【作者】 刘超；

【导师】 刘树伟；

【作者基本信息】 山东大学 ， 人体解剖与组织胚胎学， 2014， 博士

【摘要】 众所周知,脑是人类中枢神经系统的主要组成部分,不但掌控着全身的感觉和运动,更是思想、记忆等高级心理活动的器官,这是其它种系的生物无法比拟的。如此超强功能的人脑是我们的古人猿先祖经过几百万年进化的产物。人类进化的总体过程中,颅容积增加被认为是人类进化的一个重要特点。随着颅容积的增大,脑的结构和功能也发生一定的变化,包括额叶体积增大、枕叶相对比例缩小以及小脑的形态特征趋向圆隆,两侧小脑半球的相对位置前移以及向矢状线靠拢等。然而,颅容积增加的这种趋势并不是一直持续下去的,许多研究表明全新世人类脑进化的趋势有所改变,主要表现为颅容积的下降。近万年来,非洲地区男性的颅容积降低了95-165cm3,女性的颅容积降低了74-106cm3,全新世欧洲男性平均颅容积由1593cm3降至现代1436cm3,女性的平均颅容积由1502cm3降至1241cm3。Ruff等人的研究表明人类颅容积在35000年以来有一个减少的趋势。另有一项研究发现,晚期智人,也称为“解剖学意义上的现代人”(AMH),其颅容积比现当代人类的颅容积大。在中国,从青铜铁器时代到现代,颅容积、颅长、颅宽、颅高、长高指数等呈明显下降趋势。这些现象均提示全新世人类脑的进化过程仍然在继续,并且以颅容积的下降为主要趋势。但是,为什么全新世人类的颅容积会呈现出与总体进化趋势不一致的表现,这是需要我们解决的首要问题。另外,人脑是由大脑、小脑、脑干组成的,而且,大脑、小脑和脑干还可以划分为更小的部分。因此,除了每一部分脑体积的均匀下降,颅容积的下降还有可能是由于一部分脑体积下降而另一部分脑体积不变或增加。伴随着颅容积的下降,全新世人脑的结构特征发生了怎样的变化,也是我们需要解决的问题。由于人类的脑组织无法长时间保存,在研究人类脑进化的不同渠道中,唯有颅内模可以展示脑的大体结构和表面形态特征,包括脑沟、脑回、血管、颅容积以及颅脑的形状,因而成为研究人类脑进化的主要渠道。因此,为了更好的研究全新世人类脑的具体进化趋势,本研究收集全新世期间两个时代的中国人颅骨CT数据,分别是距今约6000年前大汶口时期的北阡新石器时代人类和现当代的中国人,构建这两个时代的人类的颅内模,测量其表面形态、结构,分别分析其性别差异和年龄变化,一方面是为了避免性别差异和年龄变化对数据统计的影响,另一方面不同时期性别差异度和年龄变化趋势的异同,亦可以反映颅脑生长发育情况的改变趋势,对比不同时期颅脑生长发育的异同,同样可以丰富人类脑进化的研究。最后,我们从不同角度对比、分析两个时代中国人颅内模的形态学差异,从而反映北阡新石器时代人类和现代中国人脑大体形态、结构的变化,进一步丰富全新世人类脑的进化过程。本研究共分为三部分,摘要如下：第一部分北阡遗址新石器时代人类颅内模的建立第一章北阡遗址新石器时代人类颅骨的形态学研究目的：北阡遗址出土的新石器时代人类颅骨数量比较大而且保存较为完整,有利于进行颅骨的形态学研究,可以用来鉴定该遗址颅骨的人种归属、年龄和性别,并且观察颅骨的变形程度,从而为全新世人类脑进化的研究提供帮助。材料和方法：选择81例北阡遗址出土的新石器时代人类颅骨,依据《人体测量方法》和《人体测量手册》的相关著述和测量标准,对该批颅骨进行非测量性形态特征的观察以及相关径线的测量；参照丁士海《颅骨性别的判别分析》和王令红《太原地区现代人头骨的研究》的相关著述和性别判分析方程,对颅骨进行精确地性别鉴定；参照吴汝康《华北人颅骨臼齿磨耗的年龄变化》所介绍的磨牙损耗度与年龄之间的相互关系,对颅骨进行年龄鉴定；将北阡新石器时代人类颅骨关于人种归属有关的测量指标与现代蒙古人种对比,进行种族的鉴定；CT扫描北阡遗址人类颅骨,运用Amira软件对颅骨进行三维重建,然后与现代人三维CT数据重建的颅骨进行对比,观察颅骨变形的差异。结果：1、性别鉴定：大体形态上性别比较明确的颅骨有41例属于男性,20例属于女性,另外还有20例大体形态性别不明确的颅骨。对颅骨进行径线测量,然后参照判别分析方程,最后判断这81例颅骨所代表的个体,男性52位,女性29位。2、年龄推测：经过对牙齿磨耗程度的观察和判断分析,北阡新石器时代人类青年男性(15岁-29岁)12人,中青年男性20人(30岁-44岁),中年男性20人(45岁-59岁)；青年女性11人,中青年女性13人,中年女性5人。3、根据对北阡新石器时代人类颅骨的初步观察和测量,发现北阡遗址颅骨较多地表现出亚洲蒙古人种的形态学特征,而且更接近东亚蒙古类型。4、北阡新石器时代人类颅骨和现代人颅骨均存在颅骨左右不对称变形和颅骨扁平现象。结论：北阡遗址新石器时代人类属于东亚蒙古人种,其年龄和性别分布以及颅骨变形的异同有助于研究全新世人类脑的进化。第二章北阡遗址新石器时代人类颅内模的性别差异和年龄变化目的：颅内模可以间接地反映脑的表面形态特征、脑量等相关信息,构建北阡新石器时代人类颅内模,并且研究、分析颅内模的性别差异和年龄变化,可以为全新世人类脑进化的研究提供数据支持和帮助。材料和方法：选择81例北阡遗址出土的新石器时代人类颅骨,采用西门子128层螺旋CT扫描整个颅骨,所有原始CT数据导入Amira软件,运用阈值分割的原理,获得颅内模的二值化数据,三维重建颅内模,并且使之位于法兰克福平面。测量颅内模的主要径线,并且以颅内模的测量指标代表脑的形态和结构,获得脑长、脑宽、脑高、额叶宽、额叶高、额叶弦长、顶叶弦长、大脑高以及相关的比值等12项数据。运用SPSS软件对这些数据统计,分析其性别差异和年龄变化。结果：本研究共获得81例北阡新石器时代人类颅内模,在12项指标中,额叶宽与脑宽比、宽长比、高宽比和高长比以及额叶弦长没有性别差异,脑长、脑宽、脑高、额叶宽、额叶高、顶叶弦长和大脑高等7项指标均为男性大于女性(p<0.05)。无论男性还是女性,12项测量指标的年龄变化均未有明显的统计学意义。结论：利用颅骨的CT数据可以很好的建立北阡新石器时代人类颅内模,并且其性别差异和年龄变化的研究为研究全新世人类脑的进化提供了数据支持和帮助。第二部分现代中国人颅内模形态的性别差异和年龄变化目的：颅内模的形态学观察和测量在人类脑进化的研究中至关重要,并且颅内模形态的性别差异和年龄变化对这些研究有明显的影响,所以有必要建立大量的现代人类颅内模,并且对其性别差异和年龄变化进行系统的研究。材料和方法：本实验按照18-29岁、30-44岁、45-59岁、60-74岁四个年龄阶段,选择731例现代中国人(男369,女362),应用西门子128层螺旋CT进行头部扫描,获得高分辨率颅脑结构的三维CT数据。将原始的三维CT数据导入Amira软件,运用阈值分割的原理分别分割颅骨和颅腔内部空间,从而获得颅骨和颅内模的二值化数据,然后三维重建颅骨和颅内模,使颅骨处于法兰克福平面以保证颅内模的标准测量。测量颅内模的主要径线,并且以颅内模的测量指标代表脑的形态和结构,获得包括脑长、脑宽、脑高、额叶宽、额叶高、额叶弦长、顶叶弦长、大脑高、额叶宽与脑宽比值、宽长比值、高宽比值和高长比值以及颅容积等13项指标。结果运用SPSS17.0软件进行统计分析。结果：1、本研究获得了颅内模主要径线和指数不同性别和年龄阶段的平均值。2、性别差异：对于测量值,除了额叶宽与脑宽比值没有性别差异,其余12项径线和指标均为男性大于女性。经过校正后,女性额叶弦长稍大,男性大脑高、顶叶弦长、脑高比女性大,额叶高、额叶宽、脑长和脑宽没有明显性别差异。3、年龄变化：对于男性测量值,脑高、额叶弦长、额叶高和大脑高没有明显的年龄变化,脑长、顶叶弦长、额叶宽与脑宽比值和高宽比值与年龄变化正相关,颅容积、脑宽、额叶宽、宽长比值和高长比值与年龄变化负相关；对于校正后男性测量值,脑高、额叶弦长没有明显的年龄变化,脑长、大脑高、额叶高及顶叶弦长与年龄变化正相关,脑宽、额叶宽与年龄变化负相关。对于女性,不论是测量值还是校正值,额叶弦长没有明显的年龄变化,脑长、顶叶弦长、额叶宽与脑宽比值和高宽比值与年龄变化正相关,颅容积、脑宽、脑高、额叶宽、宽长比值和高长比值、额叶高和大脑高与年龄变化负相关。