Artificial Reflex Arc Research Articles

Paraffin-Enabled Superlattice Customization for a Photostimulated Gradient-Responsive Artificial Reflex Arc.

The development of photostimulated-motion artificial reflex arcs - a neural circuit inspired by light-driven motion reflexes - holds significant promises for advancements in robotic perception, navigation, and motion control. However, the fabrication of such systems, especially those that accommodate multiple actions and exhibit gradient responses, remains challenging. Here, a gradient-responsive photostimulated-motion artificial reflex arc is developed by integrating a programmable and tunable photoreceptor based on folded MoS2 at different twist angles. The twisted folded bilayer MoS2 used as photoreceptors can be customized via the transfer technique using patternable paraffin, where the twist angle and fold-line could be controlled. The photoluminescence (PL) intensity is 3.7 times higher at a twist angle of 29° compared to that at 0°, showing a monotonically decreasing indirect bandgap. Through tunable interlayer carrier transport, photoreceptors fabricated using folded bilayer MoS2 at different twist angles demonstrate gradient response time, enabling the photostimulated-motion artificial reflex arc for multiaction responses. They are transformed to digital command flow and studied via machine learning to control the gestures of a robotic hand, showing a prototype of photostimulated gradient-responsive artificial reflex arcs for the first time. This work provides a unique idea for developing intelligent soft robots and next-generation human-computer interfaces.

Advanced Impacts of Nanotechnology and Intelligence

Fundamental contributions of nanotechnology include but are not limited to miniaturization, energy efficiency, higher efficiency and/or effectiveness. The exploration of new computing paradigms such as bioinspired computation and quantum computing belongs to the latter. Continuous advances in semiconductor technology include “more Moore” technology, which follows Moore's law of scaling, and “more than Moore” technology realized by hybrid integration with new materials. Much success appears in functionality and scaling in the fields of electronics, optics, sensors, and biomedical applications. In this article, we will show how one can further combine graphene, new 2D materials, and novel nanomaterials extending into the quantum realm that are at the cutting-edge of modern scientific and engineering research. This article demonstrates the impacts of nanotechnology and quantum computing including materials to devices, module demonstration, and the quantum era. In addition, a hybrid-transistor-based artificial reflex arc (ARA) and artificial pain modulation system (APMS) are discussed that illustrate future intelligent alarm systems, neuroprosthetics, and neurorobotics.

Cell Differentiation-Inspired, Salt-Induced Multifunctional Gels for an Intelligent Soft Robot with an Artificial Reflex Arc

To make soft robotics intelligent, dazzling artificial skin and actuators have been created. However, compared to rigid commercial robots, the sophisticated demands of raw materials become a key challenge for autonomous soft actuators to realize manufacturing repeatability and reproducibility. Inspired by the stem cell, which has the potential to differentiate into multifunctional cells with the same original compositions, a potential multifunctional gel is presented. With well-designed polymer chains, the gel has a salt-induced regulating module, conductivity, and other bionic properties. Making use of this advantage, the gel acts as a double-duty electrode for both the actuator and sensor. An artificial reflex arc is therefore formed by their tight integration via an e-brain: a computing unit that specifically responds to organism intervention. This efficient strategy to obtain diverse components with minimal raw materials is promising for effortlessly fabricating fully soft robotics.

Polarity‐Differentiated Dielectric Materials in Monolayer Graphene Charge‐Regulated Field‐Effect Transistors for an Artificial Reflex Arc and Pain‐Modulation System of the Spinal Cord

The nervous system is a vital part of organisms to survive and it endows them with remarkable abilities, such as perception, recognition, regulation, learning, and decision-making, by intertwining myriad neurons. To realize such outstanding efficacies and functions, many artificial devices and systems have been investigated to emulate the operating principles of the nervous system. Here, an artificial reflex arc (ARA) and artificial pain modulation system (APMS) are proposed to imitate the unconscious behaviors of the spinal cord. Gdx Oy - and Alx Oy -based charge-regulated field-effect transistors (CRFETs) with a monolayer graphene channel are fabricated and adopted as inhibitory and excitatory synapses, respectively, under the same pulse signals to mimic the biological reflex arc through a connection with a poly(vinylidene fluoride-co-trifluoroethylene)-based actuator. Additionally, a memristor is integrated with a CRFET as the interneuron to regulate the Dirac point by controlling the voltage drop on the graphene channel, analogous to the descending pain-inhibition system in the spinal cord, to prevent excessive pain perception. The proposed ARA and APMS provide a significant step forward to realizing the functions of the nervous system, giving promising potential for developing future intelligent alarm systems, neuroprosthetics, and neurorobotics.

