bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Head-Neck System of the BlowflyCalliphora:1. Anatomic Organization of Neck Muscles, Motoneurons, and Multimodal and Visual Inputs
Authors: Strausfeld Nicholas J. 
Published: April 2012

AbstractInsects offer highly accessible model systems for the study of neural integration and the design of circuits underlying compensatory and voluntary orbital movement. One advantage of such circuitry is that it is simpler in design than in an animal that can move its head and eyes separately. The two eyes of an insect are part of its exoskeleton and their major excursions in the horizontal and vertical planes are conjugate. This chapter tackles the skeletal and neuromuscular organization of the head-neck system in Calliphora erythrocephala, outlines its major sensory neurons and interneurons, and predicts the functional organization of the system by connecting the organization of retinitopic visual neurons to specific neck muscle pathways.
Control of Gaze in Salamanders
Authors: Manteuffel Gerhard 
Published: April 2012

AbstractStudies of amphibian gaze control stems back to the 1930s and 1940s, when Birukow and Sperry investigated the optokinetic reflex in anurans and newts. In these initial researches, they discovered such fundamental properties as the unidirectionality of nystagmus under monocular vision. Birukow found the rostral in the frog Rana temporaria and presented indirect proof of the presence of an optokinetic after-reaction abolishing vestibular after-nystagmus. On the basis of optic nerve regeneration, Sperry found that retinal position and velocity signals rule the direction of gaze movements, even after functionally inadequate regeneration. Main visual relays in the control of optokinetic nystagmus are situated in the pretectum and the accessory optic nucleus. Vertical directional preferences in the accessory optic system and horizontal directional selectivity corroborate the lesion results.
Development of the Vertebral Joints (C3 through T2) in Man
Authors: Putz Reinhard 
Published: April 2012

AbstractThe wide range of literature on the primary development of the vertebral column is mainly concerned with the vertebral bodies and the intervertebral disks. The earliest conclusive document of the reorganization of the vertebral column was given by Sensenig. Tondury focused himself majorly on the time and order of appearance of the centers of ossification in the vertebrae, and the fusion of the neural arches with the bodies. It was Verbout who finally provided a clear view of the definitive segmentation of the elements of the vertebral column. Regarding clinical literature, a huge amount of work exists on the functional interpretation of the vertebral joints, which are referred as the “guide rails of movement.”
Head-Trunk Coordination and Locomotor Equilibrium in 3-to 8-Year-Old Children
Authors: Assaiante Christine , Amblard and Bernard 
Published: April 2012

AbstractThirty-six healthy normal children from three to eight years of age joined in this experiment. Six age groups of six children each were formed. The subjects were asked to walk normally on flat ground on a straight line drawn on flat ground or on a beam. Each of these locomotory tasks was made twice according to pseudorandom plan, so that for a particular task, the results of two trials with each subject could be averaged. The kinematics of the locomotor movements was analyzed through an optical automatic TV image processor. Three markers were arranged on a frame fixed to the subject's left shoulder to calculate positions and orientations of the trunk. The last marker was placed on the ankle joint in order to monitor stepping.
Relationship between Force and Cross-Sectional Area of Postcervical Muscles in Man: Influence of Variations in the Morphology of the Neck
Authors: Mayoux-Benhamou Marie-Anne , Wybier Marc , Barbet Jacques Patrick , Labbé Sylvain , Revel Michel 
Published: April 2012

AbstractNeck muscles have both dynamic and static functionalities, since they move the head in all directions and since they also have a postural role as antagonists of gravity. The static function depends on the strength and endurance of these muscles. The spine is a single weight-bearing column, and it depends solely upon muscular strength for both its lateral and its anteroposterior stabilization. The normal curvature observed in the sagittal plane is constantly subject to gravitational torques, which tends to increase lordosis and cause the head to fall forward. The neck muscles must work against these two effects of gravity. Calculating the absolute force given by neck muscles in static situations needs an accurate knowledge of forces present and of lever arms involved.
Multidimensional Geometry Intrinsic to Head Movements around Distributed Centers of Rotation: A Neurocomputer Paradigm
Authors: Pellionisz Andáas J. , Goff Bertrand Le , Laczkó Jozsef 
Published: April 2012

