The thoracolumbar transversospinal muscles are vital in normal function and are implicated in the pathogenesis of different forms of spinal pathology and pain. They are the target for specific forms of clinical intervention such as exercise regimens and the release of �trigger points�, and are often analysed through imaging studies and electromyographic recordings. Despite the importance of these muscles, there is a paucity of knowledge in regard to aspects of their functional morphology. The aim of this thesis was to examine the thoracolumbar transversospinal muscles between the mid-thoracic spine and sacrum, examining their gross morphology, fibre arrangement, fibre types, and an animal model in order to provide a better understanding of their functional morphology. The gross morphology of these muscles was studied by micro-dissection of cadaveric material. Their form was found to differ from that published in either text book or peer reviewed articles, clearly indicating the existence of a �semispinalis� muscle in the lumbar spine. In addition, the arrangement of these muscles was found to be homologous between the thoracic and lumbar regions, which is contrary to published descriptions. Arrangement of the muscle fibres was examined by identifying motor endplates with acetylcholinesterase histochemistry in all muscles throughout the area of interest. Only one endplate per fibre was observed, and no in-series fibres were found. All muscles showed a complex multipinnate form with large areas of muscle tendon intruding into each muscle. Fibre type proportions in each muscle were investigated by immunohistochemistry. Results indicate the percentage of total muscle area occupied by type I fibres decreased the more caudad the vertebral level of origin, for all muscles. There were significant differences in the area percentage of type I fibres between many different vertebral levels. These differences were mostly found between the most cranial and most caudal levels examined. The percentage of type I fibres recorded suggest all muscles are likely postural in function, and the gradual decrease in type I fibres and the lack of a distinct thoracic / lumbar boundary in the data suggests the thoracic and lumbar transversospinal muscles are homologous. The thoracolumbar transversospinal muscles of the MLC3F nlacZ transgenic mouse were micro-dissected to determine their morphology, and their fibre arrangement subsequently determined using acetylcholinesterase histochemistry. These muscles showed a homogeneous form throughout the thoracolumbar spine, and no in-series muscle fibres were observed with all muscles having one motor endplate per fibre. Results indicated similarities between the morphology of mouse and human transversospinal muscles, perhaps indicative of an adaptation to an upright posture. This thesis provides information that facilitates a more complete understanding of the morphology and function of the thoracolumbar transversospinal muscles. In addition, results indicate that these muscles are homologous through the thoracic and lumbar spine, and therefore the classification and nomenclature used to describe these muscles should be re-examined. Furthermore, the morphological evidence, combined with recent embryological studies, supports the use of the term �spinotransverse� to more accurately describe this muscle group.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2002. / Härtill 5 uppsatser.

Thesis (Ph.D.)--University of Western Sydney, Macarthur, Faculty of Health, 1999. / References: p. 194-201.

Thesis (M.A.)--University of Delaware, 2007. / Principal faculty advisor: Anna Klintsova, Dept. of Psychology. Includes bibliographical references.

Thesis (M. Med. Sc.)--University of Hong Kong, 2003. / Includes bibliographical references (leaves 81-94). Also available in print.

