Orthographic and phonological processing in the left ventral occipitotemporal cortex during Chinese word reading.

The left ventral occipitotemporal cortex (lvOT) has been consistently identified as a crucial structure in word reading, and its function varies across subregions. Nevertheless, the specific function of the lvOT and its subregions remains controversial because the obvious grapheme-to-phoneme correspondence rules of alphabetic languages make it difficult to disentangle the contributions of orthography and phonology to neural activations. To explore information processing in lvOT subregions, the present study manipulated the orthography and phonology in a factorial design and used the fMRI rapid adaptation paradigm. The results revealed a posterior-to-anterior functional gradient in lvOT in Chinese word reading and specified that the functional transition from sublexical to lexical processing occurred in the middle subregion close to the classic VWFA. More importantly, we found that the middle and posterior subregions of lvOT are responsible for processing both orthographic and phonological information during Chinese word reading. These results elaborated the function of the lvOT in Chinese word reading.

Sensory modality and spoken language shape reading network in blind readers of Braille.

The neural basis of reading is highly consistent across many languages and scripts. Are there alternative neural routes to reading? How does the sensory modality of symbols (tactile vs. visual) influence their neural representations? We examined these questions by comparing reading of visual print (sighted group, n = 19) and tactile Braille (congenitally blind group, n = 19). Blind and sighted readers were presented with written (words, consonant strings, non-letter shapes) and spoken stimuli (words, backward speech) that varied in word-likeness. Consistent with prior work, the ventral occipitotemporal cortex (vOTC) was active during Braille and visual reading. A posterior/anterior vOTC word-form gradient was observed only in sighted readers with more anterior regions preferring larger orthographic units (words). No such gradient was observed in blind readers. Consistent with connectivity predictions, in blind compared to sighted readers, posterior parietal cortices were recruited to a greater degree and contained word-preferring patches. Lateralization of Braille in blind readers was predicted by laterality of spoken language and reading hand. The effect of spoken language increased along a cortical hierarchy, whereas effect of reading hand waned. These results suggested that the neural basis of reading is influenced by symbol modality and spoken language and support connectivity-based views of cortical function.

Emergence of a compositional neural code for written words: Recycling of a convolutional neural network for reading.

The visual word form area (VWFA) is a region of human inferotemporal cortex that emerges at a fixed location in the occipitotemporal cortex during reading acquisition and systematically responds to written words in literate individuals. According to the neuronal recycling hypothesis, this region arises through the repurposing, for letter recognition, of a subpart of the ventral visual pathway initially involved in face and object recognition. Furthermore, according to the biased connectivity hypothesis, its reproducible localization is due to preexisting connections from this subregion to areas involved in spoken-language processing. Here, we evaluate those hypotheses in an explicit computational model. We trained a deep convolutional neural network of the ventral visual pathway, first to categorize pictures and then to recognize written words invariantly for case, font, and size. We show that the model can account for many properties of the VWFA, particularly when a subset of units possesses a biased connectivity to word output units. The network develops a sparse, invariant representation of written words, based on a restricted set of reading-selective units. Their activation mimics several properties of the VWFA, and their lesioning causes a reading-specific deficit. The model predicts that, in literate brains, written words are encoded by a compositional neural code with neurons tuned either to individual letters and their ordinal position relative to word start or word ending or to pairs of letters (bigrams).

How Does Literacy Affect Speech Processing? Not by Enhancing Cortical Responses to Speech, But by Promoting Connectivity of Acoustic-Phonetic and Graphomotor Cortices.

