Jonathan Wirsich, João Jorge, Giannina Rita Iannotti, Elhum Shamshiri, Frédéric Grouiller, Rodolfo Abreu, François Lazeyras, Anne-Lise Giraud, Rolf Gruetter, Sepideh Sadaghiani, Serge Vulliémoz,
Both electroencephalography (EEG) and functional Magnetic Resonance Imaging (fMRI) are non-invasive methods that show complementary aspects of human brain activity. Despite measuring different proxies of brain activity, both the measured blood-oxygenation (fMRI) and neurophysiological recordings (EEG) are indirectly coupled. The electrophysiological and BOLD signal can map the underlying functional connectivity structure at the whole brain scale at different timescales. Previous work demonstrated a ...
Tópico(s): Advanced Neuroimaging Techniques and Applications
2021 - Elsevier BV | NeuroImage
Rodolfo Abreu, João Jorge, Alberto Leal, Thomas Koenig, Patrícia Figueiredo,
Tópico(s): EEG and Brain-Computer Interfaces
2020 - Springer Science+Business Media | Brain Topography
Rodolfo Abreu, Marco Simões, Miguel Castelo‐Branco,
Functional magnetic resonance imaging (fMRI) is the technique of choice for detecting large-scale functional brain networks and to investigate their dynamics. Because fMRI measures brain activity indirectly, electroencephalography (EEG) has been recently considered a feasible tool for detecting such networks, particularly the resting-state networks (RSNs). However, a truly unbiased validation of such claims is still missing, which can only be accomplished by using simultaneously acquired EEG and fMRI ...
Tópico(s): EEG and Brain-Computer Interfaces
2020 - Frontiers Media | Frontiers in Neuroscience
Rodolfo Abreu, Alberto Leal, Patrícia Figueiredo,
Abstract Most fMRI studies of the brain’s intrinsic functional connectivity (FC) have assumed that this is static; however, it is now clear that it changes over time. This is particularly relevant in epilepsy, which is characterized by a continuous interchange between epileptic and normal brain states associated with the occurrence of epileptic activity. Interestingly, recurrent states of dynamic FC (dFC) have been found in fMRI data using unsupervised learning techniques, assuming either their sparse ...
Tópico(s): Advanced Neuroimaging Techniques and Applications
2019 - Nature Portfolio | Scientific Reports
Athanasios Vourvopoulos, Carolina Jorge, Rodolfo Abreu, Patrícia Figueiredo, Jean-Claude Fernandes, Sergi Bermúdez i Badia,
To maximize brain plasticity after stroke, a plethora of rehabilitation strategies have been explored. These include the use of intensive motor training, motor-imagery (MI), and action-observation (AO). Growing evidence of the positive impact of virtual reality (VR) techniques on recovery following stroke has been shown. However, most VR tools are designed to exploit active movement, and hence patients with low level of motor control cannot fully benefit from them. Consequently, the idea of directly ...
Tópico(s): Functional Brain Connectivity Studies
2019 - Frontiers Media | Frontiers in Human Neuroscience
Produção Nacional
Revisado por pares
Milan Chytrý, Valério D. Pillar, Jodi N. Price, Viktoria Wagner, Susan K. Wiser, David Zelený,
... reviewed more than twice are indicated by asterisks. Rodolfo Abreu Shalom Daniel Addo-Danso Munemitsu Akasaka Morodoluwa Akin- ...
Tópico(s): Soil erosion and sediment transport
2023 - Wiley | Applied Vegetation Science
João Valente Duarte, Rodolfo Abreu, Miguel Castelo‐Branco,
It remains to be understood how biological motion is hierarchically computed, from discrimination of local biological motion animacy to global dynamic body perception. Here, we addressed this functional separation of the correlates of the perception of local biological motion from perception of global motion of a body. We hypothesized that local biological motion processing can be isolated, by using a single dot motion perceptual decision paradigm featuring the biomechanical details of local realistic ...
