N170 ERPs could represent a logographic processing strategy in visual word recognition

The effect of inter-letter spacing on the N170 during visual word recognition: An event-related potentials experiment

Previous behavioral studies have shown that inter-letter spacing affects visual word recognition and reading. While condensed spacing may hinder the early stages of letter encoding because of increased crowding effects, the impact of expanded inter-letter spacing is still unclear. To examine the electrophysiological signature of inter-letter spacing on visual word recognition, we presented words in three different inter-letter spacing conditions (default, condensed [-1.5 points] or expanded [+1.5 points]) in an event-related potentials go/no-go semantic categorization task. Our focus was on the N170, an event-related potentials component associated with the early encoding of orthographic information, which also is sensitive to crowding effects. Results revealed that the N170 amplitude reached the largest values for the condensed condition than for the default and expanded spacing conditions, which did not differ. While increased crowding impacted the early encoding of orthographic information, extra letter spacing (compared with default spacing) did not. This outcome is consistent with the Modified Receptive Field hypothesis, in which letter receptors adapt their size to cope with letter crowding. These findings reveal that reducing the space between letters more than the default spacing impairs the ability to process written words, whereas slightly expanding the space between letters does not provide any additional benefit.

Electrophysiological markers of orthographic pattern learning in school-aged children with reading challenges: An ERP investigation

BACKGROUND

Previous studies suggested that children with reading difficulty have impaired statistical learning ability in extracting distributional orthographic regularities. However, the neural mechanisms underlying have not been fully investigated.

AIMS

The current study aimed to identify the electrophysiological markers and to examine the neural underpinnings of statistical learning of orthographic regularities in children with reading difficulties.

METHODS AND PROCEDURES

Using the event-related potentials (ERPs) and the orthographic learning task, 157 children were exposed to a sequence of artificial pseudocharacters with varying levels of positional and semantic consistency (low at 60 %, moderate at 80 %, and high at 100 %).

OUTCOMES AND RESULTS

Poor readers elicited an increased N170 response in the low consistency and a lack of left-lateralized P300 effect when learning positional regularities of radicals. Similarly, larger N170 effects were observed in poor readers, while similar N400 effects were found in both poor and average readers when learning semantic regularities of radicals.

CONCLUSIONS AND IMPLICATIONS

Our findings indicate that poor readers may have trouble using statistical information for early-stage orthographic pattern extraction, yet they can identify semantic inconsistencies after sufficient exposure. These results deepen our understanding of the neural mechanisms involved in statistical learning for poor readers and aid in improving criteria for differentiating between typically developing children and those with reading challenges.

Social anxiety modulating early processing for social threat words: an ERP study

Even though some recent research revealed individuals with HSA typically display enhanced processing in the early stages of emotional information processing due to hypervigilance and vulnerability to negative stimuli, it is still unclear whether social anxiety affects the time course underlying processing bias for emotional stimuli. Therefore, the present study aimed to explore the early stage of processing social threat stimuli in high social anxiety (HSA) individuals by recording RTs and EEG data in the emotional Stroop task. Behavioral data showed that the HSA group responded to the threat words faster than neutral words (i.e. negative bias), but no emotional effects in the low social anxiety (LSA) group. Although the P1 component did not show any early effects, ERP data exhibited an enhanced N170 for HSA than for LSA groups. Threat words elicited larger N170 than neutral words in the LSA group only; this emotion effect was not evident in the HSA group. These findings indicated that social anxiety modulates early processing for social threat words. This study revealed the neural mechanisms underlying early emotional processing in individuals with social anxiety, providing insights for the evaluation and intervention of social anxiety.

Music literacy improves reading skills via bilateral orthographic development

Considerable evidence suggests that musical education induces structural and functional neuroplasticity in the brain. This study aimed to explore the potential impact of such changes on word-reading proficiency. We investigated whether musical training promotes the development of uncharted orthographic regions in the right hemisphere leading to better reading abilities. A total of 60 healthy, right-handed culturally matched professional musicians and controls took part in this research. They were categorised as normo-typical readers based on their reading speed (syl/sec) and subdivided into two groups of relatively good and poor readers. High density EEG/ERPs were recorded while participants engaged in a note or letter detection task. Musicians were more fluent in word, non-word and text reading tests, and faster in detecting both notes and words. They also exhibited greater N170 and P300 responses, and target-non target differences for words than controls. Similarly, good readers showed larger N170 and P300 responses than poor readers. Increased reading skills were associated to a bilateral activation of the occipito/temporal cortex, during music and word reading. Source reconstruction also showed a reduced activation of the left fusiform gyrus, and of areas devoted to attentional/ocular shifting in poor vs. good readers, and in controls vs. musicians. Data suggest that music literacy acquired early in time can shape reading circuits by promoting the specialization of a right-sided reading area, whose activity was here associated with enhanced reading proficiency. In conclusion, music literacy induces measurable neuroplastic changes in the left and right OT cortex responsible for improved word reading ability.

