Pitiriasis rosada como manifestación dermatológica de infección por SARS-CoV-2: a propósito de un caso / Pityriasis rosea as a cutaneous manifestation associated with SARS-CoV-2 infection: case report

Las manifestaciones cutáneas relacionadas a la infección por el coronavirus SARS-CoV-2, causante de COVID-19, se han descrito entre el 0,2% y 20,4% de las personas que cursan con esta enfermedad. Las más frecuentemente descritas son: lesiones maculopapulares (47%), lesiones acrales eritematosas con vesículas o pústulas (pseudoperniosis) (19%), urticariales (19%), lesiones vesiculosas (9%) y livedo/necrosis (6%). En particular, la pitiriasis rosada es una dermatosis autolimitada de etiología desconocida, sin embargo, se ha visto asociada a la infección por SARS-CoV-2, con algunos reportes de casos en la literatura. El mecanismo fisiopatológico de las lesiones cutáneas en COVID-19 no es claro, y se han planteado algunas teorías, entre las cuales está el papel que juega la enzima convertidora de angiotensina 2 (ACE2) utilizada por el virus para infectar las células, los infiltrados linfocíticos, los depósitos de factores del complemento en la piel, y la reactivación de virus latentes como los herpes virus humanos. Se presenta el caso de una paciente con pitiriasis rosada asociada a COVID-19 y se describen los casos reportados hasta la fecha

Factores tempranos asociados a apendicectomía negativa / Early factors associated with negative appendectomy

Objetivo: analizar características predictoras de apendicectomía negativa (AN) en una cohorte de pacientes llevados a cirugía durante el año 2018 en una institución de salud de alta complejidad de la ciudad de Medellín, Colombia. Materiales y Métodos: seguimiento retrospectivo a una cohorte basada en registros médicos. Se analizaron pacientes adultos sometidos a apendicectomía. Se estimó la tasa de AN y se describieron características clínicas, paraclínicas y sociodemográficas. Se analizaron predictores de AN mediante el modelo lineal generalizado familia binomial, enlace logarítmico. Se presentan razones de riesgo (RR) observadas y ajustadas junto con intervalos de confianza del 95% (IC95%). Para el modelo multivariado se estimó el área bajo la curva del operador receptor (ROC). Resultados: la tasa de AN fue de 5,2%. No se solicitó tomografía computarizada (TC) de abdomen en el 48,9% de los casos, 4,1% de los pacientes presentaron disuria. Entre los factores estudiados, la disuria, no solicitud de TC, edad y leucocitosis, se asociaron significativamente con mayor riesgo de AN. Resaltan particularmente los pacientes que presentaron disuria y no les fue solicitado TC, en quienes el riesgo ajustado de AN fue de 30,3% (RR = 17,31; IC95% 5,00 ­ 59,87). ROC fue 0,834. Conclusiones: los pacientes llevados a cirugía sin TC y que se presentaron con disuria, particularmente los de mayor edad, concentraron el mayor riesgo de AN. Considerar estas características al definir el manejo quirúrgico del paciente con sospecha de apendicitis aguda, puede contribuir a disminuir las AN..(Au)

Objective: to analyze predictive characteristics of negative appendectomy (NA) in a cohort of patients who underwent surgery during 2018 in a high complexity healthcare institution in the city of Medellín, Colombia. Materials and Methods: retrospective follow-up to a cohort of adult patients who underwent appendectomy. The rate of NA was estimated and the clinical, paraclinical and sociodemographic characteristics were described. The analysis of predictors of NA was carried out using the generalized linear model binomial family, logarithmic link. Observed and adjusted risk ratios (RR) are presented along with 95% confidence intervals (95% CI). For the multivariate model, the area under the receiver operator curve (ROC) was estimated. Results: the NA rate was 5.2%. Abdominal computed tomography (CT) was not requested in 48.9% of the cases, 4.1% of the patients had dysuria. Among the factors studied, dysuria, nonrequest for CT, age and leukocytosis were significantly associated with a higher risk of NA. Is worth noting that the adjusted risk of NA of the patients who presented with dysuria and those in which no CT was requested, was 30.3% (RR = 17.31; 95% CI 5.00 - 59.87). ROC was 0.834. Conclusions: patients who underwent surgery without CT and presented with dysuria, particularly the older ones, had the highest risk of NA. Considering these characteristics when defining the surgical management of patients with suspected acute appendicitis can help reduce NA..(Au)

CoVidAffect, real-time monitoring of mood variations following the COVID-19 outbreak in Spain.

The COVID-19 outbreak and the ensuing confinement measures are expected to bear a significant psychological impact on the affected populations. To date, all available studies designed to investigate the psychological effects of this unprecedented global crisis are based on cross-sectional surveys that do not capture emotional variations over time. Here, we present the data from CoVidAffect, a nationwide citizen science project aimed to provide longitudinal data of mood changes following the COVID-19 outbreak in the spanish territory. Spain is among the most affected countries by the pandemic, with one of the most restrictive and prolonged lockdowns worldwide. The project also collected a baseline of demographic and socioeconomic data. These data can be further analyzed to quantify emotional responses to specific measures and policies, and to understand the effect of context variables on psychological resilience. Importantly, to our knowledge this is the first dataset that offers the opportunity to study the behavior of emotion dynamics in a prolonged lockdown situation.

