bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular markers associated with nonepithelial ovarian cancer in formalin‐fixed, paraffin‐embedded specimens by genome wide expression profiling
Authors: Vui‐Kee Koon , Mohd Dali Ahmad Zailani Hatta , Mohamed Rose Isa , Ghazali Razmin , Jamal Rahman , Mokhtar Norfilza Mohd
Published: April 2012

Nonepithelial ovarian cancer (NEOC) is a rare cancer that is often misdiagnosed as other malignant tumors. Research on this cancer using fresh tissues is nearly impossible because of its limited number of samples within a limited time provided. The study is to identify potential genes and their molecular pathways related to NEOC using formalin‐fixed paraffin embedded samples. Total RNA was extracted from eight archived NEOCs and seven normal ovaries. The RNA samples with RNA integrity number >2.0, purity >1.7 and cycle count value <28 cycles were hybridized to the Illumina Whole‐Genome DASL assay (cDNA‐mediated annealing, selection, extension, and ligation). We analyzed the results using the GeneSpring GX11.0 and FlexArray software to determine the differentially expressed genes. Microarray results were validated using an immunohistochemistry method. Statistical analysis identified 804 differentially expressed genes with 443 and 361 genes as overexpressed and underexpressed in cancer, respectively. Consistent findings were documented for the overexpression of eukaryotic translation elongation factor 1 alpha 1, E2F transcription factor 2, and fibroblast growth factor receptor 3, except for the down‐regulated gene, early growth response 1 (EGR1). The immunopositivity staining for EGR1 was found in the majority of cancer tissues. This finding suggested that the mRNA level of a transcript did not always match with the protein expression in tissues. The current gene profile can be the platform for further exploration of the molecular mechanism of NEOC.
Breast carcinoma metastasized to vestibular schwannoma: A rare case of tumor‐to‐tumor metastasis and literature review
Authors: Lua Boon‐Kee , Lieu Ann‐Shung , Hwang Shiuh‐Lin
Published: April 2012

Tumor‐to‐tumor metastasis is a well‐recognized phenomenon. However, cerebellopontine angle tumor, especially vestibular schwannoma, is a rare location of metastasis, with only six cases being reported previously in English‐language literature reviews. We report a case of a 57‐year‐old woman with underlying breast cancer (T2N3M1, stage IV) who presented with unilateral facial tics, paresthesia and hearing loss, who turned out to have vestibular schwannoma with adenocarcinoma metastasis.
Rethinking Carelessness on Job Analysis Surveys
Authors: Stetz Thomas A. , Button Scott B. , Quist Joshua
Published: April 2012

This study examines bogus tasks embedded in a job analysis survey as a method to contribute to our understanding of the factors that impact the accuracy of job analysis ratings. The results show that incumbents accurately report if they have performed a task within the past 12 months, but were inaccurate when deciding if they were expected to perform a bogus task. Also, carelessness was positively correlated with ratings on valid tasks and supervisors and incumbents were equally careless. These findings contribute to the literature by showing that the rating “inferential leap” applies to the rating scale as well as the descriptor. They also provide additional support for removing inaccurate raters from the analysis. Finally, the findings suggest that raters may focus on broader role expectations rather than the specific task statements while completing job analysis questionnaires.
Multiagent simulation of evolutive plate tectonics applied to the thermal evolution of the Earth
Authors: Combes M. , Grigné C. , Husson L. , Conrad C. P. , Le Yaouanq S. , Parenthoën M. , Tisseau C. , Tisseau J.
Published: April 2012

The feedback between plate tectonics and mantle convection controls the Earth's thermal evolution via the seafloor age distribution. We therefore designed the MACMA model to simulate time‐dependent plate tectonics in a 2D cylindrical geometry with evolutive plate boundaries, based on multiagent systems that express thermal and mechanical interactions. We compute plate velocities using a local force balance and use explicit parameterizations to treat tectonic processes such as trench migration, subduction initiation, continental breakup and plate suturing. These implementations allow the model to update its geometry and thermal state at all times. Our approach has two goals: (1) to test how empirically‐ and analytically‐determined rules for surface processes affect mantle and plate dynamics, and (2) to investigate how plate tectonics impact the thermal regime. Our predictions for driving forces, plate velocities and heat flux are in agreement with independent observations. Two time scales arise for the evolution of the heat flux: a linear long‐term decrease and high‐amplitude short‐term fluctuations due to surface tectonics. We also obtain a plausible thermal history, with mantle temperature decreasing by less than 200 K over the last 3 Gyr. In addition, we show that on the long term, mantle viscosity is less thermally influential than tectonic processes such as continental breakup or subduction initiation, because Earth's cooling rate depends mainly on its ability to replace old insulating seafloor by young thin oceanic lithosphere. We infer that simple convective considerations alone cannot account for the nature of mantle heat loss and that tectonic processes dictate the thermal evolution of the Earth.
40Ar/39Ar ages for deep (∼3.3 km) samples from the Hawaii Scientific Drilling Project, Mauna Kea volcano, Hawaii
Authors: Jourdan Fred , Sharp Warren D. , Renne Paul R.
Published: April 2012

