Regiones del encéfalo vinculadas a la interpretación del dolor / Regions of the brain involved with the interpretation of the pain

Introducción: Entre el lugar del daño tisular y la percepción del dolor, ocurre una serie de eventos electroquímicos que se conocen como nocicepción y comprenden cuatro procesos neurofisiológicos conocidos como: transducción, transmisión, modulación y percepción. Objetivo: Aportar información actualizada sobre las regiones del encéfalo vinculadas a la interpretación del dolor. Material y Método: Se realizó una revisión bibliográfica, con vistas a esclarecer la interpretación de la señal nociceptiva. Se consultaron treinta y cinco artículos científicos, se determinó escoger un total de veintinueve por su relación directa con el propósito de la búsqueda, veintitrés de los cuales corresponden a los últimos 5 años publicados en revistas internacionales y nacionales. Desarrollo: Los axones nociceptivos se clasifican como A δ; y C, participan en la conducción de los potenciales de acción de la periferia al sistema nervioso central. La transmisión de la señal en forma de potenciales de acción se descodifica en áreas relacionadas con aspectos cognoscitivos, afectivo, emocional y conductual del dolor. Este disímil conjunto de estructuras se reconoce en la actualidad como matriz encefálica del dolor. Conclusiones: La matriz del dolor, corresponde a áreas encefálicas como las cortezas somestésicas SI y SII, implicadas en el aspecto discriminativo del dolor. La corteza cingulada anterior y la corteza insular están asociadas al componente afectivo emocional del dolor(AU)

Introduction: A series of electrochemical events called nociception occur between the tissue damage and the perception of pain. They include four neurophysiological processes known as: transduction, transmission, perception, and modulation. Objective: To provide up-to-date information about the regions of the brain involved with the interpretation of pain. Material and Method: A bibliographic review was carried out with the aim of clarifying the interpretation of the nociceptive signal. Thirty-five scientific articles were consulted, and a total of twenty-nine were chosen due to their direct relationship with the aim of the search, twenty-three of which correspond to the last five years of publication in national and international journals. Development: Nociceptive axons are classified as Aδ; and C, and participate in the conduction of action potential of the peripheral nervous system (PNS). The transmission of the signal in the form of action potential is decoded in areas related to cognoscitive, affective, and emotional aspects, and the behavioral area of pain. This dissimilar group of structures is recognized at present as the brain matrix of pain. Conclusions: The pain matrix corresponds to brain areas such as SI and SII somatosensory cortices, implied in the discriminative aspect of pain. Both the anterior cingulate cortex (ACC) and the anterior insular cortex (AIC) are associated with the emotional and affective component of pain(AU)

Neural circuit remodeling and structural plasticity in the cortex during chronic pain

Damage in the periphery or spinal cord induces maladaptive plastic changes along the somatosensory nervous system from the periphery to the cortex, often leading to chronic pain. Although the role of neural circuit remodeling and structural synaptic plasticity in the 'pain matrix' cortices in chronic pain has been thought as a secondary epiphenomenon to altered nociceptive signaling in the spinal cord, progress in whole brain imaging studies on human patients and animal models has suggested a possibility that plastic changes in cortical neural circuits may actively contribute to chronic pain symptoms. Furthermore, recent development in two-photon microscopy and fluorescence labeling techniques have enabled us to longitudinally trace the structural and functional changes in local circuits, single neurons and even individual synapses in the brain of living animals. These technical advances has started to reveal that cortical structural remodeling following tissue or nerve damage could rapidly occur within days, which are temporally correlated with functional plasticity of cortical circuits as well as the development and maintenance of chronic pain behavior, thereby modifying the previous concept that it takes much longer periods (e.g. months or years). In this review, we discuss the relation of neural circuit plasticity in the 'pain matrix' cortices, such as the anterior cingulate cortex, prefrontal cortex and primary somatosensory cortex, with chronic pain. We also introduce how to apply long-term in vivo two-photon imaging approaches for the study of pathophysiological mechanisms of chronic pain.