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Recent frameworks in cognitive neuroscience and behavioral neurology underscore interoceptive priors as core modulators of negative emotions. However, the field lacks experimental designs manipulating the priming of emotions via interoception and exploring their multimodal signatures in neurodegenerative models. Here, we designed a novel task that involves interoceptive and control-exteroceptive priming conditions followed by post-interoception and post-exteroception facial emotion recognition (FER). We recruited 114 participants, including healthy controls (HCs) as well as patients with behavioral variant frontotemporal dementia (bvFTD), Parkinson's disease (PD), and Alzheimer's disease (AD). We measured online EEG modulations of the heart-evoked potential (HEP), and associations with both brain structural and resting-state functional connectivity patterns. Behaviorally, post-interoception negative FER was enhanced in HCs but selectively disrupted in bvFTD and PD, with AD presenting generalized disruptions across emotion types. Only bvFTD presented impaired interoceptive accuracy. Increased HEP modulations during post-interoception negative FER was observed in HCs and AD, but not in bvFTD or PD patients. Across all groups, post-interoception negative FER correlated with the volume of the insula and the ACC. Also, negative FER was associated with functional connectivity along the (a) salience network in the post-interoception condition, and along the (b) executive network in the post-exteroception condition. These patterns were selectively disrupted in bvFTD (a) and PD (b), respectively. Our approach underscores the multidimensional impact of interoception on emotion, while revealing a specific pathophysiological marker of bvFTD. These findings inform a promising theoretical and clinical agenda in the fields of nteroception, emotion, allostasis, and neurodegeneration.SIGNIFICANCE STATEMENTWe examined whether and how emotions are primed by interoceptive states combining multimodal measures in healthy controls and neurodegenerative models. In controls, negative emotion recognition and ongoing HEP modulations were increased after interoception. These patterns were selectively disrupted in patients with atrophy across key interoceptive-emotional regions (e.g., the insula and the cingulate in frontotemporal dementia, frontostriatal networks in Parkinson's disease), whereas persons with Alzheimer's disease presented generalized emotional processing abnormalities with preserved interoceptive mechanisms. The integration of both domains was associated with the volume and connectivity (salience network) of canonical interoceptive-emotional hubs, critically involving the insula and the anterior cingulate. Our study reveals multimodal markers of interoceptive-emotional priming, laying the groundwork for new agendas in cognitive neuroscience and behavioral neurology.

Across Latin American and Caribbean countries (LACs), the fight against dementia faces pressing challenges, such as heterogeneity, diversity, political instability, and socioeconomic disparities. These can be addressed more effectively in a collaborative setting that fosters open exchange of knowledge. In this work, the Latin American and Caribbean Consortium on Dementia (LAC-CD) proposes an agenda for integration to deliver a Knowledge to Action Framework (KtAF). First, we summarize evidence-based strategies (epidemiology, genetics, biomarkers, clinical trials, nonpharmacological interventions, networking, and translational research) and align them to current global strategies to translate regional knowledge into transformative actions. Then we characterize key sources of complexity (genetic isolates, admixture in populations, environmental factors, and barriers to effective interventions), map them to the above challenges, and provide the basic mosaics of knowledge toward a KtAF. Finally, we describe strategies supporting the knowledge creation stage that underpins the translational impact of KtAF. Fil: Parra, Mario Alfredo. Universidad Autónoma del Caribe; Colombia Fil: Baez, Sandra. Universidad de los Andes; Colombia Fil: Sedeño, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Gonzalez Campo, Cecilia. Universidad de San Andrés; Argentina Fil: Santamaría García, Hernando. Pontificia Universidad Javeriana; Colombia Fil: Aprahamian, Ivan. No especifíca; Fil: Bertolucci, Paulo. Universidade Federal de Sao Paulo; Brasil