Señales de amenaza y sesgo atencional en lafobia a la sangre, inyecciones y heridasy en la fobia a las serpientes

El objetivo de esta investigación fue estudiar el efecto de una señal que indica la aparición de una imagen fóbica sobre la actividad electrocortical provocada por el estímulo relevante para el trastorno en la fobia a la sangre por lesión en inyección (BII) y la fobia a las serpientes. Una muestra de 13 participantes con fobia BII, 12 individuos con fobia a las serpientes y 14 controles no fóbicos se sometieron a una tarea S1-S2, donde S1 era una palabra que describía el contenido de una imagen posterior (relacionada con la sangre, serpiente y neutral) que apareció 2 segundos después (S2). Obtuvimos las amplitudes ERP P200 y P300 provocadas por las imágenes. Nuestros resultados revelan que P200 no diferenciaba entre el contenido de las imágenes en la fobia BII mientras que, por el contrario, las imágenes relacionadas con la serpiente y la sangre provocaron las respuestas más grandes en los participantes con fobia a las serpientes. Tanto las imágenes relacionadas con la sangre como las de serpientes provocaron amplitudes de P300 mayores que las imágenes neutrales en todos los grupos. Las señales de amenaza redujeron la reacción electrocortical del BII, posiblemente por la provocación de respuestas anticipatorias o reguladoras. Estos resultados son indicativos de una baja atención automática exógena hacia los estímulos temidos en la fobia BII, como lo revela P200, probablemente relacionado con una falta de sesgo de atención al objeto fóbico. The aim of this research was to study the effect of a cue signalling the upcoming of a phobic picture on the electrocortical activity provoked by the disorder-relevant stimulus in in blood-injection-injury (BII) phobia and snake phobia. A sample of 13 BII phobia participants, 12 snake phobia individuals and 14 non-phobic controls underwent an S1-S2 task, where S1 was a word that described the content of a subsequent picture (blood-related, snake and neutral) that appeared 2 seconds later (S2). We obtained the P200 and P300 ERP amplitudes provoked by the pictures. Our results reveal that P200 did not differentiate between picture contents in BII phobia while, in contrast, snake and blood-related pictures provoked the largest responses in snake phobia participants. Both blood-related and snake pictures provoked greater P300 amplitudes than neutral pictures in all the groups. Threat cues reduced the electrocortical reaction of the BII, possibly by the elicitation of anticipatory or regulatory responses. These results are indicative of a low automatic, exogenous attention towards the feared stimuli in BII phobia, as revealed by P200, probably related to a lack of attentional bias to the phobic object.

Head-Down Tilt Position, but Not the Duration of Bed Rest Affects Resting State Electrocortical Activity

Adverse cognitive and behavioral conditions and psychiatric disorders are considered a critical and unmitigated risk during future long-duration space missions (LDSM). Monitoring and mitigating crew health and performance risks during these missions will require tools and technologies that allow to reliably assess cognitive performance and mental well-being. Electroencephalography (EEG) has the potential to meet the technical requirements for the non-invasive and objective monitoring of neurobehavioral conditions during LDSM. Weightlessness is associated with fluid and brain shifts, and these effects could potentially challenge the interpretation of resting state EEG recordings. Head-down tilt bed rest (HDBR) provides a unique spaceflight analog to study these effects on Earth. Here, we present data from two long-duration HDBR experiments, which were used to systematically investigate the time course of resting state electrocortical activity during prolonged HDBR. EEG spectral power significantly reduced within the delta, theta, alpha, and beta frequency bands. Likewise, EEG source localization revealed significantly lower activity in a broad range of centroparietal and occipital areas within the alpha and beta frequency domains. These changes were observed shortly after the onset of HDBR, did not change throughout HDBR, and returned to baseline after the cessation of bed rest. EEG resting state functional connectivity was not affected by HDBR. The results provide evidence for a postural effect on resting state brain activity that persists throughout long-duration HDBR, indicating that immobilization and inactivity per se do not affect resting state electrocortical activity during HDBR. Our findings raise an important issue on the validity of EEG to identify the time course of changes in brain function during prolonged HBDR, and highlight the importance to maintain a consistent body posture during all testing sessions, including data collections at baseline and recovery.

