Restorative Neurology and Neuroscience - Volume 42, issue 2

Article Type: Editorial

DOI: 10.3233/RNN-249001

Citation: Restorative Neurology and Neuroscience, vol. 42, no. 2, pp. 91-92, 2024

Authors: Rivi, Veronica | Batabyal, Anuradha | Lukowiak, Ken

Article Type: Review Article

Abstract:  There has been a significant increase in the incidence of multiple neurodegenerative and terminal diseases in the human population with life expectancy increasing in the current times. This highlights the urgent need for a more comprehensive understanding of how different aspects of lifestyle, in particular diet, may affect neural functioning and consequently cognitive performance as well as in enhancing overall health. Flavonoids, found in a variety of fruits, vegetables, and derived beverages, provide a new avenue of research that shows a promising influence on different aspects of brain function. However, despite the promising evidence, most bioactive compounds lack strong …clinical research efficacy. In the current scoping review, we highlight the effects of Flavonoids on cognition and neural plasticity across vertebrates and invertebrates with special emphasis on the studies conducted in the pond snail, Lymnaea stagnalis , which has emerged to be a functionally dynamic model for studies on learning and memory. In conclusion, we suggest future research directions and discuss the social, cultural, and ethnic dependencies of bioactive compounds that influence how these compounds are used and accepted globally. Bridging the gap between preclinical and clinical studies about the effects of bioactive natural compounds on brain health will surely lead to lifestyle choices such as dietary Flavonoids being used complementarily rather than as replacements to classical drugs bringing about a healthier future. Show more

Keywords: Invertebrates, Flavonoids, memory, learning, cognitive functions, neurodegenerative disorders, psychiatric disorders

DOI: 10.3233/RNN-230150

Citation: Restorative Neurology and Neuroscience, vol. 42, no. 2, pp. 93-111, 2024

Authors: Negen, James | Slater, Heather | Nardini, Marko

Article Type: Research Article

Abstract: Background: Sensory substitution and augmentation systems (SSASy) seek to either replace or enhance existing sensory skills by providing a new route to access information about the world. Tests of such systems have largely been limited to untimed, unisensory tasks. Objective: To test the use of a SSASy for rapid, ballistic motor actions in a multisensory environment. Methods: Participants played a stripped-down version of air hockey in virtual reality with motion controls (Oculus Touch). They were trained to use a simple SASSy (novel audio cue) for the puck’s location. They were tested on ability to strike an …oncoming puck with the SASSy, degraded vision, or both. Results: Participants coordinated vision and the SSASy to strike the target with their hand more consistently than with the best single cue alone, t (13) = 9.16, p <.001, Cohen’s d  = 2.448. Conclusions: People can adapt flexibly to using a SSASy in tasks that require tightly timed, precise, and rapid body movements. SSASys can augment and coordinate with existing sensorimotor skills rather than being limited to replacement use cases – in particular, there is potential scope for treating moderate vision loss. These findings point to the potential for augmenting human abilities, not only for static perceptual judgments, but in rapid and demanding perceptual-motor tasks. Show more

Keywords: Multisensory, visuomotor, training, augmentation, substitution

DOI: 10.3233/RNN-221279

Citation: Restorative Neurology and Neuroscience, vol. 42, no. 2, pp. 113-120, 2024

Authors: Augenstein, Thomas E. | Oh, Seonga | Norris, Trevor A. | Mekler, Joshua | Sethi, Amit | Krishnan, Chandramouli