Aves como indicadoras ecológicas de etapas sucesionales en un bosque secundario, Antioquia, Colombia

Las áreas que se recuperan perturbaciones tales como actividades agrícolas y ganaderas, generan un aumento de bosques secundarios que causan cambios en la cantidad y calidad del hábitat disponible para las aves. El Índice de Integridad Biótica (IIB) compara la estructura, composición y función del ensamblaje de las aves en una regeneración secundaria del bosque, desde edades tempranas hasta maduras, para evaluar su condición ecológica. Se estudió la integridad ecológica utilizando el IIB en cuatro etapas de sucesión de bosque secundario. El IBI se calculóutilizando ensamblajes de aves encontrados en estas cuatro etapas de la sucesión de bosques, y su desempeño se comparócon la riqueza general y elíndice de diversidad de Shannon. Se realizaron cinco muestreos de campo entre junio 2016 y febrero 2017, en los que se registraron las aves utilizando recuentos de puntos de radio fijo. En total, se registraron 9 516 individuos de 187 especies de aves pertenecientes a 42 familias y 15 órdenes. Para cada especie se estableció hábitat de presencia, gremio de forrajeo y grupos de indicadores potenciales. La riqueza de especies y el Índice de Abundancia Puntual (PAI) de todas las categorías, se utilizaron como métricas candidatas y luego de evaluar un total de 34 métricas, se seleccionaron 13 para los análisis. Las métricas que se correlacionaron positivamente con el gradiente, de mayor a menor perturbación, fueron: riqueza de insectívoros de interior de bosque, abundancia de especies exclusivamente de interior de bosque, abundancia de especies de interior y borde, abundancia de especies endémicas y abundancia de especies amenazadas. Las métricas que se correlacionaron negativamente con el gradiente, de mayor a menor perturbación, fueron abundancia de especies de áreas abiertas, abundancia de especies de áreas abiertas y de borde, abundancia de frugívoros, abundancia de granívoros, abundancia de omnívoros, abundancia de insectívoros, abundancia de carroñeros y abundancia de especies migratorias. El IBI mostró una correlación lineal significativa positiva con el gradiente de regeneración secundaria del bosque, desde edades tempranas hasta maduras, mientras que la riqueza total de especies y el índice de diversidad de Shannon mostraron una correlación lineal negativa. El IBI, en este caso particular, demostró ser mejor que las medidas clásicas de la riqueza de especies y el índice de diversidad de Shannon para evaluar e interpretar la condición ecológica y ambiental de las etapas de la sucesión del bosque secundario evaluado.

Recovering areas from disturbance, after agriculture and livestock activities, increases secondary forests extension, which might change the quantity and quality of available habitat for birds. The Index of Biotic Integrity (IBI) compare the structure, composition and function of bird assemblages in secondary regeneration forest, from early succession to mature forest, to evaluate the ecological condition. Thus, the ecological condition along four stages of secondary forest in Antioquia, Colombia were studied using the IBI. This index was compared with richness and Shannon's diversity Index of the same bird assemblages. Five field surveys were conducted between June 2016 and February 2017, using fixed-radius point counts. In total 9 516 individuals, from 187 bird species, belonging to 42 families and 15 orders were recorded. Habitat of occurrence, foraging guild and potential indicators groups were established for every species. Species richness and Punctual Abundance Index (PAI) of all categories were defined as candidate metrics, and after evaluating a total of 34 metrics, 13 were selected for further analysis. Metrics that were positively correlated with successional forest gradient, from highest to lowest disturbance, were: species richness of forest interior insectivorous, abundance of exclusively forest species, abundance of forest interior and edge species, abundance of endemic species and abundance of threatened species. Metrics that were negatively correlated with successional forest gradient, from highest to lowest disturbance, were: abundance of species from open areas, abundance of open areas and edge species, abundance of frugivorous, abundance of granivorous, abundance of omnivorous, abundance of insectivorous, abundance of scavengers and abundance of migratory species. IBI showed a positive significant linear correlation with the gradient of secondary forest regeneration, from early to mature forest, while Shannon´s diversity Index and species richness showed a negative significant linear correlation. So that, in this particular case, IBI proved to be better indicator that the classical measures for assessing and interpreting ecological and environmental condition along the secondary forest succession evaluated.

Circadian rhythms and decision-making: a review and new evidence from electroencephalography.