Fil: Bustin, Julian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; Argentina Fil: Camargos Bicalho, Maria Aparecida. Universidade Federal de Minas Gerais; Brasil Fil: Cano Gutierrez, Carlos. Hospital Universitario San Ignacio; Colombia Fil: Caramelli, Paulo. Universidade Federal de Minas Gerais; Brasil Fil: Chaves, Marcia L. F.. Universidade Federal do Rio Grande do Sul; Brasil Fil: Perez Cogram, Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; Argentina Fil: Beber, Bárbara Costa. Universidade Federal do Rio Grande do Sul; Brasil Fil: Court, Felipe A.. Universidad Mayor; Chile Fil: de Souza, Leonardo Cruz. Universidade Federal de Minas Gerais; Brasil Fil: Custodio, Nilton. Peruvian Institute of Neurosciences; Perú Fil: Damian, Andres. Universidad de la República; Uruguay Fil: de la Cruz, Myriam. University of California; Estados Unidos Fil: Diehl Rodriguez, Roberta. Universidade de Sao Paulo; Brasil Fil: Dozzi Brucki, Sonia Maria. Universidade de Sao Paulo; Brasil Fil: Fajersztajn, Lais. Universidade de Sao Paulo; Brasil Fil: Farías, Gonzalo A.. Universidad de Chile; Chile Fil: De Felice, Fernanda G.. Universidade Federal do Rio de Janeiro; Brasil Fil: Ferrari, Raffaele. Colegio Universitario de Londres; Reino Unido Fil: Ferreira de Oliveira, Fabricio. Universidade de Sao Paulo; Brasil Fil: Ferreira, Sergio Teixeira. Universidade Federal do Rio de Janeiro; Brasil Fil: Ferretti, Ceres. Universidade de Sao Paulo; Brasil Fil: Figueredo Balthazar, Marcio Luiz. Universidade Estadual de Campinas; Brasil Fil: Ferreira Frota, Norberto Anizio. Universidade de Fortaleza; Brasil Fil: Fuentes, Patricio. No especifíca; Fil: García, Adolfo Martín. Universidad Nacional de Cuyo; Argentina. Universidad de San Andrés; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Garcia, Patricia J.. Cayetano Heredia University; Perú Fil: de Gobbi Porto, Fábio Henrique. Universidade de Sao Paulo; Brasil Fil: Duque Peñailillo, Lissette. Ecuadorian Dementia Association; Ecuador Fil: Engler, Henry Willy. Universidad de la República; Uruguay Fil: Maier, Irene. Universidad de Chile; Chile Fil: Mata, Ignacio F.. University of Pittsburgh; Estados Unidos Fil: González Billault, Christian. Universidad de Chile; Chile Fil: Lopez, Oscar L.. University of Pittsburgh; Estados Unidos Fil: Morelli, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina Fil: Nitrini, Ricardo. Universidade de Sao Paulo; Brasil Fil: Quiroz, Yakeel T.. Harvard Medical School; Estados Unidos Fil: Guerrero Barragan, Alejandra. Universidad de la Sabana; Colombia Fil: Huepe, David. Universidad Adolfo Ibañez; Chile Fil: Pio, Fabricio Joao. Hospital Governador Celso Ramos; Brasil Fil: Suemoto, Claudia Kimie. Universidade de Sao Paulo; Brasil Fil: Kochhann, Renata. Pontificia Universidade Católica do Rio Grande do Sul; Brasil Fil: Kochen, Sara Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; Argentina Fil: Kumfor, Fiona. University of Western Sydney; Australia Fil: Lanata, Serggio. University of California; Estados Unidos Fil: Miller, Bruce. University of California; Estados Unidos Fil: Lessa Mansur, Leticia. Universidade de Sao Paulo; Brasil Fil: Lie Hosogi, Mirna. Universidade de Sao Paulo; Brasil Fil: Lillo, Patricia. Universidad de Chile; Chile Fil: Llibre Guerra, Jorge. University of California; Estados Unidos Fil: Lira, David. Peruvian Institute of Neurosciences; Perú Fil: Lopera, Francisco. Universidad de Antioquia; Colombia Fil: Comas, Adelina. No especifíca; Fil: Avila Funes, José Alberto. Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán; México Fil: Sosa, Ana Luisa. Instituto Nacional de Neurología y Neurocirugía; México Fil: Ramos, Claudia. University of California; Estados Unidos Fil: de Paula França Resende, Elisa. University of California; Estados Unidos Fil: Snyder, Heather M.. No especifíca; Fil: Tarnanas, Ioannis. University of California; Estados Unidos Fil: Yokoyama, Jenifer. University of California; Estados Unidos Fil: Llibre, Juan. Centro de Estudios de Alzheimer; Cuba Fil: Cardona Londoño, Juan Felipe. Universidad del Valle; Colombia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Possin, Kate. University of California; Estados Unidos Fil: Kosik, Kenneth. University of California; Estados Unidos Fil: Montesinos, Rosa. Peruvian Institute of Neurosciences; Perú Fil: Moguilner, Sebastian Gabriel. University of California; Estados Unidos Fil: Solis, Patricia Cristina Lourdes. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic; Argentina. Universidad Nacional Arturo Jauretche; Argentina. Universidad de Buenos Aires; Argentina Fil: de Lucena Ferretti Rebustini, Renata Eloah. Universidade de Sao Paulo; Brasil Fil: Ramirez, Jeronimo Martin. No especifíca; Fil: Matallana, Diana. Pontificia Universidad Javeriana; Colombia Fil: Mbakile Mahlanza, Lingani. University of California; Estados Unidos Fil: Mendonça Marques Ton, Alyne. Universidade Federal do Rio de Janeiro; Brasil Fil: Melo Tavares, Ronnielly. Centro Universitario de Belo Horizonte.; Brasil Fil: Miotto, Eliane C.. Universidade de Sao Paulo; Brasil Fil: Muniz-Terrera, Graciela. University of Edinburgh; Reino Unido Fil: MuñozN evárez, Luis Arnoldo. University of California; Estados Unidos Fil: Orozco, David. Universidad Nacional del Sur; Argentina Fil: Okada de Oliveira, Maira. University of California; Estados Unidos Fil: Piguet, Olivier. University of Western Sydney; Australia Fil: Pintado Caipa, Maritza. University of California; Estados Unidos Fil: Piña Escudero, Stefanie Danielle. University of California; Estados Unidos Fil: Porcello Schilling, Lucas. Pontificia Universidade Católica do Rio Grande do Sul; Brasil Fil: Rodrigues Palmeira, André Luiz. Hospital Ernesto Dornelles; Brasil Fil: Sanches Yassuda, Mônica. Universidade de Sao Paulo; Brasil Fil: Santacruz Escudero, Jose Manuel. Pontificia Universidad Javeriana; Colombia Fil: Serafim, Rodrigo Bernardo. Universidade Federal do Rio de Janeiro; Brasil Fil: Smid, Jerusa. Universidade de Sao Paulo; Brasil Fil: Slachevsky, Andrea. Universidad de Chile; Chile Fil: Serrano, Cecilia Mariela. No especifíca; Fil: Soto Añari, Marcio. Universidad Católica San Pablo; Perú Fil: Takada, Leonel Tadao. Universidade de Sao Paulo; Brasil Fil: Tenenholz Grinberg, Lea. Universidade de Sao Paulo; Brasil Fil: Teixeira, Antonio Lucio. Universidade Federal de Minas Gerais; Brasil Fil: Tonidandel Barbosa, Maira. Universidade Federal de Minas Gerais; Brasil Fil: Trépel, Dominic. Trinity College; Estados Unidos Fil: Ibañez, Agustin Mariano. Universidad Autónoma del Caribe; Colombia. Universidad Adolfo Ibañez; Chile. Universidad de San Andrés; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Research on how the brain construes meaning during language use has prompted two conflicting accounts. According to the ‘grounded view’, word understanding involves quick reactivations of sensorimotor (embodied)experiences evoked by the stimuli, with simultaneous or later engagement of multimodal (conceptual)systems integrating information from various sensory streams. Contrariwise, for the ‘symbolic view’, this capacity depends crucially on multimodal operations, with embodied systems playing epiphenomenal roles after comprehension. To test these contradictory hypotheses, the present magnetoencephalography study assessed implicit semantic access to grammatically constrained action and non-action verbs (n = 100 per category)while measuring spatiotemporally precise signals from the primary motor cortex (M1, a core region subserving bodily movements)and the anterior temporal lobe (ATL, a putative multimodal semantic hub). Convergent evidence from sensor- and source-level analyses revealed that increased modulations for action verbs occurred earlier in M1 (∼130–190 ms)than in specific ATL hubs (∼250–410 ms). Moreover, machine-learning decoding showed that trial-by-trial classification peaks emerged faster in M1 (∼100–175 ms)than in the ATL (∼345–500 ms), with over 71% accuracy in both cases. Considering their latencies, these results challenge the ‘symbolic view’ and its implication that sensorimotor mechanisms play only secondary roles in semantic processing. Instead, our findings support the ‘grounded view’, showing that early semantic effects are critically driven by embodied reactivations and that these cannot be reduced to post-comprehension epiphenomena, even when words are individually classified. Briefly, our study offers non-trivial insights to constrain fine-grained models of language and understand how meaning unfolds in neural time. Fil: García, Adolfo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; Argentina. Universidad Nacional de Cuyo. Facultad de Educación Elemental y Especial; Argentina Fil: Moguilner, Sebastian Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro | Universidad Nacional de Cuyo. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro; Argentina Fil: Torquati, Kathya. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencias Cognitivas y Traslacional; Argentina Fil: García Marco, Enrique. Universidad de La Laguna; España. Universidad Nacional de Educación a Distancia; España Fil: Herrera, Eduar. Universidad Icesi; Colombia Fil: Muñoz, Edison. Universidad de Santiago de Chile; Chile Fil: Castillo, Eduardo. Florida Hospital for Children; Estados Unidos Fil: Kleineschay, Tara. Florida Hospital for Children; Estados Unidos Fil: Sedeño, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencias Cognitivas y Traslacional; Argentina Fil: Ibañez, Agustin Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencias Cognitivas y Traslacional; Argentina. Universidad Adolfo Ibañez; Chile. Universidad Autónoma del Caribe; Colombia

Dementia is becoming increasingly prevalent in Latin America, contrasting with stable or declining rates in North America and Europe. This scenario places unprecedented clinical, social, and economic burden upon patients, families, and health systems. The challenges prove particularly pressing for conditions with highly specific diagnostic and management demands, such as frontotemporal dementia. Here we introduce a research and networking initiative designed to tackle these ensuing hurdles, the Multi-partner consortium to expand dementia research in Latin America (ReDLat). First, we present ReDLat's regional research framework, aimed at identifying the unique genetic, social, and economic factors driving the presentation of frontotemporal dementia and Alzheimer's disease in Latin America relative to the US. We describe ongoing ReDLat studies in various fields and ongoing research extensions. Then, we introduce actions coordinated by ReDLat and the Latin America and Caribbean Consortium on Dementia (LAC-CD) to develop culturally appropriate diagnostic tools, regional visibility and capacity building, diplomatic coordination in local priority areas, and a knowledge-to-action framework toward a regional action plan. Together, these research and networking initiatives will help to establish strong cross-national bonds, support the implementation of regional dementia plans, enhance health systems' infrastructure, and increase translational research collaborations across the continent.

From molecular mechanisms to global brain networks, atypical fluctuations are the hallmark of neurodegeneration. Yet, traditional fMRI research on resting-state networks (RSNs) has favored static and average connectivity methods, which by overlooking the fluctuation dynamics triggered by neurodegeneration, have yielded inconsistent results. The present multicenter study introduces a data-driven machine learning pipeline based on dynamic connectivity fluctuation analysis (DCFA) on RS-fMRI data from 300 participants belonging to three groups: behavioral variant frontotemporal dementia (bvFTD) patients, Alzheimer's disease (AD) patients, and healthy controls. We considered non-linear oscillatory patterns across combined and individual resting-state networks (RSNs), namely: the salience network (SN), mostly affected in bvFTD; the default mode network (DMN), mostly affected in AD; the executive network (EN), partially compromised in both conditions; the motor network (MN); and the visual network (VN). These RSNs were entered as features for dementia classification using a recent robust machine learning approach (a Bayesian hyperparameter tuned Gradient Boosting Machines (GBM) algorithm), across four independent datasets with different MR scanners and recording parameters. The machine learning classification accuracy analysis revealed a systematic and unique tailored architecture of RSN disruption. The classification accuracy ranking showed that the most affected networks for bvFTD were the SN + EN network pair (mean accuracy = 86.43%, AUC = 0.91, sensitivity = 86.45%, specificity = 87.54%); for AD, the DMN + EN network pair (mean accuracy = 86.63%, AUC = 0.89, sensitivity = 88.37%, specificity = 84.62%); and for the bvFTD vs. AD classification, the DMN + SN network pair (mean accuracy = 82.67%, AUC = 0.86, sensitivity = 81.27%, specificity = 83.01%). Moreover, the DFCA classification systematically outperformed canonical connectivity approaches (including both static and linear dynamic connectivity). Our findings suggest that non-linear dynamical fluctuations surpass two traditional seed-based functional connectivity approaches and provide a pathophysiological characterization of global brain networks in neurodegenerative conditions (AD and bvFTD) across multicenter data.

