Motor Nervous Systems Research Articles

Body Balance Analysis in the Visually Impaired Individuals Aged 18-24 Years.

Proper body balance is maintained by both sensory, i.e., vision, hearing, vestibular, and proprioception, and motor nervous systems. Visual control facilitates balance both in a static position, as well as during movement. Visual dysfunctions can adversely affect balance and stability control. The study comprised a group of 30 individuals visually impaired from birth aged 18-24 years. The control group consisted of 50 persons in the same age range as the study group. The trial was performed as four separate tests: two on a stable surface platform, and two on an unstable surface platform. No statistically significant differences were found in the posturography test on the stable platform between the study groups. When tested on an unstable ground surface, the visually impaired subjects obtained showed worse performance than the sighted persons. Statistically significant differences were observed in the majority of the analyzed results. Visually impaired individuals present a poorer ability to maintain balance under dynamic conditions. Tests conducted on the unstable surface platform seem to be more relevant and applicable in the diagnosis of the subjects with visual impairment, as they differentiate the subjects to a greater extent.

Phase advancing is a common property of multiple neuron classes in the mouse retina.

Behavioral interactions with moving objects are challenged by response latencies within the sensory and motor nervous systems. In vision, the combined latency from phototransduction and synaptic transmission from the retina to central visual areas amounts to 50–100 ms, depending on stimulus conditions. Time required for generating appropriate motor output adds to this latency and further compounds the behavioral delay. Neuronal adaptations that help counter sensory latency within the retina have been demonstrated in some species, but how general these specializations are, and where in the circuitry they originate, remains unclear. To address this, we studied the timing of object motion-evoked responses at multiple signaling stages within the mouse retina using two-photon fluorescence calcium and glutamate imaging, targeted whole-cell electrophysiology, and computational modeling. We found that both ON-type and OFF-type ganglion cells, as well as the bipolar cells that innervate them, temporally advance the position encoding of a moving object and so help counter the inherent signaling delay in the retina. Model simulations show that this predictive capability is a direct consequence of the spatial extent of the cells’ linear visual receptive field, with no apparent specialized circuits that help predict beyond it.

Neuromorphic Skin Based on Emerging Artificial Synapses

AbstractNeuromorphic skin is an emerging electronic skin that demonstrates sensory, memory, learning, and motor responses in a neuromorphic way by using advanced artificial synaptic devices that emulate the biological nervous system and its neural plasticity. Many types of artificial synapses that emulate brain‐inspired computing have been developed and are being integrated in electronic skin to demonstrate artificial sensory and motor nervous systems. The neuromorphic skin, which operates using voltage spikes thereof, precisely mimics the energy‐efficient information processing of biological nervous system in the brain and body and enables the implementation of power‐ and time‐efficient cognitive sensors and computing, biomimetic robotics and electronics, and biocompatible neuroprosthetics. Here, biological synapses and emerging artificial synapses are introduced, and recent research is reviewed on neuromorphic skins that use artificial synapses for sensing, memory, learning, and motor systems. Finally, the outlook and challenges to be addressed are provided for future advanced neuromorphic skin in which all neuromorphic parts are integrated with brain‐inspired computing and bioinspired robotics.

Sympathomimetics regulate quantal acetylcholine release at neuromuscular junctions through various types of adrenoreceptors

The studies of the interaction between the sympathetic and motor nervous systems are extremely relevant due to therapy for many neurodegenerative and cardiovascular disorders involving adrenergic compounds. Evidences indicate close contact between sympathetic varicosities and neuromuscular synapses. This raises questions about the effects of catecholamines on synaptic transmission. The currently available information is contradictory, and the types of adrenoreceptors responsible for modulation of neurotransmitter release have not been identified in mammalian neuromuscular synapses. Our results have shown that the α1A, α1B, α2A, α2B, α2C, and β1 adrenoreceptor subtypes are expressed in mouse diaphragm muscle containing neuromuscular synapses and sympathetic varicosities. Pharmacological stimulation of adrenoreceptors affects both spontaneous and evoked acetylcholine quantal secretion. Agonists of the α1, α2 and β1 adrenoreceptors decrease spontaneous release. Activation of the α2 and β1 adrenoreceptors reduces the number of acetylcholine quanta released in response to a nerve stimulus (quantal content), but an agonist of the β2 receptors increases quantal content. Activation of α2 and β2 adrenoreceptors alters the kinetics of acetylcholine quantal release by desynchronizing the neurosecretory process. Specific blockers of these receptors eliminate the effects of the specific agonists. The action of blockers on quantal acetylcholine secretion indicates possible action of endogenous catecholamines on neuromuscular transmission. Elucidating the molecular mechanisms by which clinically utilized adrenomimetics and adrenoblockers regulate synaptic vesicle release at the motor axon terminal will lead to the creation of improved and safer sympathomimetics for the treatment of various neurodegenerative diseases with synaptic defects.