Tópico(s): Neural dynamics and brain function
2022 - Elsevier BV | NeuroImage
Rodolfo Abreu, Alberto Leal, Fernando Lopes da Silva, Patrícia Figueiredo,
We hypothesize that the hypersynchronization associated with epileptic activity is best described by EEG synchronization measures, and propose to use these as predictors of epilepsy-related BOLD fluctuations.We computed the phase synchronization index (PSI) and global field synchronization (GFS), within two frequency bands, a broadband (1-45 Hz) and a narrower band focused on the presence of epileptic activity (3-10 Hz). The associated epileptic networks were compared with those obtained using conventional ...
Tópico(s): Neural dynamics and brain function
2018 - Elsevier BV | Clinical Neurophysiology
Rodolfo Abreu, Alberto Leal, Patrícia Figueiredo,
The simultaneous acquisition of electroencephalography (EEG) with functional magnetic resonance imaging (fMRI) is a very promising non-invasive technique for the study of human brain function. Despite continuous improvements, it remains a challenging technique, and a standard methodology for data analysis is yet to be established. Here we review the methodologies that are currently available to address the challenges at each step of the data analysis pipeline. We start by surveying methods for pre- ...
Tópico(s): Neural dynamics and brain function
2018 - Frontiers Media | Frontiers in Human Neuroscience
Rodolfo Abreu, S.F. Nunes, Alberto Leal, Patrícia Figueiredo,
Tópico(s): ECG Monitoring and Analysis
2016 - Elsevier BV | NeuroImage
Rodolfo Abreu, Marco Leite, João Jorge, Frédéric Grouiller, Wietske van der Zwaag, Alberto Leal, Patrícia Figueiredo,
The ballistocardiogram (BCG) artifact is currently one of the most challenging in the EEG acquired concurrently with fMRI, with correction invariably yielding residual artifacts and/or deterioration of the physiological signals of interest. In this paper, we propose a family of methods whereby the EEG is decomposed using Independent Component Analysis (ICA) and a novel approach for the selection of BCG-related independent components (ICs) is used (PROJection onto Independent Components, PROJIC). Three ...
Tópico(s): Functional Brain Connectivity Studies
2016 - Elsevier BV | NeuroImage
Marco Simões, Rodolfo Abreu, Bruno Direito, Alexandre Sayal, João Castelhano, P. Carvalho, Miguel Castelo‐Branco,
fMRI-based neurofeedback (NF) interventions represent the method of choice for the neuromodulation of localized brain areas. Although we have already validated an fMRI-NF protocol targeting the facial expressions processing network (FEPN), its dissemination is hampered by the economical and logistical constraints of fMRI-NF interventions, which may be however surpassed by transferring it to EEG setups, due to their low cost and portability. One of the major challenges of this procedure is then to ...
Tópico(s): Neural dynamics and brain function
2020 - IOP Publishing | Journal of Neural Engineering
Rodolfo Abreu, Marco Leite, Alberto Leal, Patrícia Figueiredo,
Independent Component Analysis (ICA) is commonly used for the identification of sources of interest in electroencephalographic (EEG) data, but the selection of the relevant components remains an open issue depending on the specific application.We propose a novel approach for the objective selection of epilepsy-related independent components (ICs) from EEG data collected during functional Magnetic Resonance Imaging (fMRI) acquisitions, called PROJection onto Independent Components (PROJIC). Inter-ictal ...
Tópico(s): Functional Brain Connectivity Studies
2015 - Elsevier BV | Journal of Neuroscience Methods
Rodolfo Abreu, Júlia F. Soares, Ana Cláudia Lima, Lívia Sousa, Sónia Batista, Miguel Castelo‐Branco, João Valente Duarte,
Reconstructing EEG sources involves a complex pipeline, with the inverse problem being the most challenging. Multiple inversion algorithms are being continuously developed, aiming to tackle the non-uniqueness of this problem, which has been shown to be partially circumvented by including prior information in the inverse models. Despite a few efforts, there are still current and persistent controversies regarding the inversion algorithm of choice and the optimal set of spatial priors to be included ...