Language Experience Modulates the Visual N200 Response for Disyllabic Chinese Words: An Event-Related Potential Study

Prior event-related potential (ERP) research on how the brain processes non-alphabetic scripts like Chinese has identified an N200 component related to early visual processing of Chinese disyllabic words. An enhanced N200 response was observed when similar prime-target pairs were presented, but it was not elicited when native Chinese speakers read Korean Hangul, a script resembling Chinese characters. This led to the proposal that N200 was not a universal marker for orthographic processing but rather specific and unique to Chinese. However, there was uncertainty due to the absence of Korean participants in the previous research. The impact of language experience on N200 remains unclear. To address this, the present pilot ERP study included three adult groups (totaling 30 participants) with varying language proficiency levels. The participants judged if randomly presented words were Chinese or Korean, while the ERP responses were recorded. The behavioral data showed high accuracy across the groups. The reaction times differed between the groups with the native speakers responding faster. The N200 patterns varied across the groups. Both Chinese native speakers and Chinese-as-second-language learners showed stronger N200 responses for Chinese words compared to Korean words regardless of whether an adaptive or a fixed-time window was used for the N200 quantification, but this was not the case for Korean native speakers. Our cross-linguistic study suggests that N200 is not exclusive to Chinese orthography. Instead, it reflects general visual processing sensitive to both orthographic features and learning experience.

Effect of retrieval reward on episodic recognition with different difficulty: ERP evidence

Previous studies found that the reward effect is stronger in more difficult retrieval tasks of item memory. However, it remains unclear whether the effect of reward is influenced by the memory task difficulty level in the source memory. We investigated the effects and neural mechanisms of the processing depth during encoding and rewards at retrieval on the item and source memory using event-related potentials (ERPs). Participants were required to carry out the congruity-judgment (deep processing) and size-judgment (shallow processing) tasks during encoding, and they completed separate object and background tests (half presented with reward) immediately after encoding. The results revealed that congruity-judgment (compare to size-judgment) task had longer response time in encoding phase, and evoked significantly greater reward differences at Prs (the hit rate minus the false alarm rate) in item retrieval, and the reward (relative to no reward) significantly improved recognition accuracy in source retrieval. ERP results also showed that congruity-judgment (compare to size-judgment) task evoked the larger N170, P3a, LPP and a decreased P3b of the stimuli in encoding phase, and elicited the wider distribution of LPC and LPN reward effects (i.e., the average amplitudes under the reward condition were significantly more positive than under the non-reward condition) in item retrieval, and the reward effects at FN400, LPC, and LPN were found only in the congruity-judged items with optimal difficulty in source retrieval. The results suggest that reward at retrieval evoked a greater boost in the congruity-judged stimuli, whether in item or source retrieval, which maybe be related to their optimal retrieval difficulty (Pr is closer to medium 0.50). This meant that the reward is more effective in memory retrieval with optimal difficulty.

Behavioral and electrophysiological analyses of written word processing in spoken and literary Arabic: New insights into the diglossia question

Diglossia in Arabic describes the existence and the use of two varieties of the same language: spoken Arabic (SA) and literary Arabic (LA). SA, the dialect first spoken by Arabic native speakers, is used in non‐formal situations for everyday conversations, and varies from one region to another in the Arabic world. LA, acquired later in life when the children learn to read and write at school, is used for formal purposes such as media, speeches in public and religious sermons. Previous research showed that, in the auditory modality, SA words are processed faster than LA ones. In the visual modality, written LA words are processed faster than SA ones, the latter comparing with low‐frequency words. This study analysed event‐related potentials (ERPs) during the processing of high‐frequency (LAHF), LA low‐frequency (LALF) and SA high‐frequency words (SAHF) in a visual lexical decision task. Faster reaction times were observed for LAHF, followed by SAHF and then by LALF. ERPs showed a modulation of the early components starting from the P100 component and of the late P600 component, supposedly related to memory processes. These findings, indicating that processing written SAHF words was largely comparable with processing of LALF, are discussed in the context of Arabic diglossia.

Brain Source Correlates of Speech Perception and Reading Processes in Children With and Without Reading Difficulties

Neural correlates in reading and speech processing have been addressed extensively in the literature. While reading skills and speech perception have been shown to be associated with each other, their relationship remains debatable. In this study, we investigated reading skills, speech perception, reading, and their correlates with brain source activity in auditory and visual modalities. We used high-density event-related potentials (ERPs), fixation-related potentials (FRPs), and the source reconstruction method. The analysis was conducted on 12–13-year-old schoolchildren who had different reading levels. Brain ERP source indices were computed from frequently repeated Finnish speech stimuli presented in an auditory oddball paradigm. Brain FRP source indices were also computed for words within sentences presented in a reading task. The results showed significant correlations between speech ERP sources and reading scores at the P100 (P1) time range in the left hemisphere and the N250 time range in both hemispheres, and a weaker correlation for visual word processing N170 FRP source(s) in the posterior occipital areas, in the vicinity of the visual word form areas (VWFA). Furthermore, significant brain-to-brain correlations were found between the two modalities, where the speech brain sources of the P1 and N250 responses correlated with the reading N170 response. The results suggest that speech processes are linked to reading fluency and that brain activations to speech are linked to visual brain processes of reading. These results indicate that a relationship between language and reading systems is present even after several years of exposure to print.

Neural Correlates of Handwriting Effects in L2 Learners

Learning to write involves integrating motor production and visual perception to develop orthographic representations. This study tries to test the effect of hand movement training as a pathway to neural correlates for L2 Chinese and L2 English readers. Twenty L2 Chinese and 20 L2 English (n = 20) adults participated in both behavioral and electroencephalogram (EEG) experiments. We designed six learning conditions: Hand Writing Chinese (HC), Viewing Chinese (VC), Drawing followed by Character Recognition in Chinese (DC), Hand Writing English (HE), Viewing English (VE), and Drawing followed by Word Recognition in English (DE). Behavioral and EEG results demonstrated that drawing facilitated visual word recognition in Chinese compared to viewing. The findings imply that hand movement could strengthen the neural processing and improve behavioral performance in Chinese character recognition for L2 Chinese learners and English word recognition for L2 Chinese learners. Furthermore, N170 amplitude at the drawing condition was positively correlated with N400 amplitudes. Thus, the early visual word recognition neural indicator (e.g., N170) was predictive of the late neural indicator of semantic processing (e.g., N400), suggesting that hand movement facilitates the neural correlates between early word recognition and later comprehension.