Assessment of CSP-based two-stage channel selection approach and local transformation-based feature extraction for classification of motor imagery/movement EEG data.

The main idea of brain-computer interfaces (BCIs) is to facilitate the lives of patients having difficulties to move their muscles due to a disorder of their motor nervous systems but healthy cognitive functions. BCIs are usually electroencephalography (EEG)-based, and the success of the BCIs relies on the precision of signal preprocessing, detection of distinctive features, usage of suitable classifiers and selection of effective channels. In this study, a two-stage channel selection and local transformation-based feature extraction are proposed for the classification of motor imagery/movement tasks. In the first stage of the channel selection, the channels were combined according to the neurophysiological information about brain functions acquired from the literature, then averaged and a single channel was formed. In the second stage, selective channels were specified with the common spatial pattern-linear discriminant analysis (CSP-LDA)-based sequential channel removal. After the channel selection phase, the feature extraction was carried out with local transformation-based methods (LTBM): local centroid pattern (LCP), one-dimensional-local gradient pattern (1D-LGP), local neighborhood descriptive pattern (LNDP) and one-dimensional-local ternary pattern (1D-LTP). The distinctions and deficiencies of these methods were compared with other methods in the literature and the classification performances of the k-nearest neighbor (k-NN) and the support vector machines (SVM) were evaluated. As a result, the proposed methods yielded the highest average classification accuracies as 99.34%, 95.95%, 98.66% and 99.90% with the LCP, 1D-LGP, LNDP and 1D-LTP when using k-NN, respectively. The two-stage channel selection and 1D-LTP method showed promising results for recognition of motor tasks. The LTBM will contribute to the development of EEG-based BCIs with the advantages of high classification accuracy, easy implementation and low computational complexity.

Organic Synapses for Neuromorphic Electronics: From Brain-Inspired Computing to Sensorimotor Nervetronics.

Living organisms have a long evolutionary history that has provided them with functions and structures that enable them to survive in their environment. The goal of biomimetic technology is to emulate these traits of living things. Research in bioinspired electronics develops electronic sensors and motor systems that mimic biological sensory organs and motor systems and that are intended to be used in bioinspired applications such as humanoid robots, exoskeletons, and other devices that combine a living body and an electronic device. To develop bioinspired robotic and electronic devices that are compatible with the living body at the neuronal level and that are operated by mechanisms similar to those in a living body, researchers must develop biomimetic electronic sensors, motor systems, brains, and nerves. Artificial organic synapses have emulated the brain's plasticity with much simpler structures and lower fabrication cost than neurons based on silicon circuits, and with smaller energy consumption than traditional von Neumann computing methods. Organic synapses are promising components of future neuromorphic systems. In this Account, we review recent research trends of neuromorphic systems based on organic synapses, then suggest research directions. We introduce the device structures and working mechanisms of reported organic synapses and the brain's plasticity, which are mainly imitated to demonstrate the learning and memory function of the organic synapses. We also introduce recent reports on sensory synapses and sensorimotor nervetronics that mimic biological sensory and motor nervous systems. Sensory nervetronics can be used to augment the sensory functions of the living body and to comprise the sensory systems of biomimetic robots. Organic synapses can also be used to control biological muscles and artificial muscles that have the same working mechanism as biological muscle. Motor nervetronics would impart life-like motion to bioinspired robots. Chemical approaches may provide insights to guide development of new organic materials, device structures, and working mechanisms to improve synaptic responses of organic neuromorphic systems. For example, organic synapses can be applied to electronic and robotic skins and bioimplantable medical devices that use mechanically stable, self-healing, and biocompatible organic materials. Biochemical approaches may expand the plasticity of the brain and nervous system. We expect that organic neuromorphic systems will be vital components in bioinspired robotic and electronic applications, including biocompatible neural prosthetics, exoskeletons, humanoid soft robots, and cybernetics devices that are integrated with biological and artificial organs.