Tópico(s): Advanced MRI Techniques and Applications
2022 - Springer Science+Business Media | Brain Topography
Alexandra Leitão, Joana Esteves, Joao Pedro Abreu, Ana Francisca Junqueira Ribeiro Pereira, Maria Teresa Boncoraglio, M Certo, Rodolfo Abreu,
Bilateral deep vein thrombosis (DVT) should prompt investigation for pro-thrombotic conditions and the exclusion of vascular compromise due to intrinsic and extrinsic factors. The authors present the case of a 47-year-old man admitted with bilateral DVT and diagnosed with inferior vena cava (IVC) infra-renal segment agenesis, and discuss the management of this rare condition.Bilateral deep vein thrombosis in young and otherwise healthy individuals should prompt investigation of the aetiology and risk ...
Tópico(s): Renal and Vascular Pathologies
2019 - SMC MEDIA SRL | European Journal of Case Reports in Internal Medicine
Ricardo Castro‐Ferreira, Maria João Nascimento Sousa Quelhas, Alberto Freitas, José Vidoedo, Emanuel Alves Silva, André Marinho, Rodolfo Abreu, Andreia Coelho, Paulo Gonçalves Dias, Sérgio Sampaio,
Abstract Objective Varicose vein (VV) surgery is frequently performed by surgeons without formal vascular training. We aimed to compare the outcomes of the procedure based on the background of the surgeon. Methods All patients registered with VV surgery between 2004 and 2016 in Portuguese public hospitals were included in the study. Intrahospital outcomes were assessed from this administrative database. A random multicenter sample of 315 patients submitted to saphenous high ligation and stripping (175 patients ...
Tópico(s): Venous Thromboembolism Diagnosis and Management
2019 - Elsevier BV | Journal of Vascular Surgery Venous and Lymphatic Disorders
Produção Nacional
Revisado por pares
Samuel W. Flake, Rodolfo Cesar Real de Abreu, Giselda Durigan, William A. Hoffmann,
Abstract Under fire suppression, many tropical savannas transform into forests. Forest expansion entails changes in environmental variables and plant community structure. We hypothesized that forest expansion into savanna results in a shift in community‐weighted mean functional traits from stress tolerance to competitiveness, with generalist species having trait values intermediate between those of specialists of savanna and forest habitats. We studied 30 plots distributed over three savanna–forest ...
Tópico(s): Plant and animal studies
2021 - Wiley | Functional Ecology
Produção Nacional
Revisado por pares
Rodolfo Cesar Real de Abreu, Giselda Durigan, Antônio Carlos Galvão de Melo, Natashi A. L. Pilon, William A. Hoffmann,
Abstract Woody encroachment into grassy biomes is a global phenomenon, often resulting in a nearly complete turnover of species, with savanna specialists being replaced by forest‐adapted species. Understanding the mechanisms involved in this change is important for devising strategies for managing savannas. We examined how isolated trees favour woody encroachment and species turnover by overcoming dispersal limitation and environmental filtering. In a savanna released from fire in south‐eastern ...
Tópico(s): Plant and animal studies
2021 - Wiley | Journal of Applied Ecology
Produção Nacional
Revisado por pares
Brooklynn M. Newberry, Collin R. Power, Rodolfo Cesar Real de Abreu, Giselda Durigan, Davi Rodrigo Rossatto, William A. Hoffmann,
Vegetation-fire feedbacks are important for determining the distribution of forest and savanna. To understand how vegetation structure controls these feedbacks, we quantified flammability across gradients of tree density from grassland to forest in the Brazilian Cerrado. We experimentally burned 102 plots, for which we measured vegetation structure, fuels, microclimate, ignition success and fire behavior. Tree density had strong negative effects on ignition success, rate of spread, fire-line intensity ...
