Maintenance Of Vigilance Research Articles

Avoiding the hope of avoiding collapse: collapsology and non-hope as an emotional practice of conviction

ABSTRACT Recent years have seen the rise of a ‘postapocalyptic environmentalism’, which sees environmental catastrophe as ongoing or inevitable and therefore rejects the hope of avoiding that catastrophe. So far, research on this form of environmentalism has pointed to the paradoxes and ambivalences involved in its rejection of hope, as well as to environmental activists’ difficulties translating non-hope into movement strategy. However, postapocalyptic environmentalists’ efforts of practicing non-hope have yet to be investigated. Drawing on interviews with participants in a Swedish online environmentalist network committed to ‘collapsology’, the present paper therefore investigates postapocalyptic environmentalist non-hope as an emotional practice of conviction. The paper approaches non-hope as a form of emotional deintegration, in which collapsologists seek to dehabituate the hope and optimism that inform the dominant emotive-cognitive frame of environmental politics in Western industrial societies. They do so by vigilantly maintaining feelings of certainty about the inevitability of civilizational collapse. More specifically, in rejecting hope, the interviewed participants articulate this non-hope as a form of conviction. However, the participants present this conviction as haunted by doubts, dissonances, and ambivalences, and therefore as needing vigilant maintenance efforts. Such efforts include what I call ‘impossibility work’. Implications for further research on postapocalyptic environmentalism and related movements are discussed.

Resting-State EEG Microstates Dynamics Associated with Interindividual Vulnerability to Sleep Deprivation.

Sleep deprivation can induce severe deficits in vigilant maintenance and alternation in large-scale networks. However, differences in the dynamic brain networks after sleep deprivation across individuals have rarely been investigated. In the present study, we used EEG microstate analysis to investigate the effects of sleep deprivation and how it differentially affects resting-state brain activity in different individuals. A total of 44healthy adults participated in a within-participant design study involving baseline sleep and 24-hour sleep deprivation, with resting-state EEG recorded during wakefulness. The psychomotor vigilance task (PVT) was used to measure vigilant attention. Participants were median split as vulnerable or resilient according to their changes in the number of lapses between the baseline sleep and sleep deprivation conditions. Sleep deprivation caused decreases in microstates A, B, and D, and increases in microstate C. We also found increased transition probabilities of microstates C and D between each other, lower transition probabilities from microstates C and D to microstate B, and higher transition probabilities from microstates A and B to microstate C. Sleep-deprived vulnerable individuals showed decreased occurrence of microstate B and transition probability from microstate C to B after sleep deprivation, but not in resilient individuals. The findings suggest that sleep deprivation critically affects dynamic brain-state properties and the differences in time parameters of microstates might be the underlying neural basis of interindividual vulnerability to sleep deprivation.

Dissociable brainstem functional connectivity changes correlate with objective and subjective vigilance decline after total sleep deprivation in healthy male subjects.

The maintenance of vigilance relies on the activation of the cerebral cortex by the arousal system centered on the brainstem. Previous studies have suggested that both objective and subjective vigilance are susceptible to sleep deprivation. This study aims to explore the alterations in brainstem arousal system functional connectivity (FC) and its involvement in these two types of vigilance decline following total sleep deprivation (TSD). Thirty-seven healthy male subjects underwent two counterbalanced resting-state fMRI scans, once in rested wakefulness (RW) and once after 36 h of TSD. The pontine tegmental area and caudal midbrain (PTA-cMidbrain), the core regions of the brainstem arousal system, were chosen as the seeds for FC analysis. The difference in PTA-cMidbrain FC between RW and TSD conditions was then investigated, as well as its associations with objective vigilance measured by psychomotor vigilance task (PVT) and subjective vigilance measured by Stanford Sleepiness Scale. The sleep-deprived subjects showed increased PTA-cMidbrain FC with the thalamus and cerebellum and decreased PTA-cMidbrain FC with the occipital, parietal, and sensorimotor regions. TSD-induced increases in PVT reaction time were negatively correlated with altered PTA-cMidbrain FC in the dorsolateral prefrontal cortex, extrastriate visual cortex, and precuneus. TSD-induced increases in subjective sleepiness were positively correlated with altered PTA-cMidbrain FC in default mode regions including the medial prefrontal cortex and precuneus. Our results suggest that different brainstem FC patterns underlie the objective and subjective vigilance declines induced by TSD.