THE BRAIN-COMPUTER INTERFACE

The Brain-Computer Interface (BCI), defined as systems that allow people to use a computer, an electromechanical arm or various neuroprostheses without the use of motor nervous systems, is a communication pathway used to establish direct communication between the brain and a peripheral interface. The brain-computer interface is often used to help or repair human cognitive or sensory motor functions. However, with today's developing technology, it hasn’t only been used for this purpose and has started to be used in many different areas from advertising, to smart peripheral systems, to games, even authentication and security applications. The increase in access to BCI devices, together with the increase in their usage, has led to an increase in the number of applications that have been developed in health, engineering, and education. We hope that in the near future BCI devices will allow us to communicate without talking and will understand our thoughts and act accordingly.

A simple machine vision-driven system for measuring optokinetic reflex in small animals

The optokinetic reflex (OKR) is useful to monitor the function of the visual and motor nervous systems. However, OKR measurement is not open to all because dedicated commercial equipment or detailed instructions for building in-house equipment is rarely offered. Here we describe the design of an easy-to-install/use yet reliable OKR measuring system including a computer program to visually locate the pupil and a mathematical procedure to estimate the pupil azimuth from the location data. The pupil locating program was created on a low-cost machine vision development platform, whose graphical user interface allows one to compose and operate the program without programming expertise. Our system located mouse pupils at a high success rate (~90%), estimated their azimuth precisely (~94%), and detected changes in OKR gain due to the pharmacological modulation of the cerebellar flocculi. The system would promote behavioral assessment in physiology, pharmacology, and genetics.

General pharmacological studies on pepleomycin sulfate (NK 631) (author's transl)

Pharmacological actions of pepleomycin sulfate (NK 631) which is a new antitumor agent derived from bleomycin were studied and the following results were obtained. NK 631 had no significant influences on the central, motor and sensory nervous systems at relatively higher doses (5 approximately 10 mg/kg, i.v., i.p., s.c.). NK 631 (5 approximately 10 mg/kg, i.v.) caused a slight decrease in blood pressure in anesthetized rats and slight increases in blood pressure, heart rate and peripheral blood flow in anesthetized dogs. NK 631 (1 approximately 3 mg) given close-arterially caused a slight increase in the developing tension in the isolated blood-perfused papillary muscle. NK 631 slightly contracted the isolated guinea pig ileum and rat uterus but did not affect the contraction of isolated guinea pig trachea. NK 631 caused significant increases in urine output and Cl excretion in saline loaded rats at 20 mg/kg, i.p. By the local injection of NK 631, a slight edema of rat paw and an increase in rabbit cutaneous permeability were observed. The intraperitoneal injection of NK 631 caused a significant increase in leakage of dye injected intravenously into the peritoneal cavity of mice. NK 631 did not affect hemolysis and prothrombin time at 10(-4) g/ml. In pharmacological actions, significant differences between NK 631 and pepleomycin were not observed.

Electromyography of pelvic floor muscles

Pelvic floor muscles (PFM) are intimately involved in function of lower urinary tract, the anorectum and sexual functions, therefore their neural control transcends the primarily important somatic innervation of striated muscle, as they are directly involved in “visceral activity”. Neural control of pelvic organs is affected by a unique co-ordination of somatic and autonomic motor nervous systems. Visceral and somatic sensory fibres supply sensory information from pelvic organs; their input influences through central integrative mechanisms also pelvic floor muscle activity. Anatomically, somatic afferent and efferent nerves of the sacral cord segments, reflexly integrated at the spinal cord and brainstem level, conduct neural control of PFM. The inputs from several higher centres influence the complex reflex control and are decisive for voluntary control, and for socially adapted behaviour related to excretory functions.

Age-related different expression patterns of the regulator of G protein signaling RGS9 protein in the rat sensory and motor nervous systems: An immunohistochemical study

Age-related different expression patterns of the regulator of G protein signaling RGS9 protein in the rat sensory and motor nervous systems: An immunohistochemical study

A purposely designed neural signal amplifier for short interval stimulation and recording microneurography using a common electrode

‘Common Electrode’ microneurography (i.e. stimulating a nerve and recording return afferent neural activity through the same microelectrode facilitates investigation of linkages between sensory and motor nervous systems in humans. Currently there is no commercial product designed specifically to conduct common electrode microneurography experiments. However, such experiments would advance investigations in several key areas including spinal injury research. In this paper, we report on the successful production and testing (on a human subject) of an integrated amplifier built specifically for this purpose. The amplifier was built using commercially available components to allow for both easy and economical manufacture. In particular, we report on the design requirements and outline our chosen design solutions. The amplifier handles low-level neural signals amidst large 50 Hz interference, with protection against potentially high stimulation voltages of over 100 V dc, with minimal cross-coupling of rapid stimulus pulses onto the high gain amplifier's input, and a short ‘blocking’ time between stimulation and recording. The amplifier also includes necessary filters, selectable gains and internal stimulator triggering circuits to provide a simple, integrated solution for common electrode operation on human subjects.