Article Type: Research Article

Abstract: Background: Previous research has shown that noninvasive brain stimulation can be used to study how the central nervous system (CNS) prepares the execution of a motor task. However, these previous studies have been limited to a single muscle or single degree of freedom movements (e.g., wrist flexion). It is currently unclear if the findings of these studies generalize to multi-joint movements involving multiple muscles, which may be influenced by kinematic redundancy and muscle synergies. Objective: The objective of this study was to characterize corticospinal excitability during motor preparation in the cortex prior to functional upper …extremity reaches. Methods: 20 participants without neurological impairments volunteered for this study. During the experiment, the participants reached for a cup in response to a visual “Go Cue”. Prior to movement onset, we used transcranial magnetic stimulation (TMS) to stimulate the motor cortex and measured the changes in motor evoked potentials (MEPs) in several upper extremity muscles. We varied each participant’s initial arm posture and used a novel synergy-based MEP analysis to examine the effect of muscle coordination on MEPs. Additionally, we varied the timing of the stimulation between the Go Cue and movement onset to examine the time course of motor preparation. Results: We found that synergies with strong proximal muscle (shoulder and elbow) components emerged as the stimulation was delivered closer to movement onset, regardless of arm posture, but MEPs in the distal (wrist and finger) muscles were not facilitated. We also found that synergies varied with arm posture in a manner that reflected the muscle coordination of the reach. Conclusions: We believe that these findings provide useful insight into the way the CNS plans motor skills. Show more

Keywords: Motor control, muscle synergy, movement planning, cortical excitability, stroke

DOI: 10.3233/RNN-231367

Citation: Restorative Neurology and Neuroscience, vol. 42, no. 2, pp. 121-138, 2024

Authors: Afzal, Aqeela | Thomas, Nagheme | Warraich, Zuha | Barbay, Scott | Mocco, J.

Article Type: Research Article

Abstract: Hematopoietic stem cells (HSC) are recruited to ischemic areas in the brain and contribute to improved functional outcome in animals. However, little is known regarding the mechanisms of improvement following HSC administration post cerebral ischemia. To better understand how HSC effect post-stroke improvement, we examined the effect of HSC in ameliorating motor impairment and cortical dysfunction following cerebral ischemia. Methods: Baseline motor performance of male adult rats was established on validated motor tests. Animals were assigned to one of three experimental cohorts: control, stroke, stroke + HSC. One, three and five weeks following a unilateral stroke all animals were tested on …motor skills after which intracortical microstimulation was used to derive maps of forelimb movement representations within the motor cortex ipsilateral to the ischemic injury. Results: Stroke + HSC animals significantly outperformed stroke animals on single pellet reaching at weeks 3 and 5 (28±3% and 33±3% versus 11±4% and 17±3%, respectively, p  < 0.05 at both time points). Control animals scored 44±1% and 47±1%, respectively. Sunflower seed opening task was significantly improved in the stroke + HSC cohort versus the stroke cohort at week five-post stroke (79±4 and 48±5, respectively, p  < 0.05). Furthermore, Stroke + HSC animals had significantly larger forelimb motor maps than animals in the stroke cohort. Overall infarct size did not significantly differ between the two stroked cohorts. Conclusion: These data suggest that post stroke treatment of HSC enhances the functional integrity of residual cortical tissue, which in turn supports improved behavioral outcome, despite no observed reduction in infarct size. Show more

Keywords: Stroke, stem cells, motor map, behavior

DOI: 10.3233/RNN-231378

Citation: Restorative Neurology and Neuroscience, vol. 42, no. 2, pp. 139-149, 2024

Authors: Hibbard, Emily A. | Du, Xiaolong | Zhang, Yihong | Xu, Xiao-Ming | Deng, Lingxiao | Sengelaub, Dale R.

