Semantic parafoveal processing in natural reading: Insight from fixation-related potentials & eye movements.

Prior research suggests that we may access the meaning of parafoveal words during reading. We explored how semantic-plausibility parafoveal processing takes place in natural reading through the co-registration of eye movements (EM) and fixation-related potentials (FRPs), using the boundary paradigm. We replicated previous evidence of semantic parafoveal processing from highly controlled reading situations, extending their findings to more ecologically valid reading scenarios. Additionally, and exploring the time-course of plausibility preview effects, we found distinct but complementary evidence from EM and FRPs measures. FRPs measures, showing a different trend than EM evidence, revealed that plausibility preview effects may be long-lasting. We highlight the importance of a co-registration set-up in ecologically valid scenarios to disentangle the mechanisms related to semantic-plausibility parafoveal processing.

Socioeconomic Status, Culture, and Reading Comprehension in Immigrant Students.

Research on reading comprehension in immigrant students is heterogeneous and conflicting. Differences in socioeconomic status and cultural origins are very likely confounds in determining whether differences to native pupils can be attributed to immigrant status. We collected data on 312 Spanish students of Native, of Hispanic origin-therefore with the same family language as native students- and Non-Hispanic origin, while controlling for socioeconomic status, non-verbal reasoning and school membership. We measured reading comprehension, knowledge of syntax, sentence comprehension monitoring, and vocabulary. Differences among groups appeared only in vocabulary and syntax (with poorer performance in the non-Hispanic group), with no differences in reading comprehension. However, regression analyses showed that most of the variability in reading comprehension was predicted by age, socioeconomic status, non-verbal reasoning, and comprehension monitoring. Group membership did not significantly contribute to explain reading comprehension variability. The present study supports the idea that socioeconomically disadvantaged students, both native and immigrants from diverse cultural backgrounds, irrespective of the language of origin, are probably equally at risk of poor reading comprehension.

Improving Early Diagnosis of Child Neglect for a Better Response in Healthcare Settings.

Early diagnosis of child neglect is an ongoing challenge with consequences of the child's safety, health, and effective referral for intervention. This study aims to obtain a selected set of family, maternal, and dyadic variables of the immediate caregiving environment for diagnosis, preventive, and intervention responses in healthcare settings. Mothers and their children under five years old: 51 in the neglected group (NG) and 89 in the non-neglected control group (CG), were recruited through pediatric primary care services and social services in Spain. Family demographics, adverse events, childhood maltreatment, maternal psychopathologies, personality variables, and observed mother-child interactions were assessed. Gradient boosting analyses were applied for the contributor's relative importance (RI), followed by logistic regression and discriminant analyses for those with higher RI. Parametric analyses showed high diagnostic accuracy (80-82% of NG and 92% of CG) for risky factors of child neglect: having a physically neglected and depressed mother, living in families in need of financial assistance, and large families; and for protective factors: having an older mother and showing higher mother-child emotional availability. Identifying a select group of features makes early diagnosis and preventive intervention more effective for mitigating the impact of child neglect and building mother-child resilience.

Social Acceptance of Gas, Wind, and Solar Energies in the Canary Islands.

BACKGROUND: This study tested a theoretical model including key psychosocial factors that could be involved in the acceptance of different energy sources (gas, wind, and solar); Methods: Participants were 550 adult residents of the Canary Islands. Variables assessed were information and utility (normative motives), perceived risk and perceived benefits (gain motives), and negative and positive emotions (hedonic motives), with acceptance of each of the three energy sources as outcome variables; Results: It was found that renewable energies (wind and solar) had a higher degree of acceptance than non-renewable energy (gas). The proposed model satisfactorily explained the social acceptance of the three energy sources, although the psychosocial factors involved differed by energy source. The gain motives, mainly perceived benefits, were associated to a greater extent with gas energy, whereas normative motives, such as utility, and hedonic motives, such as positive emotions, had greater weight for renewables. Gender differences in gas energy were found. Information about renewable energy increased positive emotions and acceptance, whereas information about fossil fuel-based energy generated more negative emotions and perceived risk, decreasing acceptance; Conclusions: Utility, perceived benefits and positive emotions were involved on the acceptance of both renewables and non-renewables. The theoretical model tested seems to be useful for understanding the psychosocial functioning of the acceptance of the various energy sources as an essential aspect for the transition of non-renewable to renewable energies.

The Cognitive Connectome in Healthy Aging.

