Top-down and bottom-up modulation in processing bimodal face/voice stimuli

<p>Abstract</p> <p>Background</p> <p>Processing of multimodal information is a critical capacity of the human brain, with classic studies showing bimodal stimulation either facilitating or interfering in perceptual processing. Comparing activity to congruent and incongruent bimodal stimuli can reveal sensory dominance in particular cognitive tasks.</p> <p>Results</p> <p>We investigated audiovisual interactions driven by stimulus properties (bottom-up influences) or by task (top-down influences) on congruent and incongruent simultaneously presented faces and voices while ERPs were recorded. Subjects performed gender categorisation, directing attention either to faces or to voices and also judged whether the face/voice stimuli were congruent in terms of gender. Behaviourally, the unattended modality affected processing in the attended modality: the disruption was greater for attended voices. ERPs revealed top-down modulations of early brain processing (30-100 ms) over unisensory cortices. No effects were found on N170 or VPP, but from 180-230 ms larger right frontal activity was seen for incongruent than congruent stimuli.</p> <p>Conclusions</p> <p>Our data demonstrates that in a gender categorisation task the processing of faces dominate over the processing of voices. Brain activity showed different modulation by top-down and bottom-up information. Top-down influences modulated early brain activity whereas bottom-up interactions occurred relatively late.</p

[Neurogenic bladder dysfunction a main disability of decompression sickness: a case report].

International audienceINTRODUCTION: Bladder dysfunction is common in the acute phase of decompression sickness and often precedes motor disorders. Few studies have reported the persistence of urinary problems, and no prior reports describe a neurogenic bladder in the primary presentation of decompression sickness. CASE REPORT: We report the case of a 21-year-old female scuba diver with no medical history. After two successive deep dives, dysbaric myelitis developed. The risk factors were foramen ovale and history of diving. The patient initially showed tetraparesia, which was quickly followed by paraparesia with urinary retention. Treatment consisted of recompression with high concentrations of inspired oxygen, aspirin administration and continuous drainage by an indwelling catheter. No lesion was found on 2 sessions of magnetic resonance imaging (MRI) (cerebral and spinal), and somatosensory-evoked potentials were normal. Motor-evoked potential onset latencies were delayed. Neuro-urodynamic investigations revealed detrusor sphincter dysynergia and detrusor overactivity. On quick, complete motor recovery, the patient returned to work and continued with sports (except scuba diving). A year later, she still had urinary and faecal urgencies which were not completely resolved with medication and altered her quality of life. CONCLUSION: Half of the cases of neurological decompression involve dysbaric myelitis. Venous ischemia is the most likely cause. Foramen ovale is an important risk factor, but the pathophysiology is obscure. Bladder problems, common in the acute phase of decompression sickness, may be the primary presentation, and may be prolonged

Sequential anti-core glycolipid immunoglobulin antibody activities in patients with and without septic shock and their relation to outcome.

OBJECTIVE: This study follows the sequential changes in anti-lipopolysaccharide antibodies in infected patients with and without septic shock. SUMMARY BACKGROUND DATA: A relation between high endogenous levels of anti-LPS antibodies and protection against bacteremia and septic shock in at-risk patient groups has been observed. However, information on the daily follow-up and kinetics of apparition or disappearance of anti-LPS antibody activities and their relations with the protective properties of the different immunoglobulin classes has not been clearly investigated. METHODS: Two hundred and five septic surgical patients were studied during their stay in the intensive care unit during a period of 3 years. Among these patients, septic shock developed in 54 and 47 died. A sensitive ELISA was used to study circulating IgM and IgG antibodies to the core glycolipid (CGL) region of Salmonella minnesota R595. The activities were measured each day when sepsis occurred and every hour during septic shock. RESULTS: Anti-CGL IgM activity was found in 32% of the septic patients. This response, however, most often appeared to be transient. A strong correlation was observed between the occurrence of septic shock and the absence of anti-CGL IgM activity on admission to the ICU (p < 0.02). Anti-CGL IgG activity was detected in 82% of the patients and better correlated with outcome for patients with high or rising activities during their hospitalization (p < 0.0005). In patients with septic shock or irreversible organ failure, a fall in the anti-CGL IgG activity was observed before death, suggesting that the IgG antibodies were consumed during this acute event. Therefore, the anti-CGL IgG activity measured by ELISA could be used as a marker of the evolution of the illness. CONCLUSIONS: Our observations demonstrate the interest to follow-up the evolution of the anti-CGL antibodies during sepsis. The fall of these antibodies during septic shock and in patients who died was an additional argument to perform, as an additive form, passive antibody therapy to decrease lethality in this group of patients