AbstractNeuroscience has increasingly polarized during the past decade. The narrowly focused searchlight targeted at the domain of microscopic components unmasked small details. As a result, molecular neurobiology has prospered. In turn, system neuroscience underwent a re-evaluation of its scope, its mathematical methods, and even its philosophical and theoretical foundation. The direction in which this broad searchlight should be targeted in order to illuminate overall neural net function has been questioned. A trend toward clarification has only recently started to unfold, under intense pressure from technologic implications in the quickly developing field of microcomputing. Research on neurocomputing aspects of gaze may thus significantly contribute to a rejuvenation of system neuroscience as it meets some important challenges.
Vestibular and Optokinetic Asymmetries in the Ocular and Cervical Reflexes
Authors: Pettorossi Vito E. , Errico Pierangelo , Ferraresi Aldo , Draicchio Francesco , Santarelli Rosa Maria , Bruni Rosa 
Published: April 2012

AbstractAsymmetries of the vertical optokinetic reflex (VOKR) and the vertical vestibulo-ocular reflex (VVOR) have been observed in many species. Gains of upward OKR slow phases were higher than those of downward OKR slow phases. An upward preponderance was also observed in the VVOR of cats. This difference between upward and downward eye responses has been shown to be largely affected by gravity. Gravity also affects the VVOR response because the animals should be pitched around the interaural axis to a 90-degree incline to reveal such vertical vestibular asymmetry. In this condition, the vertical canals were stimulated without activating the otolithic receptors since the direction of gravity's action on the maculae was constant.
Cervicovestibular Interactions in Coriolis-Like Effects
Authors: Bles Willem , Bos Jelte E. 
Published: April 2012

AbstractHuman cervical mechanisms are very deeply connected to the vestibular system, and the contribution of the neck reflexes in postural control is mostly hidden. Consequently, neck reflexes are a subject of minor interest in neurology; clinical practice does not provide methodology to evaluate the contribution of the neck. However, because of the increasing number of patients with cervical ataxia due to acceleration trauma, research on the topic of cervicovestibular interactions is needed in order to find a methodology to sort out the contribution of the neck and the vestibular system in postural control. As a first approach to this research field, the authors did two pilot studies on horizon perception in healthy subjects.
Head Position versus Head Motion in the Inhibition of Horizontal Postrotary Nystagmus
Authors: Koenig Eberhard , Dengler Wilhelm , Fetter Michael , Hann Asta , Dichgans Johannes 
Published: April 2012

AbstractA tilt from the prior erect position to a horizontal head position stimulates not only the otoliths but also the vertical semicircular canals and neck afferents. To clarify further the inputs needed for inhibition, the authors compared static head tilts having only one dynamic component with head movements giving predominantly dynamic components. In addition, intermittent head tilts of different durations and at different times after the stop were used to study the dynamics of the “dumping” process. Head tilts after the presumed end of the peripheral input were used to study whether the effect of the inhibitory stimulus changes in the absence of peripheral input from the horizontal semicircular canals.
Organization of the Motor Nuclei Innervating Epaxial Muscles in the Neck and Back
Authors: Sugiuchi Yuriko , Shinoda Yoshikazu 
Published: April 2012

AbstractThe epaxial muscles are axial muscles innervated by the dorsal rami of the spinal nerves. These muscles demonstrate continued action in such a way as to counteract gravity in a decerebrate preparation, and thus they are classified as physiologic extensors. The epaxial muscles, neck muscles in particular, are under the strong influence of long descending motor tracts, especially the vestibulospinal and reticulospinal tracts, and play a significant role in control of postures in standing, in locomotion, and even during voluntary movements of extremities. A relatively small phylogenetic change of the epaxial musculature has occurred from the lower vertebrates to the mammals, as compared with the striking phylogenetic transformation of the hypaxial musculature among vertebrates.
Electrophysiology and Pharmacology of Two Types of Neurons in the Medial Vestibular Nucleus and Nucleus Gigantocellularis of the Guinea Pig In Vitro
Authors: Serafin Mauro , Khateb Asaid , Waele Catherine De , Vidal Pierre Paul , Mühlethaler Michel 
Published: April 2012