Objectives: Cognitive aging has been extensively investigated using both univariate and multivariate analyses. Sophisticated multivariate approaches such as graph theory could potentially capture unknown complex associations between multiple cognitive variables. The aim of this study was to assess whether cognition is organized into a structure that could be called the "cognitive connectome," and whether such connectome differs between age groups. Methods: A total of 334 cognitively unimpaired individuals were stratified into early-middle-age (37-50 years, n = 110), late-middle-age (51-64 years, n = 106), and elderly (65-78 years, n = 118) groups. We built cognitive networks from 47 cognitive variables for each age group using graph theory and compared the groups using different global and nodal graph measures. Results: We identified a cognitive connectome characterized by five modules: verbal memory, visual memory-visuospatial abilities, procedural memory, executive-premotor functions, and processing speed. The elderly group showed reduced transitivity and average strength as well as increased global efficiency compared with the early-middle-age group. The late-middle-age group showed reduced global and local efficiency and modularity compared with the early-middle-age group. Nodal analyses showed the important role of executive functions and processing speed in explaining the differences between age groups. Conclusions: We identified a cognitive connectome that is rather stable during aging in cognitively healthy individuals, with the observed differences highlighting the important role of executive functions and processing speed. We translated the connectome concept from the neuroimaging field to cognitive data, demonstrating its potential to advance our understanding of the complexity of cognitive aging.

Distinctive Frontal and Occipitotemporal Surface Features in Neglectful Parenting.

Although the brain signatures of adaptive human parenting are well documented, the cortical features associated with maladaptive caregiving are underexplored. We investigated whether cortical thickness and surface area vary in a small group of mothers who had neglected their children (24 in the neglect group, NG) compared to a control group of mothers with non-neglectful caregiving (21 in the control group, CG). We also tested whether the cortical differences were related to dyadic mother-child emotional availability (EA) in a play task with their children and whether alexithymia involving low emotional awareness that characterizes the NG could play a role in the cortical-EA associations. Whole-brain analysis of the cortical mantle identified reduced cortical thickness in the right rostral middle frontal gyrus and an increased surface area in the right lingual and lateral occipital cortices for the NG with respect to the CG. Follow-up path analysis showed direct effects of the right rostral middle frontal gyrus (RMFG) on the emotional availability (EA) and on the difficulty to identify feelings (alexithymia factor), with a marginal indirect RMFG-EA effect through this factor. These preliminary findings extend existing work by implicating differences in cortical features associated with neglectful parenting and relevant to mother-child interactive bonding.

Comparing different approaches for operationalizing subjective cognitive decline: impact on syndromic and biomarker profiles.

Subjective cognitive decline (SCD) has been proposed as a risk factor for future cognitive decline and dementia. Given the heterogeneity of SCD and the lack of consensus about how to classify this condition, different operationalization approaches still need to be compared. In this study, we used the same sample of individuals to compare  different SCD operationalization approaches. We included 399 cognitively healthy individuals from a community-based cohort. SCD was assessed through nine questions about memory and non-memory subjective complaints. We applied four approaches to operationalize SCD: two hypothesis-driven approaches and two data-driven approaches. We characterized the resulting groups from each operationalization approach using multivariate methods on comprehensive demographic, clinical, cognitive, and neuroimaging data. We identified two main phenotypes: an amnestic phenotype characterized by an Alzheimer's Disease (AD) signature pattern of brain atrophy; and an anomic phenotype, which was mainly related to cerebrovascular pathology. Furthermore, language complaints other than naming helped to identify a subgroup with subclinical cognitive impairment and difficulties in activities of daily living. This subgroup also showed an AD signature pattern of atrophy. The identification of SCD phenotypes, characterized by different syndromic and biomarker profiles, varies depending on the operationalization approach used. In this study we discuss how these findings may be used in clinical practice and research.

