663 research outputs found

    Middle short gyrus of the insula implicated in speech production: intracerebral electric stimulation of patients with epilepsy.

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    International audiencePURPOSE: Different lines of evidence have suggested an involvement of the insular cortex in speech production. These have included results from lesion studies, functional imaging techniques, and electrical stimulation of the human insular cortex during invasive evaluation of epileptic patients. METHODS: We evaluated 25 patients who had drug refractory focal epilepsy with at least one electrode stereotactically implanted in the insular cortex. RESULTS: Eight responses to insular cortex electrical stimulation were reported by five patients as speech arrest (five responses) and a lowering of voice intensity (three responses). CONCLUSIONS: Data from this study implicate the middle short gyrus of the insula in the production of speech and show the importance of intrainsular electrode implantation during invasive pre-resection evaluation by stereo-electroencephalography (SEEG) when speech arrest occurs early in seizure semiology

    What Electrophysiology Tells Us About Alzheimer’s Disease::A Window into the Synchronization and Connectivity of Brain Neurons

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    Electrophysiology provides a real-time readout of neural functions and network capability in different brain states, on temporal (fractions of milliseconds) and spatial (micro, meso, and macro) scales unmet by other methodologies. However, current international guidelines do not endorse the use of electroencephalographic (EEG)/magnetoencephalographic (MEG) biomarkers in clinical trials performed in patients with Alzheimer’s disease (AD), despite a surge in recent validated evidence. This Position Paper of the ISTAART Electrophysiology Professional Interest Area endorses consolidated and translational electrophysiological techniques applied to both experimental animal models of AD and patients, to probe the effects of AD neuropathology (i.e., brain amyloidosis, tauopathy, and neurodegeneration) on neurophysiological mechanisms underpinning neural excitation/inhibition and neurotransmission as well as brain network dynamics, synchronization, and functional connectivity reflecting thalamocortical and cortico-cortical residual capacity. Converging evidence shows relationships between abnormalities in EEG/MEG markers and cognitive deficits in groups of AD patients at different disease stages. The supporting evidence for the application of electrophysiology in AD clinical research as well as drug discovery pathways warrants an international initiative to include the use of EEG/MEG biomarkers in the main multicentric projects planned in AD patients, to produce conclusive findings challenging the present regulatory requirements and guidelines for AD studies

    The role of the anterior insular cortex in self-monitoring: a novel study protocol with electrical stimulation mapping and functional magnetic resonance imaging

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    Becoming aware of one's own states is a fundamental aspect for self-monitoring, allowing us to adjust our beliefs of the world to the changing context. Previous evidence points out to the key role of the anterior insular cortex (aIC) in evaluating the consequences of our own actions, especially whenever an error has occurred. In the present study, we propose a new multimodal protocol combining electrical stimulation mapping (ESM) and functional magnetic resonance imaging (fMRI) to explore the functional role of the aIC for self-monitoring in patients undergoing awake brain surgery. Our results using a modified version of the Stroop task tackling metacognitive abilities revealed new direct evidence of the involvement of the aIC in monitoring our performance, showing increased difficulties in detecting action-outcome mismatches when stimulating a cortical site located at the most posterior part of the aIC as well as significant BOLD activations at this region during outcome incongruences for self-made actions. Based on these preliminary results, we highlight the importance of assessing the aIC's functioning during tumor resection involving this region to evaluate metacognitive awareness of the self in patients undergoing awake brain surgery. In a similar vein, a better understanding of the aIC's role during self-monitoring may help shed light on action/outcome processing abnormalities reported in several neuropsychiatric disorders such as schizophrenia, anosognosia for hemiplegia or major depression

    Neuroinflammation and amyloid-β in early Alzheimer’s disease. Insight into the earliest events using mouse models

