Substitution of natural sensory input by artificial neurostimulation of an amputated trigeminal nerve does not prevent the degeneration of basal forebrain cholinergic circuits projecting to the somatosensory cortex

Peripheral deafferentation downregulates acetylcholine (ACh) synthesis in sensory cortices. However, the responsible neural circuits and processes are not known. We irreversibly transected the rat infraorbital nerve and implanted neuroprosthetic microdevices for proximal stump stimulation, and assessed cytochrome-oxidase and choline- acetyl-transferase (ChAT) in somatosensory, auditory and visual cortices; estimated the number and density of ACh-neurons in the magnocellular basal nucleus (MBN); and localized down-regulated ACh-neurons in basal forebrain using retrograde labeling from deafferented cortices. Here we show that nerve transection, causes down regulation of MBN cholinergic neurons. Stimulation of the cut nerve reverses the metabolic decline but does not affect the decrease in cholinergic fibers in cortex or cholinergic neurons in basal forebrain. Artifical stimulation of the nerve also has no affect of ACh-innervation of other cortices. Cortical ChAT depletion is due to loss of corticopetal MBN ChAT-expressing neurons. MBN ChAT downregulation is not due to a decrease of afferent activity or to a failure of trophic support. Basalocortical ACh circuits are sensory specific, ACh is provided to each sensory cortex “on demand” by dedicated circuits. Our data support the existence of a modality-specific cortex-MBN-cortex circuit for cognitive information processing

Editorial: Neuromodulation in COVID-19: From basic research to clinical applications

RECEIVED 20 January 2023; ACCEPTED 08 February 2023; PUBLISHED 16 February 2023Unidad Docente de Biodiversidad, Ecología y EvoluciónFac. de Óptica y OptometríaTRUEpu

Silk Fibroin: An Ancient Material for Repairing the Injured Nervous System

Silk refers to a family of natural fibers spun by several species of invertebrates such as spiders and silkworms. In particular, silkworm silk, the silk spun by Bombyx mori larvae, has been primarily used in the textile industry and in clinical settings as a main component of sutures for tissue repairing and wound ligation. The biocompatibility, remarkable mechanical performance, controllable degradation, and the possibility of producing silk-based materials in several formats, have laid the basic principles that have triggered and extended the use of this material in regenerative medicine. The field of neural soft tissue engineering is not an exception, as it has taken advantage of the properties of silk to promote neuronal growth and nerve guidance. In addition, silk has notable intrinsic properties and the by-products derived from its degradation show anti-inflammatory and antioxidant properties. Finally, this material can be employed for the controlled release of factors and drugs, as well as for the encapsulation and implantation of exogenous stem and progenitor cells with therapeutic capacity. In this article, we review the state of the art on manufacturing methodologies and properties of fiber-based and non-fiber-based formats, as well as the application of silk-based biomaterials to neuroprotect and regenerate the damaged nervous system. We review previous studies that strategically have used silk to enhance therapeutics dealing with highly prevalent central and peripheral disorders such as stroke, Alzheimer’s disease, Parkinson’s disease, and peripheral trauma. Finally, we discuss previous research focused on the modification of this biomaterial, through biofunctionalization techniques and/or the creation of novel composite formulations, that aim to transform silk, beyond its natural performance, into more efficient silk-based-polymers towards the clinical arena of neuroprotection and regeneration in nervous system diseases

Atlas electrónico de registros de retinográficos y tomográficos: cribado, derivación, y modelización matématica. Parte III: Retinopatía Diabética

El objetivo de este proyecto es continuar con el Atlas retinográfico iniciado en las convocatorias anteriores con imágenes obtenidas con los principales y novedosos instrumentos utilizados en la actualidad para el diagnóstico de patologías retinianas. El Atlas presentará, además de las imágenes, una detallada descripción de los aspectos que debe tenerse en cuenta en el momento de realizar el cribado. Y además, se realizará un novedoso modelizado matemático de las imágenes. Esta tercera parte se centrará en el diagnóstico de RETINOPATÍAS DIABÉTICAS, una patología con una prevalencia del 4% de la población en general y que constituye una de las primeras causas de ceguera no reversible en los países desarrollados, causando incapacidad laboral permanente. El Atlas puede ser de gran interés para los enfermos de DIABETES ya que está probado que el 100% de los afectados a los 15 años padecen RETINOPATÍAS DIABÉTICAS. Por lo que conviene que sepan el estado del fondo de su ojo. Estará constituida por una extensa relación de retinografías (fotografías del fondo de ojo – retina) y tomografías de coherencia óptica (imágenes de cortes histológicos de la retina en vivo), exponiendo casos reales de patologías comunes y poco comunes. Constituye una herramienta con triple función: por un lado será un elemento didáctico para el aprendizaje de patologías retinianas y el método de diagnóstico por imagen; en segundo lugar, podrá utilizarse para realizar evaluaciones tipo test; y, en tercer lugar, constituirá una completa base de datos que podrá ser utilizado como material de consulta y diagnóstico comparado en la práctica clínica. En definitiva, se trata de una herramienta muy económica de gran utilidad para un amplio grupo de profesionales sanitarios expertos y especialistas en visión y en sistema ocular