结论：现代中国人男、女两性的颅内模形状有明显的区别,而且一般男性大于女性；不论男性还是女性,随着年龄的增加,不仅颅内模的径线测量数据有所改变,其大体形状也由圆形趋向于椭圆形。第三部分现代中国人比北阡遗址新石器时代人类脑额叶增宽但是脑高减小目的：许多研究表明全新世人类脑进化的趋势有所改变,主要体现在颅容积的下降,但是,伴随颅容积的下降,人脑的形态特征是如何进化的还未见报道。因为颅内模可以体现脑的外部形态,所以有必要对比新石器时代和现代人类颅内模的表面形态,研究并分析其变化,从而反映全新世人类脑的进化过程。材料和方法：本实验首先选择年龄小于60岁的592例现代中国人(男302,女290),应用西门子128层螺旋CT进行头部扫描,获得高分辨率颅脑结构的三维CT数据。然后选择北阡遗址出土的经过鉴定均小于60岁的81例古人颅骨(男52,女29),按照同样的扫描条件进行CT扫描。所有原始的三维CT数据均导入Amira软件,运用阈值分割的原理分别分割颅骨和颅腔内部空间,获得颅骨和颅内模的二值化数据,然后三维重建颅骨和颅内模,使颅骨处于法兰克福平面以保证颅内模的标准测量。测量颅内模的主要径线,并且以颅内模的测量指标代表脑的形态和结构,主要测量值和指数包括脑长、脑宽、脑高、额叶宽、额叶高、额叶弦长、顶叶弦长、大脑高、额叶宽与脑宽比值、宽长比值、高宽比值和高长比值以及颅容积。结果运用SPSS17.0软件进行统计分析。结果：13项测量指标中,现代人的额叶宽、脑长、额叶宽与脑宽比值大于新石器时代人类,新石器时代人类的颅容积、脑高、额叶高、额叶弦长、顶叶弦长、高长比值和高宽比值大于现代人。在与自身颅容积做了校正后,男性脑高、额叶宽、脑长、额叶高、额叶弦长、顶叶弦长以及女性的脑高、额叶宽、脑长、额叶弦长有明显的时代差异。对于新石器时代人类,脑长、脑宽、脑高、额叶宽、大脑高、额叶高、顶叶弦长和颅容积男性大于女性,余指标未有明显性别差异；对于现代人类,除了颅内模的宽长比值未有明显性别差异,余指标均为男性大于女性。性别二态性的时代差异主要体现在颅容积、脑高、额叶弦和顶叶弦长以及颅内模的高宽比值、高长比值,并且是现代人的性别差异更加明显。结论：总的来说,从北阡新石器时代到现代,人类脑的结构发生了明显的改变,其主要趋势为脑高和颅容积减小,额叶宽增加以及两性间差异程度的增加。这种变化应该是与基因随机改变和相应环境引起的基因改变密切相关。更多还原

【Abstract】 The human brain governs a wide range of essential functions, comprising not only sensation and movement, but also thought, memory, and other advanced psychological functions. This powerful organ is the product of long-term evolutionary trends from our hominoid ancestors-Sahelanthropus tchadensis. Increasing cranial capacity has been considered to be an important feature of hominid evolution. With the increase in cranial capacity, the structure of the brain underwent changes; these included a rounded, widened frontal lobe, decreased size of the occipital lobe relative to the overall brain, a rounded cerebellum, and the drift of the two hemispheres of the cerebellum close to the median sagittal line.However, the proposed increase in cranial capacity during hominid evolution is now being challenged. Many recent studies indicate that trends in the evolution of the human brain changed slightly during the Holocene. The major change was towards a decrease in cranial capacity. From the Late Stone Age to modern times, the cranial capacities of Africans decreased by95-165cm3for males and74-106cm3for females. One study found that over the last35,000years, the average absolute brain size has decreased in Homo sapiens. Other studies suggested a decrease in endocranial volume between fossil AMH and recent humans. Chinese cranial and facial sizes decreased during Holocene, and that the head became progressively more globular after the Neolithic Age. Therefore, human brain during Holocene has been in constant change during Holocene. Since the global size reduction in H. sapiens was considered an exception to the trend toward brain size increase during hominin evolution, how the exception happened attracted our attention and what resulted in the decrease in cranial capacity became the primary objectives of our study. In addition, the human brain is composed of the cerebrum, cerebellum, and brainstem, which is subdivided into many smaller parts, respectively. Therefore, besides the decrease in the volume of every parts of the brain, the decrease in cranial capacity can be caused by one case that the volume of many parts of the brain decrease while other parts do not change or increase. Then how the structure of human brain changed with the decrease in cranial capacity became another major objective of our study.Since endocasts can reproduce details of external brain morphology, including cranial capacity and shape, they have played the most