Previous research suggests that literacy, specifically learning alphabetic letter-to-phoneme mappings, modifies online speech processing and enhances brain responses, as indexed by the BOLD, to speech in auditory areas associated with phonological processing (Dehaene et al., 2010). However, alphabets are not the only orthographic systems in use in the world, and hundreds of millions of individuals speak languages that are not written using alphabets. In order to make claims that literacy per se has broad and general consequences for brain responses to speech, one must seek confirmatory evidence from nonalphabetic literacy. To this end, we conducted a longitudinal fMRI study in India probing the effect of literacy in Devanagari, an abubgida, on functional connectivity and cerebral responses to speech in 91 variously literate Hindi-speaking male and female human participants. Twenty-two completely illiterate participants underwent 6 months of reading and writing training. Devanagari literacy increases functional connectivity between acoustic-phonetic and graphomotor brain areas, but we find no evidence that literacy changes brain responses to speech, either in cross-sectional or longitudinal analyses. These findings shows that a dramatic reconfiguration of the neurofunctional substrates of online speech processing may not be a universal result of learning to read, and suggest that the influence of writing on speech processing should also be investigated.SIGNIFICANCE STATEMENT It is widely claimed that a consequence of being able to read is enhanced auditory processing of speech, reflected by increased cortical responses in areas associated with phonological processing. Here we find no relationship between literacy and the magnitude of brain response to speech stimuli in individuals who speak Hindi, which is written using a nonalphabetic script, Devanagari, an abugida. We propose that the exact nature of the script under examination must be considered before making sweeping claims about the consequences of literacy for the brain. Further, we find evidence that literacy enhances functional connectivity between auditory processing areas and graphomotor areas, suggesting a mechanism whereby learning to write might influence speech perception.

Disentangling influences of dyslexia, development, and reading experience on effective brain connectivity in children.

Altered brain connectivity between regions of the reading network has been associated with reading difficulties. However, it remains unclear whether connectivity differences between children with dyslexia (DYS) and those with typical reading skills (TR) are specific to reading impairments or to reading experience. In this functional MRI study, 132 children (M = 10.06 y, SD = 1.46) performed a phonological lexical decision task. We aimed to disentangle (1) disorder-specific from (2) experience-related differences in effective connectivity and to (3) characterize the development of DYS and TR. We applied dynamic causal modeling to age-matched (ndys = 25, nTR = 35) and reading-level-matched (ndys = 25, nTR = 22) groups. Developmental effects were assessed in beginning and advanced readers (TR: nbeg = 48, nadv = 35, DYS: nbeg = 24, nadv = 25). We show that altered feedback connectivity between the inferior parietal lobule and the visual word form area (VWFA) during print processing can be specifically attributed to reading impairments, because these alterations were found in DYS compared to both the age-matched and reading-level-matched TR. In contrast, feedforward connectivity from the VWFA to parietal and frontal regions characterized experience in TR and increased with age and reading skill. These directed connectivity findings pinpoint disorder-specific and experience-dependent alterations in the brain's reading network.

Intact reading ability despite lacking a canonical visual word form area in an individual born without the left superior temporal lobe.

The visual word form area (VWFA), a region canonically located within left ventral temporal cortex (VTC), is specialized for orthography in literate adults presumbly due to its connectivity with frontotemporal language regions. But is a typical, left-lateralized language network critical for the VWFA's emergence? We investigated this question in an individual (EG) born without the left superior temporal lobe but who has normal reading ability. EG showed canonical typical face-selectivity bilateraly but no wordselectivity either in right VWFA or in the spared left VWFA. Moreover, in contrast with the idea that the VWFA is simply part of the language network, no part of EG's VTC showed selectivity to higher-level linguistic processing. Interestingly, EG's VWFA showed reliable multivariate patterns that distinguished words from other categories. These results suggest that a typical left-hemisphere language network is necessary for acanonical VWFA, and that orthographic processing can otherwise be supported by a distributed neural code.

Pseudomonas putida Biofilm Depends on the vWFa-Domain of LapA in Peptides-Containing Growth Medium.