Psychometric Properties of the Schizotypal Personality Questionnaire (SPQ) in a Mexican Population: Invariance Across Gender and Age / Propiedades Psicométricas del Cuestionario de Personalidad Esquizotípica (SPQ) en Población Mexicana: Invarianza en Función del Género y la Edad

BACKGROUND: The present study tested the factorial structure of the Schizotypal Personality Questionnaire (SPQ) in Mexican adults. Although this instrument has been validated in different cultural contexts, there are no studies to date that analyze its psychometric properties in a Mexican sample. METHOD: 307 adults completed the SPQ, seven participants were removed for being at high risk of psychosis. The final sample was made up of 300 participants (M = 34.58, SD = 13.77), of whom 62.8% were female. Raine's three-factor model and Stefanis et al.'s four-factor model were tested. RESULTS: The results indicated that both factor structures had a good fit to the data. However, the best evidence was for the three-factor solution. Configural, metric, and scalar invariance according to gender and age for the three-factor model was displayed. Further analyses showed women scored slightly higher in excessive social anxiety but this result was not statistically significant. Younger participants had higher scores on ideas of reference, excessive social anxiety, no close friends, and odd speech than the older group. CONCLUSIONS: These findings provide support for the use of the SPQ in the Mexican population

ANTECEDENTES: el presente estudio probó la estructura factorial del Cuestionario de personalidad esquizotípica (SPQ) en una muestra de adultos mexicanos. Aunque este instrumento ha sido validado en diferentes contextos culturales, no se han encontrado estudios que analicen las propiedades psicométricas en una muestra mexicana. MÉTODO: el SPQ fue cumplimentado por 307 adultos, aunque siete participantes fueron eliminados por estar en alto riesgo de psicosis. La muestra final incluyó 300 participantes (M = 34.58, SD = 13.77), de los cuales el 62,8% eran mujeres. Se probó la estructura factorial con tres factores, según la propuesta de Raine, y con cuatro factores según sugiere Stefanis et al. RESULTADOS: los resultados indicaron que ambas estructuras factoriales se ajustaban bien a los datos. Sin embargo, se encontró un mejor ajuste para la solución de tres factores. Este modelo demostró invariancia configuracional, métrica y escalar en función del sexo y la edad. Además, se encontró que las mujeres obtuvieron puntuaciones ligeramente más altas en ansiedad social, aunque no fue significativo. Los adultos jóvenes mostraron mayor puntuación en ideas de referencia, ansiedad social, sin amigos cercanos y discurso extraño comparados con el grupo de adultos mayores. CONCLUSIONES: estos hallazgos apoyan la utilidad del SPQ en población mexicana

Neglectful maternal caregiving involves altered brain volume in empathy-related areas.

The maternal brain undergoes adaptations to sensitive caregiving that are critical for infant well-being. We investigated structural alterations associated with neglectful caregiving and their effects on mother-child interactive behavior. High-resolution 3D volumetric images were obtained on 25 neglectful (NM) and 23 non-neglectful control (CM) mothers. Using voxel-based morphometry, we compared differences in gray and white matter (GM and WM, respectively) volume. Mothers completed an empathy scale and participated with their children in a play task (Emotional Availability Scale, EA). Neglectful mothers showed smaller GM volume in the right insula, anterior/middle cingulate (ACC/MCC), and right inferior frontal gyrus and less WM volume in bilateral frontal regions than did CM. A greater GM volume was observed in the right fusiform and cerebellum in NM than in CM. Regression analyses showed a negative effect of greater fusiform GM volume and a positive effect of greater right frontal WM volume on EA. Mediation analyses showed the role of emotional empathy in the positive effect of the insula and right inferior frontal gyrus and in the negative effect of the cerebellum on EA. Neglectful mothering involves alterations in emotional empathy-related areas and in frontal areas associated with poor mother-child interactive bonding, indicating how critical these areas are for sensitive caregiving.

Cognitive compensatory mechanisms in normal aging: a study on verbal fluency and the contribution of other cognitive functions.

Verbal fluency has been widely studied in cognitive aging. However, compensatory mechanisms that maintain its optimal performance with increasing age are not completely understood. Using cross-sectional data, we investigated differentiation and dedifferentiation processes in verbal fluency across the lifespan by analyzing the association between verbal fluency and numerous cognitive measures within four age groups (N=446): early middle-age (32-45 years), late middle-age (46-58 years), early elderly (59-71 years), and late elderly (72-84 years). ANCOVA was used to investigate the interaction between age and fluency modality. Random forest models were conducted to study the contribution of cognition to semantic, phonemic, and action fluency. All modalities declined with increasing age, but semantic fluency was the most vulnerable to aging. The most prominent reduction in performance was observed during the transition from middle-age to early elderly, when cognitive variables stopped contributing (differentiation), and new cognitive variables started contributing (dedifferentiation). Lexical access, processing speed, and executive functions were among the most contributing functions. We conclude that the association between age and verbal fluency is masked by age-specific influences of other cognitive functions. Differentiation and dedifferentiation processes can coexist. This study provides important data for better understanding of cognitive aging and compensatory processes.