Since emotions and regulatory control are relevant for decision-making, their circadian fluctuation should influence the outcome of such decisions, but this question has been rarely addressed. A review of the literature suggests that the evidence regarding circadian synchrony effects (better performance at optimal vs. non-optimal times of day according to chronotype) on decision-making is mixed, likely due to the use of different approaches to estimate chronotype. The current experiment studied economic decision-making as a function of both chronotype and the time of day when decisions are made. The influence of chronotype (Morning-type: N = 28 vs. Evening-type: N = 30) and time of day (8 am vs. 10 pm) on decision-making was measured by the acceptance rate of unfair and fair offers in the Ultimatum Game, and the event-related potentials time-locked to such offers. Subjective affect (PANAS), and appraisal of emotional images (IAPS) were also measured. Chronotype was estimated through questionnaires (MEQ, rMEQ, MCTQ) and the circadian rhythm of wrist temperature. Synchrony effects were found for both wrist temperature and subjective affect, but not for behavioral performance. Morning-types showed earlier phases of circadian rhythms in temperature, reported better sleep quality, more positive affective balance, accepted more unfair offers, and their frontal P200 potential was attenuated as compared to Evening-types in the Ultimatum Game. Acceptance rate of unfair offers correlated with the chronotype measured by questionnaires (positive correlation with rMEQ and MEQ scores, and negative correlation with Midsleep time in workdays -MSWsc from MCTQ) but not with midsleep time estimated through wrist temperature. Finally, participants who accepted more unfair offers later judged positive IAPS stimuli as more pleasant. We did not observe a synchrony effect in the Ultimatum Game, but morningness was related to rational decision-making as indexed by increased acceptance of unfair offers. Since morning-types show higher emotional regulation and positive mood than evening-types, it is possible that unfair offers did not elicit negative emotions as intense in morning-types as in evening-types, making it easier for them to accept.Abbreviations: ACC: anterior cingulate cortex; ANOVA: analysis of variance; BART: Balloon Analogue Risk Task; DLPFC: dorsolateral prefrontal cortex; EEG: electroencephalography; IAPS: International Affective Picture System; ICA: Independent component analysis; KSS: Karolinska Sleepiness Scale; LPP: Late Positive Potential; M: mean; MCTQ: Munich Chronotype Questionnaire; MEQ: Morningness Eveningness Questionnaire; MFN: Medial Frontal Negativity; MSWsc: midsleep time for working days corrected for sleep debt; MSFsc: midsleep time for free days corrected for sleep debt; N: number of participants; PANAS: Positive and Negative Affect Schedule; PSQI: Pittsburgh Sleep Quality Index; PVT: Psychomotor Vigilance Task; rMEQ: reduced Morningness Eveningness Questionnaire; RNA: Ribonucleic acid; RT: reaction time; SAM: Self-Assessment Manikin; SD: standard deviation; UG: Ultimatum Game.

Temporal preparation in patients with Neglect syndrome

The right parietal cortex has been widely associated with a spatial orienting network. Its damage frequently produces the Neglect syndrome consisting in deficits in spatial attention to the left hemifield. Neglect has also been related to temporal deficits (such as the estimation of the duration of a stimulus or the discrimination of two stimuli that occur at the same spatial location but at different time intervals). Such attentional deficits have been much less studied in the temporal as compared to the spatial domain. The current research focused on the study of temporal attention processes in patients with Neglect syndrome, specifically, on temporal preparation. We recruited 10 patients with Neglect syndrome, 10 patients without Neglect syndrome, as well as 11 healthy individuals. Each participant completed an experimental task which measures three main temporal preparation effects described in the literature: Temporal orienting and Foreperiod effects (both related to control mechanisms and prefrontal areas) and Sequential effects (automatic in nature and related to parietal and subcortical structures). The results showed a deficit in the sequential effects only in those patients who suffered from Neglect syndrome. The results suggest a causal relation between Neglect syndrome and the automatic mechanisms of temporal preparation. Since our sample of Neglect patients had suffered lesions mainly in the parietal cortex, the results are discussed taking into account the role of the parietal lobe in the processing of time and the models explaining sequential effects

La corteza parietal derecha ha sido asociada con una red de orientación espacial. Su daño produce frecuentemente el síndrome de Heminegligencia que consiste en déficits en la atención espacial al hemicampo izquierdo. Dicho síndrome también se ha relacionado con déficits temporales (como la estimación de la duración de un estímulo o la discriminación de dos estímulos que ocurren en la misma ubicación espacial pero en diferentes intervalos de tiempo). Sin embargo, tales déficits atencionales han sido menos estudiados en el ámbito temporal que en el espacial. La presente investigación pretende el estudio de los procesos de atención temporal en pacientes con síndrome de Heminegligencia. Se reclutaron 10 pacientes con síndrome de Heminegligencia, 10 pacientes sin Heminegligencia y 11 individuos sanos. Cada participante realizó una tarea experimental que estudia tres efectos principales de preparación temporal descritos en la literatura: Orientación temporal y Foreperiod (ambos relacionados con mecanismos de control y áreas prefrontales) y Efectos secuenciales (de naturaleza más automática y relacionados con estructuras parietales y subcorticales). Los resultados mostraron un déficit en los efectos secuenciales únicamente en los pacientes con Heminegligencia. Esto sugiere una relación causal entre el síndrome de Heminegligencia y los mecanismos automáticos de preparación temporal. Dado que nuestra muestra de pacientes heminegligentes había sufrido lesiones principalmente en la corteza parietal, los resultados se discuten teniendo en cuenta el papel del lóbulo parietal en el procesamiento del tiempo, y en el marco de los modelos que explican los efectos secuenciales

