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1.
Clin Hematol Int ; 3(4): 161-168, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34938988

RESUMO

Gastrointestinal complications (GICs) represent the major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Differential diagnosis of GICs is of paramount importance since early and reliable identification of graft-versus-host disease (GVHD) is essential for a correct management of the patients. The aim of the present retrospective study was to evaluate the occurrence of GICs after allo-HSCT and to assess the diagnostic performance of a quick endoscopic and histological assessment in the differential diagnosis between GVHD and other GI conditions. Between January 2015 and August 2019, 122 consecutive patients receiving an allo-HSCT were managed by an interdisciplinary team, supported by a dedicated endoscopic service. Clinical, therapeutic, endoscopic and histological data were analyzed for each patient. Collectively, 94 of the patients developed GICs (77%). A moderate-severe mucositis was the most frequent complication, occurring in 79 patients (84%). Acute GI-GVHD was diagnosed in 35 patients (37% of whom with GICs) and 19 of them with a moderate-severe grade. Infective acute colitis developed in eight patients, mainly due to Clostridium difficile (CD) and Cytomegalovirus infections (8.5%). Rectal biopsy showed the highest sensitivity and specificity (80% and 100%, respectively). However, when biopsy procedures were guided by symptoms and performed on apparently intact mucosa, upper histology also provided a high negative predictive value (80%). Our multidisciplinary approach with a quick endoscopic/histologic investigation in the patients receiving an allo-HSCT and who suffered GICs could improve diagnostic and therapeutic management in this challenging setting.

2.
J Cogn Neurosci ; 33(12): 2477-2493, 2021 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-34407193

RESUMO

The cognitive and neural bases of visual perception are typically studied using pictures rather than real-world stimuli. Unlike pictures, real objects are actionable solids that can be manipulated with the hands. Recent evidence from human brain imaging suggests that neural responses to real objects differ from responses to pictures; however, little is known about the neural mechanisms that drive these differences. Here, we tested whether brain responses to real objects versus pictures are differentially modulated by the "in-the-moment" graspability of the stimulus. In human dorsal cortex, electroencephalographic responses show a "real object advantage" in the strength and duration of mu (µ) and low beta (ß) rhythm desynchronization-well-known neural signatures of visuomotor action planning. We compared desynchronization for real tools versus closely matched pictures of the same objects, when the stimuli were positioned unoccluded versus behind a large transparent barrier that prevented immediate access to the stimuli. We found that, without the barrier in place, real objects elicited stronger µ and ß desynchronization compared to pictures, both during stimulus presentation and after stimulus offset, replicating previous findings. Critically, however, with the barrier in place, this real object advantage was attenuated during the period of stimulus presentation, whereas the amplification in later periods remained. These results suggest that the "real object advantage" is driven initially by immediate actionability, whereas later differences perhaps reflect other, more inherent properties of real objects. The findings showcase how the use of richer multidimensional stimuli can provide a more complete and ecologically valid understanding of object vision.


Assuntos
Eletroencefalografia , Percepção Visual , Córtex Cerebral , Humanos , Estimulação Luminosa
3.
Endosc Int Open ; 9(4): E629-E634, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33880397

RESUMO

Background and study aims COVID-19 has dramatically impacted endoscopy practice because upper endoscopy procedures can be aerosol-generating. Most elective procedures have been rescheduled. Endoscopic retrograde cholangiopancreatography (ERCP) is frequently performed in emergency or urgent settings in which rescheduling is not possible. We evaluated the impact of the COVID-19 pandemic on ERCP in Italy during the SARS-CoV-2 lockdown, in areas with high incidence of COVID-19. Patients and methods We performed a retrospective survey of centers performing ERCP in high COVID-19 prevalence areas in Italy to collect information regarding clinical data from patients undergoing ERCP, staff, case-volume and organization of endoscopy units from March 8, 2020 to April 30, 2020. Results We collected data from 31 centers and 804 patients. All centers adopted a triage and/or screening protocol for SARS-CoV-2 and performed follow-up of patients 2 weeks after the procedure. ERCP case-volume was reduced by 44.1 % compared to the respective 2019 timeframe. Of the 804 patients undergoing ERCP, 22 (2.7 %) were positive for COVID-19. Adverse events occurred at a similar rate to previously published data. Of the patients, endoscopists, and nurses, 1.6 %, 11.7 %, and 4.9 %, respectively, tested positive for SARS-CoV-2 at follow up. Only 38.7 % of centers had access to a negative-pressure room for ERCP. Conclusion The case-volume reduction for ERCP during lockdown was lower than for other gastrointestinal endoscopy procedures. No definitive conclusions can be drawn about the percentage of SARS-CoV-2-positive patients and healthcare workers observed after ERCP. Appropriate triage and screening of patients and adherence to society recommendations are paramount.