Altered vigilant maintenance and reorganization of rich-clubs in functional brain networks after total sleep deprivation.

Sleep deprivation strongly deteriorates the stability of vigilant maintenance. In previous neuroimaging studies of large-scale networks, neural variations in the resting state after sleep deprivation have been well documented, highlighting that large-scale networks implement efficient cognitive functions and attention regulation in a spatially hierarchical organization. However, alterations of neural networks during cognitive tasks have rarely been investigated. The present study used a within-participant design of 35 healthy right-handed adults and used task-based functional magnetic resonance imaging to examine the neural mechanism of attentional decline after sleep deprivation from the perspective of rich-club architecture during a psychomotor vigilance task. We found that a significant decline in the hub disruption index was related to impaired vigilance due to sleep loss. The hierarchical rich-club architectures were reconstructed after sleep deprivation, especially in the default mode network and sensorimotor network. Notably, the relatively fast alert response compensation was correlated with the feeder organizational hierarchy that connects core (rich-club) and peripheral nodes. Our findings provide novel insights into understanding the relationship of alterations in vigilance and the hierarchical architectures of the human brain after sleep deprivation, emphasizing the significance of optimal collaboration between different functional hierarchies for regular attention maintenance.

Silent circulation of Zika and dengue virus in Aedes aegypti (Diptera: Culicidae) during a non-epidemic year in the state of Sergipe, northeastern Brazil.

Dengue virus (DENV) and Zika virus (ZIKV) have a severe impact on human health worldwide. To understand the dynamics of these viruses in mosquito populations, it is necessary to maintain surveillance during non-epidemic years. We aimed to assess the presence of DENV and ZIKV in Aedes aegypti females in the state of Sergipe, northeastern Brazil, during a non-epidemic year. The Ae. aegypti females collected were sectioned, and the heads and thorax were used to analyze the infection rate. Each female was first analyzed to detect Flavivirus using RT-PCR. Flavivirus-positive samples were further screened to detect ZIKV and DENV types 1, 2, 3 and 4. A total of 184 females were collected. ZIKV was identified in 5.4% of the sample and DENV in 7.1%, with the DENV-positive samples belonging to subtypes 2, 3 and 4. The presence of coinfected vectors was also observed. Of the four cities tested, only one was negative for all viruses. These results show that the maintenance of vigilance during non-epidemic years can provide data on viruses circulating before the onset of outbreaks. This can enable the planning and implementation of local control measures to prevent the appearance of new outbreaks.

The Role of the Central Histaminergic System in Behavioral State Control.

Histamine is a small monoamine signaling molecule that plays a role in many peripheral and central physiological processes, including the regulation of wakefulness. The tuberomammillary nucleus is the sole neuronal source of histamine in the brain, and histamine neurons are thought to promote wakefulness and vigilance maintenance - under certain environmental and/or behavioral contexts - through their diffuse innervation of the cortex and other wake-promoting brain circuits. Histamine neurons also contain a number of other putative neurotransmitters, although the functional role of these co-transmitters remains incompletely understood. Within the brain histamine operates through three receptor subtypes that are located on pre- and post-synaptic membranes. Some histamine receptors exhibit constitutive activity, and hence exist in an activated state even in the absence of histamine. Newer medications used to reduce sleepiness in narcolepsy patients in fact enhance histamine signaling by blunting the constitutive activity of these histamine receptors. In this chapter, we provide an overview of the central histamine system with an emphasis on its role in behavioral state regulation and how drugs targeting histamine receptors are used clinically to treat a wide range of sleep-wake disorders.

Evaluation of rickettsial infection in free-range capybaras (Hydrochoerus hydrochaeris Linnaeus, 1766) (Rodentia: Caviidae) and ticks (Acari: Ixodidae) in the Western Amazon, Brazil