Cognitive entrainment to isochronous rhythms is independent of both sensory modality and top-down attention

The anisochrony of a stimulus sequence was manipulated parametrically to investigate whether rhythmic entrainment is stronger in the auditory modality than in the visual modality (Experiment 1), and whether it relies on top-down attention (Experiment 2). In Experiment 1, participants had to respond as quickly as possible to a target presented after a sequence of either visual or auditory stimuli. The anisochrony of this sequence was manipulated parametrically, rather than in an all or none fashion; that is, it could range from smaller to larger deviations of the isochrony (0, 10, 20, 50, 100, 150 and 200 ms). We compared rhythmic entrainment patterns for auditory and visual modalities. Results showed a peak of entrainment for both isochrony and deviations of isochrony up to 50 ms (i. e. , participants were equally fast both after the isochronous sequences and after 10, 20 and 50 ms deviations), suggesting that anisochronous sequences can also produce entrainment. Beyond this entrainment window, the reaction times became progressively slower. Surprisingly, no differences were found between the entrainment patterns for auditory and visual rhythms. In Experiment 2, we used a dual-task methodology by adding a working memory n-back task to the procedure of Experiment 1. Results did not show interference of the secondary task in either auditory or visual modalities, with participants showing the same entrainment pattern as in Experiment 1. These results suggest that rhythmic entrainment constitutes a cognitive process that occurs by default (automatically), regardless of the modality in which the stimuli are presented, and independent of top-down attention, to generate behavioural benefits

La anisocronía de una secuencia de estímulos se ha manipulado paramétricamente para investigar si la sincronización rítmica es más potente en la modalidad auditiva que en la visual (Experimento 1), y si esta depende de procesos de la atención de tipo arriba-abajo (Experimento 2). En el Experimento 1, los participantes tenían que responder lo más rápido posible ante un estímulo objetivo presentado después de una secuencia de estímulos que podían ser visuales o auditivos. La anisocronía de esta secuencia era manipulada paramétricamente en lugar de siguiendo un procedimiento discreto del tipo "todo o nada"; es decir, la anisocronía podía variar en un rango de pequeñas a mayores desviaciones (0, 10, 20, 50, 100, 150 y 200 ms). Los patrones resultantes de la sincronización rítmica fueron comparados para las modalidades auditiva y visual. Los resultados mostraron un pico de sincronización para las condiciones de isocronía y las condiciones de anisocronía que tenían hasta un máximo de 50 ms de desviación (es decir, los participantes respondían igual de rápido para las condiciones de desviación 0, 10, 20 y 50 ms), lo cual sugiere que las secuencias anisócronas también pueden producir sincronización rítmica. A partir de esta ventana de sincronización, los tiempos de reacción fueron progresivamente más altos. Sorprendentemente, no encontramos diferencias en los patrones de sincronización entre los ritmos auditivos y los visuales. En el Experimento 2, utilizamos una metodología de tarea dual mediante la inclusión de una tarea n-back de memoria de trabajo al procedimiento del Experimento 1. Los resultados no mostraron una interferencia de la tarea secundaria ni en la modalidad auditiva ni en la visual, pues los participantes mostraron el mismo patrón de sincronización que en el Experimento 1. Estos resultados sugieren que la sincronización rítmica constituye un proceso cognitivo que beneficia el comportamiento, que ocurre por defecto (automáticamente), independientemente de la modalidad por la que se presenten los estímulos, y que es independiente de procesos "arriba-abajo" de la atención

Electroencephalographic and peripheral temperature dynamics during a prolonged psychomotor vigilance task.

Attention lapses and fatigue are a main source of impaired performance that can lead to accidents. This study analyzed electroencephalographic (EEG) dynamics and body skin temperature as markers of attentional fluctuations in non-sleep deprived subjects during a 45min Psychomotor Vigilance Task (PVT). Independent Component Analysis and time-frequency analysis were used to evaluate the EEG data. Results showed a positive association between distal and distal-to-proximal gradient (DPG) temperatures and reaction time (RT); increments in EEG power in alpha-, theta- and beta-band frequencies in parieto-occipital, central-medial and frontal components, were associated with poor performance (slower RT) in the task. This generalized power increment fits with an increased activity in the default mode network, associated with attention lapses. This study highlights the potential use of the PVT as a tool to obtain individual physiological indices of vigilance and fatigue that could be applied to other vigilance tasks typically performed in occupational settings.

Application of Machine Learning Methods to Ambulatory Circadian Monitoring (ACM) for Discriminating Sleep and Circadian Disorders.