4.
Sci Rep ; 11(1): 1549, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33452300

RESUMO

Site conditions and forest management affect dendrometric parameters of chestnut (Castanea sativa Mill.) coppices, but there is modest knowledge on the effect of stand dendrometric characters on physical and mechanical wood characteristics. The aim of this study was to verify these relationships in chestnut coppices that were 12-14 years old. Wood density, compression and bending strength, shrinkages were measured on shoots of five different stand in a vulcanic site in Monte Amiata (Central - Italy). Investigated stands differ in number of stools/ha and dominant height, diameter/basal area of the shoots. The main difference in the physical characters among the stands is density. The initial results of the study showed that physical, mechanical wood characters are more dependent by the shoot than by the site. There is a positive relationships between the number of stools/ha and density and a negative one among shoot dominant height and basal area with wood density. Spectroscopic profile by FTIR has not showed relevant differences among the stands. Wood anatomy has showed the breakpoint at cellular level.


Assuntos
Agricultura/métodos , Fagaceae/metabolismo , Fagaceae/fisiologia , Conservação dos Recursos Naturais/métodos , Agricultura Florestal/métodos , Florestas , Itália , Árvores/crescimento & desenvolvimento , Madeira/análise
5.
Behav Brain Res ; 391: 112702, 2020 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-32461134

RESUMO

Value-directed strategic processing is an ability that appears to be relatively preserved with aging, but the neurophysiological mechanisms underlying strategic processing in older adults are not well understood. The current study examined age-related spectral power differences in EEG oscillations linked to processing of high-value versus low-value information in a value-directed strategic processing task in 24 younger adults (mean age: 22.4 ± 1.2 years) and 24 older adults (mean age: 63.2 ± 6.4 years). Both groups exhibited comparable strategic processing ability behaviorally with preferential recall of high- compared to low-value words. Both groups exhibited comparable theta band power with greater synchronization for low- compared to high-value words, but age-related differences in processing were noted in alpha band power. Older adults showed more prolonged alpha desynchronization for high- compared to low-value words relative to younger adults. This neurophysiological modulation in the alpha band in older adults might reflect a compensatory neural mechanism or increased effort linked to selective engagement of neural resources, allowing them to perform similarly to younger adults behaviorally on a value-directed strategic processing task.


Assuntos
Fatores Etários , Cognição/fisiologia , Rememoração Mental/fisiologia , Envelhecimento/fisiologia , Ritmo alfa/fisiologia , Encéfalo/fisiologia , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ritmo Teta/fisiologia , Adulto Jovem
6.
Nanomaterials (Basel) ; 10(5)2020 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-32443438

RESUMO

Sustainability and ecotoxicity issues call for innovations regarding eco-friendly adhesives in the production of biocomposite wood materials, and solutions involving nano-scale and bio-based compounds represent a valid and promising target. One possible approach is to increase the performance of adhesives such as polyvinyl acetate (PVAc) or melamine-urea-formaldehyde (MUF) by means of nanoparticles in order to obtain a material with better mechanical and environmental resistance. When applying cellulose-based nanoparticles or tannin, the concept of a circular economy is successfully implemented into the forest/wood value chain, and chances are created to develop new value chains using byproducts of forestry operations. In this study, assortments coming from young sweet chestnut (Castanea sativa Mill.) coppice stands were utilized for the preparation of single lap joint assemblies using different commercial adhesives (PVAc, MUF) and cellulose nanocrystals (CNC) and tannin as additives. The results showed that addition of CNC and tannin to PVAc glue increased tensile shear strength in lap joint tests presenting a promising base for future tests regarding the addition of CNC and tannin in MUF or PVAc adhesive formulations. Unfortunately, the tested bio-based additives did not reveal the same encouraging results when tested in the wet state.