Ubiquitin immunoreactivity in the midbrain as a marker of stress to motor nervous systems in fatal injury

Previous studies showed an increase in the ubiquitin (Ub)-immunoreactive structures in the midbrain in acute deaths from asphyxiation and in fires in adult subjects. The present study examined the Ub-immunoreactivity in the midbrain as a marker of stress to motor nervous systems in fatal injury cases (over 35 years of age, n=140: blunt injuries, n=82; sharp injuries, n=58), compared with that in control groups ( n=61) including death by strangulation, acute cardiac and cerebrovascular diseases. The intranuclear Ub-immunopositive inclusion of the pigmented dopaminergic neurons of the substantia nigra (inclusion Ub-index) and the granular ‘dot-like’ Ub-immunoreactivity area (‘dot-like’ Ub-area) in the crus cerebri were analyzed. In blunt injuries, those markers were high in abdomen and back injuries and low in head and chest injuries. The inclusion Ub-index was higher in the crush/pressure injury group than in those with injuries due to impact traffic accidents and falls. ‘Dot-like’ Ub-area was also low in falls. In sharp injury cases, cardiac injury with hemopericardium showed a higher inclusion Ub-index. These findings suggested that the stress to the motor nervous system may be very intense in crush/pressure injury and hemopericardium than in impact injury and fatal hemorrhages, respectively, and in abdomen and back injuries than in head and chest injuries.

Ubiquitin-immunoreactive structures in the midbrain of methamphetamine abusers

Ubiquitin (Ub) is involved in neurodegeneration and various stress responses in the brain. The present study investigated the Ub-immunoreactive structures in the midbrain of methamphetamine (MA) abusers as a marker of drug-induced neurodegeneration. Medico-legal autopsy cases were examined: fatal MA intoxication ( n=14), other fatalities of MA abusers ( n=23) including those due to injuries, asphyxiation, drowning, fire and natural diseases, and control groups ( n=260). In the motor nervous systems, MA abusers showed a mild increase in the diffuse-type nuclear Ub-positivity in the pigmented neurons of the substantia nigra, depending on the blood MA level and irrespectively of the immediate causes of death. The intranuclear inclusion-type Ub-positivity of the nigral neurons and the granular ‘dot-like’ Ub-immunoreactivity area in the crus cerebri (cortico-spinal tracts) were usually low in MA abusers, and any increases were related to the immediate causes of death and the age of subjects. Acute MA fatality showed a higher neuronal Ub-positivity in the midbrain periaqueductal gray matter (PGM), which is involved in processing pain, fear and anxiety, and regulation of respiration and circulation. These findings suggest dysfunction of the nigral dopaminergic neurons and PGM neurons in the midbrain in MA abuse, which may account for the clinical symptoms.

Anatomy and Neurocontrol of the Pelvic Floor

Neural control of pelvic organs is affected by a unique coordination of somatic and autonomic motor nervous systems. Sensory information and feedback is supplied by both visceral and somatic sensory fibers. The anatomical features of the pelvic floor and perineal muscles, and their innervation are described. Altogether more detailed information is known in humans on the peripheral innervation as compared to the central nervous system centers and connections of pelvic organ neurocontrol. Controversies in regional neuroanatomy are explained. Reports on individual variability and asymmetry – the former particularly with methods revealing structures, and the latter with functional methods – are interesting but need further validation.

Intragenic deletion in the gene encoding ubiquitin carboxy-terminal hydrolase in gad mice.

