STECHER GUZMAN, XIMENA PATRICIA
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STECHER GUZMAN, XIMENA PATRICIA
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xstecher@udd.cl
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56394442700

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Now showing 1 - 10 of 18
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Cervical Artery Dissection in Postpartum Women after Cesarean and Vaginal Delivery

2022 , Francisca Urrutia , MAZZON AGURTO, ENRICO , BRUNSER, ALEJANDRO , DIAZ TAPIA, VIOLETA DEL CARMEN , CALDERON GIADROSIC, JUAN FRANCISCO , STECHER GUZMAN, XIMENA PATRICIA , Tomas Bernstein , Paulo Zuñiga , SCHILLING REDLICH, ANDREA INGRID , MUÑOZ VENTURELLI, PAULA

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Lateral prefrontal activity as a compensatory strategy for deficits of cortical processing in Attention Deficit Hyperactivity Disorder

2017-12-01 , ZAMORANO MENDIETA, FRANCISCO JAVIER , BILLEKE BOBADILLA, PABLO ERNESTO , Kausel, Leonie , Larrain, Josefina , STECHER GUZMAN, XIMENA PATRICIA , Hurtado, Jose M. , López, Vladimir , Carrasco, Ximena , Aboitiz, Francisco

Attention Deficit Hyperactivity Disorder (ADHD) is the most common neuropsychiatric disorder in childhood and is characterized by a delay of cortical maturation in frontal regions. In order to investigate interference control, which is a key function of frontal areas, a functional MRI study was conducted on 17 ADHD boys and 17 typically developing (TD) boys, while solving the multi source interference task (MSIT). This task consists of two conditions, a "congruent condition" and an "incongruent condition". The latter requires to inhibit information that interferes with task-relevant stimuli. Behavioral results showed that ADHD subjects committed more errors than TD children. In addition, TD children presented a larger MSIT effect -A greater difference in reaction times between the incongruent and the congruent conditions- than ADHD children. Associated to the MSIT effect, neuroimaging results showed a significant enhancement in the activation of the right lateral prefrontal cortex (rlPFC) in ADHD than in TD subjects. Finally, ADHD subjects presented greater functional connectivity between rlPFC and bilateral orbitofrontal cortex than the TD group. This difference in connectivity correlated with worse performance in both groups. Our results could reflect a compensatory strategy of ADHD children resulting from their effort to maintain an adequate performance during MSIT.

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Radiología en el estudio de la macrocefalia. ¿Por qué?, ¿cuándo?, ¿cómo?

2022 , V. Schonstedt Geldres , STECHER GUZMAN, XIMENA PATRICIA , C. Manterola Mordojovich , À. Rovira

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Children with epilepsy demonstrate macro- and microstructural changes in the thalamus, putamen, and amygdala

2020 , Sarah J. MacEachern , Jonathan D. Santoro , Kara J. Hahn , Zachary A. Medress , STECHER GUZMAN, XIMENA PATRICIA , Matthew D. Li , Jin S. Hahn , Kristen W. Yeom , Nils D. Forkert

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Neural Dynamics of Improved Bimodal Attention and Working Memory in Musically Trained Children

2020 , Leonie Kausel , Francisco Zamorano , BILLEKE BOBADILLA, PABLO ERNESTO , Mary E. Sutherland , Josefina Larrain-Valenzuela , Gottfried Schlaug , STECHER GUZMAN, XIMENA PATRICIA , Francisco Aboitiz

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Us versus them mentality in football fans: Significant social defeat engages the mentalization network and disengages cognitive control areas

2022 , ZAMORANO MENDIETA, FRANCISCO , CARVAJAL PAREDES, PATRICIO ALEJANDRO , SOTO ICAZA, PATRICIA , César Salinas , STECHER GUZMAN, XIMENA PATRICIA , MUÑOZ REYES, JOSÉ ANTONIO , Vladimir López , Waldemar Méndez , Joel Barrera , Gonzalo Aragón-Caqueo , BILLEKE BOBADILLA, PABLO ERNESTO

Social affiliation is one of the building blocks that shapes cultures and communities. This motivation contributes to the development of social bonding among individuals within a group, enjoying rights, assuming obligations, and strengthening its identity. Evidence has shown that social affiliation has inspired different social phenomena, such as wars, political movements, social struggles, among others, based on two human motivations: the ingroup love and the outgroup hate. One contemporary group to study as a proxy of social affiliation, and ingroup and outgroup motivations is the sports competition. However, this affiliation model has been poorly considered in social neuroscience research. This research aimed to shed light on the neurobiological networks that are related to social affiliation in football fans of two of the most popular Chilean football teams. Methods: To this end, 43 male fans of two football rival teams watched videos of winning and losing goals of their favorite team while their brain activity was measured with functional magnetic resonance imaging (fMRI). Results: The results showed that while the activation of the reward system was observed in fans when their team scores goals against the rival, both the activation of the mentalization network and the inhibition of the dorsal anterior cingulate cortex were associated with the emotional correlates of defeat in football fans. Conclusions: Taking these findings together could contribute to a deeper understanding of social affiliation, and more importantly, of extreme affiliation phenomena, and fanaticism.