7.
Cognition ; 196: 104129, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31765925

RESUMO

Visual search can be guided by top-down and bottom-up processes, with either one dominating the other depending on the task (e.g., feature versus conjunction). Moreover, different search tasks bring about different expectations about the type, or frequency, of distractor stimuli. These expectations could promote top-down "task-sets" that may impact performance even when distractors are temporarily absent. Here, we characterized the role and extent of recruitment of proactive top-down processes for distractor expectation in feature and conjunction search. Participants conducted feature and conjunction search tasks for a visual target among distractors, which were either frequently presented or completely absent. The effects of the recruitment of proactive top-down processes for distractor expectation entailed slower responses, yet more accurate, on distractor-absent trials in the frequent-distractor (versus no-distractor) context of both tasks. These effects were larger in the conjunction versus feature task and were not impacted by stimulus duration and time pressure (short/present in Experiment 1, unlimited/absent in Experiment 2, respectively). Results were replicated when the presence/absence of distractors at each trial was fully predictable (Experiment 3), and when several parameters of visual search were changed (Experiment 4). Our findings indicate that top-down task-sets related to distractor expectation entail performance costs and benefits in visual search. These effects occur throughout task blocks rather than trial-to-trial, are modulated by search type, and confirm that proactive top-down processes intervene in feature search.


Assuntos
Atenção , Motivação , Humanos , Tempo de Reação , Percepção Visual
8.
J Neurosci ; 39(38): 7591-7603, 2019 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-31387915

RESUMO

In visual search, the presence of a salient, yet task-irrelevant, distractor in the stimulus array interferes with target selection and slows down performance. Neuroimaging data point to a key role of the frontoparietal dorsal attention network in dealing with visual distractors; however, the respective roles of different nodes within the network and their hemispheric specialization are still unresolved. Here, we used transcranial magnetic stimulation (TMS) to evaluate the causal role of two key regions of the dorsal attention network in resisting attentional capture by a salient singleton distractor: the frontal eye field (FEF) and the cortex within the intraparietal sulcus (IPS). The task of the participants (male/female human volunteers) was to discriminate the pointing direction of a target arrow while ignoring a task-irrelevant salient distractor. Immediately after stimulus onset, triple-pulse 10 Hz TMS was delivered either to IPS or FEF on either side of the brain. Results indicated that TMS over the right FEF significantly reduced the behavioral cost engendered by the salient distractor relative to left FEF stimulation. No such effect was obtained with stimulation of IPS on either side of brain. Interestingly, this FEF-dependent reduction in distractor interference interacted with the contingent trial history, being maximal when no distractor was present on the previous trial relative to when there was one. Our results provide direct causal evidence that the right FEF houses key mechanisms for distractor filtering, pointing to a pivotal role of the frontal cortex of the right hemisphere in limiting interference from an irrelevant but attention-grabbing stimulus.SIGNIFICANCE STATEMENT Visually conspicuous stimuli attract our attention automatically and interfere with performance by diverting resources away from the main task. Here, we applied transcranial magnetic stimulation over four frontoparietal cortex locations (frontal eye field and intraparietal sulcus in each hemisphere) to identify regions of the dorsal attention network that help limit interference from task-irrelevant, salient distractors. Results indicate that the right FEF participates in distractor-filtering mechanisms that are recruited when a distracting stimulus is encountered. Moreover, right FEF implements adjustments in distraction-filtering mechanisms following recent encounters with distractors. Together, these findings indicate a different hemispheric contribution of the left versus right dorsal frontal cortex to distraction filtering. This study expands our understanding of how our brains select relevant targets in the face of task-irrelevant, salient distractors.