Tópico(s): Fire effects on ecosystems
2020 - Wiley | New Phytologist
Produção Nacional
Revisado por pares
Natashi A. L. Pilon, Mário G. B. Cava, William A. Hoffmann, Rodolfo Cesar Real de Abreu, Alessandra Fidélis, Giselda Durigan,
Abstract Disentangling species strategies that confer resilience to natural disturbances is key to conserving and restoring savanna ecosystems. Fire is a recurrent disturbance in savannas, and savanna vegetation is highly adapted to and often dependent on fire. However, although the woody component of tropical savannas is well studied, we still do not understand how ground‐layer plant communities respond to fire, limiting conservation and management actions. We investigated the effects of prescribed ...
Tópico(s): Plant and animal studies
2020 - Wiley | Journal of Ecology
Produção Nacional
Revisado por pares
Natashi A. L. Pilon, Giselda Durigan, Jess Rickenback, R. Toby Pennington, Kyle G. Dexter, William A. Hoffmann, Rodolfo Cesar Real de Abreu, Caroline E. R. Lehmann,
Abstract Aim In savannas, a grass‐dominated ground layer is key to ecosystem function via grass–fire feedbacks that maintain open ecosystems. With woody encroachment, tree density increases, thereby decreasing light in the ground layer and potentially altering ecosystem function. We investigated how light availability can filter individual grass species distributions and whether different functional traits are associated with response to a shade gradient in a landscape experiencing woody encroachment. ...
Tópico(s): Plant and animal studies
2020 - Wiley | Journal of Vegetation Science
Produção Nacional
Revisado por pares
Giselda Durigan, Natashi A. L. Pilon, Rodolfo Cesar Real de Abreu, William A. Hoffmann, Marcio Roberto Martins, Bruno Ferreto Fiorillo, Alexsander Zamorano Antunes, Ana Paula Carmignotto, Jonas Maravalhas, J.B. Vieira, Heraldo L. Vasconcelos,
Although savannas are fire-adapted ecosystems, prescribing fire for biodiversity conservation remains controversial at least in some regions where savannas occur. Faced with uncertainty, many decision makers and even scientists are still reluctant to prescribe fire for conservation purposes in fire-prone ecosystems, invoking the precautionary principle. Knowledge gaps on the ideal fire regime, such as how and when to burn, and especially the fear of biodiversity losses, are among the main arguments ...
Tópico(s): Ecology and Vegetation Dynamics Studies
2020 - Frontiers Media | Frontiers in Forests and Global Change
Produção Nacional
Revisado por pares
Natashi A. L. Pilon, William A. Hoffmann, Rodolfo Cesar Real de Abreu, Giselda Durigan,
Background: Fire has been reported to trigger the production of flowers and fruits in many fire-prone ecosystems around the world. However, for tropical savannas, little is known about the effects of fire on flower production at community and species scale, especially for the ground-layer.Aims: We assessed the role of fire as a trigger to short-term flowering in cerrado grassland, compared with unburned vegetation.Methods: We recorded the presence of flowers or fruits in 2,441 individuals from 47 ...
Tópico(s): Ecology and Vegetation Dynamics Studies
2018 - Taylor & Francis | Plant Ecology & Diversity
Produção Nacional
Revisado por pares
William A. Hoffmann, Samuel W. Flake, Rodolfo Cesar Real de Abreu, Natashi A. L. Pilon, Davi Rodrigo Rossatto, Giselda Durigan,
Abstract The ability of vegetation to ameliorate or exacerbate environmental extremes can generate feedbacks that mediate the distribution of biomes. It has been suggested that feedbacks between vegetation and frost damage may be important for maintaining savanna, particularly at the edge of the tropics. We quantified frost damage and air temperature across a network of 30 permanent plots distributed across tropical savanna–forest boundaries in Brazil during an uncommonly hard frost. Tree cover ...
