中国古人类颅内模及脑演化研究进展

颅内模保存有脑表面的形态结构,是脑演化研究的直接证据。中国最早复原和研究的颅内模来自20世纪20年代北京周口店遗址发现的3号猿人头骨;此后虽然中国境内也相继发现了一些古人类的头骨化石,但由于古人类标本非常珍贵,不允许对其进行实体解剖,加上多数头骨破碎或者内部附有地层胶结物,导致颅内模无法成功复原。受技术水平及研究手段的限制,研究者一般只是侧重于化石外表形态结构的研究。高分辨率工业CT和3D软件的应用,可以在不损坏标本的情况下,虚拟复原出化石的内部解剖结构,使得一些重要的古人类化石标本的颅内模被复原出来,促进了脑演化的研究。近年来,本文第一作者采用新技术、新方法复原了南京直立人、柳江人等一些重要的中国古人类头骨的颅内模,通过对其颅容量、脑沟回特征、脑不对称性、脑表面的动、静脉血管压迹、各脑叶的大小、形状及比例的研究,获取了中国古人类脑形态特征变化的数据,为探讨东亚地区古人类的演化提供了参考信息。     

Geometric morphometrics and paleoneurology: brain shape evolution in the genus Homo

Paleoneurology concerns the study and analysis of fossil endocasts. Together with cranial capacity and discrete anatomical features, shape can be analysed to consider the spatial relationships between structures and to investigate the endocranial structural system. A sample of endocasts from fossil specimens of the genus Homo has been analysed using traditional metrics and 2D geometric morphometrics based on lateral projections of endocranial shape. The maximum and frontal widths show a size-related pattern of variation shared by all the taxa considered. Furthermore, as cranial capacity increases in the non-modern morphotypes there is a general endocranial vertical stretching (mainly centred at the anterior ascending circumvolution) with flattening and relative shortening of the parietal areas. This pattern could have involved some structural stress between brain development and vault bones at the parietal midsagittal profile in the heavy encephalised Neandertals. In contrast, modern humans show a species-specific neomorphic hypertrophy of the parietal volumes, leading to a dorsal growth and ventral flexion (convolution) and consequent globularity of the whole structure. Brain tensors such as the falx cerebri have been hypothesised to represent one of the main physical constraints on morphogenetic trajectories, with additional influences from cranial base structures. The neurofunctional inferences discussed here stress the role of the parietal areas in the visuo-spatial coordination and integration, which can be involved in higher cerebral functions and related to conceptual thinking.     

3D虚拟复原精度的差异对头骨测量数值的影响——以Mimics软牛为例

近年来,根据三维软件虚拟复原的头骨来获取测量数据的方法被越来越多地应用在古生物,特别是古人类学的研究中,然而对于三维软件不同精度虚拟复原的头骨,其测量数值是否有差异,研究者并不是很清楚。本文以Mimics软件为例,根据其复原模型简化规则,选择未精简的最佳精度模型作为标准进行配对t检验或非参数检验,通过对43例云南人头骨的顶骨矢状弦长、颅周长、头盖部面积、乳突小房表面积、颅容量、乳突小房体积等六个测量项目的对比和分析,对Mimics软件低、中、高、最佳四种精度3D虚拟复原头骨间的测量差异进行了研究。结果显示：颅周长、头盖部面积、颅容量、乳突小房体积四项的所有简化精度模型的测量数据均与最佳精度模型测量数据的差异具有显著性;而除高精度组外,顶骨矢状弦长及乳突小房表面积的其余精度组测量数据均与最佳精度组差异具有显著性;此外,顶骨矢状弦长、颅周长、头盖部面积、颅容量的简化精度与最佳精度的测量差异占比均小于3%.而乳突小房表面积的低精度与最佳精度测量差异占比可超过50%,乳突小房体积的低精度与最佳精度测量差异占比可超过120%。这一结果提示我们,在测量Mimics复原的三维模型时,体量大差异小的测量项可以在较低精度的复原模型上进行测量;而对头骨内部腔窦这样体量小表面粗糙的结构,复原模型的精度选择及测量数据比较需要格外谨慎。     