Assuntos
Atenção/fisiologia , Lobo Frontal/fisiologia , Lobo Parietal/fisiologia , Estimulação Magnética Transcraniana , Percepção Visual/fisiologia , Mapeamento Encefálico/métodos , Feminino , Humanos , Masculino , Adulto Jovem
9.
J Neural Eng ; 16(5): 054001, 2019 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-31096191

RESUMO

OBJECTIVE: Electroencephalography (EEG) is widely used by clinicians, scientists, engineers and other professionals worldwide, with an increasing number of low-cost, commercially-oriented EEG systems that have become available in recent years. One such system is the Cognionics Quick-20 (Cognionics Inc., San Diego, USA), which uses dry electrodes and offers the convenience of portability thanks to its built-in amplifier and wireless connection. Because of such characteristics, this system has been used in several applications for both clinical and basic research studies. However, an investigation of the quality of the signals that are recorded using this system has not yet been reported. APPROACH: To bridge this gap, here we conducted a systematic comparison of signal quality between the Cognionics Quick-20 system and the Brain Products actiCAP/actiCHamp (Brain Products GmbH, Munich, Germany), a state-of-the-art, wet-electrode, research-oriented EEG system. Resting-state EEG data were recorded from twelve human participants at rest in eyes open and eyes closed conditions. For both systems we evaluated the similarity of mean recorded power spectral density, and detection of alpha suppression associated with eyes open relative to eyes closed. MAIN RESULTS: Power spectral densities were highly correlated across systems, with only minor topographical variability across the scalp. Both systems recorded alpha suppression during eyes open relative to eyes closed conditions. SIGNIFICANCE: These results attest to the robustness and reliability of the dry-electrode Cognionics system relatively to the widely used Brain Products laboratory EEG system, and thus validate its utility for clinical and basic research purposes, at least in studies in which participants do not move.


Assuntos
Encéfalo/fisiologia , Eletrodos/normas , Eletroencefalografia/instrumentação , Eletroencefalografia/normas , Descanso/fisiologia , Tecnologia sem Fio/normas , Amplificadores Eletrônicos/normas , Feminino , Humanos , Masculino , Tecnologia sem Fio/instrumentação
10.
Eur J Intern Med ; 64: 76-84, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31047747

RESUMO

OBJECTIVE: Arthritis is the most frequent extra-intestinal manifestation in patients with inflammatory bowel diseases (IBD). The coexistence of intestinal and articular inflammation advocates the need for a multidisciplinary management of patients with IBD-associated spondyloarthritis. METHODS: Consecutive IBD patients were evaluated jointly by the gastroenterologist and the rheumatologist in a combined clinic. All the patients were assessed and screened for articular involvement, disease activity and health related quality of life. After the prescription of a shared treatment, patients with spondyloarthritis were followed up for 24 months. RESULTS: Two hundred sixty-two IBD patients, including 80 who were classified as affected by spondyloarthritis according to the ASAS criteria, were included in the study. At baseline, patients with both IBD and spondyloarthritis showed worse quality of life in both the physical and mental domains. The multidisciplinary management provided a significant improvement of gastrointestinal and articular manifestations, as well as the health-related quality of life. Moreover, global and gastrointestinal-specific quality of life significantly correlated with articular disease activity. CONCLUSION: The multidisciplinary management significantly improves both articular and gastrointestinal disease activities and the quality of life of patients with IBD-associated spondyloarthritis. An appropriate screening strategy and the integrated management of these patients should be encouraged and employed in clinical practice.


Assuntos
Colite Ulcerativa/tratamento farmacológico , Doença de Crohn/tratamento farmacológico , Espondilartrite/tratamento farmacológico , Adulto , Antirreumáticos/efeitos adversos , Antirreumáticos/uso terapêutico , Produtos Biológicos/efeitos adversos , Produtos Biológicos/uso terapêutico , Colite Ulcerativa/diagnóstico , Procedimentos Clínicos , Doença de Crohn/diagnóstico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Equipe de Assistência ao Paciente , Medidas de Resultados Relatados pelo Paciente , Qualidade de Vida , Indução de Remissão , Espondilartrite/diagnóstico , Fatores de Tempo , Resultado do Tratamento , Fluxo de Trabalho
11.
Behav Brain Res ; 367: 210-214, 2019 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-30943420

RESUMO

Strategic processing allows for value-based preferential encoding of information. Event-related spectral perturbations can provide insights into neural processes linked to the different aspects of strategic processing. This study examined theta and alpha band power differences linked to processing of high- versus low-value information. Thirty-three young adults (17 F; mean age: 21.2 ± 1.5 years) completed a value-directed word list learning task. The task consisted of five word lists that each contained a unique set of high- and low-value words that were visually presented one at a time and EEG corresponding to these words were examined. To encourage strategic processing, participants were informed that after each list they would be asked to recall as many words as possible with their goal being to maximize their score. Overall, participants recalled more high-value words for each of the five lists as compared to low-value words, which supports that participants engaged in strategic processing. Frontal theta band power showed greater positivity during processing of low- compared to high-value words, whereas parietal alpha band power showed greater negativity during processing of high- compared to low-value words. These findings suggest that theta and alpha bands index different aspects of strategic processing, namely inhibition and selective attention, and have future applications for understanding the effects of aging and brain diseases/disorders.