Typical and Atypical Development of Visual Expertise for Print as Indexed by the Visual Word N1 (N170w): A Systematic Review

The visual word N1 (N170w) is an early brain ERP component that has been found to be a neurophysiological marker for print expertise, which is a prelexical requirement associated with reading development. To date, no other review has assimilated existing research on reading difficulties and atypical development of processes reflected in the N170w response. Hence, this systematic review synthesized results and evaluated neurophysiological and experimental procedures across different studies about visual print expertise in reading development. Literature databases were examined for relevant studies from 1995 to 2020 investigating the N170w response in individuals with or without reading disorders. To capture the development of the N170w related to reading, results were compared between three different age groups: pre-literate children, school-aged children, and young adults. The majority of available N170w studies (N = 69) investigated adults (n = 31) followed by children (school-aged: n = 21; pre-literate: n = 4) and adolescents (n = 1) while some studies investigated a combination of these age groups (n = 12). Most studies were conducted with German-speaking populations (n = 17), followed by English (n = 15) and Chinese (n = 14) speaking participants. The N170w was primarily investigated using a combination of words, pseudowords, and symbols (n = 20) and mostly used repetition-detection (n = 16) or lexical-decision tasks (n = 16). Different studies posed huge variability in selecting electrode sites for analysis; however, most focused on P7, P8, and O1 sites of the international 10–20 system. Most of the studies in adults have found a more negative N170w in controls than poor readers, whereas in children, the results have been mixed. In typical readers, N170w ranged from having a bilateral distribution to a left-hemispheric dominance throughout development, whereas in young, poor readers, the response was mainly right-lateralized and then remained in a bilateral distribution. Moreover, the N170w latency has varied according to age group, with adults having an earlier onset yet with shorter latency than school-aged and pre-literate children. This systematic review provides a comprehensive picture of the development of print expertise as indexed by the N170w across age groups and reading abilities and discusses theoretical and methodological differences and challenges in the field, aiming to guide future research.

Curved vs. Straight-Line Handwriting Effects on Word Recognition in Typical and Dyslexic Readers Across Chinese and English

Handwriting serves to link auditory and motor routines with visual word processing, which is a hallmark of successful reading. The current study aims to explore the effect of multisensory integration as a pathway to neural specialization for print among typical and dyslexic readers across writing systems. We identified 9-10-year-old dyslexic Chinese children (n = 24) and their typically developing counterparts (n = 24) on whom we conducted both behavioral and electroencephalogram (EEG) experiments. We designed four learning conditions: Handwriting Chinese (HC), Viewing Chinese (VC), Drawing followed by Character Recognition in Chinese (D-C), and Drawing followed by Word Recognition in English (D-E). In both handwriting and drawing conditions, we also designed curved vs. straight-line stimuli. Both behavioral and EEG results showed that handwriting straight line strokes facilitated visual word recognition in Chinese compared to handwriting curved lines. Handwriting conditions resulted in a lateralization of the N170 in typical readers, but not the dyslexic readers. Interestingly, drawing curved lines facilitate word recognition in English among dyslexic readers. Taken together, the results of the study suggest benefits of handwriting on the neural processing and behavioral performance in response to Chinese character recognition and curved-line drawing effects on English word recognition among dyslexic readers. But the lack of handwriting effects in dyslexic readers suggest that students who have deficits in reading may also be missing the link between multisensory integration and word recognition in the visual word form areas. The current study results have implications for maintaining handwriting practices to promote perception and motor integration for visual word form area development for normal readers and suggest that drawing practices might benefit Chinese dyslexic readers in reading English.

Words as Visual Objects: Neural and Behavioral Evidence for High-Level Visual Impairments in Dyslexia

Developmental dyslexia is defined by reading impairments that are disproportionate to intelligence, motivation, and the educational opportunities considered necessary for reading. Its cause has traditionally been considered to be a phonological deficit, where people have difficulties with differentiating the sounds of spoken language. However, reading is a multidimensional skill and relies on various cognitive abilities. These may include high-level vision—the processes that support visual recognition despite innumerable image variations, such as in viewpoint, position, or size. According to our high-level visual dysfunction hypothesis, reading problems of some people with dyslexia can be a salient manifestation of a more general deficit of high-level vision. This paper provides a perspective on how such non-phonological impairments could, in some cases, cause dyslexia. To argue in favor of this hypothesis, we will discuss work on functional neuroimaging, structural imaging, electrophysiology, and behavior that provides evidence for a link between high-level visual impairment and dyslexia.

Whole-object effects in visual word processing: Parallels with and differences from face recognition

Visual words and faces differ in their structural properties, but both are objects of high expertise. Holistic processing is said to characterize expert face recognition, but the extent to which whole-word processes contribute to word recognition is unclear, particularly as word recognition is thought to proceed by a component-based process. We review the evidence for experimental effects in word recognition that parallel those used to support holistic face processing, namely inversion effects, the part-whole task, and composite effects, as well as the status of whole-word processing in pure alexia and developmental dyslexia, contrasts between familiar and unfamiliar languages, and the differences between handwriting and typeset font. The observations support some parallels in whole-object influences between face and visual word recognition, but do not necessarily imply similar expert mechanisms. It remains to be determined whether and how the relative balance between part-based and whole-object processing differs for visual words and faces.

