Functionally Separable Font-invariant and Font-sensitive Neural Populations in Occipitotemporal Cortex

2019 ◽  
Vol 31 (7) ◽  
pp. 1018-1029 ◽  
Author(s):  
Zhiheng Zhou ◽  
Tutis Vilis ◽  
Lars Strother
Keyword(s):  
Visual Word ◽  
Neural Mechanisms ◽  
Word Form ◽  
Invariant Representation ◽  
Visual Word Form Area ◽  
Repetition Suppression ◽  
Neural Populations ◽  
Occipitotemporal Cortex ◽  
Middle Occipital Gyrus ◽  
Repeated Words

Reading relies on the rapid visual recognition of words viewed in a wide variety of fonts. We used fMRI to identify neural populations showing reduced fMRI responses to repeated words displayed in different fonts (“font-invariant” repetition suppression). We also identified neural populations showing greater fMRI responses to words repeated in a changing font as compared with words repeated in the same font (“font-sensitive” release from repetition suppression). We observed font-invariant repetition suppression in two anatomically distinct regions of the left occipitotemporal cortex (OT), a “visual word form area” in mid-fusiform cortex, and a more posterior region in the middle occipital gyrus. In contrast, bilateral shape-selective lateral occipital cortex and posterior fusiform showed considerable sensitivity to font changes during the viewing of repeated words. Although the visual word form area and the left middle occipital gyrus showed some evidence of font sensitivity, both regions showed a relatively greater degree of font invariance than font sensitivity. Our results show that the neural mechanisms in the left OT involved in font-invariant word recognition are anatomically distinct from those sensitive to font-related shape changes. We conclude that font-invariant representation of visual word form is instantiated at multiple levels by anatomically distinct neural mechanisms within the left OT.

scholarly journals Repetition Probability Effects for Words Depend on Language Knowledge

2021 ◽  
Author(s):  
Chenglin Li ◽  
Gyula Kovacs
Keyword(s):  
Word Processing ◽  
Mother Tongue ◽  
Visual Word ◽  
Neural Mechanisms ◽  
Chinese Characters ◽  
Visual Word Form Area ◽  
Repetition Suppression ◽  
Language Knowledge ◽  
Prior Experiences ◽  
Predictive Processes

The magnitude of repetition suppression (RS), measured by fMRI, is modulated by the probability of repetitions (P(rep)) for various sensory stimulus categories. It has been suggested that for visually presented simple letters this P(rep) effect depends on the prior practices of the participants with the stimuli. Here we tested further if previous experiences affect the neural mechanisms of RS, leading to the modulatory effects of stimulus P(rep), for more complex lexical stimuli as well. We measured the BOLD signal in the Visual Word Form Area (VWFA) of native Chinese and German participants and estimated the P(rep) effects for Chinese characters and German words. The results showed a significant P(rep) effect for stimuli of the mother tongue in both participant groups. Interestingly, Chinese participants, learning German as a second language, also showed a significant P(rep) modulation of RS for German words while the German participants who had no prior experiences with the Chinese characters showed no such effects. Our findings suggest that P(rep) effects on RS are manifest for visual word processing as well, but only for words of a language with which the participants have prior experiences. These results support further the idea that predictive processes, estimated by P(rep) modulations of RS, require prior experiences.

scholarly journals The Visual Word Form Area natively processes shape sequences: Implications for developmental dyslexia

2019 ◽  
Author(s):  
Carol Whitney ◽  
Paddy Ross ◽  
Zhiheng Zhou ◽  
Lars Strother
Keyword(s):  
Word Recognition ◽  
Developmental Dyslexia ◽  
Recognition System ◽  
Visual Word ◽  
Cortical Region ◽  
Word Form ◽  
Phonological Decoding ◽  
Visual Word Form Area ◽  
Occipitotemporal Cortex ◽  
Whole Word

The Visual Word Form Area (VWFA) is a cortical region that adapts to support fluent word recognition. Surprisingly, the region of ventrolateral occipitotemporal cortex that becomes VWFA is specialized for processing the motion of inanimate objects that change shape. Such motion is neurally analyzed as a temporal sequence of shape 'snapshots'. We have proposed that the VWFA develops in this region because letter representations are serially activated in occipitotemporal cortex during typical reading acquisition. Therefore, the region that analyzes inanimate shape sequences is recruited to recognize letter sequences. We discuss the implications of this account for developmental dyslexia. In particular, inability to focus attention down to a single letter may preclude the serial letter selection that typically drives VWFA formation. Such a deficit would also interfere with acquisition of cortical letter-phoneme connections. Instead, compensated dyslexics employ the ventromedial object-recognition system for whole-word recognition, and the subcortical procedural system for phonological decoding.

scholarly journals A novel hypothesis for the original functionality of the Visual Word Form Area: Processing shape sequences

2019 ◽  
Author(s):  
Carol Whitney ◽  
Paddy Ross ◽  
Zhiheng Zhou ◽  
Lars Strother
Keyword(s):  
Visual Word ◽  
Cortical Region ◽  
Word Form ◽  
Visual Word Form Area ◽  
Action Analysis ◽  
Sequential Activation ◽  
Occipitotemporal Cortex ◽  
Fmri Analysis ◽  
Biological Shape ◽  
New Hypothesis