Capybaras (Hydrochoerus hydrochaeris Linnaeus, 1766) (Rodentia: Caviidae) are important hosts of Amblyomma ticks (Acari: Ixodidae), which in turn can transmit rickettsiae to humans and animals. However, there is a scarcity of studies about the tick fauna and rickettsial infection in the Amazon region. The present study evaluated rickettsial infection in capybaras and ticks in different areas of the municipality of Rio Branco, state of Acre, in the Western Brazilian Amazon, where rickettsiosis has never been reported. Blood sera from 43 capybaras from four localities in Rio Branco were tested by indirect immunofluorescence assay using Rickettsia rickettsii antigens. Ticks were collected from capybaras and from vegetation as well. Ticks were taxonomically identified to the species level and some of them were tested by PCR, targeting a fragment of the rickettsial gltA gene. Additionally, ticks were tested for bacteria from the genus Borrelia and family Anaplasmatacae. All capybaras submitted to the serological examination were considered non-reactive to R. rickettsii. A total of 410 ticks were collected directly from the capybaras. Amblyomma dubitatum Neumann, 1899 was the most abundant species (82.4%), followed by Amblyomma naponense (Packard, 1869) (14.3%), Amblyomma humerale Koch, 1844 (0.7%), Amblyomma pacae Aragão, 1911 (0.4%), Amblyomma rotundatum Koch 1844 (0.2%) and Amblyomma sp. (1.7%). From the environment 262 ticks were collected: Rhipicephalus microplus (Canestrini, 1888) (88.9%), Dermacentor nitens Neumann, 1897 (9.9%), Amblyomma varium Koch, 1844 (0.7%) and A. rotundatum (0.3%). With the exception of A. humerale, A. rotundatum and R. microplus, all other species are reported here for the first time in the state. Some of the ticks sampled (N = 317) were tested by molecular methods for infection by Rickettsia spp. Rickettsia bellii was identified infecting A. dubitatum and A. rotundatum, while Rickettsia amblyommatis only was found infecting A. humerale and Rickettsia sp. strain Tapirapé was found in A. naponense. This is the first detection of R. bellii and Rickettsia sp. strain Tapirapé in Acre. No Borrelia or Anaplasmataceae were found in the tested ticks. These results add relevant knowledge about the Rickettsia spp. and the acarological fauna in the region of the Western Amazon, and are essential for the maintenance of vigilance about possible pathogens that occur in the state and determination of the risks that they pose to humans and animals that inhabit the region.

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.

Brain Areas Responsible for Vigilance: An EEG Source Imaging Study.

Vigilance, sometimes referred to as sustained attention, is an important type of human attention as it is closely associated with cognitive activities required in various daily-life situations. Although many researchers have investigated which brain areas control the maintenance of vigilance, findings have been inconsistent. We hypothesized that this inconsistency might be due to the use of different experimental paradigms in the various studies. We found that most of the previous studies used paradigms that included specific cognitive tasks requiring a high cognitive load, which could complicate identification of brain areas associated only with vigilance. To minimize the influence of cognitive processes other than vigilance on the analysis results, we adopted the d2-test of attention, which is a well-known neuropsychological test of attention that does not require high cognitive load, and searched for brain areas at which EEG source activities were temporally correlated with fluctuation of vigilance over a prolonged period of time. EEG experiments conducted with 31 young adults showed that left prefrontal cortex activity was significantly correlated with vigilance variation in the delta, beta1, beta2, and gamma frequency bands, but not the theta and alpha frequency bands. Our study results suggest that the left prefrontal cortex plays a key role in vigilance modulation, and can therefore be used to monitor individual vigilance changes over time or serve as a potential target of noninvasive brain stimulation.

Current stress and poor oral health.

BackgroundPsychological stress appears to contribute to poor oral health systemically in combination with other chronic diseases. Few studies directly examine this relationship.MethodsData from a cross-sectional study of 2,412 participants between the ages of 25–64 years old living in the City of Toronto between 2009 and 2012 were used to examine the relationship between current stress and two self-rated oral health outcomes (general oral health and oral pain). Dental care utilization and access to dental insurance were examined as effect modifiers.ResultsA positive relationship between current stress and poor oral health was observed for both outcomes (oral pain coefficient 0.32, 95 % CI 0.26–0.38; general oral health coefficient 0.28, 95 % CI 0.19–0.36). Effects on oral pain were stronger for the uninsured, while effects on general oral health were stronger with decreasing socioeconomic position.ConclusionsOur findings suggest that individuals with greater perceived stress also report poorer oral health, and that this relationship is modified by dental insurance and socioeconomic position. These findings warrant a greater focus on the role of psychological stress in the development of oral disease, including how perceived stress contributes to health inequities in self-reported oral health status. Patients experiencing stressful lives may differentially require closer monitoring and more vigilant maintenance of their oral health, above and beyond that which is needed to achieve a state of health in the oral environment of less stressed individuals. There may be health promoting effects of addressing psychosocial concerns related to dental care - particularly for the poor and uninsured.

