Neurocognitive Assessment: Neurocognitive assessment will be performed by a team of trained psychologist. Patients will be evaluated using classical well-validated paradigms designed to measure a set cold and hot executive functions in a touch screen interactive platform (Cold functions: sustained attention, shifting attention, response inhibition, working memory; hot functions: conditioned learning, sensibility to reward). The system allows to individualize the characteristics (response time, correct/incorrect trials, etc.) of the responses from each one of the presented stimuli, with important flexibilities for posterior data analysis. The following paradigms were pre-selected for this study: Attentional Blink,49 CPT,50 Flanker Test,51 …show more content…
Serum sphingolipids will be analyzed in the Department of Pathology and Cell Biology of Columbia University, as part of an active collaboration with Dr. Tilla S. Worgall and/or in the Laboratory of Toxicology and HPLC of the Department of Clinical Laboratories, Pontificia Universidad Católica de Chile. Sphingolipid levels will be quantified by high performance liquid chromatography-triple quadrupole-tandem mass spectrometry (HPLC-MS/MS) on an Agilent 1200 HPLC system, equipped with an Agilent C18 column as described in protocol implemented and validated by our group2. Sphingolipid profiles will include the following molecular species: 1) sphinganine-1-phosphate and sphingosine-1-phosphate; 2) Ceramides C16:0, C18:0, C20:0, C22:0, C24:0 and C24:1; dihydroceramides C18, C18:1, C24:0 and C24:1; deoxy-ceramide C16:0 and C24:1 and deoxy-dihydroceramides C16:0 and C24:1; 3) sphingomyelins (SM) SM C16:0, SM C18:0, SM C18:1 and SM C24:1. The limits of sphingolipid quantification range from 1nM for all long chain bases, including deoxy and desoxy-sphinganines and 0.01 uM for sphinganine and sphinganine-1-phosphate. All measurements will be performed in