The biofilm of Pseudomonas putida is complexly regulated by several intercellular and extracellular factors. The cell surface adhesin LapA of this bacterium is a central factor for the biofilm and, consequently, the regulation of lapA expression, for example, by Fis. It has been recently shown that peptides in growth media enhance the formation of P. putida biofilm, but not as a source of carbon and nitrogen. Moreover, the peptide-dependent biofilm appeared especially clearly in the fis-overexpression strain, which also has increased LapA. Therefore, we investigate here whether there is a relationship between LapA and peptide-dependent biofilm. The P. putida strains with inducible lapA expression and LapA without the vWFa domain, which is described as a domain similar to von Willebrand factor domain A, were constructed. Thereafter, the biofilm of these strains was assessed in growth media containing extracellular peptides in the shape of tryptone and without it. We show that the vWFa domain in LapA is necessary for biofilm enhancement by the extracellular peptides in the growth medium. The importance of vWFa in LapA was particularly evident for the fis-overexpression strain F15. The absence of the vWFa domain diminished the positive effect of Fis on the F15 biofilm.

Linguistic experience acquisition for novel stimuli selectively activates the neural network of the visual word form area.

The human ventral visual cortex is functionally organized into different domains that sensitively respond to different categories, such as words and objects. There is heated debate over what principle constrains the locations of those domains. Taking the visual word form area (VWFA) as an example, we tested whether the word preference in this area originates from the bottom-up processes related to word shape (the shape hypothesis) or top-down connectivity of higher-order language regions (the connectivity hypothesis). We trained subjects to associate identical, meaningless, non-word-like figures with high-level features of either words or objects. We found that the word-feature learning for the figures elicited the neural activation change in the VWFA, and learning performance effectively predicted the activation strength of this area after learning. Word-learning effects were also observed in other language areas (i.e., the left posterior superior temporal gyrus, postcentral gyrus, and supplementary motor area), with increased functional connectivity between the VWFA and the language regions. In contrast, object-feature learning was not associated with obvious activation changes in the language regions. These results indicate that high-level language features of stimuli can modulate the activation of the VWFA, providing supportive evidence for the connectivity hypothesis of words processing in the ventral occipitotemporal cortex.

Word inversion sensitivity as a marker of visual word form area lateralization: An application of a novel multivariate measure of laterality.

An area within the ventral occipitotemporal cortex (vOTC), the "visual word form area" (VWFA), typically exhibits a strongly left-lateralized response to orthographic stimuli in skilled readers. While individual variation in VWFA lateralization has been observed, the behavioral significance of laterality differences remains unclear. Here, we test the hypothesis that differences in VWFA lateralization reflect differing preferences for holistic orthographic analysis. To examine this hypothesis, we implemented a new multivariate method that uses machine learning to assess functional lateralization, along with a traditional univariate lateralization method. We related these neural metrics to behavioral indices of holistic orthographic analysis (inversion sensitivity). The multivariate measure successfully detected the lateralization of orthographic processing in the VWFA, and as hypothesized, predicted behavioral differences in holistic orthographic analysis. An exploratory whole brain analysis identified further regions with a relationship between inversion sensitivity and lateralization: one near the junction of the inferior frontal and precentral sulci, and another along the superior temporal gyrus. We conclude that proficient native readers of English exhibit differences in cortical lateralization of the VWFA that have significant implications for reading behavior.

Development of the Visual Word Form Area Requires Visual Experience: Evidence from Blind Braille Readers.