Assuntos
Ritmo alfa/fisiologia , Atenção/fisiologia , Córtex Cerebral/fisiologia , Inibição Psicológica , Reconhecimento Visual de Modelos/fisiologia , Ritmo Teta/fisiologia , Aprendizagem Verbal/fisiologia , Adolescente , Adulto , Potenciais Evocados/fisiologia , Feminino , Humanos , Masculino , Leitura , Adulto Jovem
12.
Data Brief ; 24: 103857, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30989095

RESUMO

Here we present a collection of electroencephalographic (EEG) data recorded from 24 observers (14 females, 10 males, mean age: 25.4) while observing individually-presented stimuli comprised of 96 real-world objects, and 96 images of the same items printed in high-resolution. EEG was recorded from 128 scalp channels. Six additional external electrodes were used to record vertical and horizontal electrooculogram, as well as the signal from the left and right mastoid. EEG has been pre-processed, segmented in non-overlapping epochs, and independent component analysis (ICA) has been conducted to reject artifacts. Moreover, supplemental pre-processing steps have been completed to facilitate the analysis of event-related potentials (ERP). These data are linked to the article "Distinct visuo-motor brain dynamics for real-world objects versus planar images". Alongside this data we provide the custom-written Matlab® code that can be used to fully reproduce all analyses and figures presented in the linked research article.

13.
Curr Opin Psychol ; 29: 135-147, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30856512

RESUMO

Distractor suppression, or the ability to disregard salient distractors while dealing with task-relevant information, is a key component of selective attention. Recent research has shown that distractor suppression can take place in different circumstances and present itself in different guises, which is presumably paralleled by a multiplicity of underlying neural mechanisms. In this review article, we discuss a number of central themes concerning distractor suppression and the underlying neural mechanisms, and also highlight several unresolved issues that will have to be addressed in future investigations.


Assuntos
Atenção , Encéfalo/fisiologia , Percepção Visual , Sinais (Psicologia) , Humanos , Imageamento por Ressonância Magnética , Estimulação Luminosa
14.
Neuroimage ; 195: 232-242, 2019 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-30776529

RESUMO

Ultimately, we aim to generalize and translate scientific knowledge to the real world, yet current understanding of human visual perception is based predominantly on studies of two-dimensional (2-D) images. Recent cognitive-behavioral evidence shows that real objects are processed differently to images, although the neural processes that underlie these differences are unknown. Because real objects (unlike images) afford actions, they may trigger stronger or more prolonged activation in neural populations for visuo-motor action planning. Here, we recorded electroencephalography (EEG) when human observers viewed real-world three-dimensional (3-D) objects or closely matched 2-D images of the same items. Although responses to real objects and images were similar overall, there were critical differences. Compared to images, viewing real objects triggered stronger and more sustained event-related desynchronization (ERD) in the µ frequency band (8-13 Hz) - a neural signature of automatic motor preparation. Event-related potentials (ERPs) revealed a transient, early occipital negativity for real objects (versus images), likely reflecting 3-D stereoscopic differences, and a late sustained parietal amplitude modulation consistent with an 'old-new' memory advantage for real objects over images. Together, these findings demonstrate that real-world objects trigger stronger and more sustained action-related brain responses than images do. The results highlight important similarities and differences between brain responses to images and richer, more ecologically relevant, real-world objects.