A uniquely modern human pattern of endocranial development. Insights from a new cranial reconstruction of the Neandertal newborn from Mezmaiskaya

The globular braincase of modern humans is distinct from all fossil human species, including our closest extinct relatives, the Neandertals. Such adult shape differences must ultimately be rooted in different developmental patterns, but it is unclear at which point during ontogeny these group characteristics emerge.Here we compared internal shape changes of the braincase from birth to adulthood in Neandertals (N = 10), modern humans (N = 62), and chimpanzees (N = 62). Incomplete fossil specimens, including the two Neandertal newborns from Le Moustier 2 and Mezmaiskaya, were reconstructed using reference-based estimation methods. We used 3D geometric morphometrics to statistically compare shapes of virtual endocasts extracted from computed-tomographic scans. Throughout the analysis, we kept track of possible uncertainties due to the missing data values and small fossil sample sizes.We find that some aspects of endocranial development are shared by the three species. However, in the first year of life, modern humans depart from this presumably ancestral pattern of development. Newborn Neandertals and newborn modern humans have elongated braincases, and similar endocranial volumes. During a ‘globularization-phase’ modern human endocasts change to the globular shape that is characteristic for Homo sapiens. This phase of early development is unique to modern humans, and absent from chimpanzees and Neandertals.Our results support the notion that Neandertals and modern humans reach comparable adult brain sizes via different developmental pathways. The differences between these two human groups are most prominent directly after birth, a critical phase for cognitive development.     

Increasing breadth of the frontal lobe but decreasing height of the human brain between two Chinese samples from a Neolithic site and from living humans

Morphological observation and measurements of endocasts have played a vital role in research on the evolution of the human brain. However, endocasts have never been used to investigate how the human brain has evolved since the Neolithic period. We investigated the evolution of the human brain during the Holocene by comparing virtual endocasts from Beiqian site (a Neolithic Chinese site) and a sample of Chinese modern‐day humans. Standardized measurements and indices were taken to provide quantification of the overall endocast shape, including the length, breadth, height, frontal breadth, and the ratio of frontal breadth to breadth, as well as the cranial capacity. We found that the height of the endocasts and cranial capacity have decreased between our two samples, whereas the frontal breadth and sexual dimorphism have increased. We argue that these changes can be caused by random genetic mutation and epigenetic change in response to changes in the environment. Am J Phys Anthropol 154:94–103, 2014. © 2014 Wiley Periodicals, Inc.     

化石人类脑演化研究概况

脑演化是人类演化的一个重要组成部分,其研究可以为人类起源、演化、人群关系及语言、智力等方面提供重要的信息。脑演化的主要证据是通过研究颅内模（endocast）及颅骨的形态得到的。颅内模是从颅骨内表面得到的脑的外部形态。有时颅骨的内腔充满泥沙,并且为钙质所结固,可以自然形成颅内模。也可以人工制作颅内模。颅内模和颅骨的内表面能够提供人类脑髓及神经进化方面的直接证据。对化石人类脑演化的研究主要包括以下几个方面的内容：测量或估计脑量的大小及其和身体大小之间的关系;研究脑量随时间的变化过程;通过对早期人类颅内模表面沟回形态特征的研究,探索脑功能区在早期人类和猿类的区别及在演化上的变化;左右大脑不对称性与一侧优势关系,探讨语言的起源和惯用手的脑功能基础等;脑膜中动脉系统、静脉窦系统及与血液循环相关的排泄孔的变化,探讨大脑各部分比例的变化和功能的日益复杂对供血需求的影响;通过对人类脑演化的研究,探讨人类进化的原因。本文通过对以上几个方面及其中国化石脑演化研究的介绍,对化石人类脑演化的研究概况作综合论述和简单回顾。     

No Effect of Ambient Odor on the Affective Appraisal of a Desktop Virtual Environment with Signs of Disorder

