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2.
Infect Dis Now ; 53(4): 104673, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36775065

RESUMO

OBJECTIVES: While persistent symptoms have been reported after the coronavirus disease-2019 (COVID-19), long-term data on outpatients with mild COVID-19 are lacking. The objective was to describe symptoms persisting for 12 months. METHODS: This prospective cohort study on 1767 sailors of an aircraft carrier in which a Covid-19 outbreak occurred during a mission in April 2020 described predefined self-reported symptoms of Long-COVID at 6, 9 and 12 months. Logistic-regression analyses were used to identify correlates for Long-COVID at months 6, 9 and 12. RESULTS: Among the 641 participants, 619 (35%) completed at least one follow-up questionnaire (413 COVID-positive and 206 COVID-negative). Symptoms of Long-COVID were reported by 53.7%, 55.2% and 54.3% of COVID-positive participants vs 31.2%, 23.3% and 40.0% in COVID-negative patients, at 6 (p <.002), 9 (p <.002) and 12 months (p =.13), respectively. The most frequent symptoms reported were concentration and memory difficulties, asthenia and sleep disorders. CONCLUSION: In this study more than half of COVID-positive outpatients reported persistent symptoms up to 12 months post-quarantine. These findings suggests that all patients, including those with mild disease, can be affected by Long-COVID. A lack of difference at 12 months with COVID-negative patienys prompts caution. The symptoms of Long-COVID are so non-specific that they may be viewed as the consequence of multiple intercurrent factors.


Assuntos
COVID-19 , Militares , Humanos , COVID-19/epidemiologia , SARS-CoV-2 , Síndrome de COVID-19 Pós-Aguda , Estudos Prospectivos , Surtos de Doenças , Aeronaves
3.
J Neurol Sci ; 446: 120579, 2023 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-36807973

RESUMO

Following vestibular neuritis (VN), long term prognosis is not dependent on the magnitude of the residual peripheral function as measured with either caloric or the video head-impulse test. Rather, recovery is determined by a combination of visuo-vestibular (visual dependence), psychological (anxiety) and vestibular perceptual factors. Our recent research in healthy individuals has also revealed a strong association between the degree of lateralisation of vestibulo-cortical processing and gating of vestibular signals, anxiety and visual dependence. In the context of several functional brain changes occurring in the interaction between visual, vestibular and emotional cortices, which underpin the aforementioned psycho-physiological features in patients with VN, we re-examined our previously published findings focusing on additional factors impacting long term clinical outcome and function. These included: (i) the role of concomitant neuro-otological dysfunction (i.e. migraine and benign paroxysmal positional vertigo (BPPV)) and (ii) the degree to which brain lateralisation of vestibulo-cortical processing influences gating of vestibular function in the acute stage. We found that migraine and BPPV interfere with symptomatic recovery following VN. That is, dizziness handicap at short-term recovery stage was significantly predicted by migraine (r = 0.523, n = 28, p = .002), BPPV (r = 0.658, n = 31, p < .001) and acute visual dependency (r = 0.504, n = 28, p = .003). Moreover, dizziness handicap in the long-term recovery stage continued to be predicted by migraine (r = 0.640, n = 22, p = .001), BPPV (r = 0.626, n = 24, p = .001) and acute visual dependency (r = 0.667, n = 22, p < .001). Furthermore, surrogate measures of vestibulo-cortical lateralisation were predictive of the amount of cortical suppression exerted over vestibular thresholds. That is, in right-sided VN patients, we observed a positive correlation between visual dependence and acute ipsilesional oculomotor thresholds (R2 0.497; p < .001), but not contralateral thresholds (R2 0.017: p > .05). In left-sided VN patients, we observed a negative correlation between visual dependence and ipsilesional oculomotor thresholds (R2 0.459; p < .001), but not for contralateral thresholds (R2 0.013; p > .05). To surmise, our findings illustrate that in VN, neuro-otological co-morbidities retard recovery, and that measures of the peripheral vestibular system are an aggregate of residual function and cortically mediated gating of vestibular input.