Limbic-visual attenuation to crying faces underlies neglectful mothering.

Neglectful mothering is one of the most common forms of childhood maltreatment, involving a severe disregard of the child's needs, yet little is known about its neural substrate. A child's needs are usually conveyed by signals of distress revealed by crying faces. We tested whether infant and adult crying faces are processed differently in two sociodemographically similar groups of Neglectful (NM) and non-neglectful Control Mothers (CM). We used functional brain imaging to analyze the BOLD response from 43 mothers (23 neglectful and 20 control) while viewing faces from infants and adults (crying and neutral). In NM as compared to CM, the BOLD responses to both infant and adult crying faces were significantly reduced in the cerebellum, lingual, fusiform, amygdala, hippocampus, parahippocampus, and inferior frontal gyrus. The reduced BOLD was also modulated by comorbid psychiatric symptoms. In the CM, frontal activation to infant versus adult crying faces was enhanced, whereas in the NM activation in the anterior cingulate cortex to infant crying was reduced compared to adult crying. The altered neural response to crying faces in NM, showing generic face and infant-specific face processing deficits, could underlie their characteristic poor social abilities as well as their poor response to infant needs, both affecting the caregiving role.

Subjective Cognitive Decline Below and Above the Age of 60: A Multivariate Study on Neuroimaging, Cognitive, Clinical, and Demographic Measures.

Subjective cognitive complaints in cognitively normal individuals are a relevant predictor of Alzheimer's disease (AD), cerebrovascular disease, and age-related tauopathy. Complaints starting after the age of 60 increase the likelihood of preclinical AD. However, this criterion is arbitrary and current data show that neurodegenerative disorders likely start before that age. Further, data on the role of subjective complaints below the age of 60 in individuals qualifying for subjective cognitive decline (SCD) are lacking. We investigated the association of subjective cognitive complaints with an extensive number of neuroimaging, demographic, clinical, and cognitive measures in individuals fulfilling criteria for SCD below and above the age of 60. Nine complaints were scored in 416 individuals. Complaints were related to a higher load of white matter signal abnormalities, and this association was stronger the more subclinical changes in personality, interest, and drive were reported. In individuals <60 years, complaints were associated with lower global cognitive performance. In individuals ≥60 years, complaints were related to greater global brain atrophy and smaller total intracranial volume, and this association was stronger the more subclinical difficulties in activities of daily living were reported. Also, complaints were associated with increased depressive symptomatology irrespective of age. We conclude that complaints below the age of 60 may be associated with subtle signs of brain pathology. In the community, screening for risk of future cognitive decline should include subjective cognitive complaints, depressive symptomatology, and subclinical reduced cognition (<60 years)/activities of daily living (≥60 years), supported by basic neuroimaging examinations.

Tracing the interplay between syntactic and lexical features: fMRI evidence from agreement comprehension.

The current fMRI study was designed to investigate whether the processing of different gender-related cues embedded in nouns affects the computation of agreement dependencies and, if so, where this possible interaction is mapped in the brain. We used the Spanish gender agreement system, which makes it possible to manipulate two different factors: the agreement between different sentence constituents (i.e., by contrasting congruent versus incongruent determiner-noun pairs) and the formal (i.e., orthographical/morphological) and/or lexical information embedded in the noun -i.e., by contrasting transparent (e.g., libromasc. [book]; lunafem. [moon]) and opaque nouns (e.g., lápizmasc. [pencil]; vejezfem. [old age]). Crucially, these data illustrated, for the first time, how the network underlying agreement is sensitive to different gender-to-ending cues: different sources of gender information associated with nouns affect the neural circuits involved in the computation of local agreement dependencies. When the gender marking is informative (as in the case of transparent nouns), both formal and lexical information is used to establish grammatical relations. In contrast, when no formal cues are available (as in the case of opaque nouns), gender information is retrieved from the lexicon. We demonstrated the involvement of the posterior MTG/STG, pars triangularis within the IFG, and parietal regions during gender agreement computation. Critically, in order to integrate the different available information sources, the dynamics of this fronto-temporal loop change and additional regions, such as the hippocampus, the angular and the supramarginal gyri are recruited. These results underpin previous neuroanatomical models proposed in the context of both gender processing and sentence comprehension. But, more importantly, they provide valuable information regarding how and where the brain's language system dynamically integrates all the available form-based and lexical cues during comprehension.