Background

Desktop virtual environments (VEs) are increasingly deployed to study the effects of environmental qualities and interventions on human behavior and safety related concerns in built environments. For these applications it is essential that users appraise the affective qualities of the VE similar to those of its real world counterpart. Previous studies have shown that factors like simulated lighting, sound and dynamic elements all contribute to the affective appraisal of a desktop VE. Since ambient odor is known to affect the affective appraisal of real environments, and has been shown to increase the sense of presence in immersive VEs, it may also be an effective tool to tune the affective appraisal of desktop VEs. This study investigated if exposure to ambient odor can modulate the affective appraisal of a desktop VE with signs of public disorder.

Method

Participants explored a desktop VE representing a suburban neighborhood with signs of public disorder (neglect, vandalism and crime), while being exposed to either room air or subliminal levels of unpleasant (tar) or pleasant (cut grass) ambient odor. Whenever they encountered signs of disorder they reported their safety related concerns and associated affective feelings.

Results

Signs of crime in the desktop VE were associated with negative affective feelings and concerns for personal safety and personal property. However, there was no significant difference between reported safety related concerns and affective connotations in the control (no-odor) and in each of the two ambient odor conditions.

Conclusion

Ambient odor did not affect safety related concerns and affective connotations associated with signs of disorder in the desktop VE. Thus, semantic congruency between ambient odor and a desktop VE may not be sufficient to influence its affective appraisal, and a more realistic simulation in which simulated objects appear to emit scents may be required to achieve this goal.     

Assessing endocranial variations in great apes and humans using 3D data from virtual endocasts

Modern humans are characterized by their large, complex, and specialized brain. Human brain evolution can be addressed through direct evidence provided by fossil hominid endocasts (i.e. paleoneurology), or through indirect evidence of extant species comparative neurology. Here we use the second approach, providing an extant comparative framework for hominid paleoneurological studies. We explore endocranial size and shape differences among great apes and humans, as well as between sexes. We virtually extracted 72 endocasts, sampling all extant great ape species and modern humans, and digitized 37 landmarks on each for 3D generalized Procrustes analysis. All species can be differentiated by their endocranial shape. Among great apes, endocranial shapes vary from short (orangutans) to long (gorillas), perhaps in relation to different facial orientations. Endocranial shape differences among African apes are partly allometric. Major endocranial traits distinguishing humans from great apes are endocranial globularity, reflecting neurological reorganization, and features linked to structural responses to posture and bipedal locomotion. Human endocasts are also characterized by posterior location of foramina rotunda relative to optic canals, which could be correlated to lesser subnasal prognathism compared to living great apes. Species with larger brains (gorillas and humans) display greater sexual dimorphism in endocranial size, while sexual dimorphism in endocranial shape is restricted to gorillas, differences between males and females being at least partly due to allometry. Our study of endocranial variations in extant great apes and humans provides a new comparative dataset for studies of fossil hominid endocasts.     

Interpretation of scanning electron microscopic images of abraded forming bone surfaces

The experimental abrasion of forming bone surfaces was conducted so that such surfaces could be characterized. This is particularly important to bone remodeling studies utilizing scanning electron microscope (SEM) imaging of archeological material. Forming surfaces derived from subadult macaque cranial bone were treated by particle abrasion, water abrasion, sliding abrasion, brushing, manual rubbing, weight, exfoliation, chipping and replication. Acetic acid treatments were also performed. The effects of abrasive agents are specific but generally fall into rough (particle and water abrasion) and smooth (sliding abrasion, brushing, rubbing and weight) categories. Protohistoric human and Plio-Pleistocene hominid subadult craniofacial remains were observed with the SEM for comparison with experimental data. The more recent material appeared smooth, probably as a result of specimen preparation procedures using brushes. Surfaces were still interpretable as forming, however, using a more abrasion-resistant feature called intervascular ridging (IVR) described in this study. The IVR pattern is also recognized on the hominid sample, confirming the possibility of performing remodeling studies on abraded fossil material. The abrasion characteristics are somewhat more difficult to classify, however. Abrasion is defined and discussed relative to remodeling studies and taphonomy. The usefulness of the experimental data reported here, however, in paleoenvironmental reconstruction, has yet to be fully realized. Acid and mechanical preparation techniques are briefly addressed. It is concluded that it is possible to characterize a forming surface as abraded according to the findings of this study and that acid, if handled with care, will more likely preserve microanatomical surface detail. It would also be in everyone's interest to employ a less abrasive cleaning regime on archeological specimens.     