Assuntos
Transtornos de Enxaqueca , Neuronite Vestibular , Humanos , Tontura/complicações , Estudos Prospectivos , Vertigem/complicações , Transtornos de Enxaqueca/complicações
4.
Rev Mal Respir ; 40(2): 156-168, 2023 Feb.
Artigo em Francês | MEDLINE | ID: mdl-36690507

RESUMO

INTRODUCTION: Recent news points to the eventuality of an armed conflict on the national territory. STATE OF THE ART: In this situation, pulmonologists will in all likelihood have a major role to assume in caring for the injured, especially insofar as chest damage is a major cause of patient death. PERSPECTIVES: The main injuries that pulmonologists may be called upon to treat stem not only from explosions, but also from chemical, biological and nuclear hazards. In this article, relevant organizational and pedagogical aspects are addressed. Since exhaustiveness on this subject is unattainable, we are proposing training on specific subjects for interested practitioners. CONCLUSION: The resilience of the French health system in a situation of armed conflict depends on the active participation of all concerned parties. With this in mind, it is of prime importance that the pneumological community be sensitized to the potential predictable severity of war-related injuries.


Assuntos
Conflitos Armados , Pneumologistas , Humanos
5.
Clin Neurophysiol ; 132(11): 2751-2762, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34583117

RESUMO

OBJECTIVE: To examine the hypothesis that small vessel disease disrupts postural networks in older adults with unexplained dizziness in the elderly (UDE). METHODS: Simultaneous electroencephalography and postural sway measurements were undertaken in upright, eyes closed standing, and sitting postures (as baseline) in 19 younger adults, 33 older controls and 36 older patients with UDE. Older adults underwent magnetic resonance imaging to determine whole brain white matter hyperintensity volumes, a measure of small vessel disease. Linear regression was used to estimate the effect of instability on electroencephalographic power and connectivity. RESULTS: Ageing increased theta and alpha desynchronisation on standing. In older controls, delta and gamma power increased, and theta and alpha power reduced with instability. Dizzy older patients had higher white matter hyperintensity volumes and more theta desynchronisation during periods of instability. White matter hyperintensity volume and delta power during periods of instability were correlated, positively in controls but negatively in dizzy older patients. Delta power correlated with subjective dizziness and instability. CONCLUSIONS: Neural resource demands of postural control increase with age, particularly in patients with UDE, driven by small vessel disease. SIGNIFICANCE: EEG correlates of postural control saturate in older adults with UDE, offering a neuro-physiological basis to this common syndrome.


Assuntos
Envelhecimento/fisiologia , Encéfalo/fisiologia , Doenças de Pequenos Vasos Cerebrais/fisiopatologia , Tontura/fisiopatologia , Eletroencefalografia/métodos , Equilíbrio Postural/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/diagnóstico por imagem , Ondas Encefálicas/fisiologia , Doenças de Pequenos Vasos Cerebrais/diagnóstico por imagem , Tontura/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiologia , Posição Ortostática , Adulto Jovem
6.
Semin Neurol ; 40(1): 116-129, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32045940

RESUMO

Environmental circumstances that result in ambiguity or conflict with the patterns of sensory stimulation may adversely affect the vestibular system. The effect of this conflict in sensory information may be dizziness, a sense of imbalance, nausea, and motion sickness sometimes even to seemingly minor daily head movement activities. In some, it is not only exposure to motion but also the observation of objects in motion around them such as in supermarket aisles or other places with visual commotion; this can lead to dizziness, nausea, or a feeling of motion sickness that is referred to as visual vertigo. All people with normal vestibular function can be made to experience motion sickness, although individual susceptibility varies widely and is at least partially heritable. Motorists learn to interpret sensory stimuli in the context of the car stabilized by its suspension and guided by steering. A type of motorist's disorientation occurs in some individuals who develop a heightened awareness of perceptions of motion in the automobile that makes them feel as though they may be rolling over on corners and as though they are veering on open highways or in streaming traffic. This article discusses the putative mechanisms, consequences and approach to managing patients with visual vertigo, motion sickness, and motorist's disorientation syndrome in the context of chronic dizziness and motion sensitivity.