AbstractThe importance of intrinsic membrane properties in shaping the firing pattern of neurons in the mammalian central nervous system is well recognized. Despite a significant literature in vivo, neither the vestibular system nor the reticulospinal systems have yet been investigated in this respect. It is of interest to identify whether such neurons are endowed with complex intrinsic properties, because they might play a crucial role in some aspects of sensory-motor transformations. The authors restricted themselves to neurons either of the medial vestibular nucleus (MVN) or the nucleus gigantocellularis (NCG). The latter were documented in an area situated above the inferior olive that is known to contain mostly reticulospinal neurons.
Spatial Innervation Patterns of Single Vestibulospinal Axons in Neck Motor Nuclei
Authors: Shinoda Yoshikazu , Ohgaki Tohru , Sugiuchi Yuriko , Futami Takahiro 
Published: April 2012

AbstractEye and head position control is an ideal paradigm for studying how central nervous system mechanisms interact to stabilize a multidimensional motor system. Head movement signals detected by the semicircular canals are mediated through vestibulo-ocular and vestibulocollic pathways that line each of the three semicircular canals to a set of eye and head muscles. For tasks needing compensatory eye and head movements, the central nervous system will program muscles to respond in particular combinations rather than to generate an infinite variety of muscle contraction patterns. Single unit recording in animals engaging in motor behavior made it possible to analyze temporal and quantitative aspects of neuronal activities in different parts of the CNS with regard to various movement parameters.
Single Vestibular Unit Recordings in the Alert Cat during Active and Passive Head Movements
Authors: Fuller James H. 
Published: April 2012

AbstractRecordings of single neurons in conscious animals started over three decades ago. In unrestrained animals, this activity was documented extracellularly and the recorded neuron was referred to as a “single unit.” Shortly after, single units were recorded in sensory-motor areas of the brain in which timing was often used to differentiate motor from sensory neuronal activity. If a cell's firing rate was systematically modified and tightly coupled to a short interval before the onset of the movement, it was assumed to be linked with motor activity. If it started after movement and/or synchronized with the leading edge or onset of a stimulus, it was assumed to be linked with sensory events.
Reticulospinal Control of Head Movements in the Cat
Authors: Sasaki Shigeto 
Published: April 2012

AbstractWhen a new object appears in the periphery of the visual field, animals direct their head and eyes to it (orienting movements). Movements of the head play a critical role in the orienting movements, especially in animals such as cats, in which the range of oculomotor movements is restricted. The superior colliculus and frontal oculomotor areas have been shown to be in involved in the control of orienting movements. Stimulations of the tectum and the cerebral peduncle have been shown to evoke disynaptic excitatory postsynaptic potentials (EPSPs) in neck motoneurons in cats. The tectal and pyramidal EPSPs are mediated by common relay neurons in the lower brain stem.
Contribution of Reticulospinal Neurons to the Dynamic Control of Head Movements: Presumed Neck Bursters
Authors: Grantyn Alexey , Berthoz Alain , Hardy Olivier , Gourdon Antoine 
Published: April 2012

AbstractThis chapter only deals with the immediate premotor neuronal organization of this coordination at the level of the brain stem. It is known that the activity of the superior colliculus contributes to the initial saccade and the head movement. The afferent collicular neurons of the crossed tectoreticulospinal pathways activate a network of neurons in the brain stem that produces the premotor neuronal signals. It is well established that the signals that are carried by descending tectoreticulospinal neurons (TRSNs) are mainly phasic bursts. It is discussed that their firing rate is related to either eye velocity or dynamic motor error signals.
Control of Vertical Head Movement via Forel's Field H
Authors: Isa Tadashi , Itouji Toru , Sasaki Shigeto 
Published: April 2012