中国古人类颅容量的推算方法比较

古人类的体质特征和现代人不同,依据现代人头骨测量数据计算出来的公式往往不适于古人类颅容量的推算。获取古人类颅容量最准确的方法是复原出其内部的颅内模;然而,由于颅内模的复原工艺复杂,加上古人类头骨化石数量稀少且多数残破,如何准确地推算其颅容量,成为古人学者研究的难点问题之一。本文通过对中国境内发现的不同演化阶段的古人类颅容量推算方法的对比和验证,试图找出推算古人类颅容量的最适合的公式法。研究结果显示：1）早期现代人解剖特征同现代人基本接近,依据现代人头骨推算出来的回归方程可以用来推算其颅容量;2）直立人头骨厚重、脑颅低矮,体质特征不同于现代人,其颅容量的推算不能使用现代人公式法。依据本文中国直立人头骨测量数据推导出来的回程方程（C=-1301.944+60606L+0.718b+9.936h）适合其颅容量的推算。采用此直立人公式法,推算出蓝田直立人的颅容量为918 mL;3）古老型智人的体质特征位于直立人和现代人之间,对其颅容量的推算不能一概而论：体质特征接近直立人的,如大荔人、华龙洞6号,可采用直立人公式法;体质特征接近早期现代人的,如许昌1号,可采用现代人公式法;体质特征位于直立人和早期现代人中间位置的,如马坝人、金牛山人,其颅容量约等于采用现代人公式法和采用直立人公式法获得的颅容量的平均值。     

Alteration of structure and penetrability of the vitelline envelope after passage of eggs from coelom to oviduct in Xenopus laevis.

The vitelline envelope (VE) that surrounds an egg released from the ovary into the coelom of Xenopus laevis differs markedly, in structure and penetrability, from the VE surrounding an oviposited egg. In a coelomic egg, the filaments that form the VE are arranged in distinct fascicles or bundles. The exterior surface of the VE is irregular in contour and is permeated by channels. In an oviposited egg, the filaments are evenly dispersed and lack a fasciculated arrangement; the exterior surface is smooth and no channels are present. The fascicular arrangement of fibrils in the coelomic VE is maintained only at neutral pH, and is not visibly altered by the cortical reaction. VEs from coelomic eggs retain their fasciculated morphology after isolation from the egg. In an in vitro test system, sperm penetrated VEs isolated from oviposited eggs, but failed to penetrate VEs isolated from coelomic eggs. The structural transformation of the VE from the coelomic type to the oviposited type occurs in the first 1-cm segment of the oviduct, prior to addition of jelly to the egg. Neither intact jelly, solubilized jelly, nor jelly extracts were capable of altering the structural organization of coelomic VEs, suggesting that the structural transformation of the VE is effected by some oviducal factor other than jelly.     

Early hominid brain evolution: a new look at old endocasts

Early hominid brain morphology is reassessed from endocasts of Australopithecus africanus and three species of Paranthropus, and new endocast reconstructions and cranial capacities are reported for four key specimens from the Paranthropus clade. The brain morphology of Australopithecus africanus appears more human like than that of Paranthropus in terms of overall frontal and temporal lobe shape. These new data do not support the proposal that increased encephalization is a shared feature between Paranthropus and early Homo. Our findings are consistent with the hypothesis that Australopithecus africanus could have been ancestral to Homo, and have implications for assessing the tempo and mode of early hominid neurological and cognitive evolution.     

