Study objectives:The injection of cholinergic drugs in the pons has been largely used to induce REM sleep as a useful model to study different processes during this period. In the present study, microinjections of carbachol in the nucleus reticularis pontis oralis (NRPO) were performed to test the hypothesis that eye movements and the behavior of extraocular ...

Study Objectives:The aim of this work was to characterize eye movements and abducens (ABD) motoneuron behavior after cholinergic activation of the nucleus reticularis pontis caudalis (NRPC).Methods:Six female adult cats were prepared for chronic recording of eye movements (using the scleral search-coil technique), ...

Oculomotor control neurons in awake, intact cats, with neurons identified through antidromic excitation is studied. Abducens motoneurons, abducens interneuron, tonic eye-position neurons, onmidirectional pause neurons, and miscellaneous types were identif...

Extraocular muscle tension associated with spontaneous eye movements has a pulse-slide-step profile similar to that of motoneuron firing rate. Existing models only relate motoneuron firing to eye position, velocity and acceleration. We measured and quantitatively compared lateral rectus muscle force and eye position with the firing of ...

Extraocular muscle tension associated with spontaneous eye movements has a pulse-slide-step profile similar to that of motoneuron firing rate. Existing models only relate motoneuron firing to eye position, velocity and acceleration. We measured and quantitatively compared lateral rectus muscle force and eye position with the firing of ...

The pattern of axonal terminations of individual premotoneuronal medium lead burst neurons (MLBs) has been elucidated with the help of the intraaxonal recording and horseradish peroxidase injection technique in alert behaving monkeys. These findings indicate that individual MLBs do not influence individual muscles; instead they influence groups of muscles. Horizontal medium lead burst neurons ...

Rubral projections to retractor bulbi motoneurones were investigated by intracellular recording in the accessory abducens nucleus in the cat. Their post-synaptic effects were compared with those of trigeminal afferent pathways. Post-synaptic potentials evoked by stimulation of the contralateral red nucleus were predominantly excitatory, with latencies in ...

Monocular organization of the goldfish horizontal neural integrator was studied during spontaneous scanning saccadic and fixation behaviors. Analysis of neuronal firing rates revealed a population of ipsilateral (37%), conjugate (59%), and contralateral (4%) eye position neurons. When monocular optokinetic stimuli were employed to maximize disjunctive horizontal eye movements, ...

... underlying wriggling and swimming. The number of motoneuron impulses and the duration of the burst in each ... underlying most vertebrate locomotor patterns includes multiple motoneuron impulses per cycle...

Motoneurons in the primate oculomotor nucleus can be divided into two categories, those supplying twitch muscle fibers and those supplying nontwitch muscle fibers. Recent studies have shown that twitch motoneurons lie within the classical oculomotor nucleus (nIII), and nontwitch motoneurons lie around the borders. Nontwitch ...

Eye movements, ponto-geniculo-occipital (PGO) waves, muscular atonia and desynchronized cortical activity are the main characteristics of rapid eye movement (REM) sleep. Although eye movements designate this phase, little is known about the activity of the oculomotor system during REM sleep. In this work, we recorded binocular eye movements by the scleral search-coil technique and the activity of ...

Proper movement of the vertebrate eye requires the formation of precisely patterned axonal connections linking cranial somatic motoneurons, located at defined positions in the ventral midbrain and hindbrain, with extraocular muscles. The aim of this research was to assess the relative contributions of intrinsic, population-specific properties and extrinsic, outgrowth ...

In the preceding series of articles, the history of vertebrate motoneuron and motor unit neurobiological studies has been discussed. In this article, we select a few examples of recent advances in neuroscience and discuss their application or potential application to the study of motoneurons and the control of movement. We conclude, like Sherrington, that ...

Lesions of the brain stem can either affect the nuclei or the fascicles of the third, fourth or sixth cranial nerves and thus produce ocular motor disorders. Lesions of the oculomotor nuclear complex differ from lesions of the third nerve, since the motoneurones in the nucleus are specifically grouped. Similarly, a lesion of the sixth nerve nucleus results in a conjugate gaze ...