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    Alzheimer’s disease (AD) is the leading cause of dementia and most common neurodegenerative disease worldwide, but there currently exists no effective treatment that can stop nor slow the progression of the disease. The current dogma in the field postulates that the appearance of extracellular amyloid-beta (Aβ) plaques, a histopathological hallmark of the disease, is the trigger for downstream, detrimental events, including neuronal loss, extensive neuroinflammation and cognitive decline. However, increasing evidence suggests that neuroinflammatory alterations and synaptic and neuronal dysfunction occur already before plaque deposition, which we have also noted in previous work done by our groups. In addition, we have found that Aβ aggregates intracellularly, especially within neurons, before plaque appearance and that this has the ability to impair synaptic function. Therefore, we wonder whether there is an interplay between the neuroinflammatory system, neuronal and synaptic alterations, and intracellular Aβ in the earliest stages of the disease. To address this, we utilize mouse-based models in vivo, primarily the 5xFAD transgenic mouse model, and in vitro neuronal culture models. In the scientific papers included in this thesis work, we explore aspects related to mechanisms and modulations related to early AD. This includes looking at the prion-like spread and properties of intracellular Aβ, identifying sex-specific effects of early-life stress on inflammatory systems as well as neurons and Aβ, and investigating the interaction between neuroinflammatory cells and early aggregated Aβ. Taken together, we have worked to elucidate the earliest events in the disease, including factors that can modulate pathogenesis and the underlying mechanisms. By fostering a greater understanding of AD, we attempt to aid efforts towards the development of an effective disease-modifying treatment

    Gestational Valproate Alters BOLD Activation in Response to Complex Social and Primary Sensory Stimuli

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    Valproic acid (VPA) has been used clinically as an anticonvulsant medication during pregnancy; however, it poses a neurodevelopmental risk due to its high teratogenicity. We hypothesized that midgestational (GD) exposure to VPA will lead to lasting deficits in social behavior and the processing of social stimuli. To test this, animals were given a single IP injection of 600 mg/kg of VPA on GD 12.5. Starting on postnatal day 2 (PND2), animals were examined for physical and behavior abnormalities. Functional MRI studies were carried out after PND60. VPA and control animals were given vehicle or a central infusion of a V1a antagonist 90 minutes before imaging. During imaging sessions, rats were presented with a juvenile test male followed by a primary visual stimulus (2 Hz pulsed light) to examine the effects of prenatal VPA on neural processing. VPA rats showed greater increases in BOLD signal response to the social stimulus compared to controls in the temporal cortex, thalamus, midbrain and the hypothalamus. Blocking the V1a receptor reduced the BOLD response in VPA animals only. Neural responses to the visual stimulus, however, were lower in VPA animals. Blockade with the V1a antagonist did not revert this latter effect. Our data suggest that prenatal VPA affects the processing of social stimuli and perhaps social memory, partly through a mechanism that may involve vasopressin V1a neurotransmission

    Time to Face Language: Embodied Mechanisms Underpin the Inception of Face-Related Meanings in the Human Brain