The present study proposes a classification model for the differential diagnosis of primary insomnia (PI) and delayed sleep phase disorder (DSPD), applying machine learning methods to circadian parameters obtained from ambulatory circadian monitoring (ACM). Nineteen healthy controls and 242 patients (PI = 184; DSPD = 58) were selected for a retrospective and non-interventional study from an anonymized Circadian Health Database (https://kronowizard.um.es/). ACM records wrist temperature (T), motor activity (A), body position (P), and environmental light exposure (L) rhythms during a whole week. Sleep was inferred from the integrated variable TAP (from temperature, activity, and position). Non-parametric analyses of TAP and estimated sleep yielded indexes of interdaily stability (IS), intradaily variability (IV), relative amplitude (RA), and a global circadian function index (CFI). Mid-sleep and mid-wake times were estimated from the central time of TAP-L5 (five consecutive hours of lowest values) and TAP-M10 (10 consecutive hours of maximum values), respectively. The most discriminative parameters, determined by ANOVA, Chi-squared, and information gain criteria analysis, were employed to build a decision tree, using machine learning. This model differentiated between healthy controls, DSPD and three insomnia subgroups (compatible with onset, maintenance and mild insomnia), with accuracy, sensitivity, and AUC >85%. In conclusion, circadian parameters can be reliably and objectively used to discriminate and characterize different sleep and circadian disorders, such as DSPD and OI, which are commonly confounded, and between different subtypes of PI. Our findings highlight the importance of considering circadian rhythm assessment in sleep medicine.

Relaciones entre la diversidad de aves y la estructura de vegetación en cuatro etapas sucesionales de bosque secundario, antioquia, colombia / Relationships between bird diversity and vegetation structure in four secondary forest successional stages, antioquia, colombia

RESUMEN Se estudió la relación entre la diversidad taxonómica y funcional del ensamblaje de aves y la estructura de vegetación, en cuatro estadios de sucesión secundaria de bosque, realizando cinco muestreos, entre junio de 2016 y febrero de 2017, en los que se registraron las aves, mediante puntos de conteo de radio fijo y se caracterizó la estructura de la vegetación de cada sucesión. Se estableció la abundancia, la preferencia, la especificidad de hábitat y el gremio trófico, así como la riqueza y la diversidad de las especies de aves y las relaciones entre la composición de las especies y los gremios tróficos con las variables del hábitat. Se registraron 9.516 individuos de 187 especies, pertenecientes a 42 familias y 15 órdenes. Se determinaron dos agrupaciones, separando los estadios sucesionales SS1 y SS2, de los estadios SS3 y SS4, con una similitud entre los dos grupos del 10%, a nivel taxonómico y del 32%, a nivel funcional. La regeneración natural posterior al abandono de prácticas agropecuarias, permiten un incremento de áreas de bosque secundario que, en la medida en que obtienen mayor complejidad estructural, se asocian con una mayor cantidad de especies con preferencia de hábitat de interior de bosque y un aumento de los gremios tróficos nectarívos y frugívoros.

ABSTRACT The relationships between taxonomic and functional diversity of bird assemblage and vegetation structure in four stages of secondary forest succession were studied. Five field samplings were carried out between June 2016 and February 2017, in which birds were recorded using fixed radius point counts, and the vegetation structure of each successional stage was characterized. Bird species were identified and their habitat preference, specificity and trophic guilds were established. The abundance, preference, habitat specificity and trophic guild, and the richness and diversity of species of birds and relationships between species composition and trophic guilds with habitat variables in the four sequences was established. 9516 individuals from 187 bird species belonging to 42 families and 15 orders were registered. Two clusters separating the SS1 and SS2 of SS3 and SS4 successional stages, were determined, with a similarity between both of 10% at taxonomic level and 32% at functional level. The natural regeneration subsequent to the abandonment of agricultural practices allow an increase in secondary forest areas, which to the extent they get greater structural complexity, are associated with increased number of forest interior species, and an increase of nectarivorous and frugivorous guilds.

Electroencephalographic and skin temperature indices of vigilance and inhibitory control / Índices de la vigilancia y el control inhibitorio basados en electroencefalografía y temperatura de la piel

Neurophysiological markers of the ability to sustain attention and exert inhibitory control of inappropriate responses have usually relied on neuroimaging methods, which are not easily applicable to real-world settings. The current research tested the ability of electroencephalographic and skin temperature markers to predict performance during the Sustained Attention to Response Task (SART), which demands vigilance and inhibitory control. In Experiment 1, we recorded the electroencephalogram (EEG) during the performance of SART and found that event-related potentials underlying inhibitory control (N1 and N2/P3) were influenced by a time on task effect, suggesting a decrement in attentional resources necessary for optimal inhibitory control. In Experiments 2 and 3, we recorded skin temperatures (distal, proximal and the distal-proximal temperature gradient - DPG) and found that they were sensitive to differential demands of mental workload, and that they were related to behavioural performance in the SART. This study suggests that the recording of EEG and skin temperature may be used to monitor fluctuations of attention in natural settings, although further research should clarify the exact psychological interpretation of these physiological indices