The AP-1 family transcription factor ATF2 is essential for development and tissue maintenance in mammals. In particular, ATF2 is highly expressed and activated in the brain and previous studies using mouse knockouts have confirmed its requirement in the cerebellum as well as in vestibular sense organs. Here we present the analysis of the requirement for ATF2 in CNS development in mouse embryos, ...

The AP-1 family transcription factor ATF2 is essential for development and tissue maintenance in mammals. In particular, ATF2 is highly expressed and activated in the brain and previous studies using mouse knockouts have confirmed its requirement in the cerebellum as well as in vestibular sense organs. Here we present the analysis of the requirement for ATF2 in CNS development in mouse embryos, ...

Motoneurons in most organisms conserve a division into low-threshold and high-threshold types that are responsible for generating powerful and precise movements. Drosophila 1b and 1s motoneurons may be analogous to low-threshold and high-threshold neurons, respectively, based on data obtained at the neuromuscular junction, although there is little ...

Retrograde transport of horseradish peroxidase (HRP) after its application into the orbit was used to investigate the development of the different ocular motor nuclei in larvae of the sea lamprey (Petromyzon marinus) and to identify their regions of origin. In the smallest larvae studied (10-19 mm in length), the oculomotor and abducens neurons were ipsilateral to the site of ...

To analyze properly the role of the cerebellum in classical conditioning of the eyeblink and nictitating membrane (NM) response, the control of conditioned response dynamics must be better understood. Previous studies have suggested that the control signal is linearly related to the CR as a result of recruitment within the accessory abducens motoneuron ...

The sensory and motor control of eye muscles are considered in this chapter. Eye muscles differ from skeletal muscles in several ways. One is the absence of muscle spindles and Golgi tendon organs in the eye muscles of some species, and their poor development in others. Second, eye muscles have an inner 'global layer', and the outer 'orbital layer', each containing different types of muscle fiber. ...

An excitatory synaptic potential in a local nonspiking interneuron of a locust is able to effect the release of chemical transmitter. The consequence is that a discrete inhibitory synaptic potential is evoked in an identified postsynaptic motoneuron. These local interactions between interneurons and motoneurons are of behavioral ...

Recent studies from our group have demonstrated the existence of a disynaptic excitatory cortico-motoneuronal (CM) pathway in macaque monkeys via propriospinal neurons in the midcervical segments. Results from behavioral studies with lesion of the direct pathway suggest that the indirect CM pathway can mediate the command for dexterous finger movements.

neurons mediating its output to the trigeminal motoneurons. Next, we will discuss the neurochemical basis for rhythmical trigeminal motoneuron activity as well as central masticatory rhythm generation. Mastication the branches of the trigeminal nerve innervating the jaw-closing and jaw-opening muscles. The rhythmical nerve

command? Because motoneurons are restricted to in- nervating the extraocular muscles, a primary function been compared with those of extraocular mo- toneurons over a broad frequency range sufficient-BT responses with those of other premotor cell types and extraocular motoneurons, tak- ing advantage of both

Whole-cell patch clamp recordings of miniature inhibitory postsynaptic currents (mIPSCs) were obtained in identified abducens motoneurons (aMns) from young rats (P5-P13). Three types of mIPSC were distinguished according to their kinetics and their sensitivity to receptor antagonists: faster decaying events mediated by glycine receptors (glyRs), slower ...

The ability of animals to carry out their normal behavioral repertoires requires exquisitely precise matching between specific motoneuron subtypes and the muscles they innervate. However, the molecular mechanisms that regulate motoneuron subtype specification remain unclear. Here, we use individually identified zebrafish primary ...

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease of unknown cause, characterized by the selective and progressive death of both upper and lower motoneurons, leading to a progressive paralysis. Experimental animal models of the disease may provide knowledge of the pathophysiological mechanisms and allow the design and testing of therapeutic strategies, ...

The central histaminergic nervous system, originating from the tuberomammillary nucleus of the hypothalamus, widely innervates almost the whole brain as well as the spinal cord. However, the effect of histamine on spinal motoneurons, the final common path for motor control, is still unknown. By using 8-14-day-old rat spinal slice preparations and intracellular recordings, the ...

