Person:
Melero Carrasco, Helena

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First Name
Helena
Last Name
Melero Carrasco
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Psicología
Department
Psicobiología y Metodología en Ciencias del Comportamiento
Area
Psicobiología
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Now showing 1 - 10 of 13
  • Publication
    Sinestesia, bases neuroanatómicas y cognitivas
    (Universidad Complutense de Madrid, 2015-06-19) Melero Carrasco, Helena; Peña Melián Lago, Ángel Luis; Ríos Lago, Marcos
    La sinestesia es un fenómeno neurológico de carácter no patológico que aparece cuando la estimulación de una vía sensorial o cognitiva produce una experiencia asociada en una segunda vía que no ha sido estimulada directamente. A pesar de que en los últimos 15 años el estudio de la sinestesia ha dado lugar a más de 500 publicaciones científicas, sus bases neurofisiológicas aún no han sido dilucidadas. Para aportar nuevos datos empíricos sobre esta cuestión, en esta tesis doctoral se ha analizado el fenómeno de la sinestesia investigando la frecuencia relativa de sus diferentes modalidades, así como sus bases neuroanatómicas y cognitivas. La tesis se divide en tres partes. En la primera (Capítulo I), se lleva a cabo una revisión sobre el estado de la cuestión, incluyendo la definición del fenómeno y sus características, los datos de prevalencia, las diferentes modalidades catalogadas, la evidencia experimental acerca de las diferencias estructurales y funcionales del cerebro sinestésico, los hallazgos genéticos y los modelos explicativos. En la segunda parte se presentan tres estudios. En el primero de ellos (Capítulo II) se analiza la presencia de sinestesia en una muestra española para conocer la frecuencia relativa de sus diferentes modalidades. Los resultados han mostrado a) que la representación de la sinestesia en una muestra española de 803 personas es elevada (13,95%); b) que las sinestesias conceptuales son las más frecuentes; c) que la variable sinestesia es independiente de las variables sexo, edad, lateralidad manual y nivel educativo. Estos hallazgos sugieren que la sinestesia está presente en un elevado número de personas, especialmente cuando se trata de modalidades conceptuales, constatando la necesidad de considerar la variable sinestesia como un factor relevante en los diseños experimentales, y de proporcionar a los profesionales del ámbito clínico un adecuado conocimiento del fenómeno y sus características. En el segundo estudio (Capítulo III), se investigan las características estructurales del cerebro sinestésico grafema-color, mediante la combinación del análisis VBM de datos 3D-T1 y DTI, atendiendo a regiones corticales y subcorticales y explorando las bases neuroanatómicas del componente emocional del fenómeno. Este análisis ha confirmado que las diferencias anatómicas se encuentran distribuidas a nivel cortical y subcortical, incluyendo áreas relacionadas con el procesamiento emocional, lo que ha motivado la propuesta de un nuevo modelo explicativo ¿el Modelo de Integración Emocional. En el tercer estudio (Capítulo IV), se exploran las bases neurofuncionales de las sinestesias acromáticas, siendo esta la primera investigación que se ha centrado en este tipo de experiencias para comprender la sinestesia grafema-color, su dimensión emocional y el efecto de congruencia sinestésica. Los datos obtenidos han permitido confirmar a) que la base funcional de la sinestesia grafema-color se encuentra distribuída en el cerebro y refleja diferentes dimensiones de la experiencia sinestésica: un componente perceptivo, otro atencional/integrador y un componente emocional; b) que el color sinestésico y el color físico no poseen una base neural idéntica; y c) que el efecto de congruencia no debe ser utilizado como criterio para diferenciar la sinestesia congénita de las asociaciones adquiridas mediante aprendizaje asociativo por las personas neurotípicas. En la tercera y última parte Capítulo V, se presenta una discusión general que integra los resultados obtenidos en las tres investigaciones y se discuten las implicaciones que la aparición de este fenómeno tiene sobre el estudio de las diferencias individuales y el conocimiento de la cognición humana en general.
