1. Influence of lexical context on MMN in recognition linguistic stimuli: an ERP-study Memetova K., Aleksandrov A., Stankevich L. Saint Petersburg State University, St.Petersburg, Russia k.memetova@spbu.ru Abstract The present study is designed to establish how lexical context influences the mismatch negativity brain potential (MMN) latency and amplitude when the pseudowords are presented. The event related potentials (ERP) were recorded according to the multi-deviant passive odd-ball paradigm by using only pseudowords (control condition) or pseudowords with Russian words with different lexical frequencies (lexical context). We found that different patterns of MMN were generated when the same pseudoword was presented in different contexts. The pseudoword presented in context with another pseudowords demonstrated the relative small amplitude and the big latency of MMN. Whereas the same pseudoword presented in context with words led to the significantly enhanced amplitude and the decreased latency of MMN between 100-200 ms. It is supposed that the pseudoword presented in context with words is percieved as conceptually different stimulus leading to the significantly enhanced MMN. Moreover, the hypothesis of lexical frequency influence on MMN has been supported. We found that the presentation of a high-frequency word led to the significantly more pronounced MMN response relative to a low-frequency one. The high-frequency words also evoked the earlier response, indicating more rapid access to a frequently used lexical entry. The results lend further support to the strength of internal connections in a memory circuit, which in turn is determined by lexical context. We hypothesize that different amounts of activation depend on the words lexical representation strength. Keywords: the event related potentials (ERP), pseudowords, words frequency, the mismatch negativity (MMN), words, language, attention. Results We compared the ERPs elicited by two different contexts: 1) only pseudowords (control condition); 2) pseudowords with Russian words with different lexical frequencies (Fig.1) (lexical context). Physical stimuli contrasts were kept identical (Fig.2). The MMN responses were elicited by deviant items, but the critical variable determining the MMN response - the standard– deviant acoustic-phonetic contrast was identical inside one context between stumuli. No significant main effects could be found for the standard stimulus in either of the two different contexts (Fig.3 ). Event-related potentials were successfully calculated for the standard and deviant stimuli in both contexts, and mismatch negativity responses could be obtained for the all stimuli (Fig.4) We found that different patterns of MMN were generated when the same pseudoword was presented in different contexts. Moreover, the presentation of a high-frequency word led to the significantly more pronounced MMN response relative to a low-frequency one. The high- frequency words also evoked the earlier response, indicating more rapid access to a frequently used lexical entry (Fig.5 ). Conclusions The pseudoword presented in context with another pseudowords demonstrated the relative small amplitude and the big latency of MMN. Whereas the same pseudoword presented in context with words led to the significantly enhanced amplitude and the decreased latency of MMN between 100- 200 ms. It is supposed that the pseudoword presented in context with words is percieved as conceptually different stimulus leading to the significantly enhanced MMN. Moreover, the hypothesis of lexical frequency influence on MMN has been supported. The results lend further support to the strength of internal connections in a memory circuit, which in turn is determined by lexical context. We hypothesize that different amounts of activation depend on the words lexical representation strength. The work was supported by the Russian Foundation of Humanity (project # 15-06-10806) Automatic processing of unattended lexical information in visual oddball presentation: neurophysiological evidence. Y.Shtyrov, G.Goryainova, S.Tugin, A.Ossadtchi, A.Shestakova Front. Hum. Neurosci., 09 August 2013 | http://dx.doi.org/10.3389/f nhum.2013.00421 Strength of Word-Specific Neural Memory Traces Assessed Electrophysiologically Alexander A Alexandrov · Daria O Boricheva · Friedemann Pulvermüller · Yury Shtyrov · PLoS ONE 08/2011; 6(8):e22999. DOI:10.1371/journal.pone. 0022999 ESCAN The 3rd international conference of the European Society for Cognitive and Affective Neuroscience, 23-26 of June, 2016, Porto, Portugal Fig.4 Identity mismatch negativity (iMMN) elicited by standard minus deviant stimuli: a) pseudowords with Russian words with different lexical frequencies (lexical context) 1 – the pseudoword “ЧАШ” (chash), 2 - the low-frequency word, 3 - the high-frequency word. б) only pseudowords (control condition) 1 - the pseudoword “ЧАШ” (chash), 2 - the pseudoword “ЧАК” (chaк), 3 - the pseudoword “ЧАЖ” (chazh). Fig.5 Event-related potentials elicited by the pseudoword “ЧАШ” (chash): a) event-related potentials elicited by deviant stimulus: 1 – control condition; 2 - lexical context. Significant ERP was elicited by the pseudoword “ЧАШ” (chash) F(1,000) = 5,587, p = 0,026). б) Identity mismatch negativity (iMMN): deviant-standard difference curves: 1 - control condition; 2 - lexical context. Significant iMMN was elicited by by the pseudoword “ЧАШ” (chash) F(1,000) = 8,924, p = 0,006). Note the more pronounced MMN in lexical context and a smaller MMN in control condition. Fig.2 Oscillograms of stimuli: the high-frequency word “ЧАС” (hour), the low-frequency word “ЧАН” (tub) and the pseudowords “ЧАШ” (chash), “ЧАК” (chaк), “ЧАЖ” (chazh). Fig.3 Event-related potentials elicited by standard stimulus without significant statistically difference:a) pseudowords with Russian words with different lexical frequencies (lexical context) 1 – the pseudoword “ЧАШ” (chash), 2 - the low-frequency word, 3 - the high-frequency word. б) only pseudowords (control condition) 1 - the pseudoword “ЧАШ” (chash), 2 - the pseudoword “ЧАК” (chaк), 3 - the pseudoword “ЧАЖ” (chazh)