Seeing a Ghost? Vigilance and Its Drivers in a Predator‐free World

AbstractVigilance is a key to the early detection of predators, but may be costly if it impairs foraging efficiency. Hence, we would expect vigilance to be suppressed and/or counter‐selected in predator‐free environments, although this might depend on the environmental drivers influencing perceived predation risk. We studied vigilance in two populations of Sitka black‐tailed deer (Odocoileus hemionus sitkensis) on Haida Gwaii (Canada) which have not been exposed to predators since they colonized the study islands approx. 60 yr ago. In this context, anti‐predator behavior should not have any obvious current benefit. Moreover, its maintenance should be particularly costly in our study populations because these deer have depleted their food resources and, thus, anti‐predator behaviors should interfere with time spent searching for scarce resources. We used bait stations equipped with camera traps to assess vigilance under standardized feeding conditions. We expected to observe lower vigilance levels than those observed elsewhere in locations with predators. We investigated how vigilance varied in relation to the amount of bait, the level of visibility, and between day and night. During the day, deer spent, on average, 14% of their time in overt vigilance during foraging bouts, a level similar to, although in the lower range of, values reported at sites where predators are present. Levels of vigilance were lower at night, and decreased with increasing visibility, but not during the day. Deer were less vigilant when bait availability was high, but only when visibility was also high. We discuss why the maintenance of vigilance is here best explained by the ghosts of predators past, and how, at the temporal scale of a few generations, the ecological factors driving vigilance levels might override the absence of significant risk from large predators.

Shoulder arthroscopy and complications: Can we afford to relax?

Shoulder arthroscopy and complications: Can we afford to relax?

Eight-year clinical and radiologic results of maxillary and mandibular implant-retained bar overdentures carried out on oxidized (TiUnite™) replace select implants placed in regenerated bone: a clinical case.

This article describes the clinical and radiologic long-term results of a healthy, nonsmoker women aged 62 at the time of treatment, with severely resorbed edentulous jaws in which bar and clip supported complete dentures were delivered in both jaws and followed for 8 years after prosthesis delivery. The patient had been edentulous in both arches since she was 50 years old. Treatment included the placement of four mandibular implants with maximum spacing anterior to the mandibular nerve, and four maxillary implants anterior to sinus wall without tilting the posterior implants, because of the insufficient bone quantity necessary to angulate implants. Guided bone regeneration was required in the maxilla, due to a bone atrophy that limited the placement of conventional dental implants. After 4 months, a second-stage surgery was performed, and after 1 month of healing time the patient received definitive restorations. Implant survival rate, patient satisfaction, marginal bone maintenance, and soft tissue conditions at the modified titanium surface of the dental implants were evaluated after 8 years of function. A multifactorial approach, clinician-patient relationship, and vigilant maintenance of oral hygiene were needed in order to ensure an optimal treatment and a long-term successful result. Positive results regarding bone maintenance in the long-term perspective, also on regenerated bone, were observed using implants with implant-retained bar overdentures, when adequate levels of oral hygiene and prosthodontic adjustments are maintained.

Diurnal Fluctuation in Histidine Decarboxylase Expression, the Rate Limiting Enzyme for Histamine Production, and Its Disorder in Neurodegenerative Diseases

Neuronal histamine shows diurnal rhythms in rodents and plays a major role in the maintenance of vigilance. No data are available on its diurnal fluctuation in humans, either in health or in neurodegenerative disorders such as Parkinson disease (PD), Alzheimer disease (AD), or Huntington disease (HD), all of which are characterized by sleep-wake disturbances. Quantitative in situ hybridization was used to study the mRNA expression of histidine decarboxylase (HDC), the key enzyme of histamine production in the tuberomammillary nucleus (TMN) in postmortem human hypothalamic tissue, obtained from 33 controls and 31 patients with a neurodegenerative disease-PD (n = 15), AD (n = 9), and HD (n = 8)-and covering the full 24-h cycle with respect to clock time of death. HDC-mRNA levels in controls were found to be significantly higher during the daytime than at night (e.g., 08:01-20:00 versus 20:01-08:00, P = 0.004). This day-night fluctuation was markedly different in patients with neurodegenerative diseases. The diurnal fluctuation of HDC-mRNA expression in human TMN supports a role for neuronal histamine in regulating day-night rhythms. Future studies should investigate histamine rhythm abnormalities in neurodegenerative disorders. Shan L; Hofman MA; van Wamelen DJ; Van Someren EJW; Bao AM; Swaab DF. Diurnal fluctuation in histidine decarboxylase expression, the rate limiting enzyme for histamine production, and its disorder in neurodegenerative diseases.