Los marcadores neurofisiológicos de la habilidad para mantener la atención y ejercer un control inhibitorio sobre respuestas inapropiadas normalmente se han basado en métodos de neuroimagen, los cuales no son fácilmente aplicables a entornos cotidianos fuera del laboratorio. La presente investigación evaluó la habilidad de marcadores electroencefalográficos y de temperatura de la piel para predecir la ejecución durante la tarea SART (Tarea de Atención Sostenida a la Respuesta), que demanda vigilancia y control inhibitorio. En el Experimento 1, registramos el electroencefalograma (EEG) durante la ejecución de la tarea SART y encontramos que los potenciales evocados relacionados con el control inhibitorio (N1 y N2/P3) fueron influenciados por un efecto de tiempo en tarea, sugiriendo un decremento en los recursos atencionales necesarios para un control inhibitorio óptimo. En los Experimentos 2 y 3, registramos tres marcadores basados en la temperatura de la piel (zonas distal, proximal y el gradiente proximal-distal - DPG) y encontramos que fueron sensibles a las demandas diferenciales de carga de trabajo mental, que además se relacionaban con la ejecución comportamental de la SART. Este estudio sugiere que el registro del EEG y de la temperatura de la piel se pueden usar para monitorizar fluctuaciones de la atención en contextos naturales, aunque investigación posterior debería proporcionar una interpretación psicológica más precisa de estos índices fisiológicos

Differential effects of intensity and response preparation components of acoustic warning signals / Efectos diferenciales de los componentes de intensidad y preparación de la respuesta para señales de alerta acústicas

It is known that the increase of intensity on a warning signal (WS) usually decreases reaction times to targets and occasionally is accompanied by a startle reflex reaction that influences the speediness of response execution. In a simple detection task (Experiment 1), a detection task with catch trials (Experiment 2) and a Go-NoGo discrimination task (Experiment 3), we studied the relationship between response preparation and alerting mechanisms operating upon the presentation of warning signals. A WS was presented either synchronously with the target (simultaneous condition) or 1400 ms before it (delayed condition). In all three experiments, the intensity of the WS and the simultaneity between WS and target were orthogonally manipulated. Results confirmed shorter reaction times by increasing the WS intensity. In Experiment 1, all conditions presented a clear acoustic intensity effect. In Experiment 2 we observed shorter reaction times in higher intensity conditions but only when the WS and the target were presented simultaneously. In Experiment 3, the intensity effect was observed only when the WS preceded the target. In all experiments, trials where the WS triggered a startle reflex showed a systematic increase in reaction time, which was independent of response preparation and task demands. In general, our findings suggest that response preparation modulates the alerting mechanisms, as a function of task set, but not the startle reflex. The dissociation between intensity, response preparation and startle supports the interdependence between these mechanisms elicited by the presentation of warning signals

El aumento de la intensidad en una señal de alerta (warning signal, WS) generalmente disminuye los tiempos de reacción al estímulo objetivo y ocasionalmente está acompañada de un reflejo de sobresalto que influye en la rapidez de la respuesta. En tres experimentos, con tarea de detección simple (Experimento 1), de detección con ensayos sin estímulos objetivo (Experimento 2) y de discriminación "Go-NoGo" (Experimento 3), hemos estudiado la relación entre los mecanismos de preparación de la respuesta y de alerta que ocurren tras la presentación de señales de alerta. Se presentó una WS simultáneamente al target (condición simultánea) o con una antelación de 1400 ms (condición demorada). En los tres experimentos se manipuló ortogonalmente la intensidad de la WS y el intervalo entre WS y estímulo objetivo. Los resultados confirmaron tiempos de reacción más cortos con el aumento de la intensidad de la WS. En el Experimento 1, todas las condiciones presentaron un claro efecto de intensidad acústica. En el Experimento 2 observamos tiempos de reacción más cortos en condiciones de mayor intensidad, pero solo cuando WS y estímulo objetivo se presentaron simultáneamente. En el Experimento 3, el efecto de intensidad se observó únicamente cuando la WS precedía al target. En todos los experimentos, los ensayos donde la WS provocaba un reflejo de sobresalto mostraron un aumento sistemático de los tiempos de reacción, que era independiente de la preparación de la respuesta y del tipo de tarea. En general, nuestros resultados sugieren que la preparación de la respuesta modula los mecanismos de alerta, en función de la tarea, pero no el reflejo de sobresalto. La disociación entre intensidad, preparación de la respuesta y sobresalto apoya la hipótesis de interdependencia entre estos mecanismos, provocados por la presentación de la señal de alerta

Blue-Enriched Light Enhances Alertness but Impairs Accurate Performance in Evening Chronotypes Driving in the Morning.

