Gabriela Romero Esquiliano

F109. An event-related brain potential study of the arithmetic skills in college students

Introduction The arithmetic is fundamental in everyday life and represent an elemental part of learning of the individuals being a tool that allows an optimal performance in the resolution of problematic situations. One of the main research objectives of human behavior is understanding of cognitive processes such as arithmetic processing through neurophysiological techniques as the Event Related Potentials (ERPs). ERPs are a series of positive or negative oscillations, result of averaging segments where visual or auditory stimuli were presented to the participant during the electroencephalogram. Arithmetic processes have been associated to the Late Positive Component (LPC) located in central-parietal regions. Methods The sample consisted of 26 participants, 17 women and 9 men, with an average age of 21.3 years (SD ± 4.4 years). The EEG was performed with the software Curry XS Neuroscan System®, using 62 Au electrodes. The original file was converted, from data format to cnt format. The obtained signal was segmented in times with an analysis window of −400 to 1600 ms, rejection of muscular and ocular artifact was made, with Independent Component Analysis. Both the verification and the production paradigms were presented on a monitor with a resolution of 1280 × 960 pixels during the EEG. The verification paradigm had a total of 80 arithmetic operations of integers with a possible response, the participant had to answer if the response showed was either correct or incorrect, to record the responses a board with two buttons was used, one button for the correct answer and one for the incorrect answer. The production paradigm had a total of 80 arithmetic operations of whole numbers, the participant had to answer verbally during a neutral stimulus. With sampling frequency of 1000 Hz. Each arithmetic operation lasted 4000 ms followed by a neutral stimulus (a point in the center of the screen) with a duration of 500 ms where the participant gave the answer. The analyses with the EEGLAB tool of the MATLAB software. The PREs of each participant were analyzed and then the average of each stimulus was made Results The right answers in the complex operations were significantly lower than the those in the simple operations x2 (1, N = 80) = 42.89, p  Conclusion There were no differences in the right answers of the participants between experimental paradigms. The type of operation and its difficulty did not affect the early ERPs however amplitude of the LPC appears to be sensitive to arithmetic production tasks.

S112. Relationship of mismatch negativity with the IQ and executive functions in school children with a history of congenital hypothyroidism. Study of cases

Introduction Congenital hypothyroidism (CH) is related to alterations in cognitive growth and development. Even with timely treatment, motor and/ or cognitive sequelae occur. Children with HC have low IQ compared to children with low biological risk; cases with atirosis (AT) have greater deficits than children with sublingual nodules (NSL). Analyzing complex cognitive processes through executive functions and mismatch negativity (MMN) will allow us to explore more deeply the alterations of the central nervous system in this syndrome. Objective- To analyze the relationship between executive functions and the mismatch negativity in school children with HC. Methods Case study, prospective and transversal. 9 children of 12 years, 4 girls (3 AT and 1 NSL) and 5 children (4 NSL and 1 AT), with initiation of hormone replacement therapy in the first 60 days of extrauterine life, attended the intervention program until the 6 years old. For the recording of auditory MMN with oddball paradigm, stimuli of 1000 Hz (80%) and 1500 Hz (20%). For the evaluation of executive functions, the neuropsychological battery ENI and the scale of intelligence Weschler for CI were used. Results In children with AT, verbal fluency, planning and organization were identified as having very low performance, children with NSL presented limit cognitive flexibility. In the IC assessment, two children with AT were borderline and 7 within the normal average. In MMN in the 9 cases there was frontal response latency with between 150 and 287 ms; 8 cases presented a central response with latencies between 157 and 315 ms. The amplitudes were variable between −.012 to −5.71  μ v. Conclusion The MMN shows late response in the discrimination of stimuli in cases with HC with a low performance EF profile and low CI.