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    In construing meaning, the brain recruits multimodal (conceptual) systems and embodied (modality-specific) mechanisms. Yet, no consensus exists on how crucial the latter are for the inception of semantic distinctions. To address this issue, we combined electroencephalographic (EEG) and intracranial EEG (iEEG) to examine when nouns denoting facial body parts (FBPs) and nonFBPs are discriminated in face-processing and multimodal networks. First, FBP words increased N170 amplitude (a hallmark of early facial processing). Second, they triggered fast (~100 ms) activity boosts within the face-processing network, alongside later (~275 ms) effects in multimodal circuits. Third, iEEG recordings from face-processing hubs allowed decoding ~80% of items before 200 ms, while classification based on multimodal-network activity only surpassed ~70% after 250 ms. Finally, EEG and iEEG connectivity between both networks proved greater in early (0-200 ms) than later (200-400 ms) windows. Collectively, our findings indicate that, at least for some lexico-semantic categories, meaning is construed through fast reenactments of modality-specific experience.Fil: García, Adolfo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Educación Elemental y Especial; Argentina. Universidad de San Andrés; Argentina. Universidad de Santiago de Chile; Chile. University of California; Estados UnidosFil: Hesse Rizzi, Eugenia Fátima. Universidad de San Andrés; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Instituto de Neurología Cognitiva. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Fundación Favaloro. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt; ArgentinaFil: Birba, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de San Andrés; ArgentinaFil: Gonzalez Adolfi, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Instituto de Neurología Cognitiva. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Fundación Favaloro. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt; ArgentinaFil: Mikulan, Ezequiel Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; Argentina. Università degli Studi di Milano; ItaliaFil: Martorell Caro, Miguel Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Instituto de Neurología Cognitiva. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Fundación Favaloro. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt; ArgentinaFil: Petroni, Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Investigación en Ciencias de la Computación. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Investigación en Ciencias de la Computación; ArgentinaFil: Bekinchstein, Tristán. University of Cambridge; Reino UnidoFil: García, María del Carmen. Hospital Italiano; ArgentinaFil: Silva, Walter. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Hospital Italiano; ArgentinaFil: Ciraolo, Carlos. Hospital Italiano; ArgentinaFil: Vaucheret Paz, Esteban Fabian. Hospital Italiano; ArgentinaFil: Sedeño, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Instituto de Neurología Cognitiva. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Fundación Favaloro. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt; ArgentinaFil: Ibañez, Agustin Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Instituto de Neurología Cognitiva. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Fundación Favaloro. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt; Argentina. Universidad de San Andrés; Argentina. University of California; Estados Unidos. Universidad Adolfo Ibañez; Chil

    Seeing the bigger picture: visual imagination and the social brain

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    I studied multi-modal aspects of visual imagination in relation to visual art and complex images, defining ‘visual imagination’ broadly as a dynamic of complex psychological processes that integrate visual information with prior experiences and knowledge to construct internal models of oneself, others and the outside world. This reflects the ultimate aim of my work to develop engaging cultural and clinical resources that strengthen social brain networks, tailored to personal interests, age and cognitive health. I pursued two interrelated research programmes based primarily at the Wellcome Collection, as part of my interdisciplinary residency with Created Out of Mind. I used complementary neuroscientific and visual research methods to probe relationships between visual imagination and the social brain in neurologically healthy adults and people living with various forms of dementia. The Social Brain Atlas and connectome (Alcalá López et al., Cerebral Cortex 2017) was recently computed from 3972 functional neuroimaging studies in 22712 healthy adults: to contextualise my research in the social brain, I first translated the social brain connectome to functional infographics (relational spatial representations) of the four hierarchical processing levels of the Social Brain Atlas, and generated visual imagination brain profiles in healthy adults and profiles of canonical dementia syndromes. I used these to generate hypotheses and guide analysis of my neuroscientific experiments. I recruited three participant cohorts: 17 neurologically healthy adults aged 20-30 years; 20 neurologically healthy adults aged 50+ years; and 11 senior adults living with various forms of dementia. These research participants took part in five neuroscientific experiments that I had designed, in which I used advanced technologies to capture physiological responses and established as well as novel visual research methods to study neuropsychological responses to visual art, complex imagery and colour experiences. I employed an arts-based facilitated conversation methodology, Visual Thinking Strategies (VTS); and I developed novel quantitative methods to analyse recorded eye tracking data, electrodermal activity and speech samples. I used both parametric and non-parametric statistical methods to compare participant cohorts. In parallel with the neuroscientific research, I developed a series of art experiments at UCL Institute of Making, and my studio at the Limehouse Art Foundation, East London. My artistic research complemented my neuroscientific work by emphasising individual experience over generic perceptual mechanisms: by creating space for personal interactions with art, the research becomes contextualised in the social world. The artistic research resulted in a public exhibition of optical instruments, visual artworks and installations that expanded on the two neuroscientific research projects, complementing the written thesis with the embodied language of visual art. Visitors could freely explore the perceptual effects of the optical instruments and were invited to reflect on the visual artworks with the Visual Thinking Strategies method
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