Machine learning enables non-Gaussian investigation of changes to peripheral nerves related to electrical stimulation.

Electrical stimulation of the peripheral nervous system (PNS) is becoming increasingly important for the therapeutic treatment of numerous disorders. Thus, as peripheral nerves are increasingly the target of electrical stimulation, it is critical to determine how, and when, electrical stimulation results in anatomical changes in neural tissue. We introduce here a convolutional neural network and support vector machines for cell segmentation and analysis of histological samples of the sciatic nerve of rats stimulated with varying current intensities. We describe the methodologies and present results that highlight the validity of the approach: machine learning enabled highly efficient nerve measurement collection, while multivariate analysis revealed notable changes to nerves' anatomy, even when subjected to levels of stimulation thought to be safe according to the Shannon current limits.

Assessing Cognitive Workload in Motor Decision-Making through Functional Connectivity Analysis: Towards Early Detection and Monitoring of Neurodegenerative Diseases.

Neurodegenerative diseases (NDs), such as Alzheimer's, Parkinson's, amyotrophic lateral sclerosis, and frontotemporal dementia, among others, are increasingly prevalent in the global population. The clinical diagnosis of these NDs is based on the detection and characterization of motor and non-motor symptoms. However, when these diagnoses are made, the subjects are often in advanced stages where neuromuscular alterations are frequently irreversible. In this context, we propose a methodology to evaluate the cognitive workload (CWL) of motor tasks involving decision-making processes. CWL is a concept widely used to address the balance between task demand and the subject's available resources to complete that task. In this study, multiple models for motor planning during a motor decision-making task were developed by recording EEG and EMG signals in n=17 healthy volunteers (9 males, 8 females, age 28.66±8.8 years). In the proposed test, volunteers have to make decisions about which hand should be moved based on the onset of a visual stimulus. We computed functional connectivity between the cortex and muscles, as well as among muscles using both corticomuscular and intermuscular coherence. Despite three models being generated, just one of them had strong performance. The results showed two types of motor decision-making processes depending on the hand to move. Moreover, the central processing of decision-making for the left hand movement can be accurately estimated using behavioral measures such as planning time combined with peripheral recordings like EMG signals. The models provided in this study could be considered as a methodological foundation to detect neuromuscular alterations in asymptomatic patients, as well as to monitor the process of a degenerative disease.

Robot-assisted implantation of a microelectrode array in the occipital lobe as a visual prosthesis: technical note.

The prospect of direct interaction between the brain and computers has been investigated in recent decades, revealing several potential applications. One of these is sight restoration in profoundly blind people, which is based on the ability to elicit visual perceptions while directly stimulating the occipital cortex. Technological innovation has led to the development of microelectrodes implantable on the brain surface. The feasibility of implanting a microelectrode on the visual cortex has already been shown in animals, with promising results. Current research has focused on the implantation of microelectrodes into the occipital brain of blind volunteers. The technique raises several technical challenges. In this technical note, the authors suggest a safe and effective approach for robot-assisted implantation of microelectrodes in the occipital lobe for sight restoration.

New Highly Fluorescent Water Soluble Imidazolium-Perylenediimides: Synthesis and Cellular Response.

The synthesis and characterization of two new water soluble 2,6-bis(imidazolylmethyl)-4-methylphenoxy-containing perylenediimides, PDI-1 and PDI-2, are described. These compounds demonstrate a high fluorescence quantum yield in water and were investigated as potential photosensitizers for generating reactive oxygen species with applications in anticancer activities. The HeLa cell line (VPH18) was used to evaluate their efficacy. Fluorescence microscopy was employed to confirm the successful internalization of PDI-1 and PDI-2, while confocal microscopy revealed the specific locations of both PDIs within the lysosomes and mitochondria. In vitro studies were conducted to evaluate the anticancer activity of PDI-1 and PDI-2. Remarkably, these photosensitizers demonstrated a significant ability to selectively eliminate cancer cells when exposed to a specific light wavelength. The water solubility, high fluorescence quantum yield, and selective cytotoxicity of these PDIs toward cancer cells highlight their potential as effective agents for targeted photodynamic therapy. In conclusion, the findings presented here provide a strong foundation for the future exploration and optimization of PDI-1 and PDI-2 as effective photosensitizers in photodynamic therapy, potentially leading to improved treatment strategies for cancer patients.

