Electroencefalografía básica para monitores de profundidad anestésica / Basic electroencephalography for anesthesia depth monitors

Resumen: Los monitores de profundidad anestésica permiten guiar el estado hipnótico del paciente durante la anestesia general. Debido a su sencillez, tradicionalmente se han empleado índices de profundidad anestésica, obtenidos a través del procesamiento del electroencefalograma mediante algoritmos matemáticos, para orientar la monitorización del nivel de consciencia. Sus beneficios han sido ampliamente recogidos en la literatura científica; sin embargo, no están exentos de importantes limitaciones. No todos los anestésicos actúan en las mismas dianas moleculares ni dichos índices tienen en cuenta las características propias del paciente (comorbilidades, edades extremas, etcétera). Estas limitaciones podrían reducirse si interpretamos directamente toda la información que nos ofrecen los monitores. Presentamos una revisión que describe los conceptos básicos necesarios para su valoración directa, así como su correlación con los estados de profundidad anestésica del paciente.

Abstract: Anesthesia depth monitors allow to guide the patient's hypnotic state during general anesthesia. Traditionally, anesthetic depth indices have been used due to their simplicity to guide the monitoring of the level of consciousness. They have been obtained by processing the electroencephalogram using mathematical algorithms and their benefits have been widely reported in the scientific literature. However, they are not exempt from important limitations. Neither all anesthetics act on the same molecular targets, nor these mentioned indices take into account the patient's own characteristics (comorbidities, extreme ages, etc.). These limitations could be far reduced if we are able to understand all the information provided by the monitors. We present a review describing the basic concepts necessary for its direct assessment, as well as their correlation with the patient's anesthetic depth states.

A Cognition-Related Neural Oscillation Pattern, Generated in the Prelimbic Cortex, Can Control Operant Learning in Rats.

The prelimbic (PrL) cortex constitutes one of the highest levels of cortical hierarchy dedicated to the execution of adaptive behaviors. We have identified a specific local field potential (LFP) pattern generated in the PrL cortex and associated with cognition-related behaviors. We used this pattern to trigger the activation of a visual display on a touch screen as part of an operant conditioning task. Rats learned to increase the presentation rate of the selected θ to ß-γ (θ/ß-γ) transition pattern across training sessions. The selected LFP pattern appeared to coincide with a significant decrease in the firing of PrL pyramidal neurons and did not seem to propagate to other cortical or subcortical areas. An indication of the PrL cortex's cognitive nature is that the experimental disruption of this θ/ß-γ transition pattern prevented the proper performance of the acquired task without affecting the generation of other motor responses. The use of this LFP pattern to trigger an operant task evoked only minor changes in its electrophysiological properties. Thus, the PrL cortex has the capability of generating an oscillatory pattern for dealing with environmental constraints. In addition, the selected θ/ß-γ transition pattern could be a useful tool to activate the presentation of external cues or to modify the current circumstances.SIGNIFICANCE STATEMENT Brain-machine interfaces represent a solution for physically impaired people to communicate with external devices. We have identified a specific local field potential pattern generated in the prelimbic cortex and associated with goal-directed behaviors. We used the pattern to trigger the activation of a visual display on a touch screen as part of an operant conditioning task. Rats learned to increase the presentation rate of the selected field potential pattern across training. The selected pattern was not modified when used to activate the touch screen. Electrical stimulation of the recording site prevented the proper performance of the task. Our findings show that the prelimbic cortex can generate oscillatory patterns that rats can use to control their environment for achieving specific goals.