The Hawaii Scientific Drilling Project recovered core from a 3.5 km deep hole from the flank of Mauna Kea volcano, providing a long, essentially continuous record of the volcano's physical and petrologic development that has been used to infer the chemical and physical characteristics of the Hawaiian mantle plume. Determining a precise accumulation rate via 40Ar/39Ar dating of the shield‐stage tholeiites, which constitute 95–98% of the volcano's volume is challenging. We applied40Ar/39Ar dating using laser‐ and furnace‐heating in two laboratories (Berkeley and Curtin) to samples of two lava flows from deep in the core (∼3.3 km). All determinations yield concordant isochron ages, ranging from 612 ± 159 to 871 ± 302 ka (2σ; with P ≥ 0.90). The combined data yield an age of 681 ± 120 ka (P = 0.77) for pillow lavas near the bottom of the core. This new age, when regressed with 40Ar/39Ar isochron ages previously obtained for tholeiites higher in the core, defines a constant accumulation rate of 8.4 ± 2.6 m/ka that can be used to interpolate the ages of the tholeiites in the HSDP core with a mean uncertainty of about ±83 ka. For example at ∼3300 mbsl, the age of 664 ± 83 ka estimated from the regression diverges at the 95% confidence level from the age of 550 ka obtained from the numerical model of DePaolo and Stolper (1996). The new data have implications for the timescale of the growth of Hawaiian volcanoes, the paleomagnetic record in the core, and the dynamics of the Hawaiian mantle plume.
Assessment of evolving TRMM‐based multisatellite real‐time precipitation estimation methods and their impacts on hydrologic prediction in a high latitude basin
Authors: Yong Bin , Hong Yang , Ren Li‐Liang , Gourley Jonathan J. , Huffman George J. , Chen Xi , Wang Wen , Khan Sadiq I.
Published: April 2012

The real‐time availability of satellite‐derived precipitation estimates provides hydrologists an opportunity to improve current hydrologic prediction capability for medium to large river basins. Due to the availability of new satellite data and upgrades to the precipitation algorithms, the Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis real‐time estimates (TMPA‐RT) have been undergoing several important revisions over the past ten years. In this study, the changes of the relative accuracy and hydrologic potential of TMPA‐RT estimates over its three major evolving periods were evaluated and inter‐compared at daily, monthly and seasonal scales in the high‐latitude Laohahe basin in China. Assessment results show that the performance of TMPA‐RT in terms of precipitation estimation and streamflow simulation was significantly improved after 3 February 2005. Overestimation during winter months was noteworthy and consistent, which is suggested to be a consequence from interference of snow cover to the passive microwave retrievals. Rainfall estimated by the new version 6 of TMPA‐RT starting from 1 October 2008 to present has higher correlations with independent gauge observations and tends to perform better in detecting rain compared to the prior periods, although it suffers larger mean error and relative bias. After a simple bias correction, this latest data set of TMPA‐RT exhibited the best capability in capturing hydrologic response among the three tested periods. In summary, this study demonstrated that there is an increasing potential in the use of TMPA‐RT in hydrologic streamflow simulations over its three algorithm upgrade periods, but still with significant challenges during the winter snowing events.
Tectonic and climatic controls on knickpoint retreat rates and landscape response times
Authors: Whittaker Alexander C. , Boulton Sarah J.
Published: April 2012

The rate at which transient knickpoints propagate through a landscape fundamentally controls the rate of geomorphic response to tectonic and climatic perturbation. Here we present knickpoint retreat rates upstream of active faults for 19 bedrock catchments in Turkey and 11 bedrock catchments in Italy where we have very good constraints on both the magnitude and timing of the tectonic perturbation and where climate histories are well documented. We show that the knickpoints have average retreat rates of between 0.2 and 2 mm/yr for catchments with drainage areas between 6 and 65 km2 and we test whether differences in rock mass strength and catchment size are sufficient to explain this range in retreat rates. Our analysis suggests that even accounting for these two variables, knickpoint propagation velocities differ markedly, and we show that channels crossing faults with higher throw rates have knickpoints that are retreating faster. The dependence of knickpoint retreat velocity on throw rate is at least as important as catchment drainage area. These results indicate, counterintuitively, that landscapes forced by large amplitude tectonic perturbations will have shorter response times than those perturbed by smaller amplitude changes. The link between the knickpoint propagation velocity and throw rate is largely (but not completely) explained by channel narrowing in areas of high uplift rate. Channel steepening upstream of the active faults may explain all of the residual dependency of knickpoint retreat rate on fault throw rate, but only if the slope exponent, n, in the standard stream power model is greater than 1.3. However, we cannot rule out a role for sediment supply in driving enhanced knickpoint retreat rate in addition to the well‐documented channel narrowing effect. Finally, we find that mean knickpoints retreat rates in Turkey are only half of those in Italy, for catchments of equivalent size, crossing faults with similar throw rates. This difference in fluvial response time is accounted for by long‐term differences in the ratio of precipitation to infiltration in the two areas over the last 1 My.
Analysis of the PLL phase error in presence of simulated ionospheric scintillation events
Authors: Forte B.
Published: April 2012

