Anatomical curve identification

Methods for capturing images in three dimensions are now widely available, with stereo-photogrammetry and laser scanning being two common approaches. In anatomical studies, a number of landmarks are usually identified manually from each of these images and these form the basis of subsequent statistical analysis. However, landmarks express only a very small proportion of the information available from the images. Anatomically defined curves have the advantage of providing a much richer expression of shape. This is explored in the context of identifying the boundary of breasts from an image of the female torso and the boundary of the lips from a facial image. The curves of interest are characterised by ridges or valleys. Key issues in estimation are the ability to navigate across the anatomical surface in three-dimensions, the ability to recognise the relevant boundary and the need to assess the evidence for the presence of the surface feature of interest. The first issue is addressed by the use of principal curves, as an extension of principal components, the second by suitable assessment of curvature and the third by change-point detection. P-spline smoothing is used as an integral part of the methods but adaptations are made to the specific anatomical features of interest. After estimation of the boundary curves, the intermediate surfaces of the anatomical feature of interest can be characterised by surface interpolation. This allows shape variation to be explored using standard methods such as principal components. These tools are applied to a collection of images of women where one breast has been reconstructed after mastectomy and where interest lies in shape differences between the reconstructed and unreconstructed breasts. They are also applied to a collection of lip images where possible differences in shape between males and females are of interest

Translational genetic modelling of 3D craniofacial dysmorphology: elaborating the facial phenotype of neurodevelopmental disorders through the prism of schizophrenia

Purpose of Review: In the context of human developmental conditions, we review the conceptualisation of schizophrenia as a neurodevelopmental disorder, the status of craniofacial dysmorphology as a clinically accessible index of brain dysmorphogenesis, the ability of genetically modified mouse models of craniofacial dysmorphology to inform on the underlying dysmorphogenic process and how geometric morphometric techniques in mutant mice can extend quantitative analysis. Recent Findings: Mutant mice with disruption of neuregulin-1, a gene associated meta-analytically with risk for schizophrenia, constitute proof-of-concept studies of murine facial dysmorphology in a manner analogous to clinical studies in schizophrenia. Geometric morphometric techniques informed on the topography of facial dysmorphology and identified asymmetry therein. Summary: Targeted disruption in mice of genes involved in individual components of developmental processes and analysis of resultant facial dysmorphology using geometric morphometrics can inform on mechanisms of dysmorphogenesis at levels of incisiveness not possible in human subjects

Stature of the Great Moravian Population in Connection with Social Status

Stature is one of the basic anthropometric information relating to man. It reflects very sensitively a number of factors such as e.g. living conditions, sex, age, ethnicity, etc. We were mainly interested in the relationship between stature and living conditions that in each historical period are significantly influenced by social class. We compared the skeletons from the Mikulčice highest social class with skeletons from the area below the castle and from distant areas that represented the background of the first two groups. Subsequently, we compared the Great-Moravian population with recent statures acquired at the end of the 20th century.Stature is one of the basic anthropometric information relating to man. It reflects very sensitively a number of factors such as e.g. living conditions, sex, age, ethnicity, etc. We were mainly interested in the relationship between stature and living conditions that in each historical period are significantly influenced by social class. We compared the skeletons from the Mikulčice highest social class with skeletons from the area below the castle and from distant areas that represented the background of the first two groups. Subsequently, we compared the Great-Moravian population with recent statures acquired at the end of the 20th century

A hierarchical curve-based approach to the analysis of manifold data

One of the data structures generated by medical imaging technology is high resolution point clouds representing anatomical surfaces. Stereophotogrammetry and laser scanning are two widely available sources of this kind of data. A standardised surface representation is required to provide a meaningful correspondence across different images as a basis for statistical analysis. Point locations with anatomical definitions, referred to as landmarks, have been the traditional approach. Landmarks can also be taken as the starting point for more general surface representations, often using templates which are warped on to an observed surface by matching landmark positions and subsequent local adjustment of the surface. The aim of the present paper is to provide a new approach which places anatomical curves at the heart of the surface representation and its analysis. Curves provide intermediate structures which capture the principal features of the manifold (surface) of interest through its ridges and valleys. As landmarks are often available these are used as anchoring points, but surface curvature information is the principal guide in estimating the curve locations. The surface patches between these curves are relatively flat and can be represented in a standardised manner by appropriate surface transects to give a complete surface model. This new approach does not require the use of a template, reference sample or any external information to guide the method and, when compared with a surface based approach, the estimation of curves is shown to have improved performance. In addition, examples involving applications to mussel shells and human faces show that the analysis of curve information can deliver more targeted and effective insight than the use of full surface information

Distal Part of the Human Hand: Study of Form Variability and Sexual Dimorphism Using Geometric Morphometrics