Effect of Handwriting on Visual Word Recognition in Chinese Bilingual Children and Adults

In a digital era that neglects handwriting, the current study is significant because it examines the mechanisms underlying this process. We recruited 9- to 10-year-old Chinese children (n = 24), who were at an important period of handwriting development, and adult college students (n = 24), for both behavioral and electroencephalogram (EEG) experiments. We designed four learning conditions: handwriting Chinese (HC), viewing Chinese (VC), drawing shapes followed by Chinese recognition (DC), and drawing shapes followed by English recognition (DE). Both behavioral and EEG results showed that HC facilitated visual word recognition compared to VC, and behavioral results showed that HC facilitated visual word recognition compared to drawing shapes. HC and VC resulted in a lateralization of the N170 in adults, but not in children. Taken together, the results of the study suggest benefits of handwriting on the neural processing and behavioral performance in response to Chinese characters. The study results argue for maintaining handwriting practices to promote the perception of visual word forms in the digital age.

ERP evidence for asymmetric orthographic transfer between traditional and simplified Chinese

Transferring orthographic processing skills from one language to new languages is important for language learning. However, the specific orthography hypothesis and condition-based transfer hypothesis have debated orthographic transfer. No study has ever examined these debates in a logographic language, and the neural correlates of orthographic transfer in a logographic language remain unknown. Therefore, the present study uses event-related potentials to examine orthographic transfer with Hong Kong (Experiment 1) and mainland China (Experiment 2) participants who only use traditional or simplified Chinese, respectively. The participants sequentially read two of the same (repetition) or different (nonrepetition) traditional or simplified Chinese characters and judged whether they were identical. The results showed that the orthography-related N200 component was smaller in the repetition condition than in the nonrepetition condition. Importantly, for traditional Chinses users, this effect was more salient in traditional Chinese than in simplified Chinese, suggesting limited transfer from traditional to simplified Chinese. For simplified Chinese users, this effect was comparable in traditional and simplified Chinese, suggesting a smooth transfer from simplified to traditional Chinese. The results supported the condition-based transfer hypothesis, and showed asymmetric transfer between simple orthographic rules and complex ones. That is, simple orthographic rules can be transferred to complex ones smoothly, but not vice versa.

Attentional and emotional brain response to message framing in context of green marketing

Background

Message framing plays an important role in advertising strategies and has been studied from various perspectives in different behavioral studies.

New method

This study employs the event-related potential technique to examine attentional and emotional brain processing as influenced by message framing in the context of green marketing.

Results

The behavioral results demonstrated that purchase preference was higher under positive framing compared to negative and neutral framing.

As per the event-related potential results, negative framing elicited a larger P1 component, which reveals that in the first stage of processing information, threatening information attracted more attention. In the second and third stage, N170 and P3, respectively, were higher for positive framing, demonstrating that there was more attention toward the processing of non-threatening emotional information.

Comparison with existing method: Message Framing has been previously examined with behavioral methods. We for the first time examined it with a neuroscientific method like Event Related Brain Potential technique in a green marketing context.

Conclusion

Our results compared to behavioral studies provide stronger evidence from underlying neural perspective for how message framing can be affected by attentional and emotional brain responses in the context of green marketing.

Multiple routes to word recognition: evidence from event-related potentials

We used event-related potentials to determine whether lexical access during semantic processing is achieved solely by the letter-based route, or by both a letter-based and word-based route. Participants determined whether words were related or unrelated to a prespecified category. To disrupt the word-based route (i.e., disrupt the processing of overall word shape), we manipulated case type. We measured the N170, assumed to be an index of holistic processing, and the N400, an index of semantic activation. Surprisingly, mixed-case words elicited a larger N170 effect than either consistent lowercase words (Experiment 1) or consistent uppercase words (Experiment 2). The N400, meanwhile, was unaffected by case mixing. In contrast, LEET words (e.g., T4BL3 instead of TABLE), which preserve overall word shape but distort letter shape, increased the N400 but did not reduce the N170 (Experiment 3). The results indicate that the N170 is in fact not a reliable index of holistic word processing. Implications for word recognition models are discussed.

Development of neural specialization for print: Evidence for predictive coding in visual word recognition

How a child's brain develops specialization for print is poorly understood. One longstanding account is selective neuronal tuning to regularity of visual-orthographic features, which predicts a monotonically increased neural activation for inputs with higher regularity during development. However, we observed a robust interaction between a stimulus' orthographic regularity (bottom-up input) and children's lexical classification ability (top-down prediction): N1 response, which is the first negative component of the event-related potential (ERP) occurring at posterior electrodes, was stronger to lower-regularity stimuli, but only in children who were less efficient in lexically classifying these stimuli (high prediction error). In contrast, N1 responses were reduced to lower-regularity stimuli in children who showed high efficiency of lexical classification (low prediction error). The modulation of children's lexical classification efficiency on their neural responses to orthographic stimuli supports the predictive coding account of neural processes of reading.