Assuntos
Condução de Veículo , Confusão , Tontura , Enjoo devido ao Movimento , Vertigem , Confusão/etiologia , Confusão/fisiopatologia , Confusão/terapia , Tontura/etiologia , Tontura/fisiopatologia , Tontura/terapia , Humanos , Enjoo devido ao Movimento/etiologia , Enjoo devido ao Movimento/fisiopatologia , Enjoo devido ao Movimento/terapia , Vertigem/etiologia , Vertigem/fisiopatologia , Vertigem/terapia
7.
Trop Biomed ; 37(1): 194-200, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33612730

RESUMO

Dipylidium caninum is a parasite that commonly infects dogs and cats worldwide. The large population of wild and stray dogs and cats may potentially transmit D. caninum to humans via their flea and lice. Humans are an accidental host, and dipylidiasis is more commonly seen in infants and children. There is scant information about human dipylidiasis in Russia. We report nine cases of dipylidiasis - eight in children and one in an adult. The patients were asymptomatic, except for excreting active proglottids in their faeces, which was the most common complaint. The clinical significance of asymptomatic dipylidiasis is not understood, except mothers were anxious because of the continuous appearance of active worms in the faeces of their children. The patients were successfully treated with praziquantel (15 mg/kg). Preventing dipylidiasis in pets and humans requires the control of fleas and lice, avoiding the outdoor defecation of definitive hosts, deworming pets, preventing children from playing with stray animals and spread of information about dipylidiasis among pet owners. Dogs and cats in many places in Russia breed freely, defecate outdoors in any area, and are not subjected to deworming and insect control. These circumstances favour the fact that, although this zoonosis is rare, it is a re-emerging disease and might reach important levels in Russia.


Assuntos
Infecções por Cestoides/epidemiologia , Zoonoses/epidemiologia , Adulto , Animais , Gatos , Cestoides , Infecções por Cestoides/tratamento farmacológico , Criança , Pré-Escolar , Cães , Fezes/parasitologia , Feminino , Humanos , Lactente , Masculino , Moscou/epidemiologia , Animais de Estimação , Praziquantel/uso terapêutico , Zoonoses/parasitologia
8.
Tropical Biomedicine ; : 194-200, 2020.
Artigo em Inglês | WPRIM (Pacífico Ocidental) | ID: wpr-823088

RESUMO

@#Dipylidium caninum is a parasite that commonly infects dogs and cats worldwide. The large population of wild and stray dogs and cats may potentially transmit D. caninum to humans via their flea and lice. Humans are an accidental host, and dipylidiasis is more commonly seen in infants and children. There is scant information about human dipylidiasis in Russia. We report nine cases of dipylidiasis – eight in children and one in an adult. The patients were asymptomatic, except for excreting active proglottids in their faeces, which was the most common complaint. The clinical significance of asymptomatic dipylidiasis is not understood, except mothers were anxious because of the continuous appearance of active worms in the faeces of their children. The patients were successfully treated with praziquantel (15 mg/kg). Preventing dipylidiasis in pets and humans requires the control of fleas and lice, avoiding the outdoor defecation of definitive hosts, deworming pets, preventing children from playing with stray animals and spread of information about dipylidiasis among pet owners. Dogs and cats in many places in Russia breed freely, defecate outdoors in any area, and are not subjected to deworming and insect control. These circumstances favour the fact that, although this zoonosis is rare, it is a re-emerging disease and might reach important levels in Russia.

9.
J Helminthol ; 93(3): 372-374, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-29720291

RESUMO

Although there have been occasional reports of rare and low-level trichinellae infestation in beavers, no human cases of beaver-associated trichinellosis have been described. This report presents a possible case of human trichinellosis linked to beaver meat. Increasing consumption of beaver meat necessitates raising awareness of this potential source of trichinellosis.


