Equivalent Responses to Lexical and Nonlexical Visual Stimuli in Occipital Cortex: A Functional Magnetic Resonance Imaging Study

Indefrey, Peter; Kleinschmidt, Andreas; Merboldt, Klaus‐Dietmar; Krüger, Gunnar; Brown, Colin; Hagoort, Peter; Frahm, Jens

doi:10.1006/nimg.1996.0232

Cited by 81 publications

(43 citation statements)

References 7 publications

(21 reference statements)

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“…1) or modulation of activation (Fig. 2) in the posterior superior temporal lobe, a region often activated by words and pronounceable nonwords in comparison to unpronounceable strings (Booth et al, 2002;Herbster et al, 1997;Howard et al, 1992;Indefrey et al, 1997;Price et al, 1996;Tagamets et al, 2000). We propose that this posterior superior temporal region (centered on the posterior superior temporal sulcus) is sensitive to the pronounceability of letter strings, consistent with its hypothesized role in phonological access and visual-auditory integration (Callan et al, 2005;Hickok et al, 2000;Indefrey and Levelt, 2000;Van Atteveldt et al, 2004;Wise et al, 2001).…”

Section: Discussionsupporting

confidence: 60%

Tuning of the human left fusiform gyrus to sublexical orthographic structure

et al. 2006

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Neuropsychological and neurophysiological evidence point to a role for the left fusiform gyrus in visual word recognition, but the specific nature of this role remains a topic of debate. The aim of this study was to measure the sensitivity of this region to sublexical orthographic structure. We measured blood oxygenation (BOLD) changes in the brain with functional magnetic resonance imaging while fluent readers of English viewed meaningless letter strings. The stimuli varied systematically in their approximation to English orthography, as measured by the probability of occurrence of letters and sequential letter pairs (bigrams) comprising the string. A whole-brain analysis showed a single region in the lateral left fusiform gyrus where BOLD signal increased with letter sequence probability; no other brain region showed this response pattern. The results suggest tuning of this cortical area to letter probabilities as a result of perceptual experience and provide a possible neural correlate for the 'word superiority effect' observed in letter perception research.Much evidence supports the idea that perceptual systems become selectively efficient at processing inputs that are encountered frequently. In learning a written language, for example, human brains appear to become tuned to the recurring visual patterns of the language represented in its orthographic structure. This is illustrated by the fact that letters embedded in words (such as S in the English word FLASH) or in word-like letter strings (S in FRISH) are more efficiently recognized than letters embedded in unusual letter strings (S in RFHSL) (McClelland and Rumelhart, 1981;Reicher, 1969). Such evidence suggests that normal readers use information about frequently recurring letter combinations, encoded as a result of experience with a specific written language, to more efficiently perceive and identify letters and letter strings.Neuropsychological evidence for an orthographic processor in the brain comes from patients who exhibit 'letter-by-letter reading' after left occipitotemporal brain injury (Binder and Mohr, 1992;Cohen et al., 2003;Leff et al., 2001;Sakurai et al., 2000). Such patients have normal language functions, including good recognition of single letters, but show profoundly impaired processing of letter strings, suggesting focal damage to systems responsible for storing or using orthographic information (Behrmann et al., 1998;Patterson and Kay, 1982;Warrington and Shallice, 1980). This localization is supported by neuroimaging experiments in normal readers, which have identified a region in the lateral left fusiform (occipitotemporal) gyrus that responds more strongly to words and word-like nonwords than to consonant letter strings or nonsense characters Dehaene et al., 2001;Polk and Farah, 2002 1999). Several elegant studies showed that this orthographic system employs an abstract code that is unaffected by changes in letter case (Dehaene et al., 2001Polk and Farah, 2002).Although activation in this brain region appears to be relat...