Orientador: Alexandre César Rodrigues da Silva / Resumo: Neste trabalho avaliou-se a segmentação da coluna vertebral humana utilizando imagens externas da região dorsal. A avaliação foi realizada utilizando imagens de 70 pessoas (58 mulheres e 12 homens). Essas imagens foram agrupadas por meio da associação entre a quantidade de informação existente, dado pelo valor de entropia da imagem e uma avaliação qualitativa de visibilidade da musculatura paravertebral, realizada por três avaliadores. A segmentação foi feita utilizando um algoritmo, chamado DISLo (Dorsal Image Spine Locator), que processa imagens da região dorsal baseando-se na informação visível. Após o processamento, o algoritmo DISLo produz uma imagem binária contendo uma linha de pixels de intensidade 255 que representam a coluna vertebral identificada. Aplicando o algoritmo em todas as imagens, obteve-se uma segmentação de mais de 75% da coluna vertebral na maioria dos casos (40 imagens), e na minoria (4 imagens), menos de 25%. Posteriormente, para avaliar a qualidade da segmentação, utilizou-se o RMSD (Root Mean Square Deviation) calculado entre os pixels da segmentação automática do DISLo e outra realizada de modo manual, obtida da média de 9 avaliações realizadas por três avaliadores. Pôde-se verificar que as segmentações possuem uma exatidão maior em imagens com mais entropia, bem como possuem uma diferença no RMSD de +-2 pixels quando comparadas a imagens radiográficas. Portanto, a utilização de imagens externas da região dorsal para identificação da coluna vertebr... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this work, the segmentation of the human vertebral column was evaluated using external images of the dorsal region. The evaluation was performed using 70 individual images (58 women and 12 men). These images were grouped using the association between the amount of existing information, given by the entropy value of the image, and a qualitative assessment of the paravertebral musculature visibility, performed by three evaluators. The segmentation was performed using an algorithm called DISLo (Dorsal Image Spine Locator) which processes images from the dorsal region, based on the visible information. After the processing, the DISLo algorithm produces a binary image containing a line with pixels having a 255 intensity value that represents the identified backbone. Applying the algorithm to all images resulted in a segmentation of more than 75% of the spine in most cases (40 images), and in the minority (4 images), less than 25%. Subsequently, to evaluate the quality of the segmentation, the RMSD (Root Mean Square Deviation) was calculated between the pixels of DISLo's automatic segmentation and a manual one, obtained from the average of 9 evaluations performed by three evaluators. It could be verified that the segmentations have a greater accuracy in images with more entropy as well as having a difference in the RMSD of +-2 pixels when compared to radiographic images. Therefore, the use of external images of the dorsal region for identification of the spine is viable, and a r... (Complete abstract click electronic access below) / Doutor

Inertial measurement units (IMUs) are being recognized as a portable and cost-effective alternative to motion analysis systems and have the potential to be introduced into clinical settings for the assessment of functional movement quality of the spine in patients with low back pain. However, uncertainties regarding sensor accuracy and reliability are limiting the widespread use and acceptance of IMU-based assessments into routine clinical practice. The objective of this work was to assess the performance of inexpensive wearable IMUs (Mbientlab MetaMotionR IMUs; Mbientlab Inc., San Francisco, USA; product specifications available in Appendix C) relative to conventional optical motion capture equipment (Vicon Motion Systems Ltd., Oxford, UK) in: 1) a controlled environment, and 2) an uncontrolled environment. The first study evaluated the performance of 2 IMUs in a controlled environment during simulated repetitive spine motion carried out by means of a motorized gimbal. Root mean square error (RMSE) and mean absolute measurement differences between cycle-to-cycle minimum, maximum, and range of motion values, as well as correlational analyses within IMUs and between IMUs and Vicon, in all movement directions (i.e., simulated flexion-extension (FE), lateral bending (LB), and axial twisting (AT)), were compared. Measurement error was low in all axes during all tests (i.e., ≤ 1.54°); however, low-to-moderate correlational results were found in one non-primary axis, and this axis changed depending on the direction of the movement (i.e., LB during FE-motion (0.244 ≤ R ≤ 0.515), AT during LB-motion (0.594 ≤ R ≤ 0.795), and FE during AT-motion (0.002 ≤ R ≤ 0.255)). The second study was designed to assess the performance of the IMUs in an uncontrolled environment during repetitive spine FE in human participants. Absolute angles and local dynamic stability were compared for individual IMUs (which were placed over T10-T12 spinous processes, and the pelvis) as well as for relative motion between IMUs. Maximum finite-time Lyapunov exponents (λmax) were used to quantify local dynamic stability and were calculated using both FE and the sum of squares (SS) from measured spine kinematics. It was found that the IMUs have acceptable performance in all axes when tracking motion (RMSE ≤ 2.43°); however, low-to-moderate correlational results were found in one non-primary axis (0.987 ≤ RFE ≤ 0.998; 0.746 ≤ RLB ≤ 0.978; 0.343 ≤ RAT ≤ 0.679). In addition, correlations between λmax estimates were high; therefore, local dynamic stability can be accurately estimated using both FE and SS data (0.807 ≤ 〖ICC〗_2,1^FE ≤ 0.919; 0.738 ≤ 〖ICC〗_2,1^SS ≤ 0.868). Correlation between λmax estimates was higher when using FE data for individual sensors/rigid-body marker clusters; however, correlation was higher when using SS data for relative motion. In general, the results of these studies show that the MetaMotionR IMUs have acceptable performance in all axes when considering absolute angle orientation and motion tracking, and measurement of local dynamic stability; however, there is low-to-moderate correlation in one non-primary axis, and that axis changes depending on the direction of motion. Future research will investigate how to optimize performance of the third axis for motion tracking; it will also focus on understanding the significance of the third axis performance when calculating specific outcome measures related to spine movement quality.