Two Extracellular Matrices From Oocytes of the Marine Shrimp Sicyonia ingentis that Independently Mediate Only Primary or Secondary Sperm Binding

During spawning, female Sicyonia ingentis simultaneously release ova and stored nonmotile sperm and mix them externally to initiate gamete interaction. Sperm bind to a thin vitelline envelope (VE) via their anterior appendage and within seconds are induced to undergo acrosomal exocytosis. The sperm penetrate the VE and become secondarily bound to the surface coat (SC), a glycocalyx on the oocyte surface. In this study, both extracellular matrices were isolated from S. ingentis oocytes. Isolated VEs mediated only primary sperm binding (i.e., before the acrosome reaction), while the isolated SCs mediated only secondary sperm binding (i.e., after acrosomal exocytosis). Isolated S. ingentis VEs were used to characterize primary sperm binding activity. The two extracellular matrices differ morphologically and possess different polypeptide profiles. Soluble fractions of isolated VEs inhibited primary sperm binding in a concentration dependent manner, and immunolocalization of VE components demonstrated highly localized VE binding sites at the tip of the sperm anterior appendage by which sperm bind eggs. Extensive Pronase digestion of VE components did not affect sperm binding activity of solubilized VE components, while complete deglycosylation with trifluoromethanesulfonic acid destroyed sperm binding activity. However, neither alkaline treatment nor enzyme digestion using glycosidases specific for asparagine and serine/ threonine linked oligosaccharides affected sperm binding activity.     

Size, shape, and asymmetry in fossil hominins: the status of the LB1 cranium based on 3D morphometric analyses

The unique set of morphological characteristics of the Liang Bua hominins (Homo floresiensis) has been attributed to explanations as diverse as insular dwarfism and pathological microcephaly. This study examined the relationship between cranial size and shape across a range of hominin and African ape species to test whether or not cranial morphology of LB1 is consistent with the basic pattern of static allometry present in these various taxa. Correlations between size and 3D cranial shape were explored using principal components analysis in shape space and in Procrustes form space. Additionally, patterns of static allometry within both modern humans and Plio-Pleistocene hominins were used to simulate the expected cranial shapes of each group at the size of LB1. These hypothetical specimens were compared to LB1 both visually and statistically. Results of most analyses indicated that LB1 best fits predictions for a small specimen of fossil Homo but not for a small modern human. This was especially true for analyses of neurocranial landmarks. Results from the whole cranium were less clear about the specific affinities of LB1, but, importantly, demonstrated that aspects of facial morphology associated with smaller size converge on modern human morphology. This suggests that facial similarities between LB1 and anatomically modern humans may not be indicative of a close relationship. Landmark data collected from this study were also used to test the degree of cranial asymmetry in LB1. These comparisons indicated that the cranium is fairly asymmetrical, but within the range of asymmetry exhibited by modern humans and all extant African ape species. Compared to other fossil specimens, the degree of asymmetry in LB1 is moderate and readily explained by the taphonomic processes to which all fossils are subject. Taken together, these findings suggest that H. floresiensis was most likely the diminutive descendant of a species of archaic Homo, although the details of this evolutionary history remain obscure.     

Carotid plaque rather than intima-media thickness as a predictor of recurrent vascular events in patients with acute ischemic stroke

Background

To investigate the impacts of carotid plaque and intima-media thickness (IMT) on future vascular events (VEs) in the patients with acute ischemic stroke.

Methods

A total of 479 consecutive Korean patients with acute ischemic stroke were divided into 2 groups according to development of VEs; VE group (65.4 ± 10.9 years) vs no VE group (62.8 ± 13.2 years). VEs were defined as the development of recurrent stroke, coronary events, peripheral arterial disease, and death. Clinical, laboratory, and imaging findings were compared between the groups.