Fil: Moguilner, Sebastian. University of California San Francisco. Global Brain Health Institute; Estados Unidos Fil: Moguilner, Sebastian. Trinity College Dublin; Reino Unido Fil: Moguilner, Sebastian. Fundación Centro Diagnóstico Nuclear; Argentina Fil: Moguilner, Sebastian. Comisión Nacional de Energía Atómica; Argentina Fil: Birba, Agustina. Universidad de San Andrés; Argentina Fil: Birba, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Fino, Daniel. Fundación Centro Diagnóstico Nuclear; Argentina Fil: Fino, Daniel. Comisión Nacional de Energía Atómica; Argentina Fil: Fino, Daniel. Fundación Argentina para el Desarrollo en Salud;, Argentina Fil: Isoardi, Roberto. Fundación Centro Diagnóstico Nuclear; Argentina Fil: Isoardi, Roberto. Comisión Nacional de Energía Atómica; Argentina Fil: Huetagoyena, Celeste. Neurociencias Médicas; Argentina Fil: Huetagoyena, Celeste. Pontificia Universidad Católica Argentina; Argentina Fil: Otoya, Raúl. Neurociencias Médicas; Argentina Fil: Tirapu, Viviana. Fundación Centro Diagnóstico Nuclear; Argentina Fil: Tirapu, Viviana. Comisión Nacional de Energía Atómica; Argentina Fil: Tirapu, Viviana. Neurociencias Médicas; Argentina Fil: Cremaschi, Fabián. Fundación Centro Diagnóstico Nuclear; Argentina Fil: Cremaschi, Fabián. Comisión Nacional de Energía Atómica; Argentina Fil: Cremaschi, Fabián. Universidad Nacional de Cuyo. Facultad de Medicina. Departamento de Neurociencias; Argentina Fil: Cremaschi, Fabián. Hospital Santa Isabel de Hungría; Argentina Fil: Sedeño, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Ibáñez, Agustín. University of California San Francisco. Global Brain Health Institute; Estados Unidos Fil: Ibáñez, Agustín. Trinity College Dublin; Reino Unido Fil: Ibáñez, Agustín. Universidad de San Andrés; Argentina Fil: Ibáñez, Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Ibáñez, Agustín. Universidad Adolfo Ibáñez; Escuela de Psicología. Centro de Neurociencia Social y Cognitiva; Chile Fil: García, Adolfo M. University of California San Francisco. Global Brain Health Institute; Estados Unidos Fil: García, Adolfo M. Trinity College Dublin; Reino Unido Fil: García, Adolfo M. Universidad de San Andrés; Argentina Fil: García, Adolfo M. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: García, Adolfo M. Universidad Nacional de Cuyo. Facultad de Educación, Argentina Fil: García, Adolfo M. Universidad de Santiago de Chile. Facultad de Humanidades. Departamento de Lingüística y Literatura; Chile Abstract: The pressing call to detect sensitive cognitive markers of frontal lobe epilepsy (FLE) remains poorly addressed. Standard frameworks prove nosologically unspecific (as they reveal deficits that also emerge across other epilepsy subtypes), possess low ecological validity, and are rarely supported by multimodal neuroimaging assessments. To bridge these gaps, we examined naturalistic action and non-action text comprehension, combined with structural and functional connectivity measures, in 19 FLE patients, 19 healthy controls, and 20 posterior cortex epilepsy (PCE) patients. Our analyses integrated inferential statistics and data-driven machine-learning classifiers. FLE patients were selectively and specifically impaired in action comprehension, irrespective of their neuropsychological profile. These deficits selectively and specifically correlated with (a) reduced integrity of the anterior thalamic radiation, a subcortical structure underlying motoric and action-language processing as well as epileptic seizure spread in this subtype; and (b) hypoconnectivity between the primary motor cortex and the left-parietal/supramarginal regions, two putative substrates of action-language comprehension. Moreover, machine-learning classifiers based on the above neurocognitive measures yielded 75% accuracy rates in discriminating individual FLE patients from both controls and PCE patients. Briefly, action-text assessments, combined with structural and functional connectivity measures, seem to capture ecological cognitive deficits that are specific to FLE, opening new avenues for discriminatory characterizations among epilepsy types.