Learning to read causes the development of a letter- and word-selective region known as the visual word form area (VWFA) within the human ventral visual object stream. Why does a reading-selective region develop at this anatomical location? According to one hypothesis, the VWFA develops at the nexus of visual inputs from retinotopic cortices and linguistic input from the frontotemporal language network because reading involves extracting linguistic information from visual symbols. Surprisingly, the anatomical location of the VWFA is also active when blind individuals read Braille by touch, suggesting that vision is not required for the development of the VWFA. In this study, we tested the alternative prediction that VWFA development is in fact influenced by visual experience. We predicted that in the absence of vision, the "VWFA" is incorporated into the frontotemporal language network and participates in high-level language processing. Congenitally blind (n = 10, 9 female, 1 male) and sighted control (n = 15, 9 female, 6 male), male and female participants each took part in two functional magnetic resonance imaging experiments: (1) word reading (Braille for blind and print for sighted participants), and (2) listening to spoken sentences of different grammatical complexity (both groups). We find that in blind, but not sighted participants, the anatomical location of the VWFA responds both to written words and to the grammatical complexity of spoken sentences. This suggests that in blindness, this region takes on high-level linguistic functions, becoming less selective for reading. More generally, the current findings suggest that experience during development has a major effect on functional specialization in the human cortex.SIGNIFICANCE STATEMENT The visual word form area (VWFA) is a region in the human cortex that becomes specialized for the recognition of written letters and words. Why does this particular brain region become specialized for reading? We tested the hypothesis that the VWFA develops within the ventral visual stream because reading involves extracting linguistic information from visual symbols. Consistent with this hypothesis, we find that in congenitally blind Braille readers, but not sighted readers of print, the VWFA region is active during grammatical processing of spoken sentences. These results suggest that visual experience contributes to VWFA specialization, and that different neural implementations of reading are possible.

Privileged Functional Connectivity between the Visual Word Form Area and the Language System.

The visual word form area (VWFA) is a region in the left occipitotemporal sulcus of literate individuals that is purportedly specialized for visual word recognition. However, there is considerable controversy about its functional specificity and connectivity, with some arguing that it serves as a domain-general, rather than word-specific, visual processor. The VWFA is a critical region for testing hypotheses about the nature of cortical organization, because it is known to develop only through experience (i.e., reading acquisition), and widespread literacy is too recent to have influenced genetic determinants of brain organization. Using a combination of advanced fMRI analysis techniques, including individual functional localization, multivoxel pattern analysis, and high-resolution resting-state functional connectivity (RSFC) analyses, with data from 33 healthy adult human participants, we demonstrate that (1) the VWFA can discriminate words from nonword letter strings (pseudowords); (2) the VWFA has preferential RSFC with Wernicke's area and other core regions of the language system; and (3) the strength of the RSFC between the VWFA and Wernicke's area predicts performance on a semantic classification task with words but not other categories of visual stimuli. Our results are consistent with the hypothesis that the VWFA is specialized for lexical processing of real words because of its functional connectivity with Wernicke's area.SIGNIFICANCE STATEMENT The visual word form area (VWFA) is critical for determining the nature of category-related organization of the ventral visual system. However, its functional specificity and connectivity are fiercely debated. Recent work concluded that the VWFA is a domain-general, rather than word-specific, visual processor with no preferential functional connectivity with the language system. Using more advanced techniques, our results stand in stark contrast to these earlier findings. We demonstrate that the VWFA is highly specialized for lexical processing of real words, and that a fundamental factor driving this specialization is its preferential intrinsic functional connectivity with core regions of the language system. Our results support the hypothesis that intrinsic functional connectivity contributes to category-related specialization within the human ventral visual system.

Local response heterogeneity indexes experience-based neural differentiation in reading.

The ability to read requires learning letter-string representations whose neural codes would be expected to vary depending on the amount of experience that an individual has with reading them. Motivated by sparse coding theories (e.g., Rolls and Tovee, 1995; Olshausen and Field, 1996), recent work has demonstrated that better-learned relative to less well-learned neural representations are associated with more strongly differentiated, locally heterogeneous blood oxygenation level dependent (BOLD) responses (e.g., Jiang et al., 2013). Here we report a novel analysis method we call local heterogeneity regression (Local-Hreg) that quantifies the cross-voxel heterogeneity of BOLD responses, thereby providing a sensitive and methodologically flexible method for quantifying the local neural differentiation of neural representations. In a study of literate adults, we applied Local-Hreg to fMRI data obtained when participants read letter strings that varied in their frequency of occurrence in the written language. Consistent with previous research identifying the left ventral occipitotemporal cortex (vOTC) as a key site for orthographic representation in reading and spelling, we found that the cross-voxel heterogeneity of neural responses in this region varies according to the frequency with which the written letter strings have been experienced. This work provides a novel approach for examining the local differentiation of neural representations, and demonstrates that well-learned words have greater representational differentiation than less well-learned or unfamiliar words.