The dopamine system plays an integral role in motor physiology. Dopamine controls movement by modulation of higher-order motor centers (e.g., basal ganglia) but may also regulate movement by directly controlling motoneuron function. Even though dopamine cells synapse onto motoneurons, which themselves express dopamine receptors, it is unknown whether ...

The mammalian oculomotor nucleus receives a strong ?-aminobutyric acid (GABA)ergic synaptic input, whereas such projections have rarely been reported in fish. In order to determine whether this synaptic organization is preserved across vertebrates, we investigated the GABAergic projections to the oculomotor nucleus in the goldfish by combining retrograde transport of biotin dextran amine, injected ...

The mammalian oculomotor nucleus receives a strong ?-aminobutyric acid (GABA)ergic synaptic input, whereas such projections have rarely been reported in fish. In order to determine whether this synaptic organization is preserved across vertebrates, we investigated the GABAergic projections to the oculomotor nucleus in the goldfish by combining retrograde transport of biotin dextran amine, injected ...

Duane syndrome is a congenital eye movement disorder characterized most typically by absence of abduction, restricted adduction, and retraction of the globe on attempted adduction. Duane syndrome can be coinherited with radial ray anomalies as an autosomal dominant trait, referred to as �Okihiro syndrome� or �Duane radial ray syndrome� (DRRS). We ascertained three pedigrees with DRRS and ...

During postnatal development, profound changes take place in the excitability of nerve cells, including modification in the distribution and properties of receptor-operated channels and changes in the density and nature of voltage-gated channels. We studied here the firing properties of abducens motoneurons (aMns) in transverse brainstem slices from ...

The passive membrane properties of motoneurons may be affected in a behavior-specific manner because of differences in synaptic drive during different motor behaviors. To explore this possibility, the changes in input resistance (R(in)) and membrane time constant (tau(m)) of single extensor motoneurons were ...

The nucleus retroambiguus (NRA) is a group of neurons, located laterally in the caudal medulla oblongata. The NRA is thought to modulate abdominal pressure in the framework of respiration, vomiting, vocalization, probably parturition, and, in all likelihood mating behavior. The NRA exerts this control through its projections to motoneurons to the nucleus ...

Prairie voles (Microtus ochrogaster) are exceptional among rodents in that many aspects of their brain and behavior are not masculinized by exogenous aromatizable androgens. However, the sexually differentiated endpoints studied to date rely on estrogenic mechanisms in other mammals. We examined whether sexual differentiation of an androgen receptor-dependent sex difference ...

... penetrations into the abducens nucleus of the monkey: eye movement recordings and histopathological evaluation of the nuclei and lateral rectus ...

Despite their importance for deciphering oculomotor commands, the mechanics of the extraocular muscles and orbital tissues (oculomotor plant) are poorly understood. In particular, the significance of plant nonlinearities is uncertain. Here primate plant dynamics were investigated by measuring the eye movements produced by stimulating the abducens nucleus with brief pulse ...

Despite their importance for deciphering oculomotor commands, the mechanics of the extraocular muscles and orbital tissues (oculomotor plant) are poorly understood. In particular, the significance of plant nonlinearities is uncertain. Here primate plant dynamics were investigated by measuring the eye movements produced by stimulating the abducens nucleus with brief pulse ...

Recent work suggests that concurrent excitation and inhibition originating in central pattern generators (CPGs) may be used to control rhythmic motoneuronal activity. The specific roles that the inhibition plays in such cases are not well understood, however, in part due to the lack of identification of presynaptic inhibitory neurons. Here we demonstrate that, in the Aplysia ...

The classic 'size principle' of motor control describes how increasingly forceful movements arise by the recruitment of motoneurons of progressively larger size and force output into the active pool. We explored the activity of pools of spinal interneurons in larval zebrafish and found that increases in swimming speed were not associated with the simple addition of cells to ...

Recent work indicated that co-activity of different motoneurons (MNs) in the leech can be regulated through a network that is centered on a pair of nonspiking (NS) neurons. Here, we investigate whether this effect generalizes to different types of MNs that display differential co-activity patterns in different motor behaviors: the dorsal longitudinal ...

