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.

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.

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.

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.

"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.

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.

Auditory temporal preparation induced by rhythmic cues during concurrent auditory working memory tasks.

The present study investigated whether participants can develop temporal preparation driven by auditory isochronous rhythms when concurrently performing an auditory working memory (WM) task. In Experiment 1, participants had to respond to an auditory target presented after a regular or an irregular sequence of auditory stimuli while concurrently performing a Sternberg-type WM task. Results showed that participants responded faster after regular compared with irregular rhythms and that this effect was not affected by WM load; however, the lack of a significant main effect of WM load made it difficult to draw any conclusion regarding the influence of the dual-task manipulation in Experiment 1. In order to enhance dual-task interference, Experiment 2 combined the auditory rhythm procedure with an auditory N-Back task, which required WM updating (monitoring and coding of the information) and was presumably more demanding than the mere rehearsal of the WM task used in Experiment 1. Results now clearly showed dual-task interference effects (slower reaction times [RTs] in the high- vs. the low-load condition). However, such interference did not affect temporal preparation induced by rhythms, with faster RTs after regular than after irregular sequences in the high-load and low-load conditions. These results revealed that secondary tasks demanding memory updating, relative to tasks just demanding rehearsal, produced larger interference effects on overall RTs in the auditory rhythm task. Nevertheless, rhythm regularity exerted a strong temporal preparation effect that survived the interference of the WM task even when both tasks competed for processing resources within the auditory modality.

Foreperiod priming in temporal preparation: testing current models of sequential effects.

Sequential foreperiod effects in temporal preparation are typically asymmetric such that a previous experience of preparation has a strong impact on participants' responses to a forthcoming target stimulus presented at the current short rather than at the current long foreperiod. The trace-conditioning model explains this asymmetry by an automatic process of trace-conditioning, which is sufficient and independent from a strategic process of conditional probability monitoring considered by the dual-process model. The present study contrasted trace-conditioning and dual-process models in three experiments that employed a non-aging distribution to keep conditional probability of target occurrence constant across foreperiod durations. In Experiment 1 (no catch trials), the typical pattern of asymmetric sequential effects was replicated, whereas in Experiments 2 and 3 (25% and 50% of catch trials, respectively) the results showed shorter RTs when previous and current foreperiods were repeated rather than alternated for both current short and long foreperiods. These results are discussed in relation to the two most influential models of sequential effects and to a novel account based on repetition priming.

Neural dissociation of automatic and controlled temporal preparation by transcranial magnetic stimulation.

Recent neuropsychological evidence suggested a role for the right prefrontal cortex in temporal orienting of attention guided by symbolic cues, and the left prefrontal cortex in preparation guided by rhythms. We tested this hypothesis by comparing the effects of 1-Hz repetitive transcranial magnetic stimulation (TMS) over prefrontal regions on the performances of two temporal preparation tasks, one using symbolic cues (short vs. long lines) and the other using regular rhythms (fast vs. slow pace) to indicate when (early vs. late) a target would be most likely to appear. Stimulation site was either the left dorsolateral prefrontal cortex (DLPFC), right DLPFC, or sham condition. The results showed that frontal TMS produced differential effects as a function of type of cuing. In symbolic cuing, TMS on either left or right frontal sites (vs. sham) increased temporal orienting effects by reducing reaction times in valid trials. In rhythmic cuing, however, frontal TMS did not influence performance. This dissociation between two forms of temporal preparation suggests a specific role for the DLPFC in the ability of temporal orienting, but not in preparation guided by rhythms.

Effects of chronotype and time of day on the vigilance decrement during simulated driving.

The current study tested for the first time the effect of individual differences in circadian rhythmicity (chronotype) on both driving performance and its evolution along time on task. Morning-type and evening-type female participants were tested in morning (8 am) and evening (8 pm) sessions, in which we controlled for prior sleep duration and prior wake. Measures of body temperature, subjective activation and affect, reaction times (RT) in the Psychomotor Vigilance Task (PVT), behavioral performance (error position) and EEG alpha power during simulated driving were collected. The main result showed strong linear increments of mean and standard deviation of error position along time on task (vigilance decrement) when evening-type participants drove at their non-optimal time of day, that is, during the morning session. In contrast, driving performance in the morning-type group remained stable over time on task and was not affected by time of day. This finding can be due to differences in personality traits (e.g., conscientiousness, sensation seeking) and task appraisal associated to extreme chronotypes. The consideration of chronotype in vigilance and driving tasks can enhance safety and human performance by promoting work schedules and countermeasures to prevent failures in the accomplishment of tasks under non-optimal circadian conditions.