Assessing the effects of caffeine and theanine on the maintenance of vigilance during a sustained attention task

Caffeine and l-theanine, both naturally occurring in tea, affect the ability to make rapid phasic deployments of attention to locations in space as reflected in behavioural performance and alpha-band oscillatory brain activity (8–14 Hz). However, surprisingly little is known about how these compounds affect an aspect of attention that has been more popularly associated with tea, namely vigilant attention: the ability to maintain focus on monotonous tasks over protracted time-periods. Twenty-seven participants performed the Sustained Attention to Response Task (SART) over a two-hour session on each of four days, on which they were administered caffeine (50 mg), theanine (100 mg), the combination, or placebo in a double-blind, randomized, cross-over fashion. Concurrently, we recorded oscillatory brain activity through high-density electroencephalography (EEG). We asked whether either compound alone, or both in combination, would affect performance of the task in terms of reduced error rates over time, and whether changes in alpha-band activity would show a relationship to such changes in performance. When treated with placebo, participants showed a rise in error rates, a pattern that is commonly observed with increasing time-on-task, whereas after caffeine and theanine ingestion, error rates were significantly reduced. The combined treatment did not confer any additional benefits over either compound alone, suggesting that the individual compounds may confer maximal benefits at the dosages employed. Alpha-band oscillatory activity was significantly reduced on ingestion of caffeine, particularly in the first hour. This effect was not changed by addition of theanine in the combined treatment. Theanine alone did not affect alpha-band activity.

Antipsychotic-Induced Somnolence in Mothers with Schizophrenia

Although it is known that many antipsychotic drugs, at the doses prescribed for schizophrenia, are sedative and cause daytime drowsiness, the effect of potentially diminished vigilance on parenting parameters has not been studied. The aim of this paper is to advise clinicians about sedative load in mothers who are prescribed antipsychotic medication. A Medline search was conducted into the sedative effects of antipsychotics, with the following search terms: sleep; sedation; somnolence; wakefulness; antipsychotics; schizophrenia, parenting, maternal behavior, and custody. The results showed that antipsychotic drugs differ in their propensity to induce sedation and do so via their effects on a variety of neurotransmitter systems. It is important to note that mothers with schizophrenia risk losing custody of their infants if they are perceived as potentially neglectful because of excessive daytime sleepiness. Clinicians must choose antipsychotic medications carefully and monitor for sedative effects whenever the patient has important responsibilities that require the maintenance of vigilance.

Antagonism of orexin 1 receptors eliminates motor hyperactivity and improves homing response acquisition in juvenile rats exposed to alcohol during early postnatal period

Consequences of prenatal alcohol exposure (AE) include motor hyperactivity, disrupted sleep and cognitive deficits. Hypothalamic orexin (ORX)-synthesizing neurons are important for the maintenance of vigilance and regulation of motor activity but their hyperactivity may contribute to anxiety disorders. Using a rat model, we tested whether ORX plays a role in behavioral consequences of prenatal AE. Male rat pups received 2.625 g/kg of alcohol (AE group) intragastrically twice daily on postnatal days (PD)4–9, a developmental period equivalent to the third trimester of human pregnancy. Control pups were sham-intubated (S group). On PD12–14, they received daily injections of either the ORX-1 receptor antagonist, SB-334867 (SB; 20 mg/kg, i.p.) or vehicle (V) during the lights-off period. On PD16, they were subjected to the homing response (HR) test. On PD17, their motor activity was monitored in a novel environment. The percentage of tests in which HR acquisition was not achieved and the number of trials needed to reach the shortest HR latency were higher, whereas the percentage of successful trials was lower, in AE–V than in S–V rats ( p = 0.0009–0.03). In contrast, these measures were not significantly different between AE–SB and either S–SB or S–V rats. Motor activity in AE–V rats was significantly higher than in S–V ( p = 0.003), S–SB ( p = 0.007) or AE–SB ( p = 0.02) rats, with no difference between S–SB and AE–SB group. Our findings suggest that excessive activity of ORX neurons contributes to motor hyperactivity and impaired HR acquisition following perinatal AE and that these symptoms may be alleviated by systemic antagonism of ORX-1 receptors.