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A novel ITPA variant causes epileptic encephalopathy with multiple-organ dysfunction

2020 , Masamune Sakamoto , Den Kouhei , Muzhirah Haniffa , Sebastián Silva , Mónica Troncoso , Paola Santander , Valeria Schonstedt , STECHER GUZMAN, XIMENA PATRICIA , Nobuhiko Okamoto , Kohei Hamanaka , Takeshi Mizuguchi , Satomi Mitsuhashi , Noriko Miyake , Naomichi Matsumoto

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Association between spontaneous internal carotid artery dissection and perivascular adipose tissue attenuation on computed tomography angiography

2023 , Kevin Cheng , Andrew Lin , STECHER GUZMAN, XIMENA PATRICIA , Tomas Bernstein , Paulo Zuñiga , Gonzalo Martinez , BRUNSER, ALEJANDRO , DIAZ TAPIA, VIOLETA DEL CARMEN , MAZZON AGURTO, ENRICO , William Cameron , Stephen J Nicholls , Sanjay Patel , Damini Dey , Dennis TL Wong , MUÑOZ VENTURELLI, PAULA ANDREA

Background: Spontaneous cervical artery dissection (sCAD) is a leading cause of ischemic stroke in young patients. Studies using high-resolution magnetic resonance imaging and positron emission tomography have suggested vessel wall inflammation to be a pathogenic factor in sCAD. Computed tomography (CT) attenuation of perivascular adipose tissue (PVAT) is an established non-invasive imaging biomarker of inflammation in coronary arteries, with higher attenuation values reflecting a greater degree of vascular inflammation. Objectives: We evaluate the CT attenuation of PVAT surrounding the internal carotid artery (PVATcarotid) with and without spontaneous dissection. Methods: Single-center prospective observational study of 56 consecutive patients with CT-verified spontaneous dissection of the internal carotid artery (ICA). Of these patients, six underwent follow-up computed tomography angiography (CTA). Twenty-two patients who underwent CTA for acute neurological symptoms but did not have dissection formed the control group. Using semi-automated research software, PVATcarotid was measured as the mean Hounsfield unit (HU) attenuation of adipose tissue within a defined volume of interest surrounding the ICA. Results: PVATcarotid was significantly higher around dissected ICA compared with non-dissected contralateral ICA in the same patients (−58.7 ± 10.2 vs −68.9 ± 8.1 HU, p < 0.0001) and ICA of patients without dissection (−58.7 ± 10.2 vs −69.3 ± 9.3 HU, p < 0.0001). After a median follow-up of 89 days, there was a significant reduction in PVATcarotid around dissected ICA (−57.5 ± 13.4 to −74.3 ± 10.5 HU, p < 0.05), while no change was observed around non-dissected contralateral ICA (−71.0 ± 4.4 to −74.1 ± 4.1 HU, p = 0.19). ICA dissection was an independent predictor of PVATcarotid following multivariable adjustment for age and the presence of ICA occlusion. Conclusion: PVATcarotid is elevated in the presence of sCAD and may decrease following the acute event.

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Patients recovering from COVID-19 who presented with anosmia during their acute episode have behavioral, functional, and structural brain alterations

2024 , Leonie Kausel , Alejandra Figueroa-Vargas , José Zamorano-abramson , STECHER GUZMAN, XIMENA PATRICIA , Mauricio Aspé-Sánchez , Claudio Román , Patricio Carvajal-Paredes , Victor Márquez-Rodríguez , Patricio Soto-Fernández , Reinaldo Uribe-San-Martín , Gabriela Valdebenito-Oyarzo , Rodrigo Henríquez-Ch , Carla Manterola , SILVA FUENTE ALBA, CLAUDIO SERGIO , Francisco Aboitiz , María Paz Martínez-Molina , Rafael Polania , Pamela Guevara , MUÑOZ VENTURELLI, PAULA ANDREA , SOTO ICAZA, PATRICIA , BILLEKE BOBADILLA, PABLO ERNESTO

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Vigabatrin-induced MRI changes associated with extrapyramidal symptoms in a child with infantile spasms

2015 , Valeria Schonstedt , Ximena Stecher , Viviana Venegas , Claudio Silva

Vigabatrin is an antiepileptic drug used for treatment of infantile spasms. We present a female patient with infantile spasms in treatment with vigabatrin who developed ataxic movements. MRI demonstrated a symmetrical pattern of thalamic and globi pallidi diffusion restriction. While these image features have been widely described to be related to the use of vigabatrin, this case highlights the development of movement disorders in association with MRI signal changes. Awareness of the reversible nature of this condition is reassuring for the treating team and avoids unjustified studies.

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