Tratamiento del vitiligo con esencias florales de Bach. Presentación de casos / Vitiligo treatment with Bach floral essences. Cases presentation

Se realiza una presentación de casos, de 2 pacientes en edades pediátricas con diagnóstico clínico de vitiligo. El objetivo del estudio fue exponer los resultados del tratamiento de esta dermatosis con esencias florales de Bach. Los pacientes estudiados fueron: RLT de 6 años, masculino, negro, remitido por lesiones en placas máculo- acrómicas, de 2 cm de diámetro, distribuidas en nuca y región lateral izquierda del cuello; el otro paciente OJTS, de 13 años, masculino, negro, que es remitido, por presentar lesiones en placas máculo-acrómicas, bordes precisos de 1 a 2 cm, de diámetro localizadas en región frontal y mejilla izquierda. Se les realizó interrogatorio, examen clínico general por el dermatólogo y el pediatra. Previo consentimiento informado se indicó tratamiento con esencias forales de Bach (Crab Apple, Willow y Walnut) y seguimiento posterior. Ambos niños llevan 5 años asintomáticos.

It is made the case presentation of two pediatric-aged patients with clinical diagnosis of vitiligo. The aim of the study was exposing the results of this dermatosis treatment with Bach floral essences. The studied patients were: RLT, aged 6 years, male, black, remitted because of lesions in macula-achromatic plaques, of 2 cm diameter, located in nape and left lateral region of the neck; the other patient, OJTS, aged 13 years, male, black, is remitted for presenting lesions in macula-achromatic plaques, precise edges, ranging from 1 to 2 cm of diameter, located in frontal region and left cheek. The dermatologist and the pediatrician made questioning and clinical general examination. After obtaining the informed consent a treatment with Bach floral essences (Crab Apple, Willow, and walnut) and they were followed up. Both children are asymptomatic already for 5 years.

Altered distribution of hippocampal interneurons in the murine Down Syndrome model Ts65Dn.

Down Syndrome, with an incidence of one in 800 live births, is the most common genetic alteration producing intellectual disability. We have used the Ts65Dn model, that mimics some of the alterations observed in Down Syndrome. This genetic alteration induces an imbalance between excitation and inhibition that has been suggested as responsible for the cognitive impairment present in this syndrome. The hippocampus has a crucial role in memory processing and is an important area to analyze this imbalance. In this report we have analysed, in the hippocampus of Ts65Dn mice, the expression of synaptic markers: synaptophysin, vesicular glutamate transporter-1 and isoform 67 of the glutamic acid decarboxylase; and of different subtypes of inhibitory neurons (Calbindin D-28k, parvalbumin, calretinin, NPY, CCK, VIP and somatostatin). We have observed alterations in the inhibitory neuropil in the hippocampus of Ts65Dn mice. There was an excess of inhibitory puncta and a reduction of the excitatory ones. In agreement with this observation, we have observed an increase in the number of inhibitory neurons in CA1 and CA3, mainly interneurons expressing calbindin, calretinin, NPY and VIP, whereas parvalbumin cell numbers were not affected. These alterations in the number of interneurons, but especially the alterations in the proportion of the different types, may influence the normal function of inhibitory circuits and underlie the cognitive deficits observed in DS.

Role of motor cortex NMDA receptors in learning-dependent synaptic plasticity of behaving mice.

The primary motor cortex has an important role in the precise execution of learned motor responses. During motor learning, synaptic efficacy between sensory and primary motor cortical neurons is enhanced, possibly involving long-term potentiation and N-methyl-D-aspartate (NMDA)-specific glutamate receptor function. To investigate whether NMDA receptor in the primary motor cortex can act as a coincidence detector for activity-dependent changes in synaptic strength and associative learning, here we generate mice with deletion of the Grin1 gene, encoding the essential NMDA receptor subunit 1 (GluN1), specifically in the primary motor cortex. The loss of NMDA receptor function impairs primary motor cortex long-term potentiation in vivo. Importantly, it impairs the synaptic efficacy between the primary somatosensory and primary motor cortices and significantly reduces classically conditioned eyeblink responses. Furthermore, compared with wild-type littermates, mice lacking NMDA receptors in the [corrected] primary motor cortex show slower learning in Skinner-box tasks. Thus, primary motor cortex NMDA receptors are necessary for activity-dependent synaptic strengthening and associative learning.