The functioning of standard phase locked loops (PLL), including those used to track radio signals from Global Navigation Satellite Systems (GNSS), is based on a linear approximation which holds in presence of small phase errors. Such an approximation represents a reasonable assumption in most of the propagation channels. However, in presence of a fading channel the phase error may become large, making the linear approximation no longer valid. The PLL is then expected to operate in a non‐linear regime. As PLLs are generally designed and expected to operate in their linear regime, whenever the non‐linear regime comes into play, they will experience a serious limitation in their capability to track the corresponding signals. The phase error and the performance of a typical PLL embedded into a commercial multiconstellation GNSS receiver were analyzed in presence of simulated ionospheric scintillation. Large phase errors occurred during scintillation‐induced signal fluctuations although cycle slips only occurred during the signal re‐acquisition after a loss of lock. Losses of lock occurred whenever the signal faded below the minimumC/N0threshold allowed for tracking. The simulations were performed for different signals (GPS L1C/A, GPS L2C, GPS L5 and Galileo L1). L5 and L2C proved to be weaker than L1. It appeared evident that the conditions driving the PLL phase error in the specific case of GPS receivers in presence of scintillation‐induced signal perturbations need to be evaluated in terms of the combination of the minimumC/N0 tracking threshold, lock detector thresholds, possible cycle slips in the tracking PLL and accuracy of the observables (i.e. the error propagation onto the observables stage).
Kilometer‐scale refolded folds caused by strike‐slip reversal and intraplate shortening in the Beishan region, China
Authors: Zhang Jin , Cunningham Dickson
Published: April 2012

Spectacular refolded folds clearly visible from space deform Permian turbidite successions in a 180 km2 fault‐bounded compartment within the Beishan region of northwestern China. The folds formed after final terrane amalgamation of the Central Asian Orogenic Belt and record an important sequence of intraplate deformation events in central Asia during the Late Permian‐Jurassic. The fold interference patterns are dominantly Type 2 refolds with kilometer‐scale wavelengths. They are bounded to the north and south by regional E‐W faults with multiple displacement histories as revealed by crosscutting ductile and brittle fabrics and kinematic indicators indicating opposing senses of motion. The proximity of the refolded folds to the main bounding faults strongly suggests that the fold interference structures were caused by strike‐slip fault reactivation and shear related bending of F1 folds combined with components of N‐S compression across the compartment. Faulting within the folded compartment is limited to an array of right‐lateral strike‐slip faults which appear to have helped accommodate room problems during the refolding event. The driving force for the deformation was likely to be distant—including regional block collision to the south, large‐scale rotations between the Siberian and North China Cratons and plate boundary convergence along the eastern Chinese margin. Our study demonstrates that continental interior regions characterized by terrane collages are susceptible to reactivation by distant plate margin effects and that polyphase reactivation of major strike‐slip and oblique‐slip faults can generate refolding within upper crustal basinal compartments. In addition, the fault‐bounded basin containing the refolded folds in the Beishan region is surrounded by older more complexly deformed crystalline basement. Therefore, the deformed basin sequence represents a unique compartmental archive of the Permian‐Triassic history of intraplate deformation north of Tibet.
Effect of storm movement on flood peaks: Analysis framework based on characteristic timescales
Authors: Seo Yongwon , Schmidt Arthur R. , Sivapalan Murugesu
Published: April 2012

The aim of this paper is to investigate, in general terms, the effects of storm movement on the resulting flood peaks, and the underlying process controls. For this purpose, we utilize a broad theoretical framework that uses characteristic time and space scales associated with stationary rainstorms as well as moving rainstorms. For a stationary rainstorm the characteristic timescales that govern the peak response include two intrinsic timescales of a catchment and one extrinsic timescale of a rainstorm. On the other hand, for a moving rainstorm, two additional extrinsic scales are required, the storm travel time and storm size. The relationship between the peak response and the timescales appropriate for a stationary rainstorm can be extended in a straightforward manner to describe the peak response for a moving rainstorm. However, the interdependence between rainfall duration and storm travel time makes the behavior of the peak response for a moving rainstorm fundamentally different from that of a stationary rainstorm. We show that the relationship between peak response and characteristic timescales also depends on the relative size of the rainstorm with respect to catchment size. For moving rainstorms, we show that the augmentation of peak response arises from both the effect of overlaying the responses from subcatchments (resonance condition) and the effect of increased responses from subcatchments due to increased duration (interdependence), which results in maximum peak response when the moving rainstorm is slower than the channel flow velocity.
Late Miocene upward and outward growth of eastern Tibet and decreasing monsoon rainfall over the northwestern Indian subcontinent since ∼10 Ma
Authors: Molnar Peter , Rajagopalan Balaji
Published: April 2012