Results

During 105.5 ± 29.0 months of follow up, VEs were developed in 142 patients (29.6%). In univariate analysis, VEs were significantly associated with age, gender, diabetes, renal function, lipid levels, left ventricular function, carotid plaque or IMT. In multivariate analysis, the presence of carotid plaque, diabetes, renal function and male gender were independent predictors of future VEs in the patients with ischemic stroke, but carotid IMT was not a predictor of future VEs. Event free survival was significantly lower in patients with carotid plaque than without carotid plaque on Kaplan-Meier analysis (log rank p < 0.001).

Conclusion

The present study demonstrated that diabetes, impaired renal function, male gender, and the presence of carotid plaque rather than IMT were independent predictors of future VEs in Korean patients with acute ischemic stroke. Active medical management and careful monitoring for the development of recurrent VEs are strongly recommended in patients with acute ischemic stroke and carotid plaque.

     

Vitelline envelope of Bufo arenarum: biochemical and biological characterization

Vitelline envelopes (VEs) of Bufo arenarum were isolated in order to study their composition and their role in fertilization. VEs are composed of four glycoproteins, with molecular masses of 120, 75, 41, and 38 kDa. To characterize its biological properties, we quantitatively determined sperm-VE binding and the induction of the acrosome reaction. Heterologous binding of B. arenarum sperm to Xenopus laevis VE components was observed with about one-third the efficiency of homologous binding. Equivalent binding of X. laevis sperm to the B. arenarum VE was observed. When B. arenarum sperm were incubated with fluorescein isothiocyanate-labeled VE, the labeled glycoproteins bound to the anterior end of the sperm head, showing a lateral distribution. Induction of the acrosome reaction was evaluated by incubating sperm in hypotonic saline media with VE glycoproteins. VEs induced the acrosome reaction in a time- and concentration-dependent manner. The acrosome reaction was maximal after 10 min. The half-maximal effect was obtained at a glycoprotein concentration of 1 microg/ml. Specificity was determined using fertilization envelope glycoproteins, which failed to induce the acrosome reaction. The B. arenarum VE is biochemically similar to other egg envelopes. It also seems that its biological properties are similar to other species in regard to sperm binding and induction of the acrosome reaction. However, as far as we are aware, this is the first observation of the VE inducing the sperm acrosome reaction in amphibians. The relatively small differences observed in heterologous sperm-VE binding in X. laevis and B. arenarum are inconsistent with the current paradigm that species specificity in fertilization is regulated at the sperm-VE binding step.     

大熊猫颅内腔的演化(英文)

描述比较了早更新世大熊猫小种(Ailuropoda microta)、晚更新世大熊猫巴氏种(A baconi)、现生大熊猫(A.melanoleuca)和北极熊(Ursus maritimus)的虚拟三维颅内模。大熊猫脑窝内模的形态在小种、巴氏种和现生种之间大致相似,而与北极熊区分明显。大熊猫的脑窝内模容积从小种到巴氏种呈增大趋势,但从巴氏种到现生种呈减小趋势。大熊猫的大脑沟回在脑窝内模上留下的印痕非常明显,并从小种经巴氏种到现生种则呈稳定增长趋势。相反,北极熊的大脑沟回在脑窝内模上留下的印痕不明显,而血管印痕在脑窝枕区的两侧很明显。嗅球窝内模腹部的纵沟在大熊猫小种发育,在巴氏种较弱,在大熊猫现生种几乎不存在,而在北极熊较发育。大熊猫的脑量商在小种、巴氏种和现生种之间差别不大,但大熊猫的脑量商明显大于北极熊。大熊猫的副鼻窦在小种、巴氏种和现生种之间的差别不大,但与北极熊差别较大。大熊猫的额窦很长、较高、背侧脊形,而北极熊的额窦长度相对较短、高度较低、宽度稍大、背侧平缓。大熊猫的上颌窦较宽,而北极熊的则较窄。大熊猫的蝶窦很小,而北极熊的则较大,覆盖在脑腔前侧。大熊猫这3个不同时期的种与北极熊在颅内腔上这些明显的差异支持将大熊猫从熊科中独立出来的分类。