Effects of Low Intensity Exercises on Recovery of Psycho-Physiological Readiness for Surveillance

This study examined the effectiveness of resting techniques for maintaining the optimal condition for surveillance. Lifesavers (n=15) participated in a pilot study that investigated the psychophysiological conditions for the best and the worst surveillance during lifesaving. Results indicated that psycho-physiological problems related to performance were sleepiness, and fatigue due to stiffness in the neck and the shoulders. Based on the results, three types of low intensity exercises: ball exercises, walking and static stretching were devised to recover arousal level and from fatigue. In an experiment devised to assess the effects of the exercises, participating lifesavers (n=13) performed a computer simulated surveillance task. The three types of exercises, or quiet sitting as the control condition, were practiced during a one-minute rest after the surveillance task. Then, the effects of these resting techniques on three dimensions of recovery; (a) recovery of arousal level, (b) recovery from fatigue and (c) maintenance of vigilance were respectively compared using the following indices: (1) Self-Rating Scale / Peripheral Skin Temperature / Two Dimensional Mood Scale, (2) Self-Rating Scale / Critical Fusion Frequency, (3) Grid Exercise.Results indicated that ball exercises and walking as a ballistic exercise were effective for the recovery of arousal level. Moreover, ball exercises and static stretching to reduce stiffness were effective for recovery from fatigue. Furthermore, ball exercises were more effective than other techniques for maintaining vigilance. It is concluded that low intensity exercises with a ball is the most effective method of maintaining the vigilance and psycho-physiological readiness for surveillance.

Post-Traumatic Stress Disorder: Basic Science and Clinical Practice

Post-Traumatic Stress Disorder: Basic Science and Clinical Practice

Supramodal and modality-specific brain mechanisms for the regulation of intrinsic alertness

Event Abstract Back to Event Supramodal and modality-specific brain mechanisms for the regulation of intrinsic alertness Robert Langner1*, K. Willmes1, T. Kellermann1, F. Boers2, K. Mathiak1 and W. Sturm1 1 RWTH Aachen University, Germany 2 Institute of Neuroscience and Biophysics , Germany Alertness is a basic nonselective function of attention and can be defined as general readiness to respond to task demands. Intrinsic alertness refers to the maintenance of an alert state without external cues (e.g., warning signals) over seconds up to minutes – in contrast to phasic alertness, which denotes the transient increase in response readiness after some cue in the millisecond range. The level of alertness is usually measured as response speed in simple reaction-time tasks. The regulation of intrinsic alertness is assumed to be subserved by a large, mainly right-lateralized cortico-thalamo-mesencephalic network. Using fMRI, this study aimed at identifying modality-dependent vs. independent parts of this network. Brain activity of 22 right-handed participants was measured while performing simple reaction-time tasks involving auditory, visual or vibrotactile stimuli. Control conditions for sensory stimulation and motor activity requiring little intrinsic alertness consisted of high-rate presentations of the respective stimuli used in the reaction-time tasks, which were accompanied by the participants’ rhythmically pressing the response button. A blocked design was used comprising six 20-s task blocks of each condition. A conjunction analysis across the three modalities revealed overlapping activity in the anterior cingulate cortex (ACC), right superior temporal gyrus (STG) and thalamus. Modality-dependent activity was found in respective higher-level sensory and posterior parietal areas. These findings support the role of the ACC, STG and thalamus in the maintenance of vigilance and arousal and suggest that they influence activity in areas mediating task-specific attention effects. Conference: 10th International Conference on Cognitive Neuroscience, Bodrum, Turkey, 1 Sep - 5 Sep, 2008. Presentation Type: Poster Presentation Topic: Attention Citation: Langner R, Willmes K, Kellermann T, Boers F, Mathiak K and Sturm W (2008). Supramodal and modality-specific brain mechanisms for the regulation of intrinsic alertness. Conference Abstract: 10th International Conference on Cognitive Neuroscience. doi: 10.3389/conf.neuro.09.2009.01.100 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 02 Dec 2008; Published Online: 02 Dec 2008. * Correspondence: Robert Langner, RWTH Aachen University, Aachen, Germany, rolangner@ukaachen.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Robert Langner K. Willmes T. Kellermann F. Boers K. Mathiak W. Sturm Google Robert Langner K. Willmes T. Kellermann F. Boers K. Mathiak W. Sturm Google Scholar Robert Langner K. Willmes T. Kellermann F. Boers K. Mathiak W. Sturm PubMed Robert Langner K. Willmes T. Kellermann F. Boers K. Mathiak W. Sturm Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.