Low back pain is the most common cause of disability in the United Kingdom with health care costs of more than 1 billion pounds per year. One reason associated with low back pain is the degeneration of intervertebral discs due to loads on the spine. Daily postures such as standing and sitting produce different loads on the discs. Previously, many studies investigated the stress and pressure within the disc in these postures. The results do not agree with each other and the experiments have many limitations. The aim of this project was to assess the feasibility of incorporating magnetic resonance (MR) imaging and finite element (FE) analysis to predict the pressure and stresses developed by different daily postures in an individual. Transient and non-transient subject specific 2D models of nine individuals in standing and sitting were created based on previously acquired MR images. The geometry of these FE models was based on supine MR images. The sitting and standing boundary conditions were calculated by comparing their MR images with the supine posture. The results showed that for six subjects sitting created more intradiscal pressure compared to standing and in one subject standing more than sitting. For two of the subjects the pressure was nearly the same in sitting and standing. Because of the 2D model’s limitations, 3D models of an individual were developed. Both transient and non-transient models of the individual were created. The intradiscal pressure results were three times lower compared to the 2D models. This was due to consideration of out of plane deformation in the 3D models. These results were in the range of in-vivo and in-vitro measurements available in the literature. In conclusion, it was possible to create kinematic transient subject specific FE models based on the MR images in different postures. 2D models provide a method for comparing the postures but 3D models may be more realistic.

O presente estudo analisou o comportamento eletromiográfico de vários níveis dos músculos póstero-mediais do tronco, bilateralmente, para verificar a ocorrência de ativação elétrica simétrica e em busca de padrões de comportamento para embasar modelos biomecânicos. A amostra foi composta por 16 indivíduos saudáveis de ambos gêneros. Todas as execuções foram filmadas para análise cinemática, enquanto a atividade elétrica foi coletada com 14 pares de eletrodos de superfície dispostos lateral e simetricamente ao longo da coluna vertebral nos níveis da sétima vértebra cervical (C7), terceira, sexta e nona vértebras torácicas (T3, T6 e T9) e primeira, terceira e quinta vértebras lombares (L1, L3 e L5). Somente os gestos considerados simétricos através da cinemetria foram analisados. Para a análise do sinal eletromiográfico o gesto de levantar a carga foi dividido em quatro fases, considerando-se apenas a fase de subida com carga. A atividade elétrica dessa fase foi normalizada pela contração isométrica voluntária máxima. Utilizando uma ANOVA, os níveis vertebrais adjacentes foram agrupados em busca de ativação elétrica similar, foi adotado o nível de significância de p<0,05. Os resultados demonstraram que a ativação eletromiográfica não ocorre de maneira simétrica e que é possível identificar zonas com comportamento elétrico distinto entre elas, sendo que as maiores médias estavam localizadas nas regiões mais inferiores do tronco. / The present study analysed the electromyographical behaviour at various levels of posterior medial muscles on trunk, bilaterally, during load lifting to verify the occurrence of symmetry on electrical activation and to search patterns which could provide or supply biomechanical models. Sixteen healthy subjects were videotaped the 2D movement and the EMG signal was registered from 14 pairs of surface electrodes arranged symmetrically and bilaterally throughout trunk, specifically at seventh cervical vertebra (C7), third, sixth and ninth thoracic vertebra (T3, T6 and T9) and first, third and fifth lumbar vertebra (L1, L3 and L5). Only the symmetrical movements, from kinematical point-of-view, were analysed. The EMG analysis was divided in four phases and it was used in the present study the load lifting part. The electrical activation values of this phase were normalized by maximal voluntary isometric contraction. ANOVA was used to provide the adjacent groups in which electrical activation were similar. Differences were considered significant at a p<0.05. The results demonstrated the electromyographical activation does not occur in symmetrical way and, besides it was possible identify zones based on different electrical behaviours, taking into account the largest means were located on lower trunk region.