Despite substantial advances in the field, particularly resulting from physiological studies in animals, the neural mechanisms underlying the generation of many motor behaviors in humans remain unclear. A recent study (Cappellini G et al. J Neurophysiol 104: 3064-3073, 2010) sheds more light on this topic. Like the string of a violin, the ?-motoneuron ...

Stroke survivors often exhibit abnormal motoneuron excitability, manifested clinically as spasticity with exaggerated stretch reflexes in resting muscles. We examined whether this abnormal excitability is a result of increased activation of intrinsic voltage-dependent persistent inward currents (PICs) or whether it is a result of enhanced synaptic inputs to the ...

Because tongue position and stiffness help insure that the pharyngeal airspace is sufficiently open during breathing, the respiration-related behavior of the tongue muscles has been studied in detail, particularly during the last two decades. Although eight different muscles act upon the mammal tongue, we know very little about the respiration-related control of the majority ...

Storage of briefly presented information in ``working'' memory correlates with persistent firing in the brain. Persistent activity in response to transient stimulation is a form of neural temporal integration. Here, the mechanism of temporal integration was explored in the oculomotor velocity-to-position neural integrator (VPNI), where persistent activity is used to maintain eye position and ...

In vitro slice preparations of CNS tissue are invaluable for studying neuronal function. However, up to now, slice protocols for adult mammal spinal motoneurons�the final common pathway for motor behaviors�have been available for only limited portions of the spinal cord. In most cases, these preparations have not been productive due to the poor ...

The sigma-1 receptor regulates various ion channel activity and possesses protein chaperone function. Using an antibody against the full sequence of the sigma-1 receptor we detected immunostaining in wild type but not in knockout mice. The receptor was found primarily in motoneurons localized to the brainstem and spinal cord. At the subcellular level the receptor is restricted ...

... neurons in the paramedian pontine reticular formation, the vestibular nucleus, abducens nucleus, oculomotor nucleus, cerebellum, substantia nigra ...

We describe a patient with ophthalmoplegic migraine and right abducens nerve palsy, in whom serial magnetic resonance imaging showed a transient, gadolinium-enhancing lesion in the right lower pons, during both headache and the headache-free period. The enhancing linear lesion was felt to represent intraparenchymal fibers of the affected abducens nerve. ...

Abducens nerve palsies associated with infectious diseases are infrequent. Scrub typhus is an acute, febrile, infectious illness caused by Orientia tsutsugamushi (formerly Rickettsia tsutsugamushi), an obligate-intracellular gram-negative bacterium. The organism has been reported to be capable of entering the nervous system, causing meningitis and focal neurologic ...

For a given eye position, firing rates of abducens neurons (ABNs) generally (Mays et al. 1984), and lateral rectus (LR) motoneurons (MNs) in particular (Gamlin et al. 1989a), are higher in converged gaze than when convergence is relaxed, whereas LR and medial rectus (MR) muscle forces are slightly lower (Miller et al. 2002). Here, we confirm this finding ...

Intrinsic cellular properties of neurons in culture or slices are usually studied by the whole cell clamp method using low-resistant patch pipettes. These electrodes allow detailed analyses with standard electrophysiological methods such as current- or voltage-clamp. However, in these preparations large parts of the network and dendritic structures may be removed, thus preventing an adequate study ...

similar motoneurons in the tobacco hornworm, Manduca sexta. J Exp Biol 199: 775�791 Sherrington CS (1906 in the larval tobacco hornworm, Manduca sexta. J Comp Physiol A 160: 315�329 Wiel DE (1995) From behavior to synapses: habituation of the proleg withdrawal re�ex in the larval tobacco hornworm, Manduca sexta. Ph

Evidence for a Novel Bursting Mechanism in Rodent Trigeminal Neurons Christopher A. Del Negro-1568 USA ABSTRACT We investigated bursting behavior in rodent trigeminal neurons. The essential mechanisms. Bursting activity in trigeminal motoneurons is consistent with a traditional mechanism employing a region

to the bridging between brain and behavioral phenomena, from spinal control modules governing multi- joint of the descending pathways from higher motor centers to spinal motoneurons depends in part on the level at the Free University of Amsterdam that continues pre- vious work on polyrhythmic tapping (e.g., Peper, Beek

Damage to peripheral nerves results in substantial changes in the function of spinal synapses that mediate the monosynaptic reflex. These alterations consist independently of those caused by axotomy of the postsynaptic neuron and those produced by axotomy of the presynaptic neuron. Synaptic transmission is depressed following interruption of either limb of the segmental reflex loop. These ...