important role in the study of human brain evolution. To study the evolution of human brain during Holocene more clear, we collected the Neolithic human skulls unearthed from Beiqian sites which were identified by the Oriental Archaeology Research Center of Shandong University as being from the early Dawenkou period (about5500-6200years old) and modern-day human skulls. And the endocasts were reconstructed based on the CT data of these skulls and were measured using Amira software. We compared the three-dimensional computed tomographic reconstructions of endocasts taken from both Neolithic humans from Beiqian sites and modern-day humans for revealing the evolution of human brain during Holocene.Part1:Reconstruction of Neolithic endocasts from Beiqian sitesSection1:Morphological research on human skulls from Beiqian sitesObjective:The Neolithic human skulls unearthed from Beiqian sites were large in quantity and were nicely preserved, which were suitable for the morphological study. Identifying the age, sex, ethnic group, and deformation of each skulls can help studying the evolution of human brain during Holocene.Materials and methods:To address this issue, we chose81human skulls unearthed from Beiqian sites. The morphological observation and measurement of the skulls were finished according to methods from "Anthropometric Methods" and "Handbook of Anthropometry". The sex were identified by observing the morphology of skulls combined with discriminant analysis according to methods from "Sexual diagnosis of Chinese crania from discriminate function analysis" and "A study on the skulls from Taiyuan, Shanxi". The age was identified by observing the degree of the occlusal abrasion according to "Attrition of molar teeth in relation to age in northern Chinese skulls". The racial type was identified by comparing the morphology of Beiqian skull and modern Mongolian. The cranial CT images of Beiqian human and modern huamn were used for the three dimensional reconstruction by Amira software and the deformation of skulls were observed by comparing the3D reconstruction of Beiqian skulls and modern humans. Results:1. There were52male skulls and29female skulls.2. There were three age groups:young person (15-29years old), middle-younger person (30-44years old) and middle person (45-59years old). For male,12young person,20middle-younger person and20middle person were concluded. For female,11young person,13middle-younger person and5middle person were identified.3. The morphological features of Beiqian humans crania showed that the racial type of Beiqian people was closely related to the modern East Asiatic Mongoloids.4. The deformation of skulls generally happened in Beiqian skulls and modern people.Conclusion:On the whole, the culture of Beiqian site belonged to the Dawenkou culture and identification of age, sex, ethnic group of Beiqian skulls can help studying the evolution of human brain during Holocene.Section2:Sexual dimorphism and age-related changes in morphology of Neolithic endocasts from Beiqian sitesObjective:Because endocasts can reproduce details of external brain morphology and have played a vital role in research on the evolution of the human brain, it is necessary to reconstruct Neolithic endocasts from Beiqian sites and study their sexual differences and age-related changes, which could provide data set for studying human evolution.Materials and methods:81skulls which were identified as being from the