Orthographic and Phonological Representations in the Fusiform Cortex.

Mental and neural representations of words are at the core of understanding the cognitive and neural mechanisms of reading. Despite extensive studies, the nature of visual word representation remains highly controversial due to methodological limitations. In particular, it is unclear whether the fusiform cortex contains only abstract orthographic representation, or represents both lower and higher level orthography as well as phonology. Using representational similarity analysis, we integrated behavioral ratings, computational models of reading and visual object recognition, and neuroimaging data to examine the nature of visual word representations in the fusiform cortex. Our results provided clear evidence that the middle and anterior fusiform represented both phonological and orthographic information. Whereas lower level orthographic information was represented at every stage of the ventral visual stream, abstract orthographic information was increasingly represented along the posterior-to-anterior axis. Furthermore, the left and right hemispheres were tuned to high- and low-frequency orthographic information, respectively. These results help to resolve the long-standing debates regarding the role of the fusiform in reading, and have significant implications for the development of psychological, neural, and computational theories of reading.

The Cytoarchitecture of Domain-specific Regions in Human High-level Visual Cortex.

A fundamental hypothesis in neuroscience proposes that underlying cellular architecture (cytoarchitecture) contributes to the functionality of a brain area. However, this hypothesis has not been tested in human ventral temporal cortex (VTC) that contains domain-specific regions causally involved in perception. To fill this gap in knowledge, we used cortex-based alignment to register functional regions from living participants to cytoarchitectonic areas in ex vivo brains. This novel approach reveals 3 findings. First, there is a consistent relationship between domain-specific regions and cytoarchitectonic areas: each functional region is largely restricted to 1 cytoarchitectonic area. Second, extracting cytoarchitectonic profiles from face- and place-selective regions after back-projecting each region to 20-µm thick histological sections indicates that cytoarchitectonic properties distinguish these regions from each other. Third, some cytoarchitectonic areas contain more than 1 domain-specific region. For example, face-, body-, and character-selective regions are located within the same cytoarchitectonic area. We summarize these findings with a parsimonious hypothesis incorporating how cellular properties may contribute to functional specialization in human VTC. Specifically, we link computational principles to correlated axes of functional and cytoarchitectonic segregation in human VTC, in which parallel processing across domains occurs along a lateral-medial axis while transformations of information within domain occur along an anterior-posterior axis.

Intrinsic Functional Connectivity in the Adult Brain and Success in Second-Language Learning.

There is considerable variability in an individual's ability to acquire a second language (L2) during adulthood. Using resting-state fMRI data acquired before training in English speakers who underwent a 12 week intensive French immersion training course, we investigated whether individual differences in intrinsic resting-state functional connectivity relate to a person's ability to acquire an L2. We focused on two key aspects of language processing--lexical retrieval in spontaneous speech and reading speed--and computed whole-brain functional connectivity from two regions of interest in the language network, namely the left anterior insula/frontal operculum (AI/FO) and the visual word form area (VWFA). Connectivity between the left AI/FO and left posterior superior temporal gyrus (STG) and between the left AI/FO and dorsal anterior cingulate cortex correlated positively with improvement in L2 lexical retrieval in spontaneous speech. Connectivity between the VWFA and left mid-STG correlated positively with improvement in L2 reading speed. These findings are consistent with the different language functions subserved by subcomponents of the language network and suggest that the human capacity to learn an L2 can be predicted by an individual's intrinsic functional connectivity within the language network. Significance statement: There is considerable variability in second-language learning abilities during adulthood. We investigated whether individual differences in intrinsic functional connectivity in the adult brain relate to success in second-language learning, using resting-state functional magnetic resonance imaging in English speakers who underwent a 12 week intensive French immersion training course. We found that pretraining functional connectivity within two different language subnetworks correlated strongly with learning outcome in two different language skills: lexical retrieval in spontaneous speech and reading speed. Our results suggest that the human capacity to learn a second language can be predicted by an individual's intrinsic functional connectivity within the language network.