Vagus Nerve Stimulation: A Personalized Therapeutic Approach for Crohn’s and Other Inflammatory Bowel Diseases

Inflammatory bowel diseases, including Crohn’s disease and ulcerative colitis, are incurable autoimmune diseases characterized by chronic inflammation of the gastrointestinal tract. There is increasing evidence that inappropriate interaction between the enteric nervous system and central nervous system and/or low activity of the vagus nerve, which connects the enteric and central nervous systems, could play a crucial role in their pathogenesis. Therefore, it has been suggested that appropriate neuroprosthetic stimulation of the vagus nerve could lead to the modulation of the inflammation of the gastrointestinal tract and consequent long-term control of these autoimmune diseases. In the present paper, we provide a comprehensive overview of (1) the cellular and molecular bases of the immune system, (2) the way central and enteric nervous systems interact and contribute to the immune responses, (3) the pathogenesis of the inflammatory bowel disease, and (4) the therapeutic use of vagus nerve stimulation, and in particular, the transcutaneous stimulation of the auricular branch of the vagus nerve. Then, we expose the working hypotheses for the modulation of the molecular processes that are responsible for intestinal inflammation in autoimmune diseases and the way we could develop personalized neuroprosthetic therapeutic devices and procedures in favor of the patients

Atlas electrónico de registros retinográficos y tomográficos: cribado, derivación, diagnóstico diferencial y seguimiento de afecciones retinianas Parte IV: Retinopatía del Prematuro

El objetivo de este proyecto es continuar con el Atlas retinográfico iniciado en las convocatorias anteriores con imágenes obtenidas con los principales y novedosos instrumentos utilizados en la actualidad para el diagnóstico de patologías retinianas. El Atlas presenta, además de las imágenes, una detallada descripción de los criterios cribado. Esta cuarta parte se centra en el diagnóstico por imagen de la retinopatía del prematuro, que se define como una vitreorretinopatía fibro y vasoproliferativa periférica que acontece en los recién nacidos inmaduros, generalmente sometidos a oxigenoterapia. El Atlas está constituido por una extensa relación de retinografías (fotografías del fondo de ojo–retina) y tomografías de coherencia óptica (imágenes de cortes histológicos de la retina en vivo), exponiendo casos reales de patologías comunes y poco comunes. Constituye una herramienta con triple función: por un lado, será un elemento didáctico para el aprendizaje de patologías retinianas y el método de diagnóstico por imagen; en segundo lugar, puede utilizarse para realizar autoevaluaciones y, en tercer lugar, constituye una completa base de datos de casos clínicos. En definitiva, se trata de una herramienta muy económica y de gran utilidad para un amplio grupo de profesionales sanitarios expertos y especialistas en sistema visual

Axonal Guidance Using Biofunctionalized Straining Flow Spinning Regenerated Silk Fibroin Fibers as Scaffold

After an injury, the limited regenerative capacity of the central nervous system makes the reconnection and functional recovery of the affected nervous tissue almost impossible. To address this problem, biomaterials appear as a promising option for the design of scaffolds that promote and guide this regenerative process. Based on previous seminal works on the ability of regenerated silk fibroin fibers spun through the straining flow spinning (SFS) technique, this study is intended to show that the usage of functionalized SFS fibers allows an enhancement of the guidance ability of the material when compared with the control (nonfunctionalized) fibers. It is shown that the axons of the neurons not only tend to follow the path marked by the fibers, in contrast to the isotropic growth observed on conventional culture plates, but also that this guidance can be further modulated through the biofunctionalization of the material with adhesion peptides. Establishing the guidance ability of these fibers opens the possibility of their use as implants for spinal cord injuries, so that they may represent the core of a therapy that would allow the reconnection of the injured ends of the spinal cord.Unidad Docente de Biodiversidad, Ecología y EvoluciónFac. de Óptica y OptometríaTRUEMinisterio de Ciencia e Innovación de EspañaComunidad de Madrid (España)Banco Santander (España)Universidad Complutense de Madrid (España)pu

Programa piloto de uso del portafolio como herramienta docente en el Grado de Biología

Memoria final del proyecto de Innovación educativa "Programa piloto de uso del portafolio como herramienta docente en el Grado de Biología

Un Modelo Matemático para el Análisis de Señales por Neuronas Oscilantes (resumen de ponencia)

Resumen de ponencia publicada en la Revista de Neurología 2001; 33 (7): 657-658Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu

Necessary conditions for signal processing by resonant neurons

We study a mathematical model for information processing and coding by means of groups of resonant neurons. We conclude that incoming signals can be expressed by means of their Fourier series which coefficients are represented by the value of the membrane potential of the resonant neurons.Depto. de Análisis Matemático y Matemática AplicadaFac. de Ciencias BiológicasTRUEpu