Article Type: Research Article

Abstract: Background: Spinal cord injury (SCI) results in lesions that destroy tissue and spinal tracts, leading to deficits in locomotor and autonomic function. We have previously shown that after SCI, surviving motoneurons innervating hindlimb muscles exhibit extensive dendritic atrophy, which can be attenuated by treadmill training or treatment with gonadal hormones post-injury. We have also shown that following SCI, both exercise and treatment with gonadal hormones improve urinary function. Animals exercised with forced running wheel training show improved urinary function as measured by bladder cystometry and sphincter electromyography, and treatment with gonadal hormones improves voiding patterns as measured by metabolic cage …testing. Objective: The objective of the current study was to examine the potential protective effects of exercise or hormone treatment on the structure and function of motoneurons innervating the external urethral sphincter (EUS) after contusive SCI. Methods: Gonadally intact young adult male rats received either a sham or a thoracic contusion injury. Immediately after injury, one cohort of animals was implanted with subcutaneous Silastic capsules filled with estradiol (E) and dihydrotestosterone (D) or left blank; continuous hormone treatment occurred for 4 weeks post-injury. A separate cohort of SCI-animals received either 12 weeks of forced wheel running exercise or no exercise treatment starting two weeks after injury. At the end of treatment, urinary void volume was measured using metabolic cages and EUS motoneurons were labeled with cholera toxin-conjugated horseradish peroxidase, allowing for assessment of dendritic morphology in three dimensions. Results: Locomotor performance was improved in exercised animals after SCI. Void volumes increased after SCI in all animals; void volume was unaffected by treatment with exercise, but was dramatically improved by treatment with E + D. Similar to what we have previously reported for hindlimb motoneurons after SCI, dendritic length of EUS motoneurons was significantly decreased after SCI compared to sham animals. Exercise did not reverse injury-induced atrophy, however E + D treatment significantly protected dendritic length. Conclusions: These results suggest that some aspects of urinary dysfunction after SCI can be improved through treatment with gonadal hormones, potentially through their effects on EUS motoneurons. Moreover, a more comprehensive treatment regime that addresses multiple SCI-induced sequelae, i.e., locomotor and voiding deficits, would include both hormones and exercise. Show more

Keywords: Estradiol, dihydrotestosterone, forced running wheel exercise, metabolic cage, neuroprotection, dendrites

DOI: 10.3233/RNN-241385

Citation: Restorative Neurology and Neuroscience, vol. 42, no. 2, pp. 151-165, 2024

Authors: Park, Chaeyoo | Woo, Youngkeun | Won, Jongim | Kim, Sujin

Article Type: Research Article

Abstract: Background: Asymmetric gait patterns are mostly observed in hemiplegic stroke patients. These abnormal gait patterns resulting in abnormal speed, and decreased ability in daily of activity living. Objective: This study aimed to determine the immediate changes in gait parameters and plantar pressure during elevation by wearing an insole on the sound side lower extremity of patients with hemiplegia. Methods: Thirty-six participants were recruited, comprising those with a post-stroke follow-up of ≥3 months and a functional ambulation category score of ≥2. The participants were asked to walk with and without a 1 cm insole in the shoe of …their sound side, and the order of wearing or not wearing the insole was randomized. Gait parameters, bilateral gait parameters, and dynamic plantar pressure were measured using the GAITRite Walkway System. Results: Paired t -test was used to examine immediate changes in gait parameters and plantar pressure with and without insoles during walking in the same group. Overall, gait velocity and step length significantly decreased (p  < 0.05), whereas step time significantly increased (p  < 0.05). The swing phase of the affected sidelower extremities significantly increased (p  < 0.05), and the stance phase significantly decreased (p  < 0.05). Double-support unloading phase (pre-swing phase) significantly increased (p  < 0.05). The changes in plantar pressure were significantly increased in some lateral zones and significantly decreased in the medial zone of the mid-hindfoot, both in terms of pressure per time and peak pressure (p  < 0.05). Conclusion: Although this study did not show immediate positive effects on gait parameters and gait cycle, it is expected that sensory input from the sole of the foot through changes in plantar pressure may help improve gait asymmetry and regulate postural symmetry. Show more

Keywords: Affected side, gait, gaitrite, gait parameters, hemiplegia, insole, plantar pressure, stroke, sound side, weight bearing, weight shifting, weight transfer

DOI: 10.3233/RNN-241389

Citation: Restorative Neurology and Neuroscience, vol. 42, no. 2, pp. 167-177, 2024