Tópico(s): Plant and animal studies
2018 - Wiley | Journal of Ecology
Produção Nacional
Revisado por pares
Rodolfo Cesar Real de Abreu, William A. Hoffmann, Heraldo L. Vasconcelos, Natashi A. L. Pilon, Davi Rodrigo Rossatto, Giselda Durigan,
Tropical savannas have been increasingly viewed as an opportunity for carbon sequestration through fire suppression and afforestation, but insufficient attention has been given to the consequences for biodiversity. To evaluate the biodiversity costs of increasing carbon sequestration, we quantified changes in ecosystem carbon stocks and the associated changes in communities of plants and ants resulting from fire suppression in savannas of the Brazilian Cerrado, a global biodiversity hotspot. Fire ...
Tópico(s): Economic and Environmental Valuation
2017 - American Association for the Advancement of Science | Science Advances
Produção Nacional
Revisado por pares
Rodolfo Cesar Real de Abreu, Francisco Ferreira de Miranda Santos, Giselda Durigan,
The recognition of a species as invasive is generally accepted when it comes from another continent or even from another country, but requires strong evidences of negative impacts to support control actions when the invasive species comes from another region in the same country. Schyzolobium parahyba – the ‘guapuruvu’, is a Brazilian tree native from the evergreen type of the Atlantic Forest, which has been recorded as invader in a number of remnants of the Seasonally Semideciduous Forest – SSF. We hypothesized ...
Tópico(s): Plant Diversity and Evolution
2013 - Elsevier BV | Acta Oecologica
Produção Nacional
Revisado por pares
Giselda Durigan, Natália Macedo Ivanauskas, Maria José Brito Zakia, Rodolfo Cesar Real de Abreu,
Biological invasions have contributed to biodiversity loss, ecosystem degradation, and impairment of ecosystem services worldwide, requiring actions towards their prevention and control.Since human and monetary resources are both limited in most countries, priorities must be settled in the real world of biological invasion prevention and control.To support the decision making process regarding plant species already introduced, we propose a classification key, based upon biogeographical and ecological ...
Tópico(s): Biological Control of Invasive Species
2013 - Elsevier BV | Natureza & Conservação
Produção Nacional
Revisado por pares
Rodolfo Cesar Real de Abreu, Giselda Durigan,
Abstract Background: The invasion by Pinus elliottii is one of the most serious threats to the remaining native cerrado vegetation in São Paulo State, Brazil, causing biodiversity losses yet to be evaluated. We conducted a study in an area where P. elliottii began establishing in 1988. Aims: To estimate diversity losses in the plant community and to understand the floristic and structural changes resulting from pine tree invasion of grassland savannah. Methods: All plants taller than 50 cm were ...
Tópico(s): African Botany and Ecology Studies
2011 - Taylor & Francis | Plant Ecology & Diversity
Produção Nacional
Revisado por pares
Rodolfo Cesar Real de Abreu, Geissianny Bessão de Assis, Sergianne Frison, Andrea Garafulic Aguirre, Giselda Durigan,
There is a widespread view that forest plantations with exotic species are green deserts, unable to sustain biodiversity. Few studies have demonstrated, however, that planted stands of exotic trees have a greater negative effect on the plant diversity of savanna vegetation. We compared the native woody flora under four stands of slash pine of about 45 years old with four stands where the previously existing native Cerrado vegetation was preserved and protected from disturbances for the same period, ...
Tópico(s): Forest ecology and management
2011 - Elsevier BV | Forest Ecology and Management
Produção Nacional
Revisado por pares
Rodolfo Cesar Real de Abreu, Pablo José Francisco Pena Rodrigues,
Abstract Artocarpus heterophyllus Lam. (jackfruit) was man made introduced in Tijuca National Park (TNP) in the mid- 1800s. Native from Southeast Asia, nowadays densely colonizes the TNP. Here we analyze some jackfruit population parameters that probably allowed the local colonization followed by successful invasion of the new habitat. Based on 20 sampleplots, randomlyplaced inside 5 sitescolonizedby jackfruit, we described subpopulations hierarchical size diameter structures. Gini’s coefficient values ...
Tópico(s): African Botany and Ecology Studies
2010 - Rio de Janeiro Botanical Garden Research Institute | Rodriguésia