bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pain in spinal cord injury
Authors: Berić Aleksandar 
Published: April 2012

AbstractSustaining 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

AbstractFunctional 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

AbstractThis 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

AbstractRecent 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

AbstractStatistical 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

AbstractThe 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

AbstractClinical, 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

AbstractAll 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

AbstractIn 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

AbstractHistorically, 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

AbstractThe 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

AbstractNeck 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

AbstractThe 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

AbstractSome 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

AbstractIn 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

AbstractThere 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

AbstractOn 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

AbstractOrienting 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

AbstractHead 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

AbstractGaze 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

AbstractIn 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

AbstractThe 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

AbstractThis 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

AbstractThis 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.
Strategies of the Eye-Head Orientation in Human Infants Related to Cognitive Development
Authors: Roucoux Marguerite , Culée Christine 
Published: April 2012

AbstractYoung infants can orient themselves toward visual targets by means of eye saccades and head movements. In this study, a population of “at-risk” infants is tested for visual preferences to evaluate the significance of a behavioral examination for such a population. A control population of fifty normal infants was also examined. It is concluded that the test of visual preferences discriminates the control group and the at-risk group after five months of age. The results have shown that there are different capabilities in selective visual discrimination for at-risk and control infants. The differences in responses just reflect the differences in later intellectual abilities.