ERP Joint Of Blurriness And Font In Character Recognition

The early stage for orthographic and phonological processing in visual word recognition is a hot argument that is drawing increasing attention in different studies in various languages.And one of the most debated issues in visual word-recognition investigations is whether sub-lexical units mediate the word-recognition.First of all,large numbers of studies applied a variety of methods on languages to confirm the important role of the fist syllable in languages,especially in Spanish.Zhou et al.,suggested that the shape of characters play a critical role in character identification.And some studies found that Chinese readers are faster and more accurate in identifying characters in Song Ti font(ST)than in Xing Kai Ti font(XKT).Sun and Wang found that highly blurred stimuli produced greater N400 than lightly blurred stimuli.Furthermore,lv and Wang suggested that font effect on amplitude was analogous to degradation effect.Thence,we combined this two properties of characters to investigate if font and blurriness showed same effect on word recognition.And by following Sternberg's addictive logics,we required to investigate if any ERP components would be jointly modulated by font and blurred characters.Our relevant ERP are following components.The N170 mostly originating from occipito-temporal which is a clear spatio-temporal response pattern and an important component of the event-related potential(ERP)peaking between 130 and 200 ms,with showing an occipito-temporally negative topography and indicated by topography displays and source reconstruction analysis.Many studys have confirmed that N170 was sensitive to expertise,That is to say,the stimuli familiar to us make us respond quickly,with an enhanced N170 generated.But not all investigation demonstrate the same pattern of results.For instance,some studies on consonant strings and words have fond that consonant strings elicited larger N170 amplitudes than words which were used in our daily life.All of these results might reveal that the N170 responses are somewhat variable across studies,which might be the result of different task and presentation modes.And most importantly,the presence of N170 appeared difference in faces which was right-lateralized or bilateral and words which was a left-lateralized topography.Such dissociation showed by the processing of words and faces may be an evidence about the famous functional distinctions within our object recognition system,with left hemispheric being sensitive to words and right hemispheric to faces.But all this conclusions originate from alphabetic scrips,which might not be identified in characters.Sun and Wang examined that the location of N170 is mainly in right hemispheric,which is similar with the N170 produced by faces.Moreover,according to a study using f MRI methodologies,the ventral occipito-temporal was unique for Chinese character-preferential.All of this investigations suggest that the unique processing of characters may produce N170 that is different from the alphabetic scrips,for instance English words.P200 had been widely observed in large numbers of visual studies and affected by divers cognition tasks.It peaks at about 200 milliseconds(varying between about 150 and 275 ms),and is located around the centro-frontal and the parieto-occipital region.In the early research on attention,P200 reflect the allocation of attention resources that the more attention resources are,the more positive the P200 amplitude is.Later,P200 was also found in word recognition,early studies on English and Hebrew words have found that P200 was sensitive to the interaction between phonological and orthographic processing,with Ziegler et al.Holding different opinion.This might result from the unique of the alphabetical words.Chen et al.found that both high and low frequency visually similar pairs of Chinese characters elicited reduced P200.Kong et al.examined that phonological and orthographic processing could affect the peak of P200 in Chinese word recognition.The N250 that the occurrence of a negative-going wave that started near 175 ms ended at approximately 300 ms and produced a clear peak near 250 ms was a pre-N400 effect,which was nearly be found by Grainger et.,The N250 has a more widespread scalp distribution being largest over midline and slightly anterior left hemisphere sites.And Hcolmb and Grainger argued that it is possible that the N250 reflected the mismatch between representations at letter level that were activated by the prime stimulus and those representations receiving activation from the target.4However,Morris et al.have shown that the N250(as well as the N400,as noted above)is sensitive to semantic relatedness when primes and targets are morphologically related.Some other studies have shown that the N250 is sensitive to perceptual mismatches between prime and target stimuli of a variety of different types(e.g.,shape,color,orientation)that they have interpreted as support for their statement that �This component represents the activity of the brain for detecting cognitive information mismatches or conflicts'N400 is a negative deflection that occurs at around 400 ms post-stimulus.Caixia Lv and Quanhong Wang found that characters printed in XKT produced greater N400 than characters printed in ST.They interpreted that this N400-like font effect on amplitude was analogous to an N400 stimulus degradation effect.And Sun and Wang found that highly blurred characters produced greater N400 than lightly blurred characters.In addition,Holcomb's found latency shifts of the N400 priming effect across degraded and intact stimulus conditions in both Experiments 1 and 2,and a latency shift of the N400 lexicality effect across these conditions,but in Experiment2 only.By contrast,the study of Caixia Lv and Quanhong Wang failed to obtain any latency shift of the N400 lexicality effect(the N400 CS effect)across font conditions.We believe it is more likely that if the failure of Lv's study were interpreted as replicating Holcomb's Experiment 1 but not Experiment 2,for the different negative deflection shown in the 500�750 ms window,then the font condition might be analogous to degraded and intact conditions.Our present study is to investigate weather the N400 font effect can be analogous to the N400 degradation effect.Following Sternberg's addictive logics,the present study investigated any ERP components would be jointly modulated by font and blurriness of characters and weather the duration of prime can affect the relationship of font and blurriness in early and late ERPs,but we mainly focus on the ERPs of N250 and N400.In experiment 1,during a character-matching test,the participants were asked to decide whether the probes were the same as the proceeding targets while Event-related brain potentials(ERPs)were recorded.The target stimulus types comprised of cross-combinations of font(Song Ti and Xing Kai Ti)and blurriness(level4 and level6).The ERP results indicated that in an N170 time window of 150-200 ms,blurriness of level6 elicited greater negative peaks than level4,ST produced greater negative peaks than XKT,,this might be involved in the expertise,that is to say,we have more expertise with characters in ST than in XKT,for the degradation effect in this time window,the blurred stimuli destroyed our expertise,leading to highly blurred stimuli producing larger negativities.Most importantly,the interaction of blurriness and font was observed in an P2 time window of 160-220 ms,N250 time window of 220-300 ms and N400 time window of 350-550 ms,above all,we could believe that blurriness and font may involve in the same stage of some cognitive process.In experiment 2 we failed to find that the duration of stimuli could affect the amplitude of N250,which may caused by the duration we chose may not short enough.