Orexin-A, synthesized by neurons of the lateral hypothalamus, helps to maintain wakefulness through excitatory projections to nuclei involved in arousal. Obvious changes in eye movements, eyelid position and pupil reactions seen in the transition to sleep led to the investigation of orexin-A projections to visuomotor cell groups to determine whether direct pathways exist that may modify visuomotor ...

In response to constant current inputs, the firing rates of motoneurons typically show a continuous decline over time. The biophysical mechanisms underlying this process, called spike-frequency adaptation, are not well understood. Spike-frequency adaptation normally exhibits a rapid initial phase, followed by a slow, later phase that continues throughout the duration of ...

Motor imagery (MI), a mental simulation of voluntary motor actions, has been used as a training method for athletes for many years. It is possible that MI techniques might similarly be useful as part of rehabilitative strategies to help people regain skills lost as a consequence of diseases or stroke. Mental activity and stress induce several different autonomic responses as part of the ...

Sep 30, 1999... motoneuron dysfunction in devastating neurodegenerative illnesses such as amyotrophic lateral sclerosis, and the design of therapies to ...

... the motoneuron excitability increases in a reflex pathway containing long delays. Descriptors : *SIMULATION, *REFLEXES, *MOTOR NEURONS ...

Spinal muscular atrophy (SMA) is a major genetic cause of death in childhood characterized by marked muscle weakness. To investigate mechanisms underlying motor impairment in SMA, we examined the spinal and neuromuscular circuitry governing hindlimb ambulatory behavior in SMA model mice (SMN?7). In the neuromuscular circuitry, we found that nearly all neuromuscular junctions ...

The spinal nucleus of bulbocavernosus (SNB) is a sexually dimorphic motor nucleus located in the anterior horn of the fifth and sixth lumbar segments of the spinal cord that plays a significant role in male sexual function. We recently found that a sexually dimorphic expression of gastrin-releasing peptide (GRP) in the lumbar spinal cord regulates male copulatory reflexes. Although it is reported ...

The abducens nerve usually travels from the brainstem to the lateral rectus muscle as a single trunk. However, it has been reported that this nerve could split into branches occasionally. We attempted to show the aberrant course of abducens nerve in a specimen with unilateral duplicated abducens nerve and review relevant literatures. ...

Control of posture and movement requires control of the output from motoneurons. Motoneurons of human lower limb muscles exhibit sustained, submaximal activity to high-frequency electrical trains, which has been hypothesized to be partly triggered by monosynaptic Ia afferents. The possibility to trigger such behavior in upper limb ...

A clival epidural hematoma is a rare lesion that usually develops after a hyperflexion or hyperextension injury of the neck, often in a child. A 5-year-old girl presented after a motor vehicle accident with multiple cranial neuropathies, including bilateral abducens nerve pareses and right facial, glossopharyngeal, and hypoglossal cranial nerve palsies. Neuroimaging identified ...

... were incubated for 3 hours in a 1% avidine-biotin complex (ABC: Streptavidin Biotin Complex Peroxidase kit, ... ...

Oscillations in the primary motor cortex are transmitted through the corticospinal track to the motoneuron pool. This pathway is believed to produce an effective and direct command from the motor cortex to the spinal motoneurons for the modulation of the force output. In this study, we used a computational model of a population of ...

The initiation, execution, and completion of complex locomotor behaviors are depending on precisely integrated neural circuitries consisting of motor pathways that activate muscles in the extremities and sensory afferents that deliver feedback to motoneurons. These projections form in tight temporal and spatial vicinities during development, yet the ...

Locomotion in segmented animals is thought to be based on the coupling of �unit burst generators�, but the biological nature of the unit burst generator has been revealed in only a few animal systems. We determined that dopamine (DA), a universal modulator of motor activity, is sufficient to activate fictive crawling in the medicinal leech, and can exert its actions within the smallest ...