  • Publication
    Abnormal functional connectivity in radiologically isolated syndrome: A resting-state fMRI study
    (2023-09-29) del Pino, Ana Belén; Aladro, Yolanda; Cuevas, Constanza; Domingo-Santos, Ángela; Galán Sánchez-Seco, Victoria; Labiano-Fontcuberta, Andrés; Gómez-López, Ana; Salgado-Cámara, Paula; Costa-Frossard. Lucienne; Monreal. Enrique; Sainz de la Maza, Susana; Montero-Escribano, Paloma; Martínez-Ginés, María Luisa; Higueras, Yolanda; Ayuso-Peralta, Lucía; Malpica, Norberto; Melero Carrasco, Helena; Benito León, Julián; Higueras Hernández, Yolanda; Matías-Guiu Guía, Jorge
    Radiologically isolated syndrome (RIS) patients might have psychiatric and cognitive deficits, which suggests an involvement of major resting-state functional networks. Notwithstanding, very little is known about the neural networks involved in RIS. Objective: To examine functional connectivity differences between RIS and healthy controls using resting-state functional magnetic resonance imaging (fMRI). Methods: Resting-state fMRI data in 25 RIS patients and 28 healthy controls were analyzed using an independent component analysis; in addition, seed-based correlation analysis was used to obtain more information about specific differences in the functional connectivity of resting-state networks. Participants also underwent neuropsychological testing. Results: RIS patients did not differ from the healthy controls regarding age, sex, and years of education. However, in memory (verbal and visuospatial) and executive functions, RIS patients’ cognitive performance was significantly worse than the healthy controls. In addition, fluid intelligence was also affected. Twelve out of 25 (48%) RIS patients failed at least one cognitive test, and six (24.0%) had cognitive impairment. Compared to healthy controls, RIS patients showed higher functional connectivity between the default mode network and the right middle and superior frontal gyri and between the central executive network and the right thalamus (pFDR < 0.05; corrected). In addition, the seed-based correlation analysis revealed that RIS patients presented higher functional connectivity between the posterior cingulate cortex, an important hub in neural networks, and the right precuneus. Conclusion: RIS patients had abnormal brain connectivity in major resting-state neural networks and worse performance in neurocognitive tests. This entity should be considered not an “incidental finding” but an exclusively non-motor (neurocognitive) variant of multiple sclerosis.
  • Publication
    Real-time fMRI feedback impacts brain activation, results in auditory hallucinations reduction: Part 1: Superior temporal gyrus -Preliminary evidence-
    (Science Direct (Elsevier), 2020-04) Okano, K.; Bauer, C. C.C.; Ghosh, S.S.; Lee, Y. J.; de los Angeles, C.; Nestor, P. G.; del Re, E. C.; Northoff, G.; Whitfield-Gabrieli, S.; Niznikiewicz, M. A.; Melero Carrasco, Helena
    Auditory hallucinations (AH) are one of the core symptoms of schizophrenia (SZ) and constitute a significant source of suffering and disability. One third of SZ patients experience pharmacology-resistant AH, so an alternative/complementary treatment strategy is needed to alleviate this debilitating condition. In this study, real-time functional Magnetic Resonance Imaging neurofeedback (rt-fMRI NFB), a non-invasive technique, was used to teach 10 SZ patients with pharmacology-resistant AH to modulate their brain activity in the superior temporal gyrus (STG), a key area in the neurophysiology of AH. A functional task was designed in order to provide patients with a specific strategy to help them modify their brain activity in the desired direction. Specifically, they received neurofeedback from their own STG and were trained to upregulate it while listening to their own voice recording and downregulate it while ignoring a stranger's voice recording. This guided performance neurofeedback training resulted in a) a significant reduction in STG activation while ignoring a stranger's voice, and b) reductions in AH scores after the neurofeedback session. A single, 21-minute session of rt-fMRI NFB was enough to produce these effects, suggesting that this approach may be an efficient and clinically viable alternative for the treatment of pharmacology-resistant AH.