Familiarity with visual forms contributes to a left-lateralized and increased N170 response for Chinese characters

While skilled readers produce an increased and left-lateralized event-related-potential (ERP) component, known as N170, for strings of letters compared to strings of less familiar units, it remains unclear whether perceptual familiarity plays an important role in driving the increased and left-lateralized N170 for print. The present study addressed this issue by examining N170 responses for regular Chinese characters and cursive Chinese characters which are visually less familiar regarding their form, yet with phonological and semantic properties. Stroke combinations, which are with unfamiliar visual form and without phonological or semantic properties, were used as low-level control stimuli. Twenty college students (22.6 ± 1.2 years) were examined. A content-irrelevant color matching task was used to control for differences of attention load across familiar and unfamiliar stimuli. A left-lateralized N170 was evoked only by regular characters, but not by cursive characters or stroke combinations. Moreover, cursive characters, which are principally readable but visually unfamiliar, produced a lower N170 than regular characters, and no N170 difference was found compared with stroke combinations. These results suggest that visual form familiarity serves as an important driver for the increased and left-lateralized N170 response.

Visual expertise for print in schizophrenia: Analysis of the N170 component

Reading deficits have been reported for patients suffering from schizophrenia namely, specific phonological processing deficits. Phonological processing skills are crucial in the learning-to-read process as they are necessary to develop visual expertise for print, which reflects the neural specialization for print. The present study is the first to test visual expertise for print in patients suffering from schizophrenia by measuring the N170 component. Patients and pair-matched healthy control participants performed a lexical decision task, in which words and symbols were presented. As expected, larger N170 amplitudes to word than to control stimuli were observed at the left occipito-temporal site PO7 but not at the PO8. More importantly, the modulation of the N170 as a function of the stimulus and hemisphere did not vary between patients and controls. This result suggests preserved visual expertise for print processing in patients suffering from schizophrenia.

Neural Correlates of Emotion Processing in Word Detection Task

In our previous study, we have proposed a three-stage model of emotion processing; in the current study, we investigated whether the ERP component may be different when the emotional content of stimuli is task-irrelevant. In this study, a dual-target rapid serial visual presentation (RSVP) task was used to investigate how the emotional content of words modulates the time course of neural dynamics. Participants performed the task in which affectively positive, negative, and neutral adjectives were rapidly presented while event-related potentials (ERPs) were recorded from 18 undergraduates. The N170 component was enhanced for negative words relative to positive and neutral words. This indicates that automatic processing of negative information occurred at an early perceptual processing stage. In addition, later brain potentials such as the late positive potential (LPP) were only enhanced for positive words in the 480-580-ms post-stimulus window, while a relatively large amplitude signal was elicited by positive and negative words between 580 and 680 ms. These results indicate that different types of emotional content are processed distinctly at different time windows of the LPP, which is in contrast with the results of studies on task-relevant emotional processing. More generally, these findings suggest that a negativity bias to negative words remains to be found in emotion-irrelevant tasks, and that the LPP component reflects dynamic separation of emotion valence.

Print-specific N170 involves multiple subcomponents for Japanese Hiragana

Print-specific N170 in event-related potentials is generally considered to reflect relatively automatic processing for letter strings, which is crucial for fluent reading. However, our previous studies demonstrated that print-specific N170 for transparent Japanese Hiragana script consists of at least two subcomponents under rapid stimulus presentation: an attention-related left-lateralized N170 and a bilateral N170 associated with more automatic orthographic processes (Okumura, Kasai & Murohashi, 2014, 2015). The present study aimed to confirm the latter component by controlling presentation frequency of letters and nonlinguistic visual controls (i.e., symbols), but found a quite different pattern of results; an enhanced occipito-temporal positivity for words (80-120ms poststimulus) followed by the typical left-lateralized N170 and an enhanced parietal negativity for nonwords (150-200ms). These results should provide further insights into the interaction processes between attention and early stages of print processing.

The Limited Impact of Exposure Duration on Holistic Word Processing

The current study explored the impact of stimuli exposure duration on holistic word processing measured by the complete composite paradigm (CPc paradigm). The participants were asked to match the cued target parts of two characters which were presented for either a long (600 ms) or a short duration (170 ms). They were also tested by two popular versions of the CPc paradigm: the “early-fixed” task where the attention cue was visible from the beginning of each trial at a fixed position, and the “delayed-random” task where the cue showed up after the study character at random locations. The holistic word effect, as indexed by the alignment × congruency interaction, was identified in both tasks and was unaffected by the stimuli duration in both tasks. Meanwhile, the “delayed-random” task did not bring about larger holistic word effect than the “early-fixed” task. These results suggest the exposure duration (from around 150 to 600 ms) has a limited impact on the holistic word effect, and have methodological implications for experiment designs in this field.

Resolving the locus of cAsE aLtErNaTiOn effects in visual word recognition: Evidence from masked priming

Determining the factors that modulate the early access of abstract lexical representations is imperative for the formulation of a comprehensive neural account of visual-word identification. There is a current debate on whether the effects of case alternation (e.g., tRaIn vs. train) have an early or late locus in the word-processing stream. Here we report a lexical decision experiment using a technique that taps the early stages of visual-word recognition (i.e., masked priming). In the design, uppercase targets could be preceded by an identity/unrelated prime that could be in lowercase or alternating case (e.g., table-TABLE vs. crash-TABLE; tAbLe-TABLE vs. cRaSh-TABLE). Results revealed that the lowercase and alternating case primes were equally effective at producing an identity priming effect. This finding demonstrates that case alternation does not hinder the initial access to the abstract lexical representations during visual-word recognition.