early Dawenkou period were scanned by Siemens128Slice Computed Tomography (CT). All endocasts were reconstructed and placed in a standard spatial position, using Amira software. Standardized measurements and indices were taken to quantify the overall endocasts shape, including the length, breadth, height, cerebral height, frontal chord, frontal height, parietal chord and the ratios of breadth to length, height to breadth, height to length and frontal breadth to breadth of each endocast. All data were analyzed with SPSS17.0statistical software.Results:81Neolithic endocasts from Beiqian sites were reconstructed and measured, and12measurements and index were got. There were no sexual differences for the frontal chord, the ratios of breadth to length, height to breadth, height to length and frontal breadth to breadth, and the other7measurements had sexual differences. There were no age-related changes of endocasts for males and females.Conclusion:Neolithic endocasts from Beiqian sites can be reconstructed by segmenting cranial CT images and the sexual differences and age-related changes in morphology of Neolithic endocasts from Beiqian sites could provide data set for studying human evolution.Part2:Sexual dimorphism and age-related changes in morphology of modern Chinese endocastsObjective:Morphological observation and measurements of endocasts have played a vital role in researches on evolution of human brains. Because the age-related changes and sexual dimorphism in endocasts morphology can influence such investigations, it is necessary to reconstruct modern endocasts and study sexual dimorphism and age-related changes in endocasts morphology.Materials and methods:To address this issue, we conducted a systematic analysis of sexual dimorphism and age-related changes in modern Chinese endocasts. We collected the cranial computed tomography images of731modern humans, which were divided into four age groups:18-29years old,30-44years old,45-59years old, and60-74years old. After reconstructing virtual endocasts using Amira software, endocasts were placed in a standard position and standardized measurements and indices were taken to provide quantification of the overall endocast shape, including cranial capacity, the length, breadth, height, cerebral height, frontal chord, frontal height, parietal chord and the ratios of breadth to length, height to breadth, height to length and frontal breadth to breadth of each endocast. All data were analyzed with SPSS17.0statistical software.Results:1. The values for the main measurements of endocasts in different age groups for male and female were got.2. For most of measurements and indices, the males were larger.3. For males measurements, the height, frontal height, frontal chord and cerebral height didn’t change with increasing age, the length, parietal chord and the ratios of frontal breadth to breadth and height to breadth were positively correlated with age, while there were negative correlations between age and cranial capacity, breadth, frontal breadth, the ratio of breadth to length as well as height to length. For males relative measurements, the height and frontal chord didn’t change with increasing age, the length, parietal chord, cerebral height and frontal height were positively correlated with age, while there were negative correlations between age and breadth, frontal breadth. For females, the frontal chord didn’t change with increasing age, the length, parietal