The gracile axonal dystrophy (gad) mouse is an autosomal recessive mutant that shows sensory ataxia at an early stage, followed by motor ataxia at a later stage. Pathologically, the mutant is characterized by 'dying-back' type axonal degeneration and formation of spheroid bodies in nerve terminals. Recent pathological observations have associated brain ageing and neurodegenerative diseases with progressive accumulation of ubiquitinated protein conjugates. In gad mice, accumulation of amyloid beta-protein and ubiquitin-positive deposits occur retrogradely along the sensory and motor nervous systems. We previously reported that the gad mutation was transmitted by a gene on chromosome 5 (refs 10,11). Here we find that the gad mutation is caused by an in-frame deletion including exons 7 and 8 of Uchl1, encoding the ubiquitin carboxy-terminal hydrolase (UCH) isozyme (Uch-l1) selectively expressed in the nervous system and testis. The gad allele encodes a truncated Uch-l1 lacking a segment of 42 amino acids containing a catalytic residue. As Uch-l1 is thought to stimulate protein degradation by generating free monomeric ubiquitin, the gad mutation appears to affect protein turnover. Our data suggest that altered function of the ubiquitin system directly causes neurodegeneration. The gad mouse provides a useful model for investigating human neurodegenerative disorders.

Distribution and role of aspartate in the nervous system of the chaetognath Sagitta.

Cholinergic control of locomotory muscles in chaetognaths is monitored by diffuse transmitter release through layers of collagen fibers that form the connective stratum of the hydroskeleton. Despite the lack of morphologically defined synaptic junctions, the control of locomotor activity in chaetognaths is highly specific and allows complex behavioral patterns. This complexity suggests the existence of neuromediators acting to modulate the effects of the main motor neurotransmitter, acetylcholine, on muscular contraction. Immunocytochemical investigations performed in Sagitta friderici by using antibodies directed against L-aspartate revealed the presence of the amino acid within abundant fiber networks regularly distributed in the head, trunk, and tail and within discrete groups of cell bodies. In addition to known components of the sensory and motor nervous systems, L-aspartate immunoreactivity revealed previously undescribed intraepidermal networks of axonal profiles. With the exception of two giant anterior fibers radiating from the ventral ganglion, L-aspartate-immunoreactive processes were usually thin and varicose, occasionally making an anastomosis. As indicated by electron microscopy, L-aspartate-immunoreactive varicosities apposed to the connective stratum were filled with synaptic-like vesicles but displayed no synaptic differentiation. Physiologic investigations suggested a potent inhibitory effect of L-aspartate on acetylcholine-induced muscle contraction. The wide distribution pattern of immunoreactive profiles suggests an important role of L-aspartate in motor and sensory functions in chaetognaths. Although classified among excitatory amino acids in vertebrates, aspartate may function as an inhibitory modulator of acetylcholine-induced muscle contraction in these enterocoelous gastroneuralians.

Neuropeptides in the nematodeAscaris suum

Most of the successful anti-nematode drugs currently available affect the nematode locomotory system. Their success is due to their interactions with molecules associated with the main neuro-transmitters of the motor nervous system, acetylcholine and GABA. These drugs tend to have a relatively broad spectrum of action, affecting a wide variety of nematodes, presumably because nematode motor nervous systems are conservative in their use of these transmitters.

Adaptive neural oscillator using continuous-time back-propagation learning

A neural network model of temporal pattern memory in animal motor systems is proposed. First, the network receives an external oscillatory input with some desired wave form, then, after sufficient learning, the network autonomously oscillates in the previously given wave form. The network has three layers. Each of the units is a continuous-time continuous-output model neuron, which is not oscillatory by itself. The wave form of the autonomous oscillation is memorized in the connecting weights between the units. The back-propagation learning algorithm is modified and applied to the continuous-time recurrent networks. The abilities of the network and the learning algorithm are examined by computer simulations. Studies on such artificial neural oscillators will be helpful in understanding the roles of complex synaptic connections between the motorneurons and the interneurons observed in the motor nervous systems of animals.

Evaluation of upper-limb function by the sensor pegboard test method.

Man moves his hands and arms to create things. These movements may be constructed as activities to change the environment favourably. Such movements result from co-ordinated control of the musculoskeletal system, by the hierarchical central nervous system. Man develops his working ability through learning, evaluation of the co-ordinated working ability of the highly advanced motor and sensory central nervous systems in addition to the ability to conduct a series of simple movements may produce valuable results which could be helpful in evaluating finger working ability. The sensor pegboard test method was developed in this study. The upper-limb motions of the subjects as they perform various specified tasks are measured and evaluated at the micromotion level (micromotion is defined here as the smallest motion element that can be distinguished with the sensor pegboard). This method can produce immediate results, which are not obtainable by conventional time and motion study methods, and can evaluate many a...