Many geologic observations suggest that the eastern portion of the Tibetan Plateau has expanded eastward and grown in height over the past 15‐10 Ma, and other observations suggest that climate over the northwestern Indian subcontinent (“NW India”) became more arid between ∼11 and 7 Ma. We suggest that they are linked: higher terrain increased orographic precipitation over eastern Tibet, which diabatically heated the atmosphere there; that heating then forced subsidence to the west via the mechanism proposed by Rodwell and Hoskins; and subsidence suppressed rainfall. Simple Gill‐model calculations for a heat source displaced from the equator show such subsidence, and a regression of July‐August outgoing long‐wave radiation (OLR) over southeastern Tibet with rainfall shows a negative relationship between eastern Tibet and NW India, consistent with the proposed link between growth of eastern Tibet and diminished South Asian monsoon rainfall over the northwestern Indian subcontinent.
Demyelination reduces brain parenchymal stiffness quantified in vivo by magnetic resonance elastography
Authors: Schregel Katharina , Wuerfel née Tysiak Eva , Garteiser Philippe , Gemeinhardt Ines , Prozorovski Timour , Aktas Orhan , Merz Hartmut , Petersen Dirk , Wuerfel Jens , Sinkus Ralph
Published: April 2012

The detection of pathological tissue alterations by manual palpation is a simple but essential diagnostic tool, which has been applied by physicians since the beginnings of medicine. Recently, the virtual “palpation” of the brain has become feasible using magnetic resonance elastography, which quantifies biomechanical properties of the brain parenchyma by analyzing the propagation of externally elicited shear waves. However, the precise molecular and cellular patterns underlying changes of viscoelasticity measured by magnetic resonance elastography have not been investigated up to date. We assessed changes of viscoelasticity in a murine model of multiple sclerosis, inducing reversible demyelination by feeding the copper chelator cuprizone, and correlated our results with detailed histological analyses, comprising myelination, extracellular matrix alterations, immune cell infiltration and axonal damage. We show firstly that the magnitude of the complex shear modulus decreases with progressive demyelination and global extracellular matrix degradation, secondly that the loss modulus decreases faster than the dynamic modulus during the destruction of the corpus callosum, and finally that those processes are reversible after remyelination.
Blitzkrieg
Authors: Briggs Asa
Published: April 2012

This chapter describes the role of broadcasting in Germany's blitzkrieg attack in Europe. Though there were regular radio messages that broadcast the move of German forces, they were not able to accurately predict the true target of the Germans. This is because Holland, Belgium, Sweden, and the Balkans were all equally possible objectives of Germany. In addition, attention to German plans on the Western Front was diverted by both the German and by the Italian radio.
Reconstruction
Authors: Briggs Asa
Published: April 2012

This chapter describes the changes in the British Broadcasting Corporation's (BBC) programming during the reconstruction period. In March 1945 BBC Director-General William Haley announced that the company would provide listeners in Great Britain with two full-scale alternative programmes and that the regional services which had been interrupted for security reasons would also return. This chapter also discusses the proposal for the BBC to maintain its sole rights within Britain to originate programmes for distribution by wire or wireless.
Early decompression of the spinal cord following injury: arguments for and against
Authors: Masri W. S. El , Meerkotter D. V.
Published: April 2012

The management of the traumatized spinal cord has remained controversial over the past half century. Arguments for and against each treatment modality exist. Each is equally likely to be adopted or disparaged until possibly all factors hindering spinal cord recovery are identified. Direct comparison between surgery and conservative management in a series of unselected patients would contribute to solving the controversy. The difficulties with the design of studies and the statistical evaluation of the results should not be underestimated. Problems of designing such comparative clinical studies are to be expected, since, even in the controlled animal studies, reproducibility is not always possible.
Spinal injury and spinal cord blood-flow: the effect of early treatment and local cooling
Authors: Hansebout Robert R.
Published: April 2012

The role of blood-flow in the acute spinal cord injury is controversial. Local cord cooling has been used to treat experimental spinal cord injury during the last fifteen years. It has shown beneficial effects in promoting the return of function after a severe injury. Spinal cord blood-flow can be measured internally, using hydrogen polarography. Using this technique in the nontraumatized spinal cord of dogs, local cooling was found to markedly decrease the internal spinal cord blood-flow. It is therefore conceivable that, following acute trauma, cooling reduces the passage of noxious substances from blood-vessels into the cord tissues, and thereby has beneficial effects.
Spasticity II: Physiological measurements
Authors: Sedgwick E. M. , Benfield J.
Published: April 2012