  • Publication
    Real-time fMRI neurofeedback reduces auditory hallucinations and modulates resting state connectivity of involved brain regions: Part 2: Default mode network -preliminary evidence
    (Science Direct (Elsevier), 2020-02) Clemens C.C. Bauer; Kana Okano; Satrajit S. Ghosh; Yoon Ji Lee; Carlo de los Angeles; Paul G. Nestor; Elisabetta C. del Re; Georg Northoff; Margaret A. Niznikiewicz; Susan Whitfield-Gabrieli; Melero Carrasco, Helena
    Auditory hallucinations (AHs) are one of the most distressing symptoms of schizophrenia (SZ) and are often resistant to medication. Imaging studies of individuals with SZ show hyperactivation of the default mode network (DMN) and the superior temporal gyrus (STG). Studies in SZ show DMN hyperconnectivity and reduced anticorrelation between DMN and the central executive network (CEN). DMN hyperconnectivity has been associated with positive symptoms such as AHs while reduced DMN anticorrelations with cognitive impairment. Using real-time fMRI neurofeedback (rt-fMRI-NFB) we trained SZ patients to modulate DMN and CEN networks. Meditation is effective in reducing AHs in SZ and to modulate brain network integration and increase DMN anticorrelations. Consequently, patients were provided with meditation strategies to enhance their abilities to modulate DMN/CEN. Results show a reduction of DMN hyperconnectivity and increase in DMNsingle bondCEN anticorrelation. Furthermore, the change in individual DMN connectivity significantly correlated with reductions in AHs. This is the first time that meditation enhanced through rt-fMRI-NFB is used to reduce AHs in SZ. Moreover, it provides the first empirical evidence for a direct causal relation between meditation enhanced rt-fMRI-NFB modulation of DMNsingle bondCEN activity and post-intervention modulation of resting state networks ensuing in reductions in frequency and severity of AHs.
  • Publication
    DeepEye: Deep convolutional network for pupil detection in real environments
    (2018-12-03) Vera-Olmos, F. J.; Pardo, E.; Malpica, N.; Melero Carrasco, Helena
    Robust identification and tracking of the pupil provides key information that can be used in several applications such as controlling gaze-based HMIs (human machine interfaces), designing new diagnostic tools for brain diseases, improving driver safety, detecting drowsiness, performing cognitive research, among others. We propose a deep convolutional neural network for eye-tracking based on atrous convolutions and spatial pyramids. DeepEye is able to handle real world problems such as varying illumination, blurring and reflections. The proposed network was trained and evaluated on 94,000 images taken from 24 data sets recorded in real world scenarios. DeepEye outperforms previous eye-tracking methods tested with these data sets. It improves the results of the current state of the art in a 26%, achieving an accuracy of more than 70% in almost every data set in terms of percentage of pupils detected with a distance error lower than 5 pixels.
  • Publication
    Variability in the analysis of a single neuroimaging dataset by many teams
    (2020-05-20) Botvinik-Nezer, R.; Holzmeister, F.; Camerer, C. F.; Dreber, A.; Huber, J.; Johannesson, M.; Kirchler, M.; Iwanir, R.; Mumford, J. A.; Adcock, R. A.; Avesani, P.; Baczkowski, B. M.; Bajracharya, A.; Bakst, L.; Ball, S.; Barilari, M.; Bault, N.; Beaton, D.; Beitner, J.; Benoit, R. G.; Berkers, R. M. W. J.; Bhanji, J. P.; Biswal, B. B.; Bobadilla-Suarez, S.; Bortolini, T.; Bottenhorn, K. L.; Bowring, A.; Braem, S.; Brooks, H. R.; Brudner, E. G.; Calderon, C. B.; Camilleri, J. A.; Castrellon, J. J.; Cecchetti, L.; Cieslik, E. C.; Cole, Z. J.; Collignon, O.; Cox, R. W.; Cunningham, W. A.; Czoschke, S.; Dadi, K.; Davis, C. P.; Luca, A. D.; Delgado, M. R.; Demetriou, L.; Dennison, J. B.; Di, X.; Dickie, E. W.; Dobryakova, E.; Donnat, C. L.; Dukart, J.; Duncan, N. W.; Durnez, J.; Eed, A.; Eickhoff, S. B.; Erhart, A.; Fontanesi, L.; Fricke, G. M.; Fu, S.; Galván, A.; Gau, R.; Genon, S.; Glatard, T.; Glerean, E.; Goeman, J. J.; Golowin, S. A. E.; González-García, C.; Gorgolewski, K. J.; Grady, C. L.; Green, M. A.; Guassi