N170 changes reflect competition between faces and identifiable characters during early visual processing

According to the neuronal recycling hypothesis, brain circuits can gain new functions through cultural learning, which are distinct from their evolutionarily established functions, creating competition between processes such as facial and identifiable character processing. In the present study, event-related potential (ERP) recording was used to examine electrophysiological correlates of identification levels of Chinese characters as well as the competition between facial and Chinese character processing after the characters were learnt. Twenty volunteers performed a lateralized face detection task, and N170 responses were recorded when the participants viewed only Chinese characters (identifiable or unidentifiable in Xiaozhuan font), or Chinese characters and faces concurrently. Viewing identifiable Chinese characters bilaterally elicited larger N170 amplitudes than viewing unidentifiable ones. N170 amplitudes in response to faces bilaterally declined when identifiable Chinese characters and faces were viewed concurrently as compared to viewing unidentifiable Chinese characters and faces concurrently. These results indicate that the N170 component is modulated by the observer's identification level of Chinese characters, and that identifiable Chinese characters compete with faces during early visual processing.

Emotional noun processing: an ERP study with rapid serial visual presentation

Reading is an important part of our daily life, and rapid responses to emotional words have received a great deal of research interest. Our study employed rapid serial visual presentation to detect the time course of emotional noun processing using event-related potentials. We performed a dual-task experiment, where subjects were required to judge whether a given number was odd or even, and the category into which each emotional noun fit. In terms of P1, we found that there was no negativity bias for emotional nouns. However, emotional nouns elicited larger amplitudes in the N170 component in the left hemisphere than did neutral nouns. This finding indicated that in later processing stages, emotional words can be discriminated from neutral words. Furthermore, positive, negative, and neutral words were different from each other in the late positive complex, indicating that in the third stage, even different emotions can be discerned. Thus, our results indicate that in a three-stage model the latter two stages are more stable and universal.

The cannabinoid system and visual processing: a review on experimental findings and clinical presumptions

Cannabis is one of the most prevalent drugs used worldwide. Regular cannabis use is associated with impairments in highly integrative cognitive functions such as memory, attention and executive functions. To date, the cerebral mechanisms of these deficits are still poorly understood. Studying the processing of visual information may offer an innovative and relevant approach to evaluate the cerebral impact of exogenous cannabinoids on the human brain. Furthermore, this knowledge is required to understand the impact of cannabis intake in everyday life, and especially in car drivers. Here we review the role of the endocannabinoids in the functioning of the visual system and the potential involvement of cannabis use in visual dysfunctions. This review describes the presence of the endocannabinoids in the critical stages of visual information processing, and their role in the modulation of visual neurotransmission and visual synaptic plasticity, thereby enabling them to alter the transmission of the visual signal. We also review several induced visual changes, together with experimental dysfunctions reported in cannabis users. In the discussion, we consider these results in relation to the existing literature. We argue for more involvement of public health research in the study of visual function in cannabis users, especially because cannabis use is implicated in driving impairments.

Visual and auditory synchronization deficits among dyslexic readers as compared to non-impaired readers: a cross-correlation algorithm analysis

Visual and auditory temporal processing and crossmodal integration are crucial factors in the word decoding process. The speed of processing (SOP) gap (Asynchrony) between these two modalities, which has been suggested as related to the dyslexia phenomenon, is the focus of the current study. Nineteen dyslexic and 17 non-impaired University adult readers were given stimuli in a reaction time (RT) procedure where participants were asked to identify whether the stimulus type was only visual, only auditory or crossmodally integrated. Accuracy, RT, and Event Related Potential (ERP) measures were obtained for each of the three conditions. An algorithm to measure the contribution of the temporal SOP of each modality to the crossmodal integration in each group of participants was developed. Results obtained using this model for the analysis of the current study data, indicated that in the crossmodal integration condition the presence of the auditory modality at the pre-response time frame (between 170 and 240 ms after stimulus presentation), increased processing speed in the visual modality among the non-impaired readers, but not in the dyslexic group. The differences between the temporal SOP of the modalities among the dyslexics and the non-impaired readers give additional support to the theory that an asynchrony between the visual and auditory modalities is a cause of dyslexia.

Orthographic recognition in late adolescents: an assessment through event-related brain potentials

Reading speed and efficiency are achieved through the automatic recognition of written words. Difficulties in learning and recognizing the orthography of words can arise despite reiterative exposure to texts. This study aimed to investigate, in native Spanish-speaking late adolescents, how different levels of orthographic knowledge might result in behavioral and event-related brain potential differences during the recognition of orthographic errors. Forty-five healthy high school students were selected and divided into 3 equal groups (High, Medium, Low) according to their performance on a 5-test battery of orthographic knowledge. All participants performed an orthographic recognition task consisting of the sequential presentation of a picture (object, fruit, or animal) followed by a correctly, or incorrectly, written word (orthographic mismatch) that named the picture just shown. Electroencephalogram (EEG) recording took place simultaneously. Behavioral results showed that the Low group had a significantly lower number of correct responses and increased reaction times while processing orthographical errors. Tests showed significant positive correlations between higher performance on the experimental task and faster and more accurate reading. The P150 and P450 components showed higher voltages in the High group when processing orthographic errors, whereas N170 seemed less lateralized to the left hemisphere in the lower orthographic performers. Also, trials with orthographic errors elicited a frontal P450 component that was only evident in the High group. The present results show that higher levels of orthographic knowledge correlate with high reading performance, likely because of faster and more accurate perceptual processing, better visual orthographic representations, and top-down supervision, as the event-related brain potential findings seem to suggest.

