ESTEBAN
SARRIAS ARRABAL

My research has primarily focused on characterising early cognitive deficits in neurodegenerative diseases and on identifying the associated functional brain biomarkers. Indeed, during my doctoral studies, novel attentional impairments were described in Multiple Sclerosis (MS) patients using high-density electroencephalography (EEG). Identifying the affected frequency band is crucial for determining the stimulation frequency in non-invasive neuromodulation protocols, but understanding the involved areas is equally essential. As part of my PhD training, I undertook a research stay at the University Foro Italico of Rome, where I mastered methods for reconstructing EEG brain sources. This enabled me to map the brain regions affected in MS and evaluate their potential for noninvasive neuromodulation using techniques such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS). Not all patients should receive the same stimulation protocol. Indeed, we found that different cognitive domains are affected in varying ways in MS patients. Furthermore, the intensity of cognitive impairment correlated with the changes observed in EEG oscillations. Furthermore, EEG modulations also identified which MS patients performed worse on the cognitive task. Therefore, this approach aims to identify functional biomarkers that effectively discriminate cognitive phenotypes (OB1) in neurological and neurodegenerative disease. Building on my expertise in designing psychophysical experiments, acquiring EEG data, and applying advanced signal processing techniques, I sought to expand my knowledge of psychophysiological tools to further enhance OB1. This led to join the Institute of Applied Linguistics at UCA. Here, I investigated the mechanisms involving the integration of visual and auditory stimuli during the syntactic and semantic processing in children with language disorders. I contributed to a methodologically challenging cutting-edge project, combining EEG and eye-tracker to track correlations between the visual system and brain oscillations. Additionally, I performed neuropsychological assessments and organised lab meetings to teach predoctoral students about EEG and eye-tracker (ET). Since mid-2022, I have been awarded with a postdoctoral Junta de Andalucía fellowship and JdC-Formación fellowship to work at UCA. Here, I explore the brain mechanisms underlying cognitive function and dysfunction in patients with Parkinson disease (PD) and MS. For that I use different functional techniques, such as , EEG and functional magnetic resonance imaging (fMRI) before and after TMS therapy. I am acquiring skills to reach my second and third scientific aims: applying non-invasive neuromodulation techniques for neurorehabilitation in neurological patients (OB2) and identifying functional and serum biomarkers of neurodegeneration and neuroplasticity in neurological patients (OB3) to predict the disease progression and the response to treatment with non-invasive neuromodulation. For OB2 and OB3, I conducted TMS sessions and moved to the Centre of Neuroscience of Bologna University to learn simultaneous TMS/EEG recordings. Furthermore, I lead a study combining tDCS and eye-tracker to investigate effects of tDCS on the performing working memory in young and old healthy people. Finally, I published four 1st-author articles, two 2nd-, and one 4th, 5th and 7th-author articles. Also, I have been one 1st- author and one 2nd- chapter book.