Erratum to "Development and evaluation of a 3d printed training model for endoscopic third ventriculostomy in low-income countries" [Brain and Spine 3 (2023) 101736].

[This corrects the article DOI: 10.1016/j.bas.2023.101736.].

Development and evaluation of a 3d printed training model for endoscopic third ventriculostomy in low-income countries.

Introduction: Pediatric hydrocephalus is highly prevalent and therefore a major neurosurgical problem in Africa. In addition to ventriculoperitoneal shunts, which have high cost and potential complications, endoscopic third ventriculostomy is becoming an increasingly popular technique especially in this part of the world. However, performing this procedure requires trained neurosurgeons with an optimal learning curve. For this reason, we have developed a 3D printed training model of hydrocephalus so that neurosurgeons without previous experience with endoscopic techniques can acquire these skills, especially in low-income countries, where specific techniques training as this, are relatively absent. Research Question: Our research question was about the possibility to develop and produce a low-cost endoscopic training model and to evaluate the usefulness and the skills acquired after training with it. Material and Methods: A neuroendoscopy simulation model was developed. A sample of last year medical students and junior neurosurgery residents without prior experience in neuroendoscopy were involved in the study. The model was evaluated by measuring several parameters, as procedure time, number of fenestration attempts, diameter of the fenestration, and number of contacts with critical structures. Results: An improvement of the average score on the ETV-Training-Scale was noticed between the first and last attempt (11.6, compared to 27.5 points; p<0.0001). A statistically significant improvement in all parameters, was observed. Discussion and Conclusion: This 3D printed simulator facilitates acquiring surgical skills with the neuroendoscope to treat hydrocephalus by performing an endoscopic third ventriculostomy. Furthermore, it has been shown to be useful to understand the intraventricular anatomical relationships.

Thiel embalming in neonates: methodology and benefits in medical training.

Current teaching and training methods for surgical techniques in the pediatric population involve artificial models (manikins), animals or adult human cadavers embalmed using various techniques. We found no references in the literature concerning the use of the Thiel method in the pediatric population. The aim of this study, therefore, was to assess the viability of using pediatric human cadavers embalmed through Thiel's technique and to compare them with standard pediatric manikins. After donation of a 24-week stillborn, the Thiel technique was carried out for fixation following the usual protocol. A video recording with eye-tracking glasses was used to perform an examination, and techniques. The same procedures were conducted on a pediatric manikin. Medical students, medical residents and physicians were asked to respond to questions in an online survey after being shown the video. A total of 92 responses were obtained. The Thiel-embalmed stillborn was assessed as superior to the manikin in all items. Our study confirmed that this technique is feasible even with extremely small donors. The value of this form of preservation for medical training is not widely known though it is receiving increasing interest. Our results show that Thiel fixation in pediatrics is clearly more highly valued than a manikin and offers great potential. This innovative application of the Thiel method in the pediatric population is technically possible. It poses no additional difficulties and is very positively assessed for undergraduate and postgraduate teaching.

The Effect of Breath Pacing on Task Switching and Working Memory.

The cortical and subcortical circuit regulating both cognition and cardiac autonomic interactions are already well established. This circuit has mainly been analyzed from cortex to heart. Thus, the heart rate variability (HRV) is usually considered a reflection of cortical activity. In this paper, we investigate whether HRV changes affect cortical activity. Short-term local autonomic changes were induced by three breathing strategies: spontaneous (Control), normal (NB) and slow paced breathing (SB). We measured the performance in two cognition domains: executive functions and processing speed. Breathing maneuvres produced three clearly differentiated autonomic states, which preconditioned the cognitive tasks. We found that the SB significantly increased the HRV low frequency (LF) power and lowered the power spectral density (PSD) peak to 0.1[Formula: see text]Hz. Meanwhile, executive function was assessed by the working memory test, whose accuracy significantly improved after SB, with no significant changes in the response times. Processing speed was assessed by a multitasking test. Consistently, the proportion of correct answers (success rate) was the only dependent variable affected by short-term and long-term breath pacing. These findings suggest that accuracy, and not timing of these two cognitive domains would benefit from short-term SB in this study population.

Real-Time Multi-Modal Estimation of Dynamically Evoked Emotions Using EEG, Heart Rate and Galvanic Skin Response.