There is ongoing debate about what characteristics of left ventral occipitotemporal cortex drive development of the Visual Word Form Area (VWFA). We offer a new hypothesis. A summary of occipitotemporal organization indicates that the VWFA falls in a cortical region supporting action analysis, rather than object recognition. We discuss evidence that letters are serially processed in a top-down manner during the initial years of reading acquisition, and propose that this sequential activation of letter representations causes the VWFA to develop in motion-sensitive cortex specialized for processing of non-biological shape sequences. Supporting this hypothesis, a new fMRI analysis identifies a left-lateralized region that responds more strongly to dynamic motion of objects than humans; this region's location (-48, -55, -8) falls almost exactly at the canonical VWFA coordinates (-45, -57, -12).

scholarly journals Neural Responses of the Anterior Ventral Occipitotemporal Cortex in Developmental Dyslexia: Beyond the Visual Word Form Area

2019 ◽  
Vol 60 (4) ◽  
pp. 1063 ◽  
Author(s):  
Ana Pina Rodrigues ◽  
José Rebola ◽  
Marcelino Pereira ◽  
Marieke van Asselen ◽  
Miguel Castelo-Branco
Keyword(s):  
Developmental Dyslexia ◽  
Visual Word ◽  
Word Form ◽  
Neural Responses ◽  
Visual Word Form Area ◽  
Occipitotemporal Cortex

scholarly journals Simulating the emergence of the Visual Word Form Area: Recycling a convolutional neural network for reading

2021 ◽  
Author(s):  
T. Hannagan ◽  
A. Agrawal ◽  
L. Cohen ◽  
S. Dehaene
Keyword(s):  
Neural Network ◽  
Convolutional Neural Network ◽  
Language Processing ◽  
Visual Pathway ◽  
Visual Word ◽  
Letter Recognition ◽  
Word Form ◽  
Invariant Representation ◽  
Visual Word Form Area ◽  
Ventral Visual Pathway

AbstractThe visual word form area (VWFA) is a region of human inferotemporal cortex that emerges at a fixed location in 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 universal localization is due to pre-existing 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. Our simulation fleshes out the neuronal recycling hypothesis, and make several testable predictions concerning the neural code for written words.

Encoding in the Visual Word Form Area: An fMRI Adaptation Study of Words versus Handwriting

2010 ◽  
Vol 22 (8) ◽  
pp. 1649-1661 ◽  
Author(s):  
Jason J. S. Barton ◽  
Christopher J. Fox ◽  
Alla Sekunova ◽  
Giuseppe Iaria
Keyword(s):  
Text Processing ◽  
Handwriting Recognition ◽  
Visual Word ◽  
Middle Temporal Gyrus ◽  
Word Form ◽  
Visual Word Form Area ◽  
Repetition Suppression ◽  
The Right ◽  
Fmri Adaptation ◽  
Left Middle Temporal Gyrus

Written texts are not just words but complex multidimensional stimuli, including aspects such as case, font, and handwriting style, for example. Neuropsychological reports suggest that left fusiform lesions can impair the reading of text for word (lexical) content, being associated with alexia, whereas right-sided lesions may impair handwriting recognition. We used fMRI adaptation in 13 healthy participants to determine if repetition–suppression occurred for words but not handwriting in the left visual word form area (VWFA) and the reverse in the right fusiform gyrus. Contrary to these expectations, we found adaptation for handwriting but not for words in both the left VWFA and the right VWFA homologue. A trend to adaptation for words but not handwriting was seen only in the left middle temporal gyrus. An analysis of anterior and posterior subdivisions of the left VWFA also failed to show any adaptation for words. We conclude that the right and the left fusiform gyri show similar patterns of adaptation for handwriting, consistent with a predominantly perceptual contribution to text processing.

scholarly journals Neurodegeneration of the visual word form area in a patient with word form alexia

2021 ◽  
Author(s):  
Adithya Chandregowda ◽  
Joseph R. Duffy ◽  
Mary M. Machulda ◽  
Val J. Lowe ◽  
Jennifer L. Whitwell ◽  
...  
Keyword(s):  
Visual Word ◽  
Word Form ◽  
Visual Word Form Area

scholarly journals Spoken language coding neurons in the Visual Word Form Area: Evidence from a TMS adaptation paradigm

NeuroImage ◽  
2019 ◽  
Vol 186 ◽  
pp. 278-285 ◽  
Author(s):  
Chotiga Pattamadilok ◽  
Samuel Planton ◽  
Mireille Bonnard
Keyword(s):  
Spoken Language ◽  
Visual Word ◽  
Word Form ◽  
Visual Word Form Area

scholarly journals Cortical selectivity driven by connectivity: Innate connectivity patterns of the visual word form area

2019 ◽  
Author(s):  
Jin Li ◽  
David E. Osher ◽  
Heather A. Hansen ◽  
Zeynep M. Saygin
Keyword(s):  
Resting State ◽  
Functional Organization ◽  
Resting State Fmri ◽  
Visual Word ◽  
Functional Specialization ◽  
Word Form ◽  
Visual Word Form Area ◽  
Connectivity Patterns ◽  
Set Up ◽  
Language Network

AbstractWhat determines the functional organization of cortex? One hypothesis is that innate connectivity patterns set up a scaffold upon which functional specialization can later take place. We tested this hypothesis by asking whether the visual word form area (VWFA), an experience-driven region, was already connected to proto language networks in neonates scanned within one week of birth. With resting-state fMRI, we found that neonates showed adult-like functional connectivity, and observed that i) language regions connected more strongly with the putative VWFA than other adjacent ventral visual regions that also show foveal bias, and ii) the VWFA connected more strongly with frontotemporal language regions than with regions adjacent to these language regions. These data suggest that the location of the VWFA is earmarked at birth due to its connectivity with the language network, providing evidence that innate connectivity instructs the later refinement of cortex.

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