Assuntos
Córtex Cerebral/fisiologia , Percepção Visual/fisiologia , Adulto , Eletroencefalografia/métodos , Potenciais Evocados/fisiologia , Feminino , Humanos , Masculino , Estimulação Luminosa , Desempenho Psicomotor/fisiologia , Adulto Jovem
15.
Front Psychol ; 9: 940, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29946281

RESUMO

Head and gaze directions are used during social interactions as essential cues to infer where someone attends. When head and gaze are oriented toward opposite directions, we need to extract socially meaningful information despite stimulus conflict. Recently, a cognitive and neural mechanism for filtering-out conflicting stimuli has been identified while performing non-social attention tasks. This mechanism is engaged proactively when conflict is anticipated in a high proportion of trials and reactively when conflict occurs infrequently. Here, we investigated whether a similar mechanism is at play for limiting distraction from conflicting social cues during gaze or head direction discrimination tasks in contexts with different probabilities of conflict. Results showed that, for the gaze direction task only (Experiment 1), inverse efficiency (IE) scores for distractor-absent trials (i.e., faces with averted gaze and centrally oriented head) were larger (indicating worse performance) when these trials were intermixed with congruent/incongruent distractor-present trials (i.e., faces with averted gaze and tilted head in the same/opposite direction) relative to when the same distractor-absent trials were shown in isolation. Moreover, on distractor-present trials, IE scores for congruent (vs. incongruent) head-gaze pairs in blocks with rare conflict were larger than in blocks with frequent conflict, suggesting that adaptation to conflict was more efficient than adaptation to infrequent events. However, when the task required discrimination of head orientation while ignoring gaze direction, performance was not impacted by both block-level and current trial congruency (Experiment 2), unless the cognitive load of the task was increased by adding a concurrent task (Experiment 3). Overall, our study demonstrates that during attention to social cues proactive cognitive control mechanisms are modulated by the expectation of conflicting stimulus information at both the block- and trial-sequence level, and by the type of task and cognitive load. This helps to clarify the inherent differences in the distracting potential of head and gaze cues during speeded social attention tasks.

16.
Cognition ; 165: 105-112, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28531806

RESUMO

The representation of the body in the brain is constantly updated to allow optimal sensorimotor interactions with the external world. In addition to dynamic features, body representation holds stable features that are still largely unknown. In the present work we explored the hypothesis that body parts have preferential associations with relative spatial locations. Specifically, in three experiments, we found consistent preferential associations between the index finger and the top position, and between the thumb and the bottom position. This association was found in a tactile sensory discrimination task, which was conducted both with and without vision, as well as at the implicit conceptual association level. These findings show that body parts and spatial locations are stably associated. Therefore, not only are body segments dynamically mapped in space for perception and action, but they also hold intrinsic spatial information that contributes to somatosensory spatial processing.


Assuntos
Imagem Corporal , Percepção Espacial , Processamento Espacial , Adulto , Discriminação Psicológica , Dedos , Humanos , Tempo de Reação , Tato , Percepção do Tato , Adulto Jovem
17.
Atten Percept Psychophys ; 79(5): 1384-1392, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28439791

RESUMO

Visual short-term memory (VSTM) enables the representation of information in a readily accessible state. VSTM is typically conceptualized as a form of "active" storage that is resistant to interference or disruption, yet several recent studies have shown that under some circumstances task-irrelevant distractors may indeed disrupt performance. Here, we investigated how task-irrelevant visual distractors affected VSTM by asking whether distractors induce a general loss of remembered information or selectively interfere with memory representations. In a VSTM task, participants recalled the spatial location of a target visual stimulus after a delay in which distractors were presented on 75% of trials. Notably, the distractor's eccentricity always matched the eccentricity of the target, while in the critical conditions the distractor's angular position was shifted either clockwise or counterclockwise relative to the target. We then computed estimates of recall error for both eccentricity and polar angle. A general interference model would predict an effect of distractors on both polar angle and eccentricity errors, while a selective interference model would predict effects of distractors on angle but not on eccentricity errors. Results showed that for stimulus angle there was an increase in the magnitude and variability of recall errors. However, distractors had no effect on estimates of stimulus eccentricity. Our results suggest that distractors selectively interfere with VSTM for spatial locations.