Assuntos
Comportamento Alimentar , Carne , Roedores , Triquinelose/diagnóstico , Triquinelose/patologia , Adulto , Albendazol/administração & dosagem , Animais , Anti-Helmínticos/administração & dosagem , Feminino , Humanos , Moscou , Triquinelose/tratamento farmacológico , Adulto Jovem
10.
Biochemistry (Mosc) ; 83(10): 1255-1262, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30472962

RESUMO

The gene for Kunitz peptidase inhibitor-like protein (KPILP) contains nested alternative open reading frame (aORF) that controls expression of the maternal mRNA. The content of NbKPILP mRNA in intact leaves of Nicotiana benthamiana plant is low but increases significantly upon extended dark exposure or when foreign nucleic acid is overexpressed in the cells. The NbKPILP gene promoter along with the expressed nested aORF are likely to play an important role in maintaining the levels of NbKPILP mRNA. To elucidate the role of NbKPILP promoter, we isolated a fragment of N. benthamiana chromosomal DNA upstream of the NbKPILP transcription start, sequenced it, and created constructs in which reporter E. coli uidA gene coding for ß-D-glucuronidase (GUS) was placed under control of the NbKPILP promoter. By assessing the efficacy of uidA mRNA synthesis directed by the NbKPILP promoter and 35S promoter of the cauliflower mosaic virus in a transient expression system, we showed that the levels of GUS accumulation were comparable for both promoters. Prolonged incubation of the agroinjected plants in the darkness stimulated accumulation of the uidA mRNA directed by the NbKPILP promoter. Our experiments indicate that along with regulation at the transcriptional level, expression of NbKPILP mRNA can be affected by expression of the nested aORF controlled by the polypurine block (PPB) located upstream of its start codon, since introduction of mutations in the PPB resulted in significant accumulation of the NbKPILP mRNA. Nucleotide replacement in the aORF start codon led to the drastic increase in the amounts of NbKPILP mRNA and its protein product.


Assuntos
Nicotiana/genética , Proteínas de Plantas/genética , Biossíntese de Proteínas , Transcrição Gênica , Agrobacterium tumefaciens/genética , Agrobacterium tumefaciens/fisiologia , Sequência de Bases , Clonagem Molecular , Códon de Iniciação , Escherichia coli/enzimologia , Genes Reporter , Glucuronidase/genética , Fases de Leitura Aberta/genética , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Regiões Promotoras Genéticas , RNA Mensageiro/metabolismo , Alinhamento de Sequência , Nicotiana/metabolismo
11.
Neuroimage Clin ; 20: 1010-1017, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30336357

RESUMO

Vestibular neuritis (VN) is characterised by acute vertigo due to a sudden loss of unilateral vestibular function. A considerable proportion of VN patients proceed to develop chronic symptoms of dizziness, including visually induced dizziness, specifically during head turns. Here we investigated whether the development of such poor clinical outcomes following VN, is associated with abnormal visuo-vestibular cortical processing. Accordingly, we applied functional magnetic resonance imaging to assess brain responses of chronic VN patients and compared these to controls during both congruent (co-directional) and incongruent (opposite directions) visuo-vestibular stimulation (i.e. emulating situations that provoke symptoms in patients). We observed a focal significant difference in BOLD signal in the primary visual cortex V1 between patients and controls in the congruent condition (small volume corrected level of p < .05 FWE). Importantly, this reduced BOLD signal in V1 was negatively correlated with functional status measured with validated clinical questionnaires. Our findings suggest that central compensation and in turn clinical outcomes in VN are partly mediated by adaptive mechanisms associated with the early visual cortex.