Attention maintenance is highly demanding and typically leads to vigilance decrement along time on task. Therefore, performance in tasks involving vigilance maintenance for long periods, such as driving, tends to deteriorate over time. Cognitive performance has been demonstrated to fluctuate over 24 h of the day (known as circadian oscillations), thus showing peaks and troughs depending on the time of day (leading to optimal and suboptimal times of day, respectively). Consequently, vigilance decrements are more pronounced along time on task when it is performed at suboptimal times of day. According to research, light exposure (especially blue-enriched white) enhances alertness. Thus, it has been proposed to prevent the vigilance decrement under such adverse circumstances. We aimed to explore the effects of blue-enriched white light (vs. dim light) on the performance of a simulated driving task at a suboptimal time of day. A group of evening-types was tested at 8 am, as this chronotype had previously shown their largest vigilance decrement at that time. In the dim light condition, vigilance decrements were expected on both subjective (as increments in the Karolinska Sleepiness Scale scores) and behavioral measures [as slower reaction times (RTs) in the auditory Psychomotor Vigilance Task, slower RTs to unexpected events during driving, and deteriorated driving accuracy along time on task]. Physiological activation was expected to decrease (as indexed by an increase of the distal-proximal temperature gradient, DPG). Under blue-enriched white light, all these trends should be attenuated. Results from the control dim light condition replicated the vigilance decrement in all measures. Most important, the blue-enriched white light attenuated this decrement, leading to both lower DPG and faster RTs. However, it impaired accuracy of driving performance, and did not have any effect on subjective sleepiness. We conclude that exposure to blue-enriched light provides an effective countermeasure to enhance vigilance performance at suboptimal times of day, according to measures such as RTs. However, it should be considered that alerting effects of light could impair accuracy in precision tasks as keeping a proper car position. The current findings provide ergonomic implications for safety and fatigue related management systems.

Dissociating Explicit and Implicit Timing in Parkinson's Disease Patients: Evidence from Bisection and Foreperiod Tasks.

A consistent body of literature reported that Parkinson's disease (PD) is marked by severe deficits in temporal processing. However, the exact nature of timing problems in PD patients is still elusive. In particular, what remains unclear is whether the temporal dysfunction observed in PD patients regards explicit and/or implicit timing. Explicit timing tasks require participants to attend to the duration of the stimulus, whereas in implicit timing tasks no explicit instruction to process time is received but time still affects performance. In the present study, we investigated temporal ability in PD by comparing 20 PD participants and 20 control participants in both explicit and implicit timing tasks. Specifically, we used a time bisection task to investigate explicit timing and a foreperiod task for implicit timing. Moreover, this is the first study investigating sequential effects in PD participants. Results showed preserved temporal ability in PD participants in the implicit timing task only (i.e., normal foreperiod and sequential effects). By contrast, PD participants failed in the explicit timing task as they displayed shorter perceived durations and higher variability compared to controls. Overall, the dissociation reported here supports the idea that timing can be differentiated according to whether it is explicitly or implicitly processed, and that PD participants are selectively impaired in the explicit processing of time.

The Role of Exercise-Induced Arousal and Exposure to Blue-Enriched Lighting on Vigilance.

It is currently assumed that exposure to an artificial blue-enriched light enhances human alertness and task performance, but recent research has suggested that behavioral effects are influenced by the basal state of arousal. Here, we tested whether the effect of blue-enriched lighting on vigilance performance depends on participants' arousal level. Twenty-four participants completed four sessions (blue-enriched vs. dim light × low vs. high arousal) at 10 pm on four consecutive days, following a repeated-measures design. Participants' arousal was manipulated parametrically through the execution of a cycling task at two intensities (low vs. moderate), and was checked by monitoring their heart rate. On each session, distal and proximal skin temperatures were recorded as a neuroergonomic index of vigilance, while participants performed a 20-min psychomotor vigilance task (PVT) under either blue-enriched light or dim light conditions. The Positive and Negative Affect Schedule (PANAS), Karolinska Sleepiness Scale (KSS), and Borg Rating of Perceived Exertion Scale (RPE) were used to measure subjective psychological state. The results showed that the exercise-induced manipulation of arousal produced robust alerting effects in most measures, while the lighting manipulation only attenuated subjective sleepiness and enhanced positive affect, but it did not influence behavior or physiology. Acute exposure to a blue-enriched light was practically ineffective when the arousal level was over baseline. The present research favored the use of acute physical exercise over acute exposure to blue-enriched lighting in order to boost humans' alertness when necessary, as in work settings where maintaining optimal levels of attention is difficult (shift work, night-work, vigilance tasks) and necessary to prevent human error and accidents.

Blue-Enriched White Light Enhances Physiological Arousal But Not Behavioral Performance during Simulated Driving at Early Night.

Vigilance usually deteriorates over prolonged driving at non-optimal times of day. Exposure to blue-enriched light has shown to enhance arousal, leading to behavioral benefits in some cognitive tasks. However, the cognitive effects of long-wavelength light have been less studied and its effects on driving performance remained to be addressed. We tested the effects of a blue-enriched white light (BWL) and a long-wavelength orange light (OL) vs. a control condition of dim light on subjective, physiological and behavioral measures at 21:45 h. Neurobehavioral tests included the Karolinska Sleepiness Scale and subjective mood scale, recording of distal-proximal temperature gradient (DPG, as index of physiological arousal), accuracy in simulated driving and reaction time in the auditory psychomotor vigilance task. The results showed that BWL decreased the DPG (reflecting enhanced arousal), while it did not improve reaction time or driving performance. Instead, blue light produced larger driving errors than OL, while performance in OL was stable along time on task. These data suggest that physiological arousal induced by light does not necessarily imply cognitive improvement. Indeed, excessive arousal might deteriorate accuracy in complex tasks requiring precision, such as driving.

"Lost in time" but still moving to the beat.