Tradičně se lidská ruka studuje prostřednictvím měření a srovnávání jednotlivých segmentů (prstů, článků prstů, záprstních kostí) bez zohlednění jejich vzájemných prostorových souvislostí. Cílem této studie je výzkum vnitro-populační variability formy lidské ruky jako celku v oblasti tříčlánkových prstů se zvláštním zaměřením na sexuální dimorfismus a vztah mezi velikostí a tvarem ruky. Pravé ruce 99 žen a 70 mužů, převážně vysokoškolských studentů, byly ve standardizované poloze z palmární strany zaznamenány běžným stolním skenerem. Na každém dvourozměrném snímku bylo umístěno 16 význačných bodů a byla studována variabilita mezi těmito konfiguracemi prostřednictvím metod geometrické morfometrie. Pro lepší pochopení vnitřních vzorců variability tvaru byl tvarový prostor rozložen na afinní a neafinní podprostor, které byly dále analyzovány samostatně. Převážná část celkové variability byla spojena s afinními tvarovými rozdíly, které jsou identické v celé studované oblasti ruky. Jejich větší část představovala střižnou změnu v proximodistálním směru, menší část pak napínání odpovídající změnám v šířce ruky. Toto napínání také silně korelovalo s velikostí ruky. Mezipohlavní rozdíly představovala afinní změna, ve které byla proximodistální střižná změna neoddělitelně spojena se změnami v relativní šířce ruky. Lokální neafinní pohlavní rozdíly byly zaznamenány v určitých článcích prstů a mohou souviset s rozdíly v poměrech délek prstů. Domníváme se, že oddělení globálních a lokálních sexuálně dimorfních znaků ruky může pomoci blíže ozřejmit původ/počátek jejich dimorfismu v rané ontogenezi – čím lokálnější znak, tím později se v ontogenezi zakládá. Dimorfní znaky lokální a globální by proto mohly být ovlivněny odlišnými ontogenetickými faktory.Traditionally, the human hand has been analyzed by measuring and comparing individual segments (fingers, phalanges, metacarpals) without considering their mutual spatial relationships. The present study aimed to analyze intra-population variability of the human hand form in the region of fingers as whole with special focus given to sexual dimorphism and the association between shape and size. Right hands of 99 females and 70 males, mostly college students, were scanned with a document scanner in standardized position from the palmar side. For each image 2-D coordinates of 16 landmarks were recorded and variability between configurations of landmarks were studied using geometric morphometrics. To understand patterns of variability, shape spaces were decomposed into affine and non-affine subspaces and further studied separately. The prevalence of the total variability was associated with affine shape change identical for the whole studied region of the hand. Its major portion was represented by shearing in proximodistal direction and to a lesser extent by straining in the relative hand width. The strain also strongly correlated with size of the hand. Intersexual differences were represented by affine change in which the proximodistal shearing was inextricably tied with the differences in relative hand width. Local non-affine sex differences were found in specific phalanges and might be associated with differences in finger length ratios. We presume that separating global and local sexually dimorphic features of the hand might shed light on the origin/onset of the dimorphism during early ontogeny – the more local the feature, the later differentiated, and thus influenced by different ontogenetic factors than global features

Functional data analysis and visualisation of three-dimensional surface shape

The dataset consists of a collection of files which provide animated versions of some of the figures in the associated paper

Enriched environment ameliorates propagation of tau pathology and improves cognition in rat model of tauopathy

IntroductionThe typical symptoms of Alzheimer’s disease (AD) are cognitive impairment, disrupted spatial orientation, behavioral and psychiatric abnormalities, and later motor deficits. Neuropathologically, AD is characterized by deposits of pathological forms of endogenous proteins – amyloid-β, and neurofibrillary tau protein pathology. The latter closely correlates with brain atrophy and clinical impairment. Pharmacological therapies for these pathologies are largely absent, raising the question whether non-pharmacological interventions could be efficacious. Environmental factors can play a role in the manifestation of AD. It is unknown whether enriched environment (EE) can ameliorate the propagation of protein aggregates or their toxic components.MethodsWe injected insoluble tau extracts from human brains with AD (600 or 900 ng per animal) into hippocampi of SHR72 transgenic rats that express non-mutated truncated human tau 151-391/4R, but usually do not develop hippocampal tangles. The rats had either standard housing, or could access an EE 5×/week for 3 months. Behavioral analysis included the Morris Water Maze (MWM). Histological analysis was used to assess the propagation of tau pathology.ResultsAnimals exposed to EE performed better in the MWM (spatial acquisition duration and total distance, probe test); unexposed animals improved over the course of acquisition trials, but their mean performance remained below that of the EE group. Enriched environment abrogated tau propagation and hippocampal tangle formation in the 600 ng group; in the 900 ng group, tangle formation was ∼10-fold of the 600 ng group, and unaffected by EE.ConclusionEven a small difference in the amount of injected human AD tau can cause a pronounced difference in the number of resulting tangles. EE leads to a noticeably better spatial navigation performance of tau-injected animals. Furthermore, EE seems to be able to slow down tau pathology progression, indicating the possible utility of similar interventions in early stages of AD where tangle loads are still low

Comparison of dental measurement systems for taxonomic assignment of first molars