AbstractReticulospinal neurons (RSNs) in the medial pontomedullary reticular formation have been suggested as being the relay station of the disynaptic pathways from the superior colliculus and the cerebral cortex to the dorsal neck motoneurons. A unilateral lesion of the nucleus reticularis pontis caudalis (NRPC) and the rostral part of the nucleus reticularis gigantocellularis (NRG) produced by kainic acid injection resulted in a severe impairment of ipsiversive orienting movements of the eyes and head in the horizontal direction. This suggests that this region plays a vital role in controlling horizontal orienting movement. However, vertical orienting movement appeared to be unfazed after the lesion, suggesting that it is regulated by separate pathways.
Role of the Lateral Mesencephalic Reticular Formation in the Control of Head Movements
Authors: Hardy Olivier , Mirenowicz Jacques 
Published: April 2012

AbstractIt is possible to consider that there are two types of combined eye and head movements involved in two behavioral strategies. In one, the objective of slow eye movements is to compensate head movements. For that aim, the eyes move in the direction opposite to head turning, stabilizing the visual world on the retina. In the second strategy, the eyes and the head rapidly move in the same direction in order to orient the gaze toward a visual stimulus or a particular direction of space but without any strict fixation constraint. Compared to the former, the rapid eye movement can be characterized as anticompensatory because the eyes move in the same direction as the head.
Brain Stem Control of Coordinated Eye-Head Gaze Shifts
Authors: Tomlinson R. David , Bance Manohar 
Published: April 2012

AbstractRecent experiments have proven that the vestibulo-ocular reflex (VOR) does not simply sum with vestibular eye movement commands during combined eye-head gaze saccades. Instead, if VOR gain is measured during combined eye-head gaze shifts, the gain is found to be a function of amplitude, decreasing from near unity during small-amplitude saccades to near zero at large amplitudes. In spite of this observation, large-amplitude saccades remain precise even if the head is perturbed during the movement. Since the VOR is not functional during these perturbed saccades, the eye trajectory does not change in response to this perturbation. Instead, the maintenance of saccadic accuracy is made by the changes in the movement duration.
Non-linear Dynamics of Involuntary Head Movements
Authors: Goldberg Jefim 
Published: April 2012

AbstractThis chapter discusses the sensory-motor origins of involuntary head movements. These movements can be regarded as a continuous sequence of deviations and succeeding corrections effected by sensory-motor mechanisms. This is important in the maintenance of static equilibrium in the vertical posture. The concept of pendulum models of equilibrium dynamics is also discussed in this chapter. It is used to represent the whole-body equilibrium in the upright posture. This model belongs to the general class of second-order dynamic systems. Moreover, the spectral analysis of involuntary head movements is also employed in this chapter. Utilizing the Fourier spectral methods, the head movement is decomposed into a sum of sinusoidal components of different frequencies and amplitudes. Based on the discussion of results, it is concluded that quantitative analysis of movement behaviors would provide a more useful measure of understanding dynamic properties than Fourier methods or other methods.
Active Head Movement Analysis of Vestibulo-ocular Reflex Dynamics
Authors: OʼLeary Dennis P. , Davis Linda L. 
Published: April 2012

AbstractThe primary role of the vestibulo-ocular reflex (VOR) is to stabilize the eyes for clear vision throughout angular eye movements. Another alternative approach to VOR testing at higher frequencies is to use active head oscillations in which a rotational sensor attached to a head strap would monitor head movement. This method needs the use of a computer and other technology in its implementation. In this chapter, the use of active head oscillations for VOR testing is reviewed in laboratories. Previous research on active head movements are also presented in the chapter. These previous studies employed active head movements at frequencies both below and above 2 Hz with an earth-fixed visual target. Certain physiologic considerations in using active head movements in place of passive chair rotations are also clarified in this chapter. The methods, test protocol, and data acquisition and analysis in VOR testing are sequentially explained. Meniere's disease is also briefly discussed.
Effect of Freeing the Head on Eye Movement Characteristics during Three-Dimensional Shifts of Gaze and Tracking
Authors: Collewijn Han , Steinman Robert M. , Erkelens Casper J. , Pizlo Zygmunt , Steen Johannes Van Der 
Published: April 2012