Autism is one of the leading causes of human intellectual disability (ID). More than 1% of the human population has autism spectrum disorders (ASDs), and it has been estimated that over 50% of those with ASDs also have ID. Fragile X syndrome (FXS) is the most common inherited form of mental retardation and is the leading known genetic cause of autism, affecting approximately 1 in 4000 males and 1 in 8000 females. Approximately 30% of boys with FXS will be diagnosed with autism in their later lives. The cause of FXS is through an over-expansion of the CGG trinucleotide repeat located at the 5’ untranslated region of the FMR1 gene, leading to hypermethylation of the surrounding sequence and eventually partially or fully silencing of the gene. Therefore, the protein product of the gene, fragile X mental retardation protein (FMRP), is reduced or missing. As a single-gene disorder, FXS offers a scientifically tractable way to examine the underlying mechanism of the disease and also shed some light on understanding ASD and ID. The mouse model of FXS (Fmr1−/y mice) is widely accepted and used as a good model, offering good structural and face validity. Since a primary deficit of FXS is believed to be altered neuronal communication, in this thesis I examined white matter tract and dendritic spine abnormalities in the mouse model of FXS. Loss of FMRP does not alter the gross morphology of the white matter. However, recent brain imaging studies indicated that loss of FMRP could lead to some minute abnormalities in different major white matter tracts in the human brain. The gross white matter morphology and myelination was unaltered in the Fmr1−/y mice, however, a small but significant increase of axon diameter in the corpus callosum (CC) was found compared to wild-type (WT) controls. Our computation model suggested that the increase of axon diameter in the Fmr1−/y mice could lead to an increase of conduction velocity in these animals. One of the key phenotypes reported previously in the loss of FMRP is the increase of “immature” dendritic spines. The increase of long and thin spines was reported in several brain regions including the somatosensory cortex and visual cortex in both FXS patients and the mouse model of FXS. Although recent studies which employed state-of-the-art microscopy techniques suggested that only minute differences were noticed between the WT and Fmr1−/y mice. In agreement with previous findings, I found an increase of dendritic spine density in the visual cortex in the Fmr1−/y mice, and spine morphology was also different between the two genotypes. We found that the spine head diameter is significantly increased in the CA1 area of the apical dendrites of the Fmr1−/y mice compared to WT controls. Dendritic spine length is also significantly increased in the same region of the Fmr1−/y mice. However, apical spine head size does not alter between the two genotypes in the V1 region of the visual cortex, and spine length is significantly decreased in the Fmr1−/y mice compared to WT animals in this region. Lovastatin, a drug known as one of the 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase inhibitors, functions as a modulator of the mitogen-activated protein kinases (MAPK) pathway through inhibiting Ras farnesylation, was used in an attempt to rescue the dendritic spine abnormalities in the Fmr1−/y mice. Mice lacking FMRP are susceptible to audiogenic seizure (AGS). Previous work has shown that 48 hr of lovastatin treatment reduced the incidence of AGS in the Fmr1−/y mice. However, chronic lovastatin treatment failed to rescue the spine density and morphology abnormalities in the Fmr1−/y mice. Mouse models are invaluable tools for modelling human diseases. However inter-strain differences have often confounded results between laboratories. In my final Chapter of this thesis, I compared two commonly used C57BL/6 substrains of mice by recording their electrophysiological responses to visual stimuli in vivo. I found a significant increase of high-frequency gamma power in adult C57BL/6JOla mice, and this phenomenon was reduced during the critical period. My results suggested that the C57BL/6JOla substrain has a significant stronger overall inhibitory network activity in the visual cortex than the C57BL/6J substrain. This is in good agreement with previous findings showing a lack of open-eye potentiation to monocular deprivation in the C57BL/6JOla substrain, and highlights the need for appropriate choice of mouse strain when studying neurodevelopmental models. They also give valuable insights into the genetic mechanisms that permit experience-dependent developmental plasticity. In summary, these findings give us a better understanding of the fine structure abnormalities of the Fmr1−/y mice, which in turn can benefit future discoveries of the underlying mechanisms of neurodevelopmental disorders such as ID and ASDs.