The present findings show that the motor system of the carnivorous sea slug Pleurobranchaea californica consists of parallel, distributed, and interconnected neuronal channels by which motor activity may emerge from the dynamics of the system rather than from "switchboard" circuitry. The findings are shown primarily through the properties of the buccal-cerebral neurons (BCNs) that extensively ...

The interaction between motoneurons was studied in the isolated spinal cord of the fish (Cyprinus carpio) by the recording of elementary EPSPs evoked in a motoneuron by intracellular stimulation of adjacent motoneuron. These EPSPs are mediated mainly by electrical transmission as evidenced by their short or negligible latencies, stable ...

Network outputs elicited by a specific stimulus may differ radically depending on the momentary network state. One class of networks states�experience-dependent states�is known to operate in numerous networks, yet the fundamental question concerning the relative role that inputs and states play in determining the network outputs remains to be investigated in a behaviorally ...

Dynamic simulation of human eye movements, with realistic physical models of extraocular muscles (EOMs), may greatly advance our understanding of the complexities of the oculomotor system and aid in treatment of visuomotor disorders. In this paper we describe the first three dimensional (3D) biomechanical model which can simulate the dynamics of ocular motility at interactive rates. We represent ...

Locusts possess an identified neuron, the descending contralateral movement detector (DCMD), conveying visual information about impending collision from the brain to thoracic motor centers. We built a telemetry system to simultaneously record, in freely behaving animals, the activity of the DCMD and of motoneurons involved in jump execution. Cocontraction of antagonistic leg ...

The motor unit recruitment threshold and firing rate were evaluated during slow and fast contraction of the first dorsal interosseous (FDI) muscle by healthy young men. Using a special quadrifilar electrode myoelectric activity was recorded during voluntary isometric contraction. Motor unit action potentials (MUAPs) were decomposed into individual MUAP trains by the electromyography (EMG) signal ...

Speech production is one of the most complex and rapid motor behaviors and involves a precise coordination of over 100 laryngeal, orofacial and respiratory muscles. Yet, we lack a complete understanding of laryngeal motor cortical control during production of speech and other voluntary laryngeal behaviors. In recent years, a number of studies have ...

Synapses, as fundamental units of the neural circuitry, enable complex behaviors. The neuromuscular junction (NMJ) is a synapse type that forms between motoneurons and skeletal muscle fibers and that exhibits a high degree of subcellular specialization. Aided by genetic techniques and suitable animal models, studies in the past decade have brought ...

The transduction of synaptic activity to impulse generation is controlled by the active and passive properties of neurons. The voltage dependent conductances of cat motoneurons, as we understand them, are presented and related to repetitive firing behavior. Both outward potassium and inward calcium currents are activated in the subthreshold region. ...

Androgens have a variety of protective and therapeutic effects in both the central and peripheral nervous systems. Here we review these effects as they related specifically to spinal and cranial motoneurons. Early in development, androgens are critical for the formation of important neuromuscular sex differences, decreasing the magnitude of normally occurring cell death in ...

Despite general capacity of peripheral nervous system to regenerate, peripheral nerve injury is often followed by incomplete recovery of function and sometimes burdened by neuropathic pain. Amyloid precursor protein (APP) was suggested to play a role in neuronal growth, however, its role in peripheral nerve repair was not studied. The aim of this study was to examine the role of APP overexpression ...

Hsp26 belongs to the small heat-shock protein family and is normally expressed in all cells during heat stress. We aimed to determine if overexpression of this protein protects behavior and neural function in Drosophila melanogaster during heat stress, as has previously been shown for Hsp70. We used the UAS-GAL4 expression system to drive expression of Hsp26 in the whole ...

The review describes a model of vocal control, based mainly on research in the squirrel monkey, which consists of two hierarchically organized pathways. One runs from the anterior cingulate cortex via the periaqueductal gray (PAG) into the reticular formation of pons and medulla oblongata, and from there to the phonatory motoneurons. This pathway controls the readiness to ...