Assuntos
Memória de Curto Prazo/fisiologia , Estimulação Luminosa/métodos , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Comportamento Espacial/fisiologia , Percepção Visual/fisiologia , Adulto , Feminino , Humanos , Masculino , Rememoração Mental/fisiologia , Adulto Jovem
18.
Exp Brain Res ; 235(3): 873-887, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27913817

RESUMO

The crossmodal congruency task is a consolidated paradigm for investigating interactions between vision and touch. In this task, participants judge the elevation of a tactile target stimulus while ignoring a visual distracter stimulus that may occur at a congruent or incongruent elevation, thus engendering a measure of visuo-tactile interference (crossmodal congruency effect, CCE). The CCE reflects perceptual, attentional, and response-related factors, but their respective roles and interactions have not been set out yet. In two experiments, we used the original version of the crossmodal congruency task as well as ad hoc manipulations of the experimental setting and of the participants' posture for characterizing the contributions of multisensory integration, body-mediated attention, and response conflict to the CCE. Results of the two experiments consistently showed that the largest amount of variance in the CCE is explained by the reciprocal elevation of visual and tactile stimuli. This finding is compatible with a major role of response conflict for the CCE. Weaker yet distinguishable contributions come from multisensory integration, observed in the absence of response conflict, and from hand-mediated attentional binding, observed with the modified posture and in the presence of response conflict. Overall, this study informs the long-standing debate about mechanisms underlying the CCE by revealing that the visuo-tactile interference in this task is primarily due to the competition between opposite response tendencies, with an additional contribution of multisensory integration and hand-mediated attentional binding.


Assuntos
Atenção/fisiologia , Conflito Psicológico , Desempenho Psicomotor/fisiologia , Percepção do Tato/fisiologia , Percepção Visual/fisiologia , Adulto , Análise de Variância , Feminino , Humanos , Masculino , Estimulação Luminosa , Tempo de Reação/fisiologia , Tato , Adulto Jovem
19.
J Gastrointestin Liver Dis ; 25(3): 317-21, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27689195

RESUMO

BACKGROUND AND AIMS: Diagnosis of pancreatic neuroendocrine tumors (p-NETs) is frequently challenging. We describe a large series of patients with p-NETs in whom both pre-operative Computed Tomography (CT) and Endoscopic Ultrasonography (EUS) were performed. METHODS: This was a retrospective analysis of prospectively collected sporadic p-NET cases. All patients underwent both standard multidetector CT study and EUS with fine-needle aspiration (FNA). The final histological diagnosis was achieved on a post-surgical specimen. Chromogranin A (CgA) levels were measured. RESULTS: A total of 80 patients (mean age: 58 +/- 14.2 years; males: 42) were enrolled. The diameter of functioning was significantly lower than that of non-functioning p-NETs (11.2 +/- 8.5 mm vs 19.8 +/- 12.2 mm; P = 0.0004). The CgA levels were more frequently elevated in non-functioning than functioning pNET patients (71.4% vs 46.9%; P = 0.049). Overall, the CT study detected the lesion in 51 (63.7%) cases, being negative in 26 (68.4%) patients with a tumor

Assuntos
Endossonografia , Tomografia Computadorizada Multidetectores , Tumores Neuroendócrinos/diagnóstico por imagem , Neoplasias Pancreáticas/diagnóstico por imagem , Adulto , Idoso , Feminino , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Tumores Neuroendócrinos/cirurgia , Neoplasias Pancreáticas/cirurgia , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Estudos Retrospectivos , Carga Tumoral
20.
Front Hum Neurosci ; 10: 446, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27630555

RESUMO

The visual system leverages organizational regularities of perceptual elements to create meaningful representations of the world. One clear example of such function, which has been formalized in the Gestalt psychology principles, is the perceptual grouping of simple visual elements (e.g., lines and arcs) into unitary objects (e.g., forms and shapes). The present study sought to characterize automatic attentional capture and related cognitive processing of Gestalt-like visual stimuli at the psychophysiological level by using event-related potentials (ERPs). We measured ERPs during a simple visual reaction time task with bilateral presentations of physically matched elements with or without a Gestalt organization. Results showed that Gestalt (vs. non-Gestalt) stimuli are characterized by a larger N2pc together with enhanced ERP amplitudes of non-lateralized components (N1, N2, P3) starting around 150 ms post-stimulus onset. Thus, we conclude that Gestalt stimuli capture attention automatically and entail characteristic psychophysiological signatures at both early and late processing stages. Highlights We studied the neural signatures of the automatic processes of visual attention elicited by Gestalt stimuli. We found that a reliable early correlate of attentional capture turned out to be the N2pc component. Perceptual and cognitive processing of Gestalt stimuli is associated with larger N1, N2, and P3.

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