Scanning Electron Microscopy of Age-Related Changes in the C57BL/6J Mouse Cochlea

Hair cells and nerve fibers inside the organ of Corti of the C57BL/6J mouse, which is known as the precocious presbycusis model, were studied using the scanning electron microscope. For this study, we used thick serial sections cut from celloidin blocks. In the 5-week-old mice, hair cell loss was not seen. The upper tunnel radial fibers crossed the upper part of the tunnel of Corti and entered the Nuel\u27s space between the outer pillar cells. The fibers varied in diameter and showed many varicosities. The basilar fibers emerged into the tunnel of Corti beneath the upper tunnel radial fibers and crossed the floor of tunnel slightly curving basalward. The outer spiral fibers ran along the lateral wall of the Nuel\u27s spaces, sometimes buried in the cytoplasm of Deiters\u27 cells. The nerve endings were clearly seen on the modiolar sides of the outer hair cell bases in the basal turn. In the 30-, 42- and 60-week-old mice, hair cell degeneration was seen both at the basal and apical portions, more pronounced in the former. The outer hair cells were affected more than the inner hair cells. In the basal turn where most of outer hair cells had degenerated, the upper tunnel radial fibers disappeared while the basilar fibers remained. These results suggest that degeneration of the efferent fibers occur earlier than those of the afferent to the outer hair cells

Brain-controlled cycling system for rehabilitation following paraplegia with delay-time prediction

Objective: Robotic rehabilitation systems have been investigated to assist with motor dysfunction recovery in patients with lower-extremity paralysis caused by central nervous system lesions. These systems are intended to provide appropriate sensory feedback associated with locomotion. Appropriate feedback is thought to cause synchronous neuron firing, resulting in the recovery of function. Approach: In this study, we designed and evaluated an ergometric cycling wheelchair, with a brain-machine interface (BMI), that can force the legs to move by including normal stepping speeds and quick responses. Experiments were conducted in five healthy subjects and one patient with spinal cord injury (SCI), who experienced the complete paralysis of the lower limbs. Event-related desynchronization (ERD) in the β band (18‐28 Hz) was used to detect lower-limb motor images. Main results: An ergometer-based BMI system was able to safely and easily force patients to perform leg movements, at a rate of approximately 1.6 seconds/step (19 rpm), with an online accuracy rate of 73.1% for the SCI participant. Mean detection time from the cue to pedaling onset was 0.83±0.31 s Significance: This system can easily and safely maintain a normal walking speed during the experiment and be designed to accommodate the expected delay between the intentional onset and physical movement, to achieve rehabilitation effects for each participant. Similar BMI systems, implemented with rehabilitation systems, may be applicable to a wide range of patients