We study the integration of multisensory and central input at the level of an identified fly motoneuron, the ventral cervical nerve motoneuron (VCNM) cell, which controls head movements of the animal. We show that this neuron receives input from a central neuron signaling flight activity, from two identified wide-field motion-sensitive neurons, from the ...

Although most spinal cord injuries are anatomically incomplete, only limited functional recovery has been observed in people and rats with partial lesions. To address why surviving fibers cannot mediate more complete recovery, we evaluated the physiological and anatomical status of spared fibers after unilateral hemisection (HX) of thoracic spinal cord in adult rats. We made intracellular and ...

The proximal leg muscles of decapod crustaceans, controlling movements at the first two joints, are anatomically more complex than the better-studied distal leg muscles. Despite extensive research on their involvement in diverse behaviors, no complete descriptions of the anatomy and innervation of these muscles for any species have been published. We describe the anatomy and ...

Using combinations of H and T reflexes, spatial summation has been studied in the human soleus motoneurone pool. With certain assumptions, mathematical treatment of the results yielded estimates of the thresholds of motoneurones to monosynaptic activation by Ia nerve fibres. It was found that, on average, about 62 EPSPs were required to discharge a ...

Regulation of Intrinsic and Synaptic Properties of Neonatal Rat Trigeminal Motoneurons of neonatal rat trigeminal motoneurons using the broad- spectrum mGluR agonist (1S,3R)-1-amino-1 excitatory transmission to trigeminal motoneurons pr- esynaptically and postsynaptically via presynaptic

The size and phenotypic properties of the neural and muscular elements of the neuromuscular unit are

Previous studies have demonstrated that a chronic change in neuronal activation can produce a change

A phasic excitation-activation (PEXA) model is presented of the process of motoneuron excitation and

Anti-ganglioside antibodies have been associated with acquired neuropathies, including Guillain-Barr� syndrome. We describe a case of acute abducens nerve palsy acquired 2 weeks after symptoms of upper respiratory tract infection and rash in a 6-month-old. Elevated anti-GM2 ganglioside immunoglobulin M antibodies were detected in the serum. The palsy slowly improved over ...

BackgroundRhythmic behaviors, such as walking and breathing, involve the coordinated activity of central pattern generators in the CNS, sensory feedback from the PNS, to motoneuron output to muscles. Unraveling the intrinsic electrical properties of these cellular components is essential to understanding this coordinated activity. Here, we examine the ...

Motoneuron loss is a significant medical problem, capable of causing severe movement disorders and even death. We have previously demonstrated that partial depletion of motoneurons induces dendritic atrophy in remaining motoneurons, with a concomitant reduction in motor activation. Treatment of male rats with testosterone attenuates ...

The cell body sizes and succinate dehydrogenase (SDH) activities of motoneurons in the dorsolateral region of the ventral horn at the cervical and lumbar segments in the rat spinal cord were determined following 9 days of spaceflight with or without 10 days of recovery on Earth. The motoneurons were divided into three types based on their cell body sizes; ...

The sense of taste is crucial in an animal�s determination as to what is edible and what is not. This gustatory function is especially important in goldfish who utilize a sophisticated oropharyngeal sorting mechanism to separate food from substrate material. The computational aspects of this detection are carried out by the medullary vagal lobe which is a large, laminated structure combining ...

A mechanistic description of the generation of whisker movements is essential for understanding the control of whisking and vibrissal active touch. We explore how facial-motoneuron spikes are translated, via an intrinsic muscle, to whisker movements. This is achieved by constructing, simulating, and analyzing a computational, biomechanical model of the motor plant, and by ...

Ionic currents underlie the firing patterns, excitability, and synaptic integration of neurons. Despite complete sequence information in multiple species, our knowledge about ion channel function in central neurons remains incomplete. This study analyzes the potassium currents of an identified Drosophila flight motoneuron, MN5, in situ. MN5 exhibits four different potassium ...

Dopaminergic neurons play important behavioral roles in locomotion, reward and aggression. The Drosophila H-cell is a dopaminergic neuron that resides at the midline of the ventral nerve cord. Both the H-cell and the glutamatergic H-cell sib are the asymmetric progeny of the MP3 midline precursor cell. H-cell sib cell fate is dependent on Notch signaling, whereas H-cell fate ...