Emotion estimation systems based on brain and physiological signals such as electro encephalography (EEG), blood-volume pressure (BVP), and galvanic skin response (GSR) are gaining special attention in recent years due to the possibilities they offer. The field of human-robot interactions (HRIs) could benefit from a broadened understanding of the brain and physiological emotion encoding, together with the use of lightweight software and cheap wearable devices, and thus improve the capabilities of robots to fully engage with the users emotional reactions. In this paper, a previously developed methodology for real-time emotion estimation aimed for its use in the field of HRI is tested under realistic circumstances using a self-generated database created using dynamically evoked emotions. Other state-of-the-art, real-time approaches address emotion estimation using constant stimuli to facilitate the analysis of the evoked responses, remaining far from real scenarios since emotions are dynamically evoked. The proposed approach studies the feasibility of the emotion estimation methodology previously developed, under an experimentation paradigm that imitates a more realistic scenario involving dynamically evoked emotions by using a dramatic film as the experimental paradigm. The emotion estimation methodology has proved to perform on real-time constraints while maintaining high accuracy on emotion estimation when using the self-produced dynamically evoked emotions multi-signal database.

MRI evidence of brain atrophy, white matter damage, and functional adaptive changes in patients with cervical spondylosis and prolonged spinal cord compression.

OBJECTIVES: To investigate the effect of cervical spondylosis (CS) in the brain with a combination of advanced neuroimaging techniques. METHODS: Twenty-seven patients with CS and 24 age- and gender-matched healthy controls were studied. Disease severity was quantified using the Modified Japanese Orthopaedic Association Scoring System (mJOHA). Magnetic resonance (MR) imaging of the brain and spinal cord, functional MR imaging (fMRI) with a bilateral rest/finger-tapping paradigm, brain diffusion tensor imaging (DTI), voxel-based morphometry (VBM), and MR spectroscopy of the sensorimotor cortex were performed. RESULTS: A total of 92.3% of patients had more than one herniated disc. In the MRI, 33.33% presented signs of myelopathy. The mJOHA score was 13.03 ± 2.83. Compared with controls, DTI results showed significant lower FA values in Corpus callosum, both corticospinal tracts and middle cerebellar peduncles (p < 0.05 corrected). Only in CS patients fMRI results showed activation in both globus pallidi, caudate nucleus, and left thalamus (p < 0.001). Subject-specific activation of the BOLD signal showed in CS patients lower activation in the sensorimotor cortex and increased activation in both cerebellum hemispheres (p < 0.05 corrected). VBM showed bilateral clusters of gray matter loss in the sensorimotor cortex and pulvinar nucleus (p < 0.05 corrected) of CS patients. NAA/Cr was reduced in the sensorimotor cortex of CS patients (p < 0.05). Linear discriminant and support vector machine analyses were able to classify > 97% of CS patients with parameters obtained from the fMRI, DTI, and MRS results. CONCLUSION: CS may lead to distal brain damage affecting the white and gray matter of the sensorimotor cortex causing brain atrophy and functional adaptive changes. KEY POINTS: • This study suggests that patients with cervical spondylosis may present anatomical and functional adaptive changes in the brain. • Cervical spondylosis may lead to white matter damage, gray matter volume loss, and functional adaptive changes in the sensorimotor cortex. • The results reported in this work may be of value to better understand the effect of prolonged cervical spine compression in the brain.

Epidemiología de la esclerosis múltiple en España / Epidemiology of multiple sclerosis in Spain

Introducción. La esclerosis múltiple es una enfermedad crónica autoinmune, inflamatoria y degenerativa del sistema nervioso central, y es el trastorno neurológico discapacitante no traumático más común en adultos jóvenes. Los estudios de prevalencia más recientes indican que la frecuencia de la enfermedad ha aumentado en el mundo en las últimas décadas, que dicho incremento de la prevalencia ocurre fundamentalmente a expensas de un mayor número de casos de mujeres con formas remitentes, y que el gradiente latitudinal de la incidencia de la enfermedad se viene atenuando. Objetivo. Revisar los estudios sobre epidemiología de esclerosis múltiple en España para verificar si las tendencias mundiales se confirman en nuestro país. Desarrollo. Búsqueda bibliográfica en las bases de datos PubMed y Teseo usando como palabras clave "epidemiology", "prevalence" e "incidence", cruzándolas con los términos "multiple sclerosis" y "Spain"; se realiza una selección inicial por título y resumen, en castellano e inglés, entre los años 1968 y 2018. Conclusiones. Un buen número de estudios epidemiológicos recientes en España confirman que es una región de prevalencia media-alta de la enfermedad a lo largo de su geografía. Las cifras de prevalencia aumentan progresivamente a lo largo de las últimas décadas hasta alcanzar en la actualidad 80-180 casos por 100.000 habitantes, y ello ha ocurrido a expensas de una mayor frecuencia de la enfermedad en las mujeres