Three stages of emotional word processing: an ERP study with rapid serial visual presentation

Rapid responses to emotional words play a crucial role in social communication. This study employed event-related potentials to examine the time course of neural dynamics involved in emotional word processing. Participants performed a dual-target task in which positive, negative and neutral adjectives were rapidly presented. The early occipital P1 was found larger when elicited by negative words, indicating that the first stage of emotional word processing mainly differentiates between non-threatening and potentially threatening information. The N170 and the early posterior negativity were larger for positive and negative words, reflecting the emotional/non-emotional discrimination stage of word processing. The late positive component not only distinguished emotional words from neutral words, but also differentiated between positive and negative words. This represents the third stage of emotional word processing, the emotion separation. Present results indicated that, similar with the three-stage model of facial expression processing; the neural processing of emotional words can also be divided into three stages. These findings prompt us to believe that the nature of emotion can be analyzed by the brain independent of stimulus type, and that the three-stage scheme may be a common model for emotional information processing in the context of limited attentional resources.

Resolving the orthographic ambiguity during visual word recognition in Arabic: an event-related potential investigation

The Arabic alphabetical orthographic system has various unique features that include the existence of emphatic phonemic letters. These represent several pairs of letters that share a phonological similarity and use the same parts of the articulation system. The phonological and articulatory similarities between these letters lead to spelling errors where the subject tends to produce a pseudohomophone (PHw) instead of the correct word. Here, we investigated whether or not the unique orthographic features of the written Arabic words modulate early orthographic processes. For this purpose, we analyzed event-related potentials (ERPs) collected from adult skilled readers during an orthographic decision task on real words and their corresponding PHw. The subjects' reaction times (RTs) were faster in words than in PHw. ERPs analysis revealed significant response differences between words and the PHw starting during the N170 and extending to the P2 component, with no difference during processing steps devoted to phonological and lexico-semantic processing. Amplitude and latency differences were found also during the P6 component which peaked earlier for words and where source localization indicated the involvement of the classical left language areas. Our findings replicate some of the previous findings on PHw processing and extend them to involve early orthographical processes.

From neural signatures of emotional modulation to social cognition: individual differences in healthy volunteers and psychiatric participants

It is commonly assumed that early emotional signals provide relevant information for social cognition tasks. The goal of this study was to test the association between (a) cortical markers of face emotional processing and (b) social-cognitive measures, and also to build a model which can predict this association (a and b) in healthy volunteers as well as in different groups of psychiatric patients. Thus, we investigated the early cortical processing of emotional stimuli (N170, using a face and word valence task) and their relationship with the social-cognitive profiles (SCPs, indexed by measures of theory of mind, fluid intelligence, speed processing and executive functions). Group comparisons and individual differences were assessed among schizophrenia (SCZ) patients and their relatives, individuals with attention deficit hyperactivity disorder (ADHD), individuals with euthymic bipolar disorder (BD) and healthy participants (educational level, handedness, age and gender matched). Our results provide evidence of emotional N170 impairments in the affected groups (SCZ and relatives, ADHD and BD) as well as subtle group differences. Importantly, cortical processing of emotional stimuli predicted the SCP, as evidenced by a structural equation model analysis. This is the first study to report an association model of brain markers of emotional processing and SCP.

How does Arabic orthographic connectivity modulate brain activity during visual word recognition: an ERP study

One of the unique features of the Arabic orthography that differentiates it from many other alphabetical ones is the fact that most letters connect obligatorily to each other. Hence, these letters change their forms according to the location in the word (i.e. beginning, middle, or end), leading to the suggestion that connectivity adds a visual load which negatively impacts reading in Arabic. In this study, we investigated the effects of the orthographic connectivity on the time course of early brain electric responses during the visual word recognition. For this purpose, we collected event-related potentials (ERPs) from adult skilled readers while performing a lexical decision task using fully connected (Cw), partially connected and non-connected words (NCw). Reaction times variance was higher and accuracy was lower in NCw compared to Cw words. ERPs analysis revealed significant amplitude and latency differences between Cw and NCw at posterior electrodes during the N170 component which implied the temporo-occipital areas. Our findings show that instead of slowing down reading, orthographic connectivity in Arabic skilled readers seems to impact positively the reading process already during the early stages of word recognition. These results are discussed in relation to previous observations in the literature.

Concurrent effects of lexical status and letter-rotation during early stage visual word recognition: evidence from ERPs

Recent studies report that the occipito-temporal N170 component of the ERP is enhanced by letter strings, relative to non-linguistic strings of similar visual complexity, with a left-lateralized distribution. This finding is consistent with underlying mechanisms that serve visual word recognition. Conclusions about the level of analysis reflected within the N170 effects, and therefore the timecourse of word recognition, have been mixed. Here, we investigated the timing and nature of brain responses to putatively low- and high-level processing difficulty. Low-level processing difficulty was modulated by manipulating letter-rotation parametrically at 0°, 22.5°, 45°, 67.5°, and 90°. Higher-level processing difficulty was modulated by manipulating lexical status (words vs. word-like pseudowords). Increasing letter-rotation enhanced the N170 led to monotonic increases in P1 and N170 amplitude up to 67.5° but then decreased amplitude at 90°. Pseudowords enhanced the N170 over left occipital-temporal sites, relative to words. These combined findings are compatible with a cascaded, interactive architecture in which lower-level analysis (e.g., word-form feature extraction) leads higher-level analysis (e.g., lexical access) in time, but that by approximately 170 ms, the brain's response to a visual word includes parallel, interactive processing at both low-level feature extraction and higher-order lexical access levels of analysis.

Does silent reading speed in normal adult readers depend on early visual processes? evidence from event-related brain potentials

Little is known about the relationship of reading speed and early visual processes in normal readers. Here we examined the association of the early P1, N170 and late N1 component in visual event-related potentials (ERPs) with silent reading speed and a number of additional cognitive skills in a sample of 52 adult German readers utilizing a Lexical Decision Task (LDT) and a Face Decision Task (FDT). Amplitudes of the N170 component in the LDT but, interestingly, also in the FDT correlated with behavioral tests measuring silent reading speed. We suggest that reading speed performance can be at least partially accounted for by the extraction of essential structural information from visual stimuli, consisting of a domain-general and a domain-specific expertise-based portion.