Direct tests by the microneuronographic recording of muscle afferent fibres of spastic human subjects show that the gamma system is not overactive, and the muscle spindles do not have an increased sensitivity to stretch in spasticity. A substantial body of work has compared the human H reflex with the tendon (T) reflex in an attempt to separate the contributions of the monosynaptic reflex as against those of the gamma system. Both electrical stimulation of the tibial nerve and a tap of the tendo Achilles would produce a monosynaptic reflex contraction of the soleus. The electrical stimulus, however, would bypass the muscle spindle, and produce an H reflex of amplitude dependent only upon the excitability of the monosynaptic reflex. Comparison of the H and T reflexes indicates the activity in the gamma system. A tendon tap produces a wave of vibration spreading through the muscle, and muscles' spindles are excited asynchronously, producing an input volley to the spinal cord lasting as long as 20–30 msec.
Bladder management
Authors: Fellows G. J.
Published: April 2012

Rehabilitation — physical, occupational, and social — is the aim of management after spinal cord injury or disease. The management of the lower urinary tract is crucial, since poor treatment may lead to unacceptable morbidity or even to renal failure and premature death. There are four overlapping phases of bladder management, as expectations of improved length and quality of life for the paralysed have risen. The management of the individual patient can be considered in four stages: early management, from the moment of injury until definitive management is instituted or the patient is discharged from hospital; intermediate management, from discharge from hospital until definitive management if the latter is delayed for any reason; definitive management; and derological surveillance, which should be lifelong for all patients. Different methods of management may need to be introduced at any stage if complications arise.
Pain in spinal cord injury
Authors: Berić Aleksandar
Published: April 2012

Sustaining a spinal cord injury (SCI), even a severe one, does not necessarily entail pain, although the majority of SCI patients in the acute phase do experience pain, which usually subsides with medical management. In the chronic phase, however, about one-third of SCI patients complain of sensory disturbances, either pain or unpleasant sensations called dysaesthesiae. In chronic SCI patients it is not only the incidence of pain, but its intractability which is important. While treating these patients two problems have to be dealth with: one is the chronic pain syndrome, with all its complexities; and the other is a chronic neurogenic dysfunction. The need for treatment of chronic pain continues, and the potential for developing drug-tolerance and addiction must be addressed prior to the onset of therapy. This chapter concentrates upon neurogenic pain in SCI, particularly pain which might have been caused by injury to the spinal cord.
Hardware for functional MRI
Authors: Glover Gary H.
Published: April 2012

Functional neuroimaging places strong demands on the MR imaging hardware because of the need for rapid acquisition, high signal-to-noise ratio and exceptional system stability. This chapter discusses the requirements for functional magnetic resonance imaging (fMRI) hardware, describing MR imaging hardware optimized for fMRI and discussing the safety implications of high magnetic fields. The choice of field strength for routine cognitive neuroscience is influenced by numerous factors. The chapter also discusses biological considerations for fast gradient switching that can induce magneto stimulation effects in humans by creating local electric potentials. The study gives an overview of gradient coils, shows a schematic diagram of transverse gradients and the longitudinal gradient, and discusses parameters that are important in the design of gradient coils. Future developments in MRI hardware are also addressed.
Spatial and temporal resolution in fMRI
Authors: Menon Ravi S. , Goodyear Bradley G.
Published: April 2012

This chapter addresses the limitations imposed by the functional magnetic resonance imaging (fMRI) technique and suggests some strategies to improve spatial and temporal resolution. It begins with the discussion of limits to spatial resolution in fMRI and shows that there are a number of factors to consider in achieving high spatial resolution with fMRI. The spatial resolution of the haemodynamics is also discussed. Since the haemodynamics are the source of the fMRI signal, the chapter also discusses how different sources contribute to the fMRI signal and reviews current opinion on how well localized the haemodynamic response actually is. It also reviews fMRI techniques that can be used to eliminate unwanted contributions to the measured signal and thereby increase the contrast-to-noise ratio of the fMRI signal directly related to submillimetre neural activity. Finally, the chapter shows an example of the high spatial resolution capabilities of fMRI in the human visual cortex.
Quantitative measurement using fMRI
Authors: Hoge Richard D. , Pike G. Bruce
Published: April 2012

Recent developments have permitted the extension of magnetic resonance imaging into the realm of quantitative physiological monitoring. This chapter reviews the various features of the physiological response that can be monitored using functional magnetic resonance imaging (fMRI), and then discusses quantitative models linking physiology and MRI-visible physical parameters. MRI offers several extremely attractive strengths that play an important role in the study of brain physiology as well as clinical practice. The chapter covers the basic physical principles involved in magnetic resonance imaging of cerebral blood flow (CBF), cerebral blood volume (CBV) and cerebral blood oxygenation, and then shows how these measurements can be incorporated into biophysical models that, in conjunction with physiological calibration procedures, can be used to estimate relative changes in the oxygen utilization rate of brain tissue. These techniques can also be used for comparing values of physiological parameters across different brain regions. Finally, the chapter shows that the challenge of measuring dynamic CBV changes while retaining the ability to monitor BOLD signal levels and flow must be overcome, and provides a solution to this problem.
Statistical analysis of activation images
Authors: Worsley Keith J.
Published: April 2012