Assuntos
Imageamento por Ressonância Magnética , Vertigem/patologia , Neuronite Vestibular/patologia , Vestíbulo do Labirinto/patologia , Córtex Visual/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Neuronite Vestibular/diagnóstico
12.
J Neurophysiol ; 118(5): 2819-2832, 2017 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-28814637

RESUMO

Self-motion perception was studied in patients with unilateral vestibular lesions (UVL) due to acute vestibular neuritis at 1 wk and 4, 8, and 12 mo after the acute episode. We assessed vestibularly mediated self-motion perception by measuring the error in reproducing the position of a remembered visual target at the end of four cycles of asymmetric whole-body rotation. The oscillatory stimulus consists of a slow (0.09 Hz) and a fast (0.38 Hz) half cycle. A large error was present in UVL patients when the slow half cycle was delivered toward the lesion side, but minimal toward the healthy side. This asymmetry diminished over time, but it remained abnormally large at 12 mo. In contrast, vestibulo-ocular reflex responses showed a large direction-dependent error only initially, then they normalized. Normalization also occurred for conventional reflex vestibular measures (caloric tests, subjective visual vertical, and head shaking nystagmus) and for perceptual function during symmetric rotation. Vestibular-related handicap, measured with the Dizziness Handicap Inventory (DHI) at 12 mo correlated with self-motion perception asymmetry but not with abnormalities in vestibulo-ocular function. We conclude that 1) a persistent self-motion perceptual bias is revealed by asymmetric rotation in UVLs despite vestibulo-ocular function becoming symmetric over time, 2) this dissociation is caused by differential perceptual-reflex adaptation to high- and low-frequency rotations when these are combined as with our asymmetric stimulus, 3) the findings imply differential central compensation for vestibuloperceptual and vestibulo-ocular reflex functions, and 4) self-motion perception disruption may mediate long-term vestibular-related handicap in UVL patients.NEW & NOTEWORTHY A novel vestibular stimulus, combining asymmetric slow and fast sinusoidal half cycles, revealed persistent vestibuloperceptual dysfunction in unilateral vestibular lesion (UVL) patients. The compensation of motion perception after UVL was slower than that of vestibulo-ocular reflex. Perceptual but not vestibulo-ocular reflex deficits correlated with dizziness-related handicap.


Assuntos
Adaptação Fisiológica , Propriocepção , Reflexo Vestíbulo-Ocular , Doenças Vestibulares , Adulto , Avaliação da Deficiência , Medições dos Movimentos Oculares , Lateralidade Funcional , Movimentos da Cabeça , Humanos , Masculino , Memória , Pessoa de Meia-Idade , Estimulação Física , Estudos Prospectivos , Psicofísica , Recuperação de Função Fisiológica , Rotação , Doenças Vestibulares/fisiopatologia , Percepção Visual , Adulto Jovem
13.
Brain Struct Funct ; 222(5): 2329-2343, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27942855

RESUMO

The brain combines visual, vestibular and proprioceptive information to distinguish between self- and world motion. Often these signals are complementary and indicate that the individual is moving or stationary with respect to the surroundings. However, conflicting visual motion and vestibular cues can lead to ambiguous or false sensations of motion. In this study, we used functional magnetic resonance imaging to explore human brain activation when visual and vestibular cues were either complementary or in conflict. We combined a horizontally moving optokinetic stimulus with caloric irrigation of the right ear to produce conditions where the vestibular activation and visual motion indicated the same (congruent) or opposite directions of self-motion (incongruent). Visuo-vestibular conflict was associated with increased activation in a network of brain regions including posterior insular and transverse temporal areas, cerebellar tonsil, cingulate and medial frontal gyri. In the congruent condition, there was increased activation in primary and secondary visual cortex. These findings suggest that when sensory information regarding self-motion is contradictory, there is preferential activation of multisensory vestibular areas to resolve this ambiguity. When cues are congruent, there is a bias towards visual cortical activation. The data support the view that a network of brain areas including the posterior insular cortex may play an important role in integrating and disambiguating visual and vestibular cues.