Biomarkers represent a critical research area in neurodegeneration disease as they can contribute to studying potential disease-modifying agents, fostering timely therapeutic interventions, and alleviating associated financial costs. Functional connectivity (FC) analysis represents a promising approach to identify early biomarkers in specific diseases. Yet, virtually no study has tested whether potential FC biomarkers prove to be reliable and reproducible across different centers. As such, their implementation remains uncertain due to multiple sources of variability across studies: the numerous international centers capable conducting FC research vary in their scanning equipment and their samples’ socio-cultural background, and, more troublingly still, no gold-standard method exists to analyze FC. In this unprecedented study, we aim to address both issues by performing the first multicenter FC research in the behavioral-variant frontotemporal dementia (bvFTD), and by assessing multiple FC approaches to propose a gold-standard method for analysis. We enrolled 52 bvFTD patients and 60 controls from three international clinics (with different fMRI recording parameters), and three additional neurological patient groups. To evaluate FC, we focused on seed analysis, inter-regional connectivity, and several graph-theory approaches. Only graph-theory analysis, based on weighted-matrices, yielded consistent differences between bvFTD and controls across centers. Also, graph metrics robustly discriminated bvFTD from the other neurological conditions. The consistency of our findings across heterogeneous contexts highlights graph-theory as a potential gold-standard approach for brain network analysis in bvFTD. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc.

The search for biomarkers of neurodegenerative diseases via fMRI functional connectivity (FC) research has yielded inconsistent results. Yet, most FC studies are blind to non-linear brain dynamics. To circumvent this limitation, we developed a “weighted Symbolic Dependence Metric” (wSDM) measure. Using symbolic transforms, we factor in local and global temporal features of the BOLD signal to weigh a robust copula-based dependence measure by symbolic similarity, capturing both linear and non-linear associations. We compared this measure with a linear connectivity metric (Pearson’s R) in its capacity to identify patients with behavioral variant frontotemporal dementia (bvFTD) and controls based on resting-state data. We recruited participants from two international centers with different MRI recordings to assess the consistency of our measure across heterogeneous conditions. First, a seed-analysis comparison of the salience network (a specific target of bvFTD) and the default-mode network (as a complementary control) between patients and controls showed that wSDM yields better identification of resting-state networks. Moreover, machine learning analysis revealed that wSDM yielded higher classification accuracy. These results were consistent across centers, highlighting their robustness despite heterogeneous conditions. Our findings underscore the potential of wSDM to assess fMRI-derived FC data, and to identify sensitive biomarkers in bvFTD. Fil: Moguilner, Sebastian Gabriel. 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 Nacional de Cuyo; Argentina. Comisión Nacional de Energía Atómica; Argentina Fil: García, Adolfo Martín. Universidad Nacional de Cuyo; 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; Argentina Fil: Mikulan, Ezequiel Pablo. 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 Fil: Hesse Rizzi, Eugenia Fátima. 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 Fil: García Cordero, Indira Ruth. 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 Fil: Melloni, Margherita. 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 Fil: Cervetto, Sabrina. 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 Fil: Serrano, Cecilia Mariela. Unidad Asistencial "Dr. César Milstein"; Argentina Fil: Herrera Murcia, Eduar. 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 Fil: Reyes, Pablo. Pontificia Universidad Javeriana; Colombia Fil: Matallana, Diana. Pontificia Universidad Javeriana; Colombia Fil: Manes, Facundo Francisco. 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 Fil: 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 Adolfo Ibañez; Chile. Universidad Autónoma del Caribe; Colombia Fil: 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; Argentina