Motor synchronization to the beat of an auditory sequence (e.g., a metronome or music) is widespread in humans. However, some individuals show poor synchronization and impoverished beat perception. This condition, termed "beat deafness", has been linked to a perceptual deficit in beat tracking. Here we present single-case evidence (L.A. and L.C.) that poor beat tracking does not have to entail poor synchronization. In a first Experiment, L.A., L.C., and a third case (L.V.) were submitted to the Battery for The Assessment of Auditory Sensorimotor and Timing Abilities (BAASTA), which includes both perceptual and sensorimotor tasks. Compared to a control group, L.A. and L.C. performed poorly on rhythm perception tasks, such as detecting time shifts in a regular sequence, or estimating whether a metronome is aligned to the beat of the music or not. Yet, they could tap to the beat of the same stimuli. L.V. showed impairments in both beat perception and tapping. In a second Experiment, we tested whether L.A., L.C., and L.V.'s perceptual deficits extend to an implicit timing task, in which they had to respond as fast as possible to a different target pitch after a sequence of standard tones. The three beat-deaf participants benefited similarly to controls from a regular temporal pattern in detecting the pitch target. The fact that synchronization to a beat can occur in the presence of poor perception shows that perception and action can dissociate in explicit timing tasks. Beat tracking afforded by implicit timing mechanisms is likely to support spared synchronization to the beat in some beat-deaf participants. This finding suggests that separate pathways may subserve beat perception depending on the explicit/implicit nature of a task in a sample of beat-deaf participants.

Economic decision-making in morning/evening-type people as a function of time of day.

Decision-making is affected by psychological factors like emotional state or cognitive control, which may also vary with circadian rhythmicity. Here, we tested the influence of chronotype (32 morning-type versus 32 evening-type) and time of day (9 a.m. versus 5 p.m.) on interpersonal decision-making as measured by the Ultimatum Game. Participants had to accept or reject different economic offers proposed by a virtual participant. Acceptance involved distribution of gains as proposed, whereas rejection resulted in no gain for either player. The results of the game showed a deviation from rational performance, as participants usually rejected the unfair offers. This behaviour was similar for both chronotype groups, and in both times of day. This result may reflect the robustness of decision-making strategies across standard circadian phases under ecological conditions. Furthermore, morning-types invested more time than evening-types to respond to high-uncertainty offers. This more cautious decision-making style of morning-types fits with our finding of higher proactive control as compared to evening-types when performing the AX-Continuous Performance Task. In line with the literature on personality traits, our results suggest that morning-types behave with more conscientiousness and less risk-taking than evening-type individuals.

Light Effects on Behavioural Performance Depend on the Individual State of Vigilance.

Research has shown that exposure to bright white light or blue-enriched light enhances alertness, but this effect is not consistently observed in tasks demanding high-level cognition (e.g., Sustained Attention to Response Task-SART, which measures inhibitory control). Individual differences in sensitivity to light effects might be mediated by variations in the basal level of arousal. We tested this hypothesis by measuring the participants' behavioural state of vigilance before light exposure, through the Psychomotor Vigilance Task. Then we compared the effects of a blue-enriched vs. dim light at nighttime on the performance of the auditory SART, by controlling for individual differences in basal arousal. The results replicated the alerting effects of blue-enriched light, as indexed by lower values of both proximal temperature and distal-proximal gradient. The main finding was that lighting effects on SART performance were highly variable across individuals and depended on their prior state of vigilance. Specifically, participants with higher levels of basal vigilance before light exposure benefited most from blue-enriched lighting, responding faster in the SART. These results highlight the importance of considering basal vigilance to define the boundary conditions of light effects on cognitive performance. Our study adds to current research delineating the complex and reciprocal interactions between lighting effects, arousal, cognitive task demands and behavioural performance.

Brain networks of temporal preparation: A multiple regression analysis of neuropsychological data.

There are only a few studies on the brain networks involved in the ability to prepare in time, and most of them followed a correlational rather than a neuropsychological approach. The present neuropsychological study performed multiple regression analysis to address the relationship between both grey and white matter (measured by magnetic resonance imaging in patients with brain lesion) and different effects in temporal preparation (Temporal orienting, Foreperiod and Sequential effects). Two versions of a temporal preparation task were administered to a group of 23 patients with acquired brain injury. In one task, the cue presented (a red versus green square) to inform participants about the time of appearance (early versus late) of a target stimulus was blocked, while in the other task the cue was manipulated on a trial-by-trial basis. The duration of the cue-target time intervals (400 versus 1400ms) was always manipulated within blocks in both tasks. Regression analysis were conducted between either the grey matter lesion size or the white matter tracts disconnection and the three temporal preparation effects separately. The main finding was that each temporal preparation effect was predicted by a different network of structures, depending on cue expectancy. Specifically, the Temporal orienting effect was related to both prefrontal and temporal brain areas. The Foreperiod effect was related to right and left prefrontal structures. Sequential effects were predicted by both parietal cortex and left subcortical structures. These findings show a clear dissociation of brain circuits involved in the different ways to prepare in time, showing for the first time the involvement of temporal areas in the Temporal orienting effect, as well as the parietal cortex in the Sequential effects.