When audition alters vision: an event-related potential study of the cross-modal interactions between faces and voices.

Ten healthy volunteers took part in this event-related potential (ERP) study aimed at examining the electrophysiological correlates of the cross-modal audio-visual interactions in an identification task. Participants were confronted either to the simultaneous presentation of previously learned faces and voices (audio-visual condition; AV), either to the separate presentation of faces (visual, V) or voices (auditive, A). As expected, an interference effect of audition on vision was observed at a behavioral level, as the bimodal condition was performed more slowly than the visual condition. At the electrophysiological level, the subtraction (AV - (A + V)) gave prominence to three distinct cerebral activities: (1) a central positive/posterior negative wave around 110 ms, (2) a central negative/posterior positive wave around 170 ms, AND (3) a central positive wave around 270 ms. These data suggest that cross-modal cerebral interactions could be independent of behavioral facilitation or interference effects. Moreover, the implication of unimodal and multisensory convergence regions in these results, as suggested by a source localization analysis, is discussed.Comparative StudyJournal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

The crossmodal facilitation effect is disrupted in alcoholism: a study with emotional stimuli.

Chronic alcoholism is classically associated with major deficits in the visual and auditory processing of emotions. However, the crossmodal (auditory-visual) processing of emotional stimuli, which occurs most frequently in everyday life, has not yet been explored. The aim of this study was to explore crossmodal processing in alcoholism, and specifically the auditory-visual facilitation effect.Comparative StudyJournal Articleinfo:eu-repo/semantics/publishe

保険法における「保険料」概念と「危険」概念の関連性-商学のからのアプローチ-

This paper shows the relevance between concept ‘premium’ and concept ‘risk’ of the new Insurance Contract Act of Japan in the light of commercial science of insurance. First, I mention that this act has the definition clause concerning ‘insurance contract,’ which describes the ‘premium’ as ‘calculated in proportion to the probability of occurrence of such a specific cause.’ This expression may be understood to limit the insurance risk to frequency risk, but it should be understood to include severity risk. Second, I mention that the articles of this act concerning ‘risk’ should also be understood to include severity risk, because this act has the similar definition clause concerning ‘risk’ to that of ‘premium.

Understanding the Black Sea ecosystem functioning during the eutrophication phase using mathematical modelling

A coupled physical-biogeochemical model has been developed to simulate the ecosystem of the Black Sea at the end of the 80's when eutrophication and invasion by gelatinous organisms seriously affected the stability and dynamics of the system. The biogeochemical model describes the foodweb from bacteria to gelatinous carnivores and explicitly represents processes in the anoxic layer down to the bottom. Additionally, in order to estimate carbon sequestration, the model includes an explicit representation of the DIC and alkalinity dynamics. For calibration and analyses purposes, the coupled model has first been run in 1D in several places in the Black Sea. The biogeochemical model involves some hundred parameters which are first calibrated by hand using published values. Then, an identifiability analysis has been performed in order to determine a subset of identifiable parameters (~15). An automatic calibration subroutine has been used to fine tune these parameters. In 1D, the model solution exhibits a complex dynamics with several years of transient adjustment. This complexity is imparted by the explicit modelling of top predators. The model has been calibrated and validated using a large set of data available in the Black Sea TU Ocean Base. The calibrated biogeochemical model is implemented in a 3D hydrodynamical model of the Black Sea. Appropriate nesting techniques are developed in order to couple at the shelf break the high resolution shelf model (~1-2 km) and the basin scale coarse model (5km). First results will be presented