Modulation of Orthographic Decoding by Frontal Cortex.

Opinions are divided on whether word reading processes occur in a hierarchical, feedforward fashion or within an interactive framework. To critically evaluate these competing theories, we recorded electrocorticographic (ECoG) data from 15 human patients with intractable epilepsy during a word completion task and evaluated brain network dynamics across individuals. We used a novel technique of analyzing multihuman ECoG recordings to identify cortical regions most relevant to processing lexical information. The mid fusiform gyrus showed the strongest, earliest response after stimulus onset, whereas activity was maximal in frontal, dorsal lateral prefrontal, and sensorimotor regions toward articulation onset. To evaluate interregional functional connectivity, ECoG data from electrodes situated over specific cortical regions of interest were fit into linear multivariate autoregressive (MVAR) models. Spectral characteristics of the MVAR models were used to precisely reveal the timing and the magnitude of information flow between localized brain regions. This is the first application of MVAR for developing a comprehensive account of interregional interactions from a word reading ECoG dataset. Our comprehensive findings revealed both top-down and bottom-up influences between higher-level language areas and the mid fusiform gyrus. Our findings thus challenge strictly hierarchical, feedforward views of word reading and suggest that orthographic processes are modulated by prefrontal and sensorimotor regions via an interactive framework. SIGNIFICANCE STATEMENT: Word reading is a critical part of everyday life. When the ability to read is disrupted, it can lead to learning disorders, as well as emotional and academic difficulties. The neural mechanisms underlying word reading are not well understood due to limitations in the spatial and temporal specificity of prior word reading studies. Our research analyzed data recorded from sensors implanted directly from surface of human brains while these individuals performed a word reading task. Our research analyzed these recordings to infer how brain regions communicate during word reading. Our original results improve upon current models of word reading and can be used to develop treatment plans for individuals with reading disabilities.

Shared orthographic neuronal representations for spelling and reading.

A central question in the study of the neural basis of written language is whether reading and spelling utilize shared orthographic representations. While recent studies employing fMRI to test this question report that the left inferior frontal gyrus (IFG) and ventral occipitotemporal cortex (vOTC) are active during both spelling and reading in the same subjects (Purcell et al., 2011a; Rapp and Lipka, 2011), the spatial resolution of fMRI limits the interpretation of these findings. Specifically, it is unknown if the neurons which encode orthography for reading are also involved in spelling of the same words. Here we address this question by employing an event-related functional magnetic resonance imaging-adaptation (fMRI-A) paradigm designed to examine shared orthographic representations across spelling and reading. First, we identified areas that independently showed adaptation to reading, and adaptation to spelling. Then we identified spatial convergence for these two separate maps via a conjunction analysis. Consistent with previous studies (Purcell et al., 2011a; Rapp and Lipka, 2011), this analysis revealed the left dorsal IFG, vOTC and supplementary motor area. To further validate these observations, we then interrogated these regions using an across-task adaptation technique, and found adaptation across reading and spelling in the left dorsal IFG (BA 44/9). Our final analysis focused specifically on the Visual Word Form Area (VWFA) in the vOTC, whose variability in location among subjects requires the use of subject-specific identification mechanisms (Glezer and Riesenhuber, 2013). Using a functional localizer for reading, we defined the VWFA in each subject, and found adaptation effects for both within the spelling and reading conditions, respectively, as well as across spelling and reading. Because none of these effects were observed during a phonological/semantic control condition, we conclude that the left dorsal IFG and VWFA are involved in accessing the same orthography-specific representations for spelling and reading.