Statistical analysis is concerned with making inference about underlying patterns in data that often contain a large amount of random error. This chapter begins by building up a model of the functional magnetic resonance imaging (fMRI) data, and discusses the haemodynamic response to the stimulus and then the random error. It deals with estimating the parameters of these models, assessing their variability and making decisions about whether the fMRI data shows any evidence of a blood oxygenation level dependent (BOLD) response to the stimulus. The chapter discusses in detail the methods for estimating both the signal and noise parameters, and also analyses the question of how to optimally design the experiment in order for the data to contain the maximum possible amount of extractable information.
Evolution of the Dorsal Muscles of the Spine in Light of Their Adaptation to Gravity Effects
Authors: Jouffroy Françoise K.
Published: April 2012

The function and morphology of the neck muscles are the outcome of a long evolutionary process that was started approximately 500 million years ago with jawless-headed, bilaterally symmetric and aquatic animals. Vertebrates are distinct from other animals by their possession of an internal, flexible axial structure and a single nerve cord running dorsally along its axial supporting structure. The major evolutionary trends of vertebrate morphology were correlated with the basic ecologic changes that vertebrates experienced. As living organisms are biologic entities comprised of integrated morphofunctional systems interacting with the environment, adaptation needs correlated with changes of all parts. However, it appears that the changing environment restrictions influenced the respiratory and locomotor systems.
Modeling of the Craniofacial Architecture during Ontogenesis and Phylogenesis
Authors: Dambricourt-Malassé Anne , Deshayes Marie-Josèphe
Published: April 2012

Clinical, paleontologic, and ontogenetic data manifest that throughout the development of primates, morphogenesis is at all times closely related to the neurocranium and the face. Now, only in man can we find a hint to understanding the fundamental principle of cranial ontogenesis from the embryonic period to senescence. A comparative analysis of the data shows that a particular ontogenetic craniofacial diagnosis exists for each primate species. This mirrors a basic phenomenon known as craniofacial contraction, developed on the craniofacial biodynamics theory. This chapter discusses the biomechanical craniofacial relationships in living primates. Next, it will discuss the paleontologic applications and implications for comprehending the evolutionary process of hominoids.
The Absence of a True Head-Neck in Decapod Crustaceans: Consequences for Orientation and Equilibration
Authors: Bévengut Michelle , Neil Douglas M.
Published: April 2012

All animals have a requirement for orientation, defined by Schone as an ability to relate the movement and position of the body and body parts to spatial cues. The processes of orientation compose the perception of the spatial relationship, the establishment of a preferred position in space, and the maintenance or change of position in space. The physical parameters of space are common for all animals. Those most widely involved in determining orientation are the substrate, the light distribution, and the gravity field. Other factors include the patterning of the visual environment, which drives optomotor and optokinetic reactions, and inertial effects linked with body movements, the best famous example of which is the action of vertebrate semicircular canals.
Comparison of Head Movement Strategies among Mammals
Authors: Fuller James H.
Published: April 2012

In this chapter, a variety of saccadic eye-head movements evoked by visual and auditory stimuli are reviewed. Variation in head movement strategies resulting from methodology as well as the subject's own biases are considered alongside factors already known to affect eye-head movements. Search strategies are compared in different tasks. First, in the relatively simple situation in which the head is immobilized; second, in the more complicated situation when the head is free to move. The variables of movement amplitude and sensory modality are compared at the same time. In the studies of Guitton and Volle as well as Bizzi et al., saccadic latency was majorly affected by the predictability of the fixation-saccade interval and the saccade amplitude and direction.
Heterogeneous Structure and Function among Intervertebral Muscles
Authors: Richmond Frances J. R. , Gordon David C. , Loeb Gerald E.
Published: April 2012

Historically, the research on head movement has emphasized the central mechanisms ruling the neck motoneurons activity. In the last decade, however, new knowledge about neck muscles has led to an increasing awareness that muscle properties also affect how these motoneurons must be recruited to achieve the needed head movements. Individual muscles differ in their cross-sectional areas and pulling directions, and they also contain different proportions of fast and slow fiber types and have highly specialized patterns of fiber architecture and motor unit distribution. All these must be taken into consideration when trying to comprehend the neural control of the head movement.
Suppression of Cervical Afferents Impairs Visual Cortical Cells Development
Authors: Buisseret Pierre
Published: April 2012

The visual experience of a kitten does not solely depend on what is actually seen. It also depends on how the kitten moves to look around. Recent studies show that the functional development of a cat's visual cortex requires some nonretinal signal linked to gaze movements. The exact nature and origin of these signals remain subject to investigation. The first developmental studies of the visual cortex showed that almost any type of visual input restriction between the third and twelfth postnatal week induced specific changes to the receptive field properties of visual cortical neurons, and that a return to normal rearing conditions before completion of this critical period could cancel the effects of the restriction.
Intrinsic Properties of Neck Motoneurons
Authors: Rose P. Kenneth
Published: April 2012