Variations in Electrocortical Activity due to Surgical Incision in Anaesthetized Cardiac Patients: Electroencephalogram-Based Quantitative Analysis

This study examines the alterations in scalp recorded cortical activity due to surgical incision in anaesthetized cardiac patients using electroencephalogram (EEG) patterns. The primary aim was to compare the changes in electrocortical activity after surgical incision. The secondary aim was to compare the changes in time, frequency, and wavelet domain parameters after loss of consciousness (LoC) and after intubation. Real-time EEG data were recorded from 19 patients undergoing cardiac surgery and signals were quantified with time, frequency, and wavelet domain parameters. An increase in hjorth activity, hjorth complexity, rms value, total band power, relative delta band power, standard deviation and maxima of approximation coefficients (a5), minima of detail coefficients (d5, d4, and d3) and decrease in hjorth mobility; approximate entropy; relative theta, alpha, and beta band power; specentropy; median, spectral edge, and mean frequency; mean of detail coefficients (d4); standard deviation of detail coefficients (d5, d4, and d3); maxima of detail coefficients (d5); and minima of approximation coefficients (a5) were observed during LoC. Decrease in hjorth activity; hjorth mobility; rms value; total band power; relative theta band power; median frequency; standard deviation of coefficients (a5, d5, d4, and d3); and maxima of coefficients (a5, d5, d4, and d3) and increase in hjorth complexity; mean of detail coefficients (d5); and minima of coefficients (a5, d5, d4, and d3) were observed after intubation. Significant decrease in hjorth activity; hjorth mobility; total band power; relative alpha band power; specentropy; median and mean frequency; standard deviation and maxima of detail coefficients (d5, d4, and d3) and increase in rms value; relative delta band power; mean of coefficients (a5 and d5); and minima of coefficients (d5, d4, and d3) were observed due to surgical incision. It can be concluded that different spectral and temporal parameters of EEG signals are highly sensitive to induction, intubation, and surgical incision which are potentially informative for measuring the depth of anaesthesia or efficacy of anaesthetic agents.

Diagnostic and predictive value of aEEG in newborns in critical state under sedation

The objective: to study the diagnostic and prognostic value of amplitude-integrated electroencephalography (aEEG) in sedated neonates in critical state, through testing the level of S100B protein. Subjects and methods: 44 patients were enrolled in the study. The study group included patients with pathological patterns of 24-hour aEEG, in the control group, all patients had normal patterns. The level of serum S100B protein was compared in the groups on the 1st and 7th day of life as well as the early neurological outcome which was used to assess the prognostic significance of aEEG. In addition, the cut-off point of S100B in predicting an adverse outcome was estimated.Results. There were no significant difference in the level of S100B of the 1st day of life between the groups, however, there was a correlation between the severity of depression of electrocortical activity and the level of S100B protein (tau = -0.36, p < 0.001). On the 7th day of life, the level of S100B protein was significantly (p = 0.047) higher in the study group (337 (251; 819) ng/l) compared to the control group (259 (136; 354) ng/l). Elevation of S100B protein by the 7th day of life was not associated with pathological aEEG patterns or the outcome. aEEG sensitivity (Se) was 87%, specificity (Sp) ‒ 62%. The cut-off point for S100B of the first day of life was 493 ng/l with Se of 52% and Sp of 91%.Conclusion. There is a correlation between the severity of depression of electrocortical activity recorded by aEEG and S100B level on the 1st and 7th days of life,which confirms the diagnostic value of aEEG in newborns in critical state despite the use of sedation. The elevated level of S100B in the first week of life has neither diagnostic nor prognostic significance. aEEG has the highest predictive sensitivity, and S100B above 493 ng/l has the highest predictive specificity.