Introduction. Multiple sclerosis is a chronic autoimmune, inflammatory and neurodegenerative disease of the central nervous system and the most common non-traumatic disabling neurological disease in young adults. In the latest decades, multiple sclerosis is increasing worldwide, especially in women. The latitudinal distribution has been progressively attenuated. Aim. To review the epidemiological studies of multiple sclerosis in Spain to verify if this worldwide trend also occurs in Spain. Development. We searched PubMed and Teseo databases using the search terms 'epidemiology', 'prevalence', 'incidence', 'multiple sclerosis' and 'Spain'. We selected articles published in Spanish and English between 1968 and 2018. Conclusions. Recent epidemiological studies confirm that Spain is a medium-high risk area for MS. The prevalence of MS has increased significantly throughout Spain in the latest years, especially in women, and recent studies show prevalence as high as 80-180 cases per 100,000

Effects of Watching Cartoons During an Echocardiography on Infants and Preschool Children. A Prospective Randomized Study.

Echocardiography is currently the main diagnostic technique in pediatric cardiology, but sometimes it is difficult to use in very young children, as a complete and accurate study depends on the patient's and family's cooperation. Children's behavior is one of the main problems for this procedure, and interventions like sedative medication have been used to facilitate its performance. The aim of this study was to analyze the effects of TV entertainment in infants and preschool children during echocardiography. We designed an experimental study in children with a heart murmur. An examination room was prepared with a TV on the ceiling, giving the children an unobstructed view during the echocardiography procedure. Fifty-eight patients were randomized into two groups: TV intervention vs. usual care (consisting of other distraction measures). The primary outcome was echocardiography time, but we also assessed blood pressure, quality of technique, child behavior, and parents' stress level. The TV group showed a statistically significant reduction in duration of the echocardiography and systolic and diastolic blood pressure, as well as better quality of technique and child behavior. Consequently, we recommend the use of a TV as a simple and useful distraction method for improving echocardiography in young children.

System-Level Design of a 64-Channel Low Power Neural Spike Recording Sensor.

This paper reports an integrated 64-channel neural spike recording sensor, together with all the circuitry to process and configure the channels, process the neural data, transmit via a wireless link the information and receive the required instructions. Neural signals are acquired, filtered, digitized and compressed in the channels. Additionally, each channel implements an auto-calibration algorithm which individually configures the transfer characteristics of the recording site. The system has two transmission modes; in one case the information captured by the channels is sent as uncompressed raw data; in the other, feature vectors extracted from the detected neural spikes are released. Data streams coming from the channels are serialized by the embedded digital processor. Experimental results, including in vivo measurements, show that the power consumption of the complete system is lower than 330 µW.

Use of Eye Tracking as an Innovative Instructional Method in Surgical Human Anatomy.

OBJECTIVE: Tobii glasses can record corneal infrared light reflection to track pupil position and to map gaze focusing in the video recording. Eye tracking has been proposed for use in training and coaching as a visually guided control interface. The aim of our study was to test the potential use of these glasses in various situations: explanations of anatomical structures on tablet-type electronic devices, explanations of anatomical models and dissected cadavers, and during the prosection thereof. An additional aim of the study was to test the use of the glasses during laparoscopies performed on Thiel-embalmed cadavers (that allows pneumoinsufflation and exact reproduction of the laparoscopic surgical technique). The device was also tried out in actual surgery (both laparoscopy and open surgery). DESIGN: We performed a pilot study using the Tobii glasses. SETTING: Dissection room at our School of Medicine and in the operating room at our Hospital. PARTICIPANTS: To evaluate usefulness, a survey was designed for use among students, instructors, and practicing physicians. RESULTS: The results were satisfactory, with the usefulness of this tool supported by more than 80% positive responses to most questions. There was no inconvenience for surgeons and that patient safety was ensured in the real laparoscopy. CONCLUSION: To our knowledge, this is the first publication to demonstrate the usefulness of eye tracking in practical instruction of human anatomy, as well as in teaching clinical anatomy and surgical techniques in the dissection and operating rooms.