Distinct but Overlapping Patterns of Response to Words and Faces in the Fusiform Gyrus.

Converging evidence suggests that the fusiform gyrus is involved in the processing of both faces and words. We used fMRI to investigate the extent to which the representation of words and faces in this region of the brain is based on a common neural representation. In Experiment 1, a univariate analysis revealed regions in the fusiform gyrus that were only selective for faces and other regions that were only selective for words. However, we also found regions that showed both word-selective and face-selective responses, particularly in the left hemisphere. We then used a multivariate analysis to measure the pattern of response to faces and words. Despite the overlap in regional responses, we found distinct patterns of response to both faces and words in the left and right fusiform gyrus. In Experiment 2, fMR adaptation was used to determine whether information about familiar faces and names is integrated in the fusiform gyrus. Distinct regions of the fusiform gyrus showed adaptation to either familiar faces or familiar names. However, there was no adaptation to sequences of faces and names with the same identity. Taken together, these results provide evidence for distinct, but overlapping, neural representations for words and faces in the fusiform gyrus.

Selective Neural Synchrony Suppression as a Forward Gatekeeper to Piecemeal Conscious Perception.

The emergence of conscious visual perception is assumed to ignite late (∼250 ms) gamma-band oscillations shortly after an initial (∼100 ms) forward sweep of neural sensory (nonconscious) information. However, this neural evidence is not utterly congruent with rich behavioral data which rather point to piecemeal (i.e., graded) perceptual processing. To address the unexplored neural mechanisms of piecemeal ignition of conscious perception, hierarchical script sensitivity of the putative visual word form area (VWFA) was exploited to signal null (i.e., sensory), partial (i.e., letter-level), and full (i.e., word-level) conscious perception. Two magnetoencephalography experiments were conducted in which healthy human participants viewed masked words (Experiment I: active task, Dutch words; Experiment II: passive task, Hebrew words) while high-frequency (broadband gamma) brain activity was measured. Findings revealed that piecemeal conscious perception did not ignite a linear piecemeal increase in oscillations. Instead, whereas late (∼250 ms) gamma-band oscillations signaled full conscious perception (i.e., word-level), partial conscious perception (i.e., letter-level) was signaled via the inhibition of the early (∼100 ms) forward sweep. This inhibition regulates the downstream broadcast to filter out irrelevant (i.e., masks) information. The findings thus highlight a local (VWFA) gatekeeping mechanism for conscious perception, operating by filtering out and in selective percepts.

Words in Context: The Effects of Length, Frequency, and Predictability on Brain Responses During Natural Reading.

Word length, frequency, and predictability count among the most influential variables during reading. Their effects are well-documented in eye movement studies, but pertinent evidence from neuroimaging primarily stem from single-word presentations. We investigated the effects of these variables during reading of whole sentences with simultaneous eye-tracking and functional magnetic resonance imaging (fixation-related fMRI). Increasing word length was associated with increasing activation in occipital areas linked to visual analysis. Additionally, length elicited a U-shaped modulation (i.e., least activation for medium-length words) within a brain stem region presumably linked to eye movement control. These effects, however, were diminished when accounting for multiple fixation cases. Increasing frequency was associated with decreasing activation within left inferior frontal, superior parietal, and occipito-temporal regions. The function of the latter region-hosting the putative visual word form area-was originally considered as limited to sublexical processing. An exploratory analysis revealed that increasing predictability was associated with decreasing activation within middle temporal and inferior frontal regions previously implicated in memory access and unification. The findings are discussed with regard to their correspondence with findings from single-word presentations and with regard to neurocognitive models of visual word recognition, semantic processing, and eye movement control during reading.