Assuntos
Mapeamento Encefálico , Imageamento por Ressonância Magnética , Percepção de Movimento/fisiologia , Vestíbulo do Labirinto/fisiologia , Córtex Visual/fisiologia , Adolescente , Adulto , Feminino , Neuroimagem Funcional/métodos , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Estimulação Luminosa/métodos , Adulto Jovem
14.
Handb Clin Neurol ; 139: 343-351, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27719854

RESUMO

Functional (psychogenic) eye movement disorders are perhaps less established in the medical literature than other types of functional movement disorders. Patients may present with ocular symptoms (e.g., blurred vision or oscillopsia) or functional eye movements may be identified during the formal examination of the eyes in patients with other functional disorders. Convergence spasm is the most common functional eye movement disorder, but functional gaze limitation, functional eye oscillations (also termed "voluntary nystagmus"), and functional convergence paralysis may be underreported. This chapter reviews the different types of functional eye movement abnormalities and provides a practical framework for their diagnosis and management.


Assuntos
Transtornos da Motilidade Ocular/diagnóstico , Transtornos da Motilidade Ocular/psicologia , Transtornos Psicofisiológicos/diagnóstico , Transtornos Somatoformes/diagnóstico , Humanos
15.
Handb Clin Neurol ; 137: 57-66, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27638062

RESUMO

This chapter provides an introduction to the topic of multisensory integration in balance control in, both, health and disease. One of the best-studied examples is that of visuo-vestibular interaction, which is the ability of the visual system to enhance or suppress the vestibulo-ocular reflex (VOR suppression). Of clinical relevance, examination of VOR suppression is clinically useful because only central, not peripheral, lesions impair VOR suppression. Visual, somatosensory (proprioceptive), and vestibular inputs interact strongly and continuously in the control of upright balance. Experiments with visual motion stimuli show that the visual system generates visually-evoked postural responses that, at least initially, can override vestibular and proprioceptive signals. This paradigm has been useful for the study of the syndrome of visual vertigo or vision-induced dizziness, which can appear after vestibular disease. These patients typically report dizziness when exposed to optokinetic stimuli or visually charged environments, such as supermarkets. The principles of the rehabilitation treatment of these patients, which use repeated exposure to visual motion, are presented. Finally, we offer a diagnostic algorithm in approaching the patient reporting oscillopsia - the illusion of oscillation of the visual environment, which should not be confused with the syndrome mentioned earlier of visual vertigo.


Assuntos
Equilíbrio Postural/fisiologia , Propriocepção/fisiologia , Reflexo Vestíbulo-Ocular/fisiologia , Visão Ocular/fisiologia , Animais , Humanos
16.
Eur J Neurosci ; 44(6): 2369-74, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27422569

RESUMO

Although a direct relationship between numerical allocation and spatial attention has been proposed, recent research suggests that these processes are not directly coupled. In keeping with this, spatial attention shifts induced either via visual or vestibular motion can modulate numerical allocation in some circumstances but not in others. In addition to shifting spatial attention, visual or vestibular motion paradigms also (i) elicit compensatory eye movements which themselves can influence numerical processing and (ii) alter the perceptual state of 'self', inducing changes in bodily self-consciousness impacting upon cognitive mechanisms. Thus, the precise mechanism by which motion modulates numerical allocation remains unknown. We sought to investigate the influence that different perceptual experiences of motion have upon numerical magnitude allocation while controlling for both eye movements and task-related effects. We first used optokinetic visual motion stimulation (OKS) to elicit the perceptual experience of either 'visual world' or 'self'-motion during which eye movements were identical. In a second experiment, we used a vestibular protocol examining the effects of perceived and subliminal angular rotations in darkness, which also provoked identical eye movements. We observed that during the perceptual experience of 'visual world' motion, rightward OKS-biased judgments towards smaller numbers, whereas leftward OKS-biased judgments towards larger numbers. During the perceptual experience of 'self-motion', judgments were biased towards larger numbers irrespective of the OKS direction. Contrastingly, vestibular motion perception was found not to modulate numerical magnitude allocation, nor was there any differential modulation when comparing 'perceived' vs. 'subliminal' rotations. We provide a novel demonstration that numerical magnitude allocation can be differentially modulated by the perceptual state of self during visual but not vestibular mediated motion.