Facial and semantic emotional interference: a pilot study on the behavioral and cortical responses to the Dual Valence Association Task

Background

Integration of compatible or incompatible emotional valence and semantic information is an essential aspect of complex social interactions. A modified version of the Implicit Association Test (IAT) called Dual Valence Association Task (DVAT) was designed in order to measure conflict resolution processing from compatibility/incompatibly of semantic and facial valence. The DVAT involves two emotional valence evaluative tasks which elicits two forms of emotional compatible/incompatible associations (facial and semantic).

Methods

Behavioural measures and Event Related Potentials were recorded while participants performed the DVAT.

Results

Behavioural data showed a robust effect that distinguished compatible/incompatible tasks. The effects of valence and contextual association (between facial and semantic stimuli) showed early discrimination in N170 of faces. The LPP component was modulated by the compatibility of the DVAT.

Conclusions

Results suggest that DVAT is a robust paradigm for studying the emotional interference effect in the processing of simultaneous information from semantic and facial stimuli.

Early Neural Markers of Implicit Attitudes: N170 Modulated by Intergroup and Evaluative Contexts in IAT

The Implicit Association Test (IAT) is the most popular measure to evaluate implicit attitudes. Nevertheless, its neural correlates are not yet fully understood. We examined event related potentials (ERPs) in response to face- and word processing while indigenous and non-indigenous participants performed an IAT displaying faces (ingroup and outgroup members) and words (positive and negative valence) as targets of category judgments. The N170 component was modulated by valence of words and by ingroup/outgroup face categorization. Contextual effects (face–words implicitly associated in the task) had an influence on the N170 amplitude modulation. On the one hand, in face categorization, right N170 showed differences according to the association between social categories of faces and affective valence of words. On the other, in word categorization, left N170 presented a similar modulation when the task implied a negative-valence associated with ingroup faces. Only indigenous participants showed a significant IAT effect and N170 differences. Our results demonstrate an early ERP blending of stimuli processing with both intergroup and evaluative contexts, suggesting an integration of contextual information related to intergroup attitudes during the early stages of word and face processing. To our knowledge, this is the first report of early ERPs during an ethnicity IAT, opening a new branch of exchange between social neuroscience and social psychology of attitudes.

Conditions for facelike expertise with objects: becoming a Ziggerin expert--but which type?

Compared with other objects, faces are processed more holistically and with a larger reliance on configural information. Such hallmarks of face processing can also be found for nonface objects as people develop expertise with them. Is this specifically a result of expertise individuating objects, or would any type of prolonged intensive experience with objects be sufficient? Two groups of participants were trained with artificial objects (Ziggerins). One group learned to rapidly individuate Ziggerins (i.e., subordinate-level training). The other group learned rapid, sequential categorizations at the basic level. Individuation experts showed a selective improvement at the subordinate level and an increase in holistic processing. Categorization experts improved only at the basic level, showing no changes in holistic processing. Attentive exposure to objects in a difficult training regimen is not sufficient to produce facelike expertise. Rather, qualitatively different types of expertise with objects of a given geometry can arise depending on the type of training.

Category specificity in early perception: face and word n170 responses differ in both lateralization and habituation properties

N170 event-related potential (ERP) responses to both faces and visual words raises questions about category specific processing mechanisms during early perception and their neural basis. Topographic differences across word and face N170s suggests a form of category specific processing in early perception – the word N170 is consistently left-lateralized, while less consistent evidence supports a right-lateralization for the face N170. Additionally, the face N170 shows a reduction in amplitude across consecutive individual faces, a form of habituation that might differ across studies thereby helping to explain inconsistencies in lateralization. This effect remains unexplored for visual words. The current study directly contrasts N170 responses to words and faces within the same subjects, examining both category-level habituation and lateralization effects. ERP responses to a series of different faces and words were collected under two contexts: blocks that alternated faces and words vs. pure blocks of a single category designed to induce category-level habituation. Global and occipito-temporal measures of N170 amplitude demonstrated an interaction between category (words, faces) and block context (alternating categories, same category). N170 amplitude demonstrated class-level habituation for faces but not words. Furthermore, the pure block context diminished the right-lateralization of the face N170, pointing to class-level habituation as a factor that might drive inconsistencies in findings of right-lateralization across different paradigms. No analogous effect for the word N170 was found, suggesting category specificity for this form of habituation. Taken together, topographic and habituation effects suggest distinct forms of perceptual processing drive the face N170 and the visual word form N170.

Differential Lateralization for Words and Faces: Category or Psychophysics?

This set of three experiments assessed the influence of different psychophysical factors on the lateralization of the N170 event-related potential (ERP) component to words and faces. In all experiments, words elicited a left-lateralized N170, whereas faces elicited a right-lateralized or nonlateralized N170 depending on presentation conditions. Experiment 1 showed that lateralization for words (but not for faces) was influenced by spatial frequency. Experiment 2 showed that stimulus presentation time influenced N170 lateralization independently of spatial frequency composition. Finally, Experiment 3 showed that stimulus size and resolution did not influence N170 lateralization, but did influence N170 amplitude, albeit differentially for words and faces. These findings suggest that differential lateralization for words and faces, at least as measured by the N170, is influenced by spatial frequency (words), stimulus presentation time, and category.