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Section: Discussionsupporting

confidence: 60%

Tuning of the human left fusiform gyrus to sublexical orthographic structure

et al. 2006

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“…Studies with a 150 ms or shorter duration generally reported more activation for words and word-like stimuli, whereas studies with a duration as long as 750 ms did not show such a pattern (Indefrey et al, 1997) and sometimes showed a reversed pattern (Xue et al, 2006). In two PET studies (Price et al, 1996(Price et al, , 1994, Price and her colleagues systematically explored the effect of presentation duration on word processing.…”

Section: The Effect Of Presentation Durationmentioning

confidence: 99%

Language experience shapes early electrophysiological responses to visual stimuli: The effects of writing system, stimulus length, and presentation duration

et al. 2008

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How language experience affects visual word recognition has been a topic of intense interest. Using event-related potentials (ERPs), the present study compared the early electrophysiological responses (i.e., N1) to familiar and unfamiliar writings under different conditions. Thirteen native Chinese speakers (with English as their second language) were recruited to passively view four types of scripts: Chinese (familiar logographic writings), English (familiar alphabetic writings), Korean Hangul (unfamiliar logographic writings), and Tibetan (unfamiliar alphabetic writings). Stimuli also differed in lexicality (words vs. nonwords, for familiar writings only), length (characters/letters vs. words), and presentation duration (100 ms vs. 750 ms). We found no significant differences between words and non-words, and the effect of language experience (familiar vs. unfamiliar) was significantly modulated by stimulus length and writing system, and to a less degree, by presentation duration. That is, the language experience effect (i.e., a stronger N1 response to familiar writings than to unfamiliar writings) was significant only for alphabetic letters, but not for alphabetic and logographic words. The difference between Chinese characters and unfamiliar logographic characters was significant under the condition of short presentation duration, but not under the condition of long presentation duration. Long stimuli elicited a stronger N1 response than did short stimuli, but this effect was significantly attenuated for familiar writings. These results suggest that N1 response might not reliably differentiate familiar and unfamiliar writings. More importantly, our results suggest that N1 is modulated by visual, linguistic, and task factors, which has important implications for the visual expertise hypothesis.

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“…Two recent studies of reading, one using PET (Mechelli, Humphreys, Mayall, Olson, & Price, 2000) and one using fMRI (Indefrey et al, 1997), revealed monotonic increases in signal strength as a function of word length. These effects were visible in the midline posterior occipital cortex, bordering on the fusiform gyrus.…”

Section: Letter String Lengthmentioning

confidence: 99%

Cortical Effects of Shifting Letter Position in Letter Strings of Varying Length

Cornelissen

Tarkiainen²,

Helenius³

et al. 2003

Journal of Cognitive Neuroscience

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Abstract& Neuroimaging and lesion studies suggest that occipitotemporal brain areas play a necessary role in recognizing a wide variety of objects, be they faces, letters, numbers, or household items. However, many questions remain regarding the details of exactly what kinds of information are processed by the occipito-temporal cortex. Here, we address this question with respect to reading. Ten healthy adult subjects performed a single word reading task. We used whole-head magnetoencephalography to measure the spatio-temporal dynamics of brain responses, and investigated their sensitivity to: (1) lexicality (defined here as the difference between words and consonant strings), (2) word length, and (3) variation in letter position. Analysis revealed that midline occipital activity around 100 msec, consistent with low-level visual feature analysis, was insensitive to lexicality and variation in letter position, but was slightly affected by string length. Bilateral occipito-temporal activations around 150 msec were insensitive to lexicality and reacted to word length only in the timing (and not strength) of activation. However, vertical shifts in letter position revealed a hemispheric imbalance: The right hemisphere activation increased with the shifts, whereas the opposite pattern was evident in the left hemisphere. The results are discussed in the light of Caramazza and Hillis's (1990) model of early reading. &

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Equivalent Responses to Lexical and Nonlexical Visual Stimuli in Occipital Cortex: A Functional Magnetic Resonance Imaging Study

Cited by 81 publications

References 7 publications

Tuning of the human left fusiform gyrus to sublexical orthographic structure

Tuning of the human left fusiform gyrus to sublexical orthographic structure

Language experience shapes early electrophysiological responses to visual stimuli: The effects of writing system, stimulus length, and presentation duration

Cortical Effects of Shifting Letter Position in Letter Strings of Varying Length

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