Assuntos
Atenção/fisiologia , Movimentos Oculares/fisiologia , Percepção de Movimento/fisiologia , Movimento (Física) , Percepção Espacial/fisiologia , Feminino , Humanos , Masculino , Modelos Neurológicos , Orientação/fisiologia , Estimulação Luminosa/métodos , Desempenho Psicomotor/fisiologia , Vestíbulo do Labirinto/fisiologia , Adulto Jovem
17.
Neuroscience ; 311: 484-9, 2015 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-26518461

RESUMO

Right hemisphere dominance for visuo-spatial attention is characteristically observed in most right-handed individuals. This dominance has been attributed to both an anatomically larger right fronto-parietal network and the existence of asymmetric parietal interhemispheric connections. Previously it has been demonstrated that interhemispheric conflict, which induces left hemisphere inhibition, results in the modulation of both (i) the excitability of the early visual cortex (V1) and (ii) the brainstem-mediated vestibular-ocular reflex (VOR) via top-down control mechanisms. However to date, it remains unknown whether the degree of an individual's right hemisphere dominance for visuospatial function can influence, (i) the baseline excitability of the visual cortex and (ii) the extent to which the right hemisphere can exert top-down modulation. We directly tested this by correlating line bisection error (or pseudoneglect), taken as a measure of right hemisphere dominance, with both (i) visual cortical excitability measured using phosphene perception elicited via single-pulse occipital trans-cranial magnetic stimulation (TMS) and (ii) the degree of trans-cranial direct current stimulation (tDCS)-mediated VOR suppression, following left hemisphere inhibition. We found that those individuals with greater right hemisphere dominance had a less excitable early visual cortex at baseline and demonstrated a greater degree of vestibular nystagmus suppression following left hemisphere cathodal tDCS. To conclude, our results provide the first demonstration that individual differences in right hemisphere dominance can directly predict both the baseline excitability of low-level brain structures and the degree of top-down modulation exerted over them.


Assuntos
Lateralidade Funcional/fisiologia , Reflexo Vestíbulo-Ocular/fisiologia , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Movimentos Oculares/fisiologia , Feminino , Humanos , Masculino , Inibição Neural , Estimulação Luminosa/métodos , Estimulação Transcraniana por Corrente Contínua/métodos , Estimulação Magnética Transcraniana/métodos , Vias Visuais/fisiologia , Adulto Jovem
18.
IEEE Trans Pattern Anal Mach Intell ; 37(9): 1821-33, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26353129

RESUMO

Parsimony, including sparsity and low rank, has been shown to successfully model data in numerous machine learning and signal processing tasks. Traditionally, such modeling approaches rely on an iterative algorithm that minimizes an objective function with parsimony-promoting terms. The inherently sequential structure and data-dependent complexity and latency of iterative optimization constitute a major limitation in many applications requiring real-time performance or involving large-scale data. Another limitation encountered by these modeling techniques is the difficulty of their inclusion in discriminative learning scenarios. In this work, we propose to move the emphasis from the model to the pursuit algorithm, and develop a process-centric view of parsimonious modeling, in which a learned deterministic fixed-complexity pursuit process is used in lieu of iterative optimization. We show a principled way to construct learnable pursuit process architectures for structured sparse and robust low rank models, derived from the iteration of proximal descent algorithms. These architectures learn to approximate the exact parsimonious representation at a fraction of the complexity of the standard optimization methods. We also show that appropriate training regimes allow to naturally extend parsimonious models to discriminative settings. State-of-the-art results are demonstrated on several challenging problems in image and audio processing with several orders of magnitude speed-up compared to the exact optimization algorithms.

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