Moreira, J. F.; Guest, O.; Hakimi, S.; Hamilton, J. P.; Hancock, R.; Handjaras, G.; Harry, B.B.; Hawco, C.; Herholz, P.; Herman, G.; Heunis, S.; Hoffstaedter, F.; Hogeveen, J.; Holmes, S.; Hu, C. P.; Huettel, S. A.; Hughes, M. E.; Iacovella, V.; Iordan, A. D.; Isager, P. M.; Isik, A. I.; Jahn, Andrew; Johnson, Matthew R.; Johnstone, Tom; Joseph, Michael J. E.; Juliano, Anthony C.; Kable, Joseph W.; Kassinopoulos, Michalis; Koba, Cemal; Kong, Xiang-Zhen; Koscik, Timothy R.; Kucukboyaci, Nuri Erkut; Kuhl, Brice A.; Kupek, Sebastian; Laird, Angela R.; Lamm, Claus; Langner, Robert; Lauharatanahirun, Nina; Lee, Hongmi; Lee, Sangil; Leemans, Alexander; Leo, Andrea; Lesage, Elise; Li, Flora; Li, Monica Y. C.; Lim, Cheng Phui; Lintz, Evan N.; Liphardt, Schuyler W.; Losecaat Vermeer, Annabel B.; Love, Bradley C.; Mack, Michael L.; Malpica, Norberto; Marins, Theo; Maumet, Camille; McDonald, Kelsey; McGuire, Joseph T.; Méndez Leal, Adriana S.; Meyer, Benjamin; Meyer, Kristin N.; Mihai, Glad; Mitsis, Georgios D.; Moll, Jorge; Nielson, Dylan M.; Nilsonne, Gustav; Notter, Michael P.; Olivetti, Emanuele; Onicas, Adrian I.; Papale, Paolo; Patil, Kaustubh R.; Peelle, Jonathan E.; Pérez, Alexandre; Pischedda, Doris; Poline, Jean-Baptiste; Prystauka,Yanina; Ray, Shruti; Reuter-Lorenz, Patricia A.; Reynolds, Richard C.; Ricciardi, Emiliano; Rieck, Jenny R.; Rodriguez-Thompson, Anais M.; Romyn, Anthony; Salo, Taylor; Samanez-Larkin, Gregory R.; Sanz-Morales, Emilio; Schlichting, Margaret L.; Schultz, Douglas H.; Shen, Qiang; Sheridan, Margaret A.; Silvers, Jennifer A.; Skagerlund, Kenny; Smith, Alec; Smith, David V.; Sokol-Hessner, Peter; Steinkamp, Simon R.; Tashjian, Sarah M.; Thirion, Bertrand; Thorp, John N.; Tinghög, Gustav; Tisdall, Loreen; Tompson, Steven H.; Toro-Serey, Claudio; Torre Tresols, Juan Jesus; Tozzi, Leonardo; Truong, Vuong; Turella, Luca; van ‘t Veer, Anna E.; Verguts, Tom; Vettel, Jean M.; Vijayarajah, Sagana; Vo, Khoi; Wall, Matthew B.; Weeda, Wouter D.; Weis, Susanne; White, David J.; Wisniewski, David; Xifra-Porxas, Alba; Yearling, Emily A.; Yoon, Sangsuk; Yuan, Rui; Yuen, Kenneth S. L.; Lei Zhang; Zhang, Xu; Zosky, Joshua E.; Thomas E. Nichols,; Poldrack, Rusell A.; Schonberg, Tom; Melero Carrasco, Helena
    Data analysis workflows in many scientific domains have become increasingly complex and flexible. Here we assess the effect of this flexibility on the results of functional magnetic resonance imaging by asking 70 independent teams to analyse the same dataset, testing the same 9 ex-ante hypotheses1. The flexibility of analytical approaches is exemplified by the fact that no two teams chose identical workflows to analyse the data. This flexibility resulted in sizeable variation in the results of hypothesis tests, even for teams whose statistical maps were highly correlated at intermediate stages of the analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Notably, a meta-analytical approach that aggregated information across teams yielded a significant consensus in activated regions. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset2–5. Our findings show that analytical flexibility can have substantial effects on scientific conclusions, and identify factors that may be related to variability in the analysis of functional magnetic resonance imaging. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for performing and reporting multiple analyses of the same data. Potential approaches that could be used to mitigate issues related to analytical variability are discussed.
