Central projections and connections of lumbar primary afferent fibers in adult rats:effectively revealed using Texas red-dextran amine tracing

Signals from lumbar primary afferent fibers are important for modulating locomotion of the hind-limbs.However,silver impregnation techniques,autoradiography,wheat germ agglutinin-horseradish peroxidase and cholera toxin B subunit-horseradish peroxidase cannot image the central projections and connections of the dorsal root in detail.Thus,we injected 3-k Da Texas red-dextran amine into the proximal trunks of L4 dorsal roots in adult rats.Confocal microscopy results revealed that numerous labeled arborizations and varicosities extended to the dorsal horn from T12–S4,to Clarke＇s column from T10–L2,and to the ventral horn from L1–5.The labeled varicosities at the L4 cord level were very dense,particularly in laminae I–Ⅲ,and the density decreased gradually in more rostral and caudal segments.In addition,they were predominately distributed in laminae I–IV,moderately in laminae V–VⅡ and sparsely in laminae VⅢ–X.Furthermore,direct contacts of lumbar afferent fibers with propriospinal neurons were widespread in gray matter.In conclusion,the projection and connection patterns of L4 afferents were illustrated in detail by Texas red-dextran amine-dorsal root tracing.

Prospects for intelligent rehabilitation techniques to treat motor dysfunction

More than half of stroke patients live with different levels of motor dysfunction after receiving routine rehabilitation treatments.Therefore,new rehabilitation technologies are urgently needed as auxiliary treatments for motor rehabilitation.Based on routine rehabilitation treatments,a new intelligent rehabilitation platform has been developed for accurate evaluation of function and rehabilitation training.The emerging intelligent rehabilitation techniques can promote the development of motor function rehabilitation in terms of informatization,standardization,and intelligence.Traditional assessment methods are mostly subjective,depending on the experience and expertise of clinicians,and lack standardization and precision.It is therefore difficult to track functional changes during the rehabilitation process.Emerging intelligent rehabilitation techniques provide objective and accurate functional assessment for stroke patients that can promote improvement of clinical guidance for treatment.Artificial intelligence and neural networks play a critical role in intelligent rehabilitation.Multiple novel techniques,such as braincomputer interfaces,virtual reality,neural circuit-magnetic stimulation,and robot-assisted therapy,have been widely used in the clinic.This review summarizes the emerging intelligent rehabilitation techniques for the evaluation and treatment of motor dysfunction caused by nervous system diseases.

The existence of propagated sensation along the meridian proved by neuroelectrophysiology

Propagated sensation along the meridian can occur when acupoints are stimulated by acupuncture or electrical impulses. In this study, participants with notable propagated sensation along the me- ridian were given electro-acupuncture at the Jianyu （LI15） acupoint of the large intestine meridian. When participants stated that the sensation reached the back of their hand, reguJar nervous system action discharge was examined using a physiological recording electrode placed on the superficial branch of the radial nerve. The topographical maps of brain-evoked potential in the primary cortical somatosensory area were also detected. When Guangming （GB37） acupoint in the lower limb and Hegu （LI4） acupoint in the upper limb were stimulated, subjects without propagated sensation along the meridian exhibited a high potential reaction in the corresponding area of the brain cortical somatosensory area. For subjects with a notable propagated sensation along the meridian, the re- action area was larger and extended into the face representative area. These electrophysiological measures directly prove the existence of propagated sensation along the meridian, and the periph- eral stimulated site is consistent with the corresponding primary cortical somatosensory area, which presents a high potential reaction.

Polyethylene glycol restores axonal conduction after corpus callosum transection

Polyethylene glycol（PEG） has been shown to restore axonal continuity after peripheral nerve transection in animal models. We hypothesized that PEG can also restore axonal continuity in the central nervous system. In this current experiment, coronal sectioning of the brains of Sprague-Dawley rats was performed after animal sacrifice. 3Brain high-resolution microelectrode arrays（MEA） were used to measure mean firing rate（MFR） and peak amplitude across the corpus callosum of the ex-vivo brain slices. The corpus callosum was subsequently transected and repeated measurements were performed. The cut ends of the corpus callosum were still apposite at this time. A PEG solution was applied to the injury site and repeated measurements were performed. MEA measurements showed that PEG was capable of restoring electrophysiology signaling after transection of central nerves. Before injury, the average MFRs at the ipsilateral, midline, and contralateral corpus callosum were 0.76, 0.66, and 0.65 spikes/second, respectively, and the average peak amplitudes were 69.79, 58.68, and 49.60 μV, respectively. After injury, the average MFRs were 0.71, 0.14, and 0.25 spikes/second, respectively and peak amplitudes were 52.11, 8.98, and 16.09 μV, respectively. After application of PEG, there were spikes in MFR and peak amplitude at the injury site and contralaterally. The average MFRs were 0.75, 0.55, and 0.47 spikes/second at the ipsilateral, midline, and contralateral corpus callosum, respectively and peak amplitudes were 59.44, 45.33, 40.02 μV, respectively. There were statistically differences in the average MFRs and peak amplitudes between the midline and non-midline corpus callosum groups（P 〈 0.01, P 〈 0.05）. These findings suggest that PEG restores axonal conduction between severed central nerves, potentially representing axonal fusion.