An Artificial Reflex Arc That Perceives Afferent Visual and Tactile Information and Controls Efferent Muscular Actions.

Neural perception and action-inspired electronics is becoming important for interactive human-machine interfaces and intelligent robots. A system that implements neuromorphic environmental information coding, synaptic signal processing, and motion control is desired. We report a neuroinspired artificial reflex arc that possesses visual and somatosensory dual afferent nerve paths and an efferent nerve path to control artificial muscles. A self-powered photoelectric synapse between the afferent and efferent nerves was used as the key information processor. The artificial reflex arc successfully responds to external visual and tactile information and controls the actions of artificial muscle in response to these external stimuli and thus emulates reflex activities through a full reflex arc. The visual and somatosensory information is encoded as impulse spikes, the frequency of which exhibited a sublinear dependence on the obstacle proximity or pressure stimuli. The artificial reflex arc suggests a promising strategy toward developing soft neurorobotic systems and prostheses.

Artificial Reflex Arc: An Environment-Adaptive Neuromorphic Camouflage Device

Cephalopods can swiftly merge into the surroundings by changing their skin color even without the involvement of brains. Inspired by this ability, we designed a tunable, environment- adaptive camouflagic artificial reflex arc that can independently activate electrochromism in response to optical stimuli. The receptor of this arc consists in a light-stimulated synaptic transistor (LSST) that also performs synaptic functions, e.g., excitatory post-synaptic current (EPSC) generation, paired-pulse facilitation (PPF), high-pass filtering, and modulation. Amplified EPSC causes color transform of an electrochromic device (ECD) upon external optical stimuli. We emulate the phenomenon that an octopus changes color according to the background light with or without intentional modulation to demonstrate the camouflage effect of our device.

An Artificial Somatic Reflex Arc.

The emulation of human sensation, perception, and action processes has become a major challenge for bioinspired intelligent robotics, interactive human-machine interfacing, and advanced prosthetics. Reflex actions, enabled through reflex arcs, are important for human and higher animals to respond to stimuli from environment without the brain processing and survive the risks of nature. An artificial reflex arc system that emulates the functions of the reflex arc simplifies the complex circuit design needed for "central-control-only" processes and becomes a basic electronic component in an intelligent soft robotics system. An artificial somatic reflex arc that enables the actuation of electrochemical actuators in response to the stimulation of tactile pressures is reported. Only if the detected pressure by the pressure sensor is above the stimulus threshold, the metal-organic-framework-based threshold controlling unit (TCU) can be activated and triggers the electrochemical actuators to complete the motion. Such responding mechanism mimics the all-or-none law in the human nervous system. As a proof of concept, the artificial somatic reflex arc is successfully integrated into a robot to mimic the infant grasp reflex. This work provides a unique and simplifying strategy for developing intelligent soft robotics, next-generation human-machine interfaces, and neuroprosthetics.

Micturition reflex arc reconstruction including sensory and motor nerves after spinal cord injury: Urodynamic and electrophysiological responses

ObjectiveTo evaluate artificial reflex arcs for micturition using urodynamics and electrophysiological recordings.DesignSixteen beagles were equally and randomly divided into two groups.MethodsIn group A, anastomosis of the proximal end of the left L7 ventral root (VR) and distal end of the left S2 VR was performed, as well as anastomosis of the L7 dorsal root (DR) and S2 DR to reconstruct the sensory and the motor function of the bladder. In group B the proximal end of the left L7 VR and the distal end of the left S2 VR were anastomosed, while the left L7 DR was kept intact to reconstruct the motor function of the bladder. Outcome measures included electrophysiological testing and the urodynamic measures. In addition, we also monitored urinary infection rates.ResultsStimulation to the left S2 DR in groups A and B both elevated the bladder pressure before and after the spinal lower motor neuron lesion. Single stimulation of the two groups both elicited evoked action potentials. Urinary infections occurred in group A (three occurrences) and in group B (eight occurrences) during the 3 months after the spinal lower motor neuron lesion.ConclusionData showed that both reconstructive methods could induce bladder micturition and evoked action potentials. However, in group A the micturition response was better and the urinary infection rates were lower after the spinal lower motor neuron lesion. Thus, the artificial physiological reflex arc reconstruction method used in group A, with sensory input above the lesion, might provide a better alternative in clinical practice.

Réinnervation vésicale par création d’un arc réflexe « somato-autonome » chez les patients blessés médullaires ou spina bifida, un traitement d’avenir ?