  • Publication
    Why is the synesthete's “A” red? Using a five-language dataset to disentangle the effects of shape, sound, semantics, and ordinality on inducer–concurrent relationships in grapheme-color synesthesia
    (2018-02) Root, Nicholas B.; Rouw, Romke; Asano, Michiko; Chai-Youn Kim; Yokosawa, Kazuhiko; Ramachandran, Vilayanur S.; Melero Carrasco, Helena
    Grapheme-color synesthesia is a neurological phenomenon in which viewing a grapheme elicits an additional, automatic, and consistent sensation of color. Color-to-letter associations in synesthesia are interesting in their own right, but also offer an opportunity to examine relationships between visual, acoustic, and semantic aspects of language. Research using large populations of synesthetes has indeed found that grapheme-color pairings can be influenced by numerous properties of graphemes, but the contributions made by each of these explanatory factors are often confounded in a monolingual dataset (i.e., only English-speaking synesthetes). Here, we report the first demonstration of how a multilingual dataset can reveal potentially-universal influences on synesthetic associations, and disentangle previously-confounded hypotheses about the relationship between properties of synesthetic color and properties of the grapheme that induces it. Numerous studies have reported that for English-speaking synesthetes, “A” tends to be colored red more often than predicted by chance, and several explanatory factors have been proposed that could explain this association. Using a five-language dataset (native English, Dutch, Spanish, Japanese, and Korean speakers), we compare the predictions made by each explanatory factor, and show that only an ordinal explanation makes consistent predictions across all five languages, suggesting that the English “A” is red because the first grapheme of a synesthete's alphabet or syllabary tends to be associated with red. We propose that the relationship between the first grapheme and the color red is an association between an unusually-distinct ordinal position (“first”) and an unusually-distinct color (red). We test the predictions made by this theory, and demonstrate that the first grapheme is unusually distinct (has a color that is distant in color space from the other letters' colors). Our results demonstrate the importance of considering cross-linguistic similarities and differences in synesthesia, and suggest that some influences on grapheme-color associations in synesthesia might be universal.
  • Publication
    Do the colors of your letters depend on your language? Language-dependent and universal influences on grapheme-color synesthesia in seven languages
    (Elsevier, 2021-09-06) Root, Nicholas; Asano, Michiko; Melero Carrasco, Helena; Kim, Chai-Youn; Sidoroff-Dorso, Anton V.; Vatakis, Argiro; Yokosawa, Kazuhiko; Ramachandrann, Vilayanur; Rouw, Romke
    Grapheme-color synesthetes experience graphemes as having a consistent color (e.g., “N is turquoise”). Synesthetes’ specific associations (which letter is which color) are often influenced by linguistic properties such as phonetic similarity, color terms (“Y is yellow”), and semantic associations (“D is for dog and dogs are brown”). However, most studies of synesthesia use only English-speaking synesthetes. Here, we measure the effect of color terms, semantic associations, and non-linguistic shape-color associations on synesthetic associations in Dutch, English, Greek, Japanese, Korean, Russian, and Spanish. The effect size of linguistic influences (color terms, semantic associations) differed significantly between languages. In contrast, the effect size of nonlinguistic influences (shape-color associations), which we predicted to be universal, indeed did not differ between languages. We conclude that language matters (outcomes are influenced by the synesthete’s language) and that synesthesia offers an exceptional opportunity to study influences on letter representations in different languages.