Neck motoneurons, like their counterparts at other levels of the spinal cord, are the final destination of tens of thousands of axon terminals. Identification of the sources of these axon terminals and characterization of the information that their parent axons transmit have been the main objectives of most studies concerned with the control of head movement. This focus is not surprising since a detailed comprehension of neural circuitry is a crucial prerequisite for a better understanding of the control of head movement. The emphasis of motoneuron connectivity can be misleading because it suggests that the activity of motoneurons is solely a consequence of the origin and timing of the signals received by motoneurons.
Examination of the Descending Projections of the Vestibular Nuclei Using Anterograde Transport ofPhaseolus vulgarisLeukoagglutinin
Authors: Donevan Anne Y. H. , Neuber-Hess Monica , Rose P. Kenneth
Published: April 2012

The vestibular system is known to play a significant role in the control of head movement. Electrophysiologic studies have proven that neck motoneurons receive monosynaptic connection from the vestibular nuclei via two descending pathways: the lateral vestibulospinal tract (LVST) and the medial vestibulo spinal tract (MVST) are differentiated by their course through the brain stem and spinal cord. The LVST follows a lateral route in the brain stem and travels in the ventrolateral funiculus of the spinal cord, whereas the MVST courses in the medial longitudinal fasciculus in the brain stem and travels in the ventromedial function of the spinal cord. The purpose of this chapter is to identify the inconsistencies in current accounts of vestibulospinal projection and to describe the results of recent studies in which Phaseolus vulgaris leukoagglutinin was used to examine vestibulospinal projections in the cat.
Vestibular Nerve Inputs to Vestibulospinal and Vestibulo-ocular Neurons of the Squirrel Monkey
Authors: Boyle Richard , Goldberg Jay M. , Highstein Stephen M.
Published: April 2012

Some vestibular nerve afferents have a regular spacing of action potentials; in others, the space is irregular. Fibers first classified as regularly or irregularly discharging also differ in their response dynamics to rotational stimuli. Among canal afferents, the responses of regular fibers parallel angular head velocity, whereas those of irregular afferents are more phasic and show a high-frequency gain enhancement together with a phase advance. Consider the vestibulo-ocular (VOR) and vestibulocollic (VCR) reflexes. The VOR is an open-loop reflex controlling a predominantly viscous load. The VCR is closed loop, the load is largely inertial, and neck muscles are more sluggish than are extraocular muscles.
Eye Movement–Related Activity in the Vestibulo-ocular and Vestibulocollic Pathways in the Cat
Authors: Iwamoto Yoshiki , Kitama Toshihiro , Yoshida Kaoru
Published: April 2012

In recent years, the vestibular system has been implicated not only in the reflex movements produced by labyrinthine inputs but also in the control of active motor behaviors, especially eye and head movements during gaze. This chapter discusses the experimental proof pertaining to the functional organization of vestibulo-ocular and vestibulo-oculo-collic pathways, with focus on recent researches of the signals carried by secondary vestibular neurons on the vertical canal systems. The synaptic organization of the vestibulo-ocular reflex (VOR) and vestibulocollic reflex (VCR) pathways stemming from the semicircular canals have been extensively studied and the fundamental patterns of excitatory and inhibitory connections with specific canal-muscles relationships have been well established. Although excitatory connections from the anterior involve the pathways through the deep reticular formations in the cat, the major part of the excitatory pathways ascend in the contralateral medial longitudinal fasciculus (MLF), and the inhibitory pathways in the ipsilateral MLF.
The Superior Colliculus and Head Movements in the Cat
Authors: Abrahams Vivian C. , Downey E. Dawne , Kori Adriana A.
Published: April 2012

There seems to be little doubt that the superior colliculus of the cat plays a crucial role in head movement. The proof comes largely from a single kind of experiment in which the superior colliculus is stimulated electrically and occasionally chemically. The movements that stimulation generates have long been regarded as close to natural movement. Some believe that stimulating the tectum and protectum led to the animals executing turning movements, and gave to them the term, “visual-grasp reflex.” The experiments by Apter were on anesthetized cats. In this case, crystals of strychnine were place on the exposed superior colliculus. The application of the crystals first caused an increase in the visual evoked potential.
Properties of Eye and Head Movements Evoked by Electrical Stimulation of the Monkey Superior Colliculus
Authors: Segraves Mark A. , Goldberg Michael E.
Published: April 2012

On monkeys and cats, microstimulation of the superior colliculus evokes gaze movements containing both eye and head movement components. The superficial layers of the superior colliculus in these species contain a simple point-to-point representation of the retina. This retinotopic map is parallel with a movement activity map in the intermediate layers produced by neurons that are stimulated before and during saccades of specific amplitude and direction. Early reports of electrical stimulation of the monkey's superior colliculus with the head restrained focused on the correspondence of sensory and motor maps, finding that the trajectories of saccadic eye movements evoked by electrical stimulation, depended mainly upon the location of the stimulation site, with the eyes' orbital position having only a very slight effect upon the amplitude and direction of the evoked eye movement.
Role of the Tectoreticulospinal System in the Coordination of Eye-Head Orienting Movements
Authors: Munoz Douglas P. , Guitton Daniel , Pélisson Denis
Published: April 2012

