interaction was proposed. The model incorporates the notion that FS and ID factors are comparably correlated, but in opposite directions, with hormonal factors implicated by other research as relevant for spatial ability differences. Finally, no support for the "anomalous dominance" hypothesis predictions was found.     

Time sharing and dichotic listening asymmetry in normal and learning-disabled children

Time-sharing and dichotic listening techniques were used to examine cerebral lateralization for language function in 48 normal and 48 learning-disabled children. All subjects were matched according to age, sex, and handedness. An analysis of results indicated that both nornal and learning-disabled children demonstrated left hemisphere lateralization of language function on the time-sharing and dichotic listening tasks. However, no developmental trends were evident for either group. Differences observed in the performance of the normal and learning-disabled children may relate to how each group utilizes “verbal strategies” and processes simultaneous information in the left hemisphere. The results strongly question the notion that attributes learning disabilities to incomplete or delayed language lateralization and lend support to the notion that cerebral lateralization is not a developmental phenomena.     

Right-nostril advantage for discrimination of odors

Olfactory discrimination was tested with eight pairs of odors presented to each nostril of each subject. Ninety-nine subjects were tested; there were equal numbers of left- and right-handers, as well as both sexes. Detection thresholds for phenylethyl alcohol were measured separately in each nostril using a forced-choice staircase procedure. In addition, a verbal dichotic listening test known to be sensitive to language lateralization was administered. Results indicated that discrimination performance was significantly better when the stimuli were presented to the right nostril than when they were presented to the left, but no differences between the nostrils in detection thresholds were found. The right-nostril advantage did not vary as a function of sex or handedness, and did not bear any relation to language lateralization as measured via dichotic listening. The asymmetry for olfactory discrimination replicates an earlier study and is interpreted in terms of a possible specialization of function within the right cerebral hemisphere.     

Atypical speech lateralization in adults with developmental coordination disorder demonstrated using functional transcranial Doppler ultrasound

Research using clinical populations to explore the relationship between hemispheric speech lateralization and handedness has focused on individuals with speech and language disorders, such as dyslexia or specific language impairment (SLI). Such work reveals atypical patterns of cerebral lateralization and handedness in these groups compared to controls. There are few studies that examine this relationship in people with motor coordination impairments but without speech or reading deficits, which is a surprising omission given the prevalence of theories suggesting a common neural network underlying both functions. We use an emerging imaging technique in cognitive neuroscience; functional transcranial Doppler (fTCD) ultrasound, to assess whether individuals with developmental coordination disorder (DCD) display reduced left‐hemisphere lateralization for speech production compared to control participants. Twelve adult control participants and 12 adults with DCD, but no other developmental/cognitive impairments, performed a word‐generation task whilst undergoing fTCD imaging to establish a hemispheric lateralization index for speech production. All participants also completed an electronic peg‐moving task to determine hand skill. As predicted, the DCD group showed a significantly reduced left lateralization pattern for the speech production task compared to controls. Performance on the motor skill task showed a clear preference for the dominant hand across both groups; however, the DCD group mean movement times were significantly higher for the non‐dominant hand. This is the first study of its kind to assess hand skill and speech lateralization in DCD. The results reveal a reduced leftwards asymmetry for speech and a slower motor performance. This fits alongside previous work showing atypical cerebral lateralization in DCD for other cognitive processes (e.g., executive function and short‐term memory) and thus speaks to debates on theories of the links between motor control and language production.     

A combined fMRI and DTI examination of functional language lateralization and arcuate fasciculus structure: Effects of degree versus direction of hand preference

The present study examined the relationship between hand preference degree and direction, functional language lateralization in Broca’s and Wernicke’s areas, and structural measures of the arcuate fasciculus. Results revealed an effect of degree of hand preference on arcuate fasciculus structure, such that consistently-handed individuals, regardless of the direction of hand preference, demonstrated the most asymmetric arcuate fasciculus, with larger left versus right arcuate, as measured by DTI. Functional language lateralization in Wernicke’s area, measured via fMRI, was related to arcuate fasciculus volume in consistent-left-handers only, and only in people who were not right hemisphere lateralized for language; given the small sample size for this finding, future investigation is warranted. Results suggest handedness degree may be an important variable to investigate in the context of neuroanatomical asymmetries.     

左利手及其形成机制:生理、病理及心理学的视角

与右利手相比,左利手在人口中占少数,并且具有明显的性别差异,男性比女性多。左利手有时会表现出认知缺陷,同时在某些领域也具有优势。左利手形成机制比较复杂,既有遗传影响,也有生理、病理方面的原因,可能的因素包括早期脑损伤,各种出生风险因素,以及孕期激素水平等,还具有深刻的心理、社会根源。     

Intentional and attentional dynamics of speech-hand coordination

Interest is rapidly growing in the hypothesis that natural language emerged from a more primitive set of linguistic acts based primarily on manual activity and hand gestures. Increasingly, researchers are investigating how hemispheric asymmetries are related to attentional and manual asymmetries (i.e., handedness). Both speech perception and production have origins in the dynamical generative movements of the vocal tract known as articulatory gestures. Thus, the notion of a "gesture" can be extended to both hand movements and speech articulation. The generative actions of the hands and vocal tract can therefore provide a basis for the (direct) perception of linguistic acts. Such gestures are best described using the methods of dynamical systems analysis since both perception and production can be described using the same commensurate language. Experiments were conducted using a phase transition paradigm to examine the coordination of speech-hand gestures in both left- and right-handed individuals. Results address coordination (in-phase vs. anti-phase), hand (left vs. right), lateralization (left vs. right hemisphere), focus of attention (speech vs. tapping), and how dynamical constraints provide a foundation for human communicative acts. Predictions from the asymmetric HKB equation confirm the attentional basis of functional asymmetry. Of significance is a new understanding of the role of perceived synchrony (p-centres) during intentional cases of gestural coordination.     

Phonological processing of words in right- and left-handers

It is commonly accepted that phonology is the exclusive domain of the left hemisphere. However, this pattern of lateralization, which posits a right visual field advantage, has been questioned by several studies. In fact, certain factors such as characteristics of the stimuli and subjects' handedness can modulate the right visual field advantage. Thus, the goal of this study was to compare the hemispheric dynamics of right-handers and left-handers during a divided visual field presentation of words that varied in terms of their phonological transparency. For non-transparent words, the left hemisphere seems more competent in both handedness groups. With regard to transparent words, the right hemisphere of both groups also appears competent. Surprisingly, left-handers achieved optimal processing with a functionally isolated left hemisphere, whereas right-handers needed the participation of both hemispheres. The pattern of performance cannot be fully explained by either the callosal or the direct access model.     

Cerebral lateralization of deaf and hearing individuals for linguistic comparison judgments.

A group of congenitally deaf adults and a group of hearing adults, both fluent in sign language, were tested to determine cerebral lateralization. In the most revealing task, subjects were given a series of trials in which they were fist presented with a videotaped sign and then with a word exposed tachistoscopically to the right visual field or left visual field, and were required to judge whether the word corresponded to the sign or not. The results suggested that the comparison processes involved in the decision were performed more efficiently by the left hemisphere for hearing subjects and by the right hemisphere for deaf subjects. However, the deaf subjects performed as well as the hearing subjects in the left hemisphere, suggesting that the deaf are not impeded by their auditory-speech handicap from developing the left hemisphere for at least some types of linguistic processing.