The restoration of physiological micturition is a major objective for patients presenting a medullary injury, which is not possible with current treatment. Several recent studies have purposed some techniques for bladder reinnervation. Their purpose was to begin a voluntary micturition by the stimulation of an artificial reflex arc created by the anastomosis of a somatic root with a root innervating the bladder. We searched on Medline and Cochrane for articles in English. The keywords used were: bladder reinnervation, spinal cord injury neurogenic bladder, reflex pathway for micturition. These studies reported a variable efficacy as high as 85% of the treated patients. These patients could begin micturition voluntarily, associated with a significant improvement observed in their postoperative urodynamic evaluation. In fact, an improvement of the detrusor external sphincter dyssynergia and/or bladder overactivity was reported, and the patients presented a better quality of life by the control of their micturition associated with an improvement in continence with no need for intermittent catheterisation. However, these results were variable from one study to the other, and certain results seem difficult to explain notably concerning the abolition of bladder overactivity and the improvement of the detrusor external sphincter dyssynergia. Further experimental studies are still required, notably with animals to confirm the encouraging results of these initial studies, and to better understand the mechanism before possible routine patient use.

Immunohistochemical characterization of pelvic neurons projecting to the bladder in rats with the artificial somatic-autonomic reflex arc

Objective Retrograde-tracing and immunohistochemical techniques were used in combination to investigate the types of putative transmitters in pelvic ganglia neurons projecting to the bladder of rats with the artificial somatic-autonomic reflex arc. Methods The artificial somatic-autonomic reflex arc was established in 8 rats by end-to-end microanastomosis of the proximal stump of the left L4 ventral root to the distal stump of L6 ventral root. The major pelvic ganglia (MPG) neurons innervating the urinary bladder were labeled by retrograde axonal tracing methods with the use of horseradish peroxidase (HRP) injected into the bladder wall and identified with TMB-HRP reaction. Then immunohistochemical (ChAT, TH, VIP, SP) and histochemical methods (NADPH-diaphorase activity and nitric oxide synthase immunoreac-tivity) were used to identify the neurotransmitters of HRP-labeled neurons projecting to the bladder. Results HRP-labeled neurons with spherical or oval shape mainly distributed in the MPG. The HRP-labeled neurons were positive for ChAT (112/279, 40. 1%), TH (50/245,20.4%), VIP(25/233, 10.7%), NOS ( 15/230, 6. 5% ) or SP (8/242, 3. 3% ) respectively. Conclusion These results suggest that ace-tylcholine and adrenaline are the predominant neurotransmitters of postganglionic neurons innervating bladder in rats with the artificial somatic-autonomic reflex arc. VIP, NO and SP may be as the neurotransmitters or neuromodulators to participate the procedure of urinary storage and voiding. Key words: Bladder; Pelvic ganglion; Neurotransmitter; Artificial reflex arc

Reconstructed Bladder Innervation Below the Level of Spinal Cord Injury: The Knee-Tendon to Bladder Artificial Reflex Arc

Background/Objective: To study the effectiveness of knee-tendon to bladder artificial reflex arc in dogs.Methods: In 6 beagles, the proximal end of the right L5 anterior motor root and the distal end of the right S2 anterior root were anastomosed to build a knee-tendon to bladder reflex, whereas the right L5 posterior sensory root was kept intact. Action potential (AP) curves and electromyograms (EMGs) of the detrusor muscle, the intravesical pressure, horseradish peroxidase (HRP)-labeled neurons, and the passing rates of myelinic nerve fibers were calculated to evaluate its feasibility.Results: AP curves and EMG detected in all 6 dogs were similar to those of the control. Six and 18 months after surgery, the means for bladder contraction induced by percussion of the right knee-tendon were 38 ± 27% and 62 ± 5% that of the normal control, respectively. The mean duration times induced by percussion of the right knee-tendon at 6 and 18 months after surgery were 51 ± 37% and 84 ± 12% that of the normal control, respectively. HRP retrograde tracing and neurohistologic observation indicated the feasibility of the artificial reflex arc.Conclusions: Our data showed the effectiveness of bladder innervation below the level of spinal cord injury producing urination by knee-tendon to bladder reflex contractions, and therefore, might provide a new clinical approach for restoring bladder function in individuals with paraplegia.