Orienting movements, which direct the visual axis to a new target of interest, often involve combined eye and head displacements. As a consequence of the mechanical limits in ocular motility, a target located beyond these limits (oculomotor range) can only be fixated by means of coordinated eye-head motion that generates a single-step saccade-like gaze shift. This dependence on eye-head coupling is especially prevalent in the cat. The eye and head segments of an orienting gaze shift are tightly connected in the cat, suggesting the presence of a strong common drive to both eye and head premotor circuits. Among possible candidates, the superior colliculus has been identified as a significant brain stem center involved in the control of the orientation.
Multiple Control Mechanisms Contribute to Functional Behaviors of the Head and Neck
Authors: Keshner Emily A. , Peterson Barry W.
Published: April 2012

Head stability is achieved through a convergence of reflex, voluntary, and biomechanical factors. Each of these mechanisms has distinct kinematic and dynamic characteristics that must be coordinated during production of normal movement patterns. An analysis of complex motor systems, such as the head and neck, should aid in revealing how the central nervous system combines and integrates these distinct control mechanisms. The frequency-related and spatial characteristics of each of these mechanisms suggest that command parameters during normal activity are not preprogrammed but dependent upon task constraints. The chapter discusses how the spatial organization of the neck muscles is altered to allow load changes during an isometric stabilization task.
Gaze Movements: Patterns Linking Latency and Vestibulo-ocular Reflex Gain
Authors: Zangemeister Wolfgang H. , Stark Lawrence
Published: April 2012

Gaze is defined as the coordinated sum of eye and head movements and gaze position is the position of the eye in space, while eye position is the position of the eye in the orbit. In this chapter, the authors discuss how several causal factors (protocol conditions including desired gaze amplitude and pathologic situations including reduced inclination to move the head in hemianopia) influence the selection of a gaze mode despite statistical selection. The results of the methods employed in this study show that there is a strong connection between the gaze type as defined by relative latency of eye and head movement and the VOR gain and gaze amplitude. It is also evident that some motor brain mechanism organizes a relative latency between head and eye movement.
Eye-Head Coordination: Direction-Specific Differences of Horizontal Saccades Executed Toward or Opposite in Direction to Concurrent Head Motion
Authors: Krafczyk Siegbert , Paulus Walter , Brandt Thomas
Published: April 2012

In this chapter, the modification of saccades executed during active head or passive body rotation is investigated. An experimental setup was designed, which confined saccades to populations with amplitudes less than 30°. It was found out that due to the nonlinear relationship of amplitude and peak velocity of saccades and a constant contribution of the head rotation velocity, the gaze analysis will show different velocity profiles because of the different saccades types. There are also two proposed mechanisms to explain the duration decrease of about 30% for the total amplitude range studies. The first one is that the saccadic burst rate is changed by superimposing the VOR activity on it. The second is that the saccadic burst modifies an ongoing eye movement.
Significance of Muscle Proprioceptive and Vestibulospinal Reflexes in the Control of Human Posture
Authors: Trippel Michael , Horstmann Gerhard A. , Dietz Volker
Published: April 2012

The vestibular system plays an important role in the stabilization of human stance. The purpose of this study is to clarify which receptors and mechanisms are involved in the regulation of posture. The changes in several biomechanical parameters affected by perturbation of the support surface are analyzed, as well as their correlation to the behavior of EMG responses generated by the leg muscles. The significance of the proprioceptive reflex mechanisms is discussed in detail in this chapter. The findings of the study suggested that the vestibular system plays the major role in the compensation of small destabilizing impulses imposed to the back of a subject. This would help to compensate the body sway before a significant stretch of the leg muscles takes place.
Different Patterns in Aiming Accuracy for Head-Movers and Non-Head Movers
Authors: Bard Chantal , Fleury Michelle , Paillard Jacques
Published: April 2012

This study aims to sharpen the evaluation of the role of head position in accuracy of aiming and encoding the target location. An aiming task was performed in order to provide a precise measure of directional errors. The errors are assumed to the encoding of gaze direction and to the head and eye signals. The pure aiming task helped in the analysis of the direction and amplitude components in the programming of an aiming reaction. The study focuses on the need to take into consideration the division into subgroups of the population with different reaction modes and strategies.
Clinical and Experimental Investigations of Visually Guided Eye and Head Movement: Role of Neck Afferents
Authors: Maeda Minoru
Published: April 2012

This study focuses on the abnormalities of gaze control in posttraumatic cervical syndrome, and the eye-head coordination test for patients with such a syndrome. The intracellular recording from abducens and dorsal neck motoneurons and tectal neurons is discussed here, as well as the eye-head coordination in patients with posttraumatic cervical syndrome and focal lesions in the superior colliculus. The main finding is that posttraumatic cervical syndrome includes several factors, and that it is difficult to determine the symptoms of the derangement of neck structure. The results show that there is both excitatory and inhibitory cervical afferent input into the tectofugal pathways to the abducens and neck motoneurons.