The impact of cognateness of word bases and suffixes on morpho-orthographic processing: A masked priming study with intermediate and high-proficiency Portuguese-English bilinguals.

Recent studies have suggested that proficient bilinguals show morphological decomposition in the L2, but the question remains as to whether this process is modulated by the cognateness of the morphemic constituents of L2 words and by L2 proficiency. To answer this question was the main goal of the present research. For that purpose, a masked priming lexical decision task was conducted manipulating for the first time the degree of orthographic overlap of the L2 word as a whole, as well as of their morphemic constituents (bases and suffixes). Thirty-four European Portuguese-English bilinguals (16 intermediate and 18 high-proficient) and 16 English native-speaking controls performed the task in English. Results revealed that both groups of bilinguals decomposed words as the native control group. Importantly, results also showed that morphological priming effects were sensitive not only to cross-language similarities of words as a whole, but also to their morphemic constituents (especially, suffixes).

Distinct subtypes of Alzheimer's disease based on patterns of brain atrophy: longitudinal trajectories and clinical applications.

Atrophy patterns on MRI can reliably predict three neuropathological subtypes of Alzheimer's disease (AD): typical, limbic-predominant, or hippocampal-sparing. A method to enable their investigation in the clinical routine is still lacking. We aimed to (1) validate the combined use of visual rating scales for identification of AD subtypes; (2) characterise these subtypes at baseline and over two years; and (3) investigate how atrophy patterns and non-memory cognitive domains contribute to memory impairment. AD patients were classified as either typical AD (n = 100), limbic-predominant (n = 33), or hippocampal-sparing (n = 35) by using the Scheltens' scale for medial temporal lobe atrophy (MTA), the Koedam's scale for posterior atrophy (PA), and the Pasquier's global cortical atrophy scale for frontal atrophy (GCA-F). A fourth group with no atrophy was also identified (n = 30). 230 healthy controls were also included. There was great overlap among subtypes in demographic, clinical, and cognitive variables. Memory performance was more dependent on non-memory cognitive functions in hippocampal-sparing and the no atrophy group. Hippocampal-sparing and the no atrophy group showed less aggressive disease progression. Visual rating scales can be used to identify distinct AD subtypes. Recognizing AD heterogeneity is important and visual rating scales may facilitate investigation of AD heterogeneity in clinical routine.

The interactive effect of demographic and clinical factors on hippocampal volume: A multicohort study on 1958 cognitively normal individuals.

Alzheimer's disease is characterized by hippocampal atrophy. Other factors also influence the hippocampal volume, but their interactive effect has not been investigated before in cognitively healthy individuals. The aim of this study is to evaluate the interactive effect of key demographic and clinical factors on hippocampal volume, in contrast to previous studies frequently investigating these factors in a separate manner. Also, to investigate how comparable the control groups from ADNI, AIBL, and AddNeuroMed are with five population-based cohorts. In this study, 1958 participants were included (100 AddNeuroMed, 226 ADNI, 155 AIBL, 59 BRC, 295 GENIC, 279 BioFiNDER, 398 PIVUS, and 446 SNAC-K). ANOVA and random forest were used for testing between-cohort differences in demographic-clinical variables. Multiple regression was used to study the influence of demographic-clinical variables on hippocampal volume. ANCOVA was used to analyze whether between-cohort differences in demographic-clinical variables explained between-cohort differences in hippocampal volume. Age and global brain atrophy were the most important variables in explaining variability in hippocampal volume. These variables were not only important themselves but also in interaction with gender, education, MMSE, and total intracranial volume. AddNeuroMed, ADNI, and AIBL differed from the population-based cohorts in several demographic-clinical variables that had a significant effect on hippocampal volume. Variability in hippocampal volume in individuals with normal cognition is high. Differences that previously tended to be related to disease mechanisms could also be partly explained by demographic and clinical factors independent from the disease. Furthermore, cognitively normal individuals especially from ADNI and AIBL are not representative of the general population. These findings may have important implications for future research and clinical trials, translating imaging biomarkers to the general population, and validating current diagnostic criteria for Alzheimer's disease and predementia stages.

Can Big Five Facets Distinguish between Hedonic and Eudaimonic Well-Being? A Dominance Analysis.

