Browsing by Author "Vargas, Lorena"

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    Beta oscillations precede joint attention and correlate with mentalization in typical development and autism
    (2019) Soto-Icaza, Patricia; Vargas, Lorena; Aboitiz, Francisco; Billeke, Pablo
    A precursor of adult social functioning is joint attention (JA), which is the capacity to share attention on an object with another person. JA precedes the development of the capacity to attribute mental states to others (i.e., mentalization or theory of mind). The neural mechanisms involved in the development of mentalization are not fully understood. Electroencephalographic recordings were made of children while they watched stimuli on a screen and their interaction with the experimenter was assessed. We tested whether neuronal activity preceding JA correlates with mentalization in typically developing (TD) children and whether this activity is impaired in children with autistic spectrum disorder (ASD) who evidence deficits in JA and mentalization skills. Both groups exhibited JA behavior with comparable frequency. TD children displayed a higher amplitude of negative central (Nc) event-related potential preceding JA behavior (similar to 500 msec after stimuli presentation), than did the ASD group. Previous to JA behavior, TD children demonstrated beta oscillatory activity in the temporoparietal region, while ASD children did not show an increase in beta activity. In both groups, the beta power correlated with mentalization, suggesting that this specific neuronal mechanism is involved in mentalization, which used during social interaction. (C) 2018 Elsevier Ltd. All rights reserved.
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    Better overall survival in patients who achieve pathological complete response after neoadjuvant chemotherapy for breast cancer in a Chilean public hospital
    (2021) Acevedo, Francisco; Petric, Militza; Walbaum, Benjamin; Robin, Julieta; Legorburu, Luisa; Murature, Geraldine; Guerra, Constanza; Navarro, Marisel; Canovas, María José; Sanchez, Cesar; Vargas, Lorena; Manzor, Manuel; Peña, José; Muñiz, Sabrina; Veglia, Paulina; Cartes, Raúl; Martinez, Raúl
    Introduction: There is extensive evidence associating the response to neoadjuvant chemotherapy (NeoCT) with breast cancer (BC) survival. However, to the author’s knowledge, there is no published data in Chile. The objective of the study is to evaluate whether achieving pathological complete response (pCR) after NeoCT is associated with greater survival and lower risk of recurrence in a Chilean Public Health Service. Methods: Retrospective analysis of a database. Patients with a diagnosis of Stages I–III BC who received NeoCT between 2009 and 2019 were included. Clinical and pathological information were extracted from the clinical records. BC subtypes were defined using hormone receptor (HR) information (HR: oestrogen and/or progesterone) and epidermal growth factor type 2 (HER2), being divided into four groups: HR /HER2−, HR /HER2 , HR−/HER2 , HR-/HER2−. pCR was defined as the absence of invasive cancer in the breast and axilla (ypT0/is N0) after NeoCT. Results: Of 3,092 patients, 17.2% received NeoCT. Of these, 40.2% corresponded to HR /HER2−, 20.9% HR /HER2 , 18.2% HR−/HER2 and 20.7% HR−/HER2−. Overall, 24.8% achieved pCR, being the lowest for HR /HER2− (10.3%) and the highest for HR−/HER2 (53.2%). In the multivariable analysis, family history, HER2 and type of chemotherapy were associated with a greater probability of pCR. With a median follow-up of 40 months, the overall survival and metastasis-free survival (MFS) at 3 years were greater for the group with pCR compared to that which did not achieve it (90.5% versus 76.7%, p = 0.03 and 88.5% versus 71.4%, p = 0.003, respectively). The multivariable analysis confirmed this finding. Brain MFS was similar in both groups. Conclusion: NeoCT is associated with greater pCR in aggressive BC subtypes. In those, achieving pCR was associated with better survival in our study. To the author’s knowledge, this is the first study which evaluates the relation between pCR and BC subtypes in a Chilean public hospital.
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    Differences in cortical processing of facial emotions in broader autism phenotype
    (2022) Soto-Icaza, Patricia; Beffara-Bret, Brice; Vargas, Lorena; Aboitiz, Francisco; Billeke, Pablo
    Autism Spectrum Disorder (ASD) is a heterogeneous condition that affects face perception. Evidence shows that there are differences in face perception associated with the processing of low spatial frequency (LSF) and high spatial frequency (HSF) of visual stimuli between non-symptomatic relatives of individuals with autism (broader autism phenotype, BAP) and typically developing individuals. However, the neural mechanisms involved in these differences are not fully understood. Here we tested whether face-sensitive event related potentials could serve as neuronal markers of differential spatial frequency processing, and whether these potentials could differentiate non-symptomatic parents of children with autism (pASD) from parents of typically developing children (pTD). To this end, we performed electroencephalographic recordings of both groups of parents while they had to recognize emotions of face pictures composed of the same or different emotions (happiness or anger) presented in different spatial frequencies. We found no significant differences in the accuracy between groups but lower amplitude modulation in the Late Positive Potential activity in pASD. Source analysis showed a difference in the right posterior part of the superior temporal region that correlated with ASD symptomatology of the child. These results reveal differences in brain processing of recognition of facial emotion in BAP that could be a precursor of ASD.