chord and the ratios of frontal breadth to breadth and height to breadth were positively correlated with age, while there were negative correlations between age and cranial capacity, breadth, height, frontal breadth, frontal height, cerebral height, the ratios of breadth to length as well as height to length.Conclusion:On the whole, there are significant sexual dimorphism and age-related changes in morphology of modern Chinese endocasts which should be taken into account in any research on endocasts.Part3:Increasing breadth of the frontal lobe but decreasing height of the human brain since the Neolithic PeriodObjective:Many recent studies indicate that trends in the evolution of the human brain changed slightly during the Holocene. The major change was towards a decrease in cranial capacity. However, there are no reports that how the human brain have evolved. Since endocasts can reproduce details of external brain morphology, including cranial capacity and shape, it is necessary to compare three-dimensional computed tomographic reconstructions of endocasts taken from both Neolithic and modern-day humans for revealing the evolution of human brain during Holocene.Materials and methods:To address this issue, we collected the cranial computed tomography images of modern adult humans, who were younger than60years of age. This sample comprised302men and209women. Then,81Beiqian skulls were scanned by Siemens128Slice CT, which included52males and29females. All the original CT data were imported into Amira software to obtain the three-dimensional skull and endocasts, which were placed in the standard position. The standardized measurements and indices were taken to provide quantification of the overall endocast shape, including cranial capacity, the length, breadth, height, frontal breadth and so on. All data were analyzed with SPSS17.0statistical software. Results:Various changes in the thirteen measurements and indices of the endocasts between our two samples were observed. The differences were statistically significant for cranial capacity, height, frontal breadth, length, the ratios of frontal breadth to breadth, height to breadth and height to length, frontal height, frontal chord and parietal chord between Beiqian humans and modern-day humans. On the contrary, there were no statistically significant differences for cerebral height, breadth, and the ratio of breadth to length between our two samples. After being scaled relatively to each individual’s cranial capacity, the differences were statistically significant for height, frontal breadth, length, frontal height, frontal chord, and parietal chord in males and the differences were statistically significant for height, frontal breadth, length and frontal chord in females between Beiqian humans and modern-day humans. The differences in sexual dimorphism were statistically significant for height, the ratios of height to breadth and height to length, frontal chord, parietal chord, and cranial capacity between Beiqian humans and modern-day humans. And what’s more, the levels of sexual dimorphism for these measurements and indices in modern-day humans are bigger than those in Beiqian humans, respectivelyConclusion:On the whole, cerebral structure has changed between two Chinese samples from Beiqian site and from living humans, and the main trends are the decrease in height and cranial capacity, and the increase in frontal breadth and sexual dimorphism.更多还原