Morphometrics of the molar crown is based traditionally on diameter measurements but is nowadays more often based on 2D image analysis of crown outlines. An alternative approach involves measurements at the level of the cervical line. We compare the information content of the two options in a three-dimensional (3D) digital sample of lower and upper first molars (M 1 and M1) of modern human and Neanderthal teeth. The cervical outline for each tooth was created by digitizing the cervical line and then sectioning the tooth with a best fit plane. The crown outline was projected onto this same plane. The curves were analyzed by direct extraction of diameters, diagonals, and area and also by principal component analysis either of the residuals obtained by regressing out these measurements from the radii (shape information) or directly by the radii (size and shape information). For M1, the crown and cervical outline radii allow us to discriminate between Neanderthals and modern humans with 90% and 95% accuracy, respectively. Fairly good discrimination between the groups (80-82.5%) was also obtained using cervical measurements. With respect to M1, general overlap of the two groups was obtained by both crown and cervical measurements; however, the two taxa were differentiable by crown outline residuals (90-97%). Accordingly, while crown diameters or crown radii should be used for taxonomic analysis of unworn or slightly worn M1s, the crown outline, after regressing out size information, could be promising for taxonomic assignment of lower M1s

Cues to fertility: Perceived attractiveness and facial shape predict reproductive success

Attractive facial features in women are assumed to signal fertility, but whether facial attractiveness predicts reproductive success in women is still a matter of debate. We investigated the association between facial attractiveness at young adulthood and reproductive life history-number of children and pregnancies-in women of a rural community. For the analysis of reproductive success, we divided the sample into women who used contraceptives and women who did not. Introducing two-dimensional geometric morphometric methodology, we analysed which specific characteristics in facial shape drive the assessment of attractiveness and covary with lifetime reproductive success. A set of 93 (semi)landmarks was digitized as two-dimensional coordinates in postmenopausal faces. We calculated the degree of fluctuating asymmetry and regressed facial shape on facial attractiveness at youth and reproductive success. Among women who never used hormonal contraceptives, we found attractive women to have more biological offspring than less attractive women. These findings are not affected by sociodemographic variables. Postmenopausal faces corresponding to high reproductive success show more feminine features-facial characteristics previously assumed to be honest cues to fertility. Our findings support the notion that facial attractiveness at the age of mate choice predicts reproductive success and that facial attractiveness is based on facial characteristics, which seem to remain stable until postmenopausal age. © 2012 Elsevier Inc

Dental disease as an indicator of ecological factors in medieval skeletal populations from Slovakia

This paper summarizes results of previous odontological research into the medieval (7th–15th c. A.D.) populations in Slovakia and presents conclusions concerning the diachronic and geographical differences in their dental disease. The dental remains from 16 cemeteries were used. The remains were divided into four chronological (Avar Period, Great-Moravian Period, Hungarian Conquest Period, Arpadian Period) and two geographical groups (east Slovakia, southwest Slovakia). The dental data, such as caries, ante-mortem tooth loss (AMTL), caries intensity, caries frequency and others, were compiled from more than 1,000 adult dentitions. The statistical analyses revealed only two kinds of significant differences within the data compared. Both differences related to females: 1) tooth-count caries rate (%C) in east and southwest Slovakia (with higher rate in east), 2) individual-count caries-AMTL rate (%indCE) across diachronic groups (showing a significant quadratic [parabolic] trend with ascending portion from Hungarian Conquest Period to Arpadian Period). Furthermore, statistical analysis of the female data showed significant quadratic trend in caries intensity (I-CE) and caries frequency (F-CE), suggesting an increase in their prevalence from the Great-Moravian to the Arpadian Period. However, most of the data obtained indicate that due to both similar ecological conditions and subsistence activities the diet of the medieval populations investigated did not substantially vary.This paper summarizes results of previous odontological research into the medieval (7th–15th c. A.D.) populations in Slovakia and presents conclusions concerning the diachronic and geographical differences in their dental disease. The dental remains from 16 cemeteries were used. The remains were divided into four chronological (Avar Period, Great-Moravian Period, Hungarian Conquest Period, Arpadian Period) and two geographical groups (east Slovakia, southwest Slovakia). The dental data, such as caries, ante-mortem tooth loss (AMTL), caries intensity, caries frequency and others, were compiled from more than 1,000 adult dentitions. The statistical analyses revealed only two kinds of significant differences within the data compared. Both differences related to females: 1) tooth-count caries rate (%C) in east and southwest Slovakia (with higher rate in east), 2) individual-count caries-AMTL rate (%indCE) across diachronic groups (showing a significant quadratic [parabolic] trend with ascending portion from Hungarian Conquest Period to Arpadian Period). Furthermore, statistical analysis of the female data showed significant quadratic trend in caries intensity (I-CE) and caries frequency (F-CE), suggesting an increase in their prevalence from the Great-Moravian to the Arpadian Period. However, most of the data obtained indicate that due to both similar ecological conditions and subsistence activities the diet of the medieval populations investigated did not substantially vary