AbstractThis chapter considers the primary method used in studying the binocular control of gaze while an unrestrained subject viewed close target objects. Also presented here is the first comparative analysis of two types of oculomotor performance: performance in a head-free condition versus performance in a “bite board” (head fixed condition). The subjects made saccades between two stationary targets and tracked a target that moved both in a lateral direction and in depth. This chapter also shows that head-free saccades are faster than saccades made using the head on a bite board, and head-free three-dimensional pursuit does not differ significantly from the pursuit with the head on a bite board. This work has concluded that it is feasible to record binocular gazed behaviors in unrestrained subjects. Another conclusion is that the performance of oculomotor control is excellent in generally natural conditions.
Coordination of Head and Eyes during the Performance of Natural (and Unnatural) Visual Tasks
Authors: Kowler Eileen , Pizlo Zygmunt , Zhu Guo-Liang , Erkelens Casper J. , Steinman Robert M. , Collewijn Han 
Published: April 2012

AbstractAccording to Lashley, the key in achieving coordinated patterns of action was to program diverse motor responses with reference to a single, central spatial map and a single internal clock. This chapter studies the coordinated head and eye movements during natural and unusual performance of visual tasks, and the results of the investigations in scanning the unusual head-eye movement combinations. Three characteristics were revealed regarding the normal coordination of head and eye movements. The first one is that moving the head can increase saccades rate. The second is that the ability to perform unusual patterns of head and eye movements is different during a task with clear cognitive components than during less natural tasks when the observer tries to direct the eye to an eccentric target without cognitive significance. Lastly, there is a natural tendency to program head and eye movements concurrently in similar spatial and temporal patterns.
Gaze Saccades to Visual Targets: Does Head Movement Change the Metrics?
Authors: Becker Wolfgang , Jürgens Reinhard 
Published: April 2012

AbstractIn this chapter, the authors addressed the question of the degree to which gaze saccades executed under natural conditions are modulated by concomitant head movements by creating a “quasi-natural” situation. Head-fixed saccades were compared to head-free saccades. The first experiment in this study cannot prove or disprove the validity of Bizzi's classical summation hypothesis for human gaze saccades confined to the oculomotor range. It rather demonstrates that the presence of a classical VOR is irrelevant for the velocity of such gaze saccades since the concurrent head movement starts too late and is too slow to impart to the saccade a significant gain in velocity in the event of a disconnected VOR. The second experiment confirms that the factor of greater importance for the dynamics of head-free saccades is the orbital eccentricity and direction of the EiH contribution to saccades.
Eye-Head Coordination During Active and Passive Head Rotations in the Dark
Authors: Schmid Roberto , Zambarbieri Daniela 
Published: April 2012

AbstractVestibular nystagmus is believed to be related to a strategy of eye-head coordination aimed to quickly orient the gaze toward a point of interest. This was suggested by Melvill Jones in 1964. Thus, in order to give further support for the interpretation of vestibular nystagmus, the authors compared eye-head coordination during active and passive head rotations in the dark by adopting similar profiles of head movement. The experiments involved subjects that were seated in the dark wearing lightweight helmets with lamps. The subjects were advised to slowly orient their heads to a position while the profiles of their head movements were recorded. The results in this study support the hypothesis that the orienting saccades observed during active head rotation is of the same nature with the fast phases of vestibular nystagmus evoked by passive rotation.
Identification of Peripheral Visual Images in a Laterally Restricted Gaze Field
Authors: Semmlow John L. , Gauthier Gabriel M. , Vercher Jean-Louis 
Published: April 2012

AbstractThe study in this chapter aims to assess the effects of degraded peripheral vision on visual performance. A series of preliminary psychological experiments were conducted to evaluate identification task performance in unrestricted viewing conditions in terms of the required time to identify a peripherally located three-digit number. This study is inspired by the case of decreased performance and discomfort of patients wearing corrective lenses with distorted peripheral fields. The experiments in the study involve three subjects whose head and eye movements were simultaneously recorded using an infrared reflection technique and an ultrasonic head movement monitor, respectively. A block diagram of a model to represent the task of identifying eccentric targets during restricted peripheral vision is constructed in this chapter. It is concluded that identification of peripheral targets when peripheral vision is restricted requires a coordinated and precise motor response from head and eyes.