Clinical observations of the effects on the lower limb function after lumbar or sacral nerve root transferring to reconstruct urination function

To observe the effects on the lower limbs function after lumbar or sacral nerve root transferring to reconstruct urination function. Nine patients with bladder dysfunction and normal lower limb function after spinal cord injury were treated with anastomosis the S2 or S3 nerve root with the normal lumbar or sacral nerve root to reconstruct a new bladder artificial reflex arc. Then the alterations on the sensation and motor function of the lower limb after the surgery were observed. Myodynamia of the legs decreased slightly, and the decreasing about half grade of the myodynamia in the plantar flexion of the ankles were detected in 4 of 9 patients with S1 transferring. And the myodynamia recovered 3 months postoperatively. No obvious decreasing of the myodynamia appeared in the other cases. No obvious effects on the motor function can be found after the single lumbar or sacral nerve root transferring to reconstruct urination function.

Establishing an artificial reflex arc restore controlled micturition of flaccid bladder after spinal cord injury: a preliminary report

目的 探索建立人工反射弧恢复脊髓圆锥损伤后所致弛缓性膀胱排尿功能的治疗方法.方法对临床1例圆锥脊髓损伤(SCI)所致弛缓性膀胱的患者行单侧T11与S2/S3神经前根经移植吻合,经一定时间轴突再生后,通过尿流动力学、尿检及排尿情况检测膀胱功能.结果随访55个月,患者膀胱充盈后可引起自控性排尿,尿流动力学显示排尿完全是由膀胱逼尿肌的收缩引发.结论建立新的人工反射弧能恢复SCI患者排尿功能,实现自控性排尿。

Artificial reflex arc: A potential solution for chronic aspiration. III: Stimulation of implanted cervical skin as a functional graft triggering glottic closure in the canine

Stroke often impairs the ability of the vocal cords to close during deglutition, resulting in aspiration. The current study is a further advance on the application of the concept of an artificial reflex arc during swallowing. The second and third cervical branches were bilaterally isolated in four dogs and baseline sensory nerve traffic was detected via tripolar perineural electrodes. Cervical skin pressure-induced suprathreshold signals were used to trigger vocal cord contraction via bipolar electrodes passed around the recurrent laryngeal nerves. Skin subtended by the cervical nerves was implanted over the lateral aspect of the pyriform sinuses for 1 week. After reexploration, glottic closure was verified on videotape as surges in sensory nerve traffic were induced by mechanical stimulation of the pharynx. The possibility of artifactual stimulation was ruled out by lack of electrode motion during pharyngeal stimulation, spontaneous firing in the sensory nerve during light anesthesia, and sensory frequency differing from ambient 60-Hz noise. This article introduces the concept of autogenous functional graft as a basis for afferent information in electronic systems for dynamic rehabilitation of swallowing disorders.

Artificial reflex arc: a potential solution for chronic aspiration. II. A canine study based on a laryngeal prosthesis.

Long-term and repeated aspiration can result in pneumonia and eventually death. To avoid current techniques which divert or close off the incompetent larynx, the authors have recently described an artificial reflex arc (ARA), in hopes of providing a dynamic solution to this problem. With this concept, a segment of skin surface with intact sensory innervation is implanted into the pharynx in the path of the food bolus. Resulting neural impulses would be detected by a perineural electrode and then channeled to both recurrent laryngeal nerves via an electronic pacemaker to cause vocal fold adduction at the critical time during swallowing. A pilot study using a tubed cervical cutaneous surface has yielded promising results in the canine. In this current study, an alternate means for information pickup based upon use of a miniature strain gage is presented. Mechanical stimulation of the hypopharynx using this "sensory" detector resulted in synchronous laryngeal adduction of the vocal folds, as documented graphically and on videotape.

Artificial reflex arc: A potential solution for chronic aspiration I. neck skin stimulation triggering strap muscle contraction in the canine

Aspiration can occur when the reflex of deglutition occurring in the brain stem is impaired. Surgical procedures involving the airway have so far failed to provide a long-term solution to this problem. Because the sphincteric properties of the larynx could be used to help separate the air from the food passages on a dynamic basis, we present the concept of an artificial reflex are (ARA) in the canine. The afferent limb of this system consists in a cervical cutaneous sensory surface containing the specific biologic sensors for pressure and stretch, subtended by a corresponding sensory nerve, destined to be eventually implanted into the pharynx. The efferent limb picks up the information resulting from the sensor's distention via a frequency modulator and an amplifier, prior to transmitting it to the recurrent laryngeal nerves through monopolar electrodes, resulting in synchronous glottic closure. In order to test this new concept as a pilot study, this principle was applied in three dogs by using an island of cervical skin tubed on itself and the contralateral strap muscles as effector. Inflation of a Foley catheter introduced into the lumen of this tube resulted in synchronous strap muscle contraction, following corresponding increase in the firing frequency in the subtended sensory nerve. The data obtained in this series of experiments should permit further application at the laryngeal level.