  • Publication
    Sex Differences in the Olfactory System: a Functional MRI Study
    (2018-09-17) Borromeo, Susana; Cristóbal-Huerta, Alexandra; Manzanedo, Eva; Luna, Guillermo; Toledano, Adolfo; Hernández-Tamames, Juan Antonio; Melero Carrasco, Helena
    Introduction Olfactory dysfunction is an early marker of neurological disease and a common symptom in psychotic disorders. Previous anatomical and functional research suggests that sex effects may be crucial in the assessment of the olfactory system. Nonetheless, the neural mechanisms through which the factor sex impacts olfactory perception are still not well understood. In this context, we use fMRI to investigate sex differences in the passive processing of chemical stimuli, in order to obtain new neuroscientific data that may help improve the assessment of odor perception. Methods Thirty healthy subjects (17 women) were stimulated with mint and butanol (event-related design) in a 3.0-T MRI scanner. A one-sample t test analysis was performed in order to observe olfactory-related activations. Intergroup differences (women vs. men) and the influence of each aroma were analyzed using a 2 × 2 ANOVA and post hoc contrasts. Results Men and women showed differential activity (males > females) in right superior/middle temporal areas, the right inferior frontal cortex, and the hypothalamus. Both groups showed a predominance of the right hemisphere for the processing of odors. Conclusion Functional differences between women and men in olfaction are not restricted to specific sensory areas and reflect a more general sex-dependent effect in multisensory integration processes. Implications Considering sex differences is essential in order to develop more specific and efficient strategies for the assessment and rehabilitation of the olfactory system and for the interpretation of the olfactory loss as an early biomarker of neurological and psychiatric diseases.
  • Publication
    Graph theory analysis of resting‐state functional magnetic resonance imaging in essential tremor
    (Wiley Open Access, 2019-07-22) Benito León, Julián; Sanz‐Morales, Emilio; Melero Carrasco, Helena; Louis, Elan D.; Romero, Juan P.; Rocon, Eduardo; Malpica, Norberto
    Essential tremor (ET) is a neurological disease with both motor and nonmotor manifestations; however, little is known about its underlying brain basis. Furthermore, the overall organization of the brain network in ET remains largely unexplored. We investigated the topological properties of brain functional network, derived from resting‐state functional magnetic resonance imaging (MRI) data, in 23 ET patients versus 23 healthy controls. Graph theory analysis was used to assess the functional network organization. At the global level, the functional network of ET patients was characterized by lower small‐worldness values than healthy controls—less clustered functionality of the brain. At the regional level, compared with the healthy controls, ET patients showed significantly higher values of global efficiency, cost and degree, and a shorter average path length in the left inferior frontal gyrus (pars opercularis), right inferior temporal gyrus (posterior division and temporo‐occipital part), right inferior lateral occipital cortex, left paracingulate, bilateral precuneus bilaterally, left lingual gyrus, right hippocampus, left amygdala, nucleus accumbens bilaterally, and left middle temporal gyrus (posterior part). In addition, ET patients showed significant higher local efficiency and clustering coefficient values in frontal medial cortex bilaterally, subcallosal cortex, posterior cingulate cortex, parahippocampal gyri bilaterally (posterior division), right lingual gyrus, right cerebellar flocculus, right postcentral gyrus, right inferior semilunar lobule of cerebellum and culmen of vermis. Finally, the right intracalcarine cortex and the left orbitofrontal cortex showed a shorter average path length in ET patients, while the left frontal operculum and the right planum polare showed a higher betweenness centrality in ET patients. In conclusion, the efficiency of the overall brain functional network in ET is disrupted. Further, our results support the concept that ET is a disorder that disrupts widespread brain regions, including those outside of the brain regions responsible for tremor.