In this study, the aim was to analyze the relative importance of Five-Factor Model (FFM) personality facets for eudaimonic or psychological well-being (PWB) and hedonic or subjective well-being (SWB) through dominance analyses. The participants were 1,403 adult residents of Spain (mean age 37.2 years, SD = 13.9). As expected, facets captured a substantial proportion of the variance in PWB and SWB, with PWB being better predicted than SWB (explaining around 36-55% of the variance of PWB vs. 25% of the variance of SWB). Some facets were common to both types of well-being such as depression (explaining between 5-33% of the variance), vulnerability (explaining between 4-21% of the variance), positive emotions (explaining between 2-9% of the variance) and achievement striving (explaining between 2-10% of the variance), whereas others made a unique contribution according to type of well-being. Certain facets had a greater relative importance for women's well-being -e.g., positive emotions explained 9% of the variance of self-acceptance for women vs. 3% for men- and others for men's well-being -e.g., achievement striving explained 9% of the variance of personal growth for men vs. 2% for women-. The present results contribute to the literature by identifying which Big Five facets showed greater relative importance in explaining and distinguishing between PWB and SWB for women and men.

Can big five facets distinguish between hedonic and eudaimonic well-being? A dominance analysis

In this study, the aim was to analyze the relative importance of Five-Factor Model (FFM) personality facets for eudaimonic or psychological well-being (PWB) and hedonic or subjective well-being (SWB) through dominance analyses. The participants were 1,403 adult residents of Spain (mean age 37.2 years, SD = 13.9). As expected, facets captured a substantial proportion of the variance in PWB and SWB, with PWB being better predicted than SWB (explaining around 36-55% of the variance of PWB vs. 25% of the variance of SWB). Some facets were common to both types of well-being such as depression (explaining between 5-33% of the variance), vulnerability (explaining between 4-21% of the variance), positive emotions (explaining between 2-9% of the variance) and achievement striving (explaining between 2-10% of the variance), whereas others made a unique contribution according to type of well-being. Certain facets had a greater relative importance for women's well-being -e.g., positive emotions explained 9% of the variance of self-acceptance for women vs. 3% for men- and others for men's well-being -e.g., achievement striving explained 9% of the variance of personal growth for men vs. 2% for women-. The present results contribute to the literature by identifying which Big Five facets showed greater relative importance in explaining and distinguishing between PWB and SWB for women and men (AU)

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Verbal and nominal agreement: An fMRI study.

Agreement computation is one of the pillars of language comprehension. In this fMRI study, we investigated the neuro-cognitive processes of agreement associated with number feature covariance in subject-verb agreement and determiner-noun concord in Spanish by creating mismatches (ella/*ellas corre, she/*they dances vs. el/*los anillo, thesg/*thepl ring). The results evidenced the engagement of a common bilateral fronto-parietal monitoring system, not language specific, and a left fronto-temporal system that seems to be specifically related to different aspects of phrase and sentence processing. In particular, the major difference was found in the anterior portion of the left MTG-STG, which we relate to fine-grained syntactic-combinatorial building mechanisms apparently controlled by the pars opercularis within the LIFG. These results suggest that general conflict-monitoring processes operate in parallel with language-specific mechanisms that are sensitive to the specificity of agreement type for the detection of feature covariance among sentence constituents. Specifically, the coupling between these frontal and temporal regions seems to be flexible enough to show sensitivity to the fine-grained combinatorial mechanisms that underlie nominal and subject-verb agreement.

Orthographic Coding: Brain Activation for Letters, Symbols, and Digits.

The present experiment investigates the input coding mechanisms of 3 common printed characters: letters, numbers, and symbols. Despite research in this area, it is yet unclear whether the identity of these 3 elements is processed through the same or different brain pathways. In addition, some computational models propose that the position-in-string coding of these elements responds to general flexible mechanisms of the visual system that are not character-specific, whereas others suggest that the position coding of letters responds to specific processes that are different from those that guide the position-in-string assignment of other types of visual objects. Here, in an fMRI study, we manipulated character position and character identity through the transposition or substitution of 2 internal elements within strings of 4 elements. Participants were presented with 2 consecutive visual strings and asked to decide whether they were the same or different. The results showed: 1) that some brain areas responded more to letters than to numbers and vice versa, suggesting that processing may follow different brain pathways; 2) that the left parietal cortex is involved in letter identity, and critically in letter position coding, specifically contributing to the early stages of the reading process; and that 3) a stimulus-specific mechanism for letter position coding is operating during orthographic processing.