Efficient visual object and word recognition relies on high spatial frequency coding in the left posterior fusiform gyrus: Evidence from a case-series of patients with ventral occipito-temporal cortex damage

Recent visual neuroscience investigations suggest that ventral occipito-temporal cortex is retinotopically organized, with high acuity foveal input projecting primarily to the posterior fusiform gyrus (pFG), making this region crucial for coding high spatial frequency information. Because high spatial frequencies are critical for fine-grained visual discrimination, we hypothesized that damage to the left pFG should have an adverse effect not only on efficient reading, as observed in pure alexia, but also on the processing of complex non-orthographic visual stimuli. Consistent with this hypothesis, we obtained evidence that a large case series (n = 20) of patients with lesions centered on left pFG: 1) Exhibited reduced sensitivity to high spatial frequencies; 2) demonstrated prolonged response latencies both in reading (pure alexia) and object naming; and 3) were especially sensitive to visual complexity and similarity when discriminating between novel visual patterns. These results suggest that the patients' dual reading and non-orthographic recognition impairments have a common underlying mechanism and reflect the loss of high spatial frequency visual information normally coded in the left pFG

Developmental surface dysgraphia without surface dyslexia

The case is reported of an individual (NK) with a developmental spelling impairment (dysgraphia) who has no apparent problems in reading. His performance is therefore similar to a case of dysgraphia without dyslexia (PJT) reported by Hepner, McCloskey & Rapp (2017), and provides further evidence of a classical dissociation between impaired spelling and preserved reading in individuals with developmental literacy problems. The dissociation is observed when NK is asked to read and spell in either his first (Greek) or his second language (English). An investigation of his spelling performance revealed that his impairment was more selective than that of PJT. Although his spelling of regular words and nonwords was normal, NK had a problem in spelling words with atypical sound-letter associations despite having no problems in reading aloud or understanding the meaning of words of this kind. It is argued that NK’s pattern of performance can be best explained in terms of normal development of an orthographic system that allows access to the meaning and pronunciation of written words during reading. In terms of a dual route model of spelling, his poor spelling appears to be the result of a developmental impairment that impedes access to the orthographic system from phonology and semantics. In terms of the triangle model, his poor spelling appears to be the result of a developmental impairment that affects activation of orthography from semantics

Lexical decision performance in developmental surface dysgraphia: Evidence for a unitary orthographic system that is used in both reading and spelling.

The relationship between spelling, written word recognition and picture naming is investigated in a study of seven bilingual adults who have developmental surface dysgraphia in both Greek (their first language) and English (their second language). Four of the cases also performed poorly at orthographic lexical decision in both languages. This finding is consistent with similar results in Italian that have been taken as evidence of a developmental impairment to a single orthographic system that is used for both reading and spelling (e.g. Angelelli, Marinelli, & Zoccolotti, 2010). The remaining three participants performed well at orthographic lexical decision. At first sight, preserved lexical decision in surface dysgraphia is less easy to explain in terms of a shared orthographic system. However, the results of subsequent experiments showed clear parallels between the nature of the reading and spelling difficulties that these three individuals experienced, consistent with the existence of a single orthographic system. The different patterns that were observed were consistent with the claims of Friedmann and Lukov (2008) and Gvion and Friedmann (2016) that several distinct sub-types of developmental surface dyslexia exist. We show that individual differences in spelling in surface dysgraphia are also consistent with these sub-types; there are different developmental deficits that can give rise, in an individual, to a combination of surface dyslexia and dysgraphia. Finally, we compare the theoretical framework used by Friedmann and her colleagues that is based upon the architecture of the DRC model (Coltheart, Rastle, Perry, Langdon, & Zeigler, 2001) with an account that relies instead upon the Triangle model of reading (Plaut, McClelland, Seidenberg & Patterson, 1996)

The production of nominal and verbal inflection in an agglutinative language: evidence from Hungarian

The contrast between regular and irregular inflectional morphology has been useful in investigating the functional and neural architecture of language. However, most studies have examined the regular/irregular distinction in non-agglutinative Indo-European languages (primarily English) with relatively simple morphology. Additionally, the majority of research has focused on verbal rather than nominal inflectional morphology. The present study attempts to address these gaps by introducing both plural and past tense production tasks in Hungarian, an agglutinative non-Indo-European language with complex morphology. Here we report results on these tasks from healthy Hungarian native-speaking adults, in whom we examine regular and irregular nominal and verbal inflection in a within-subjects design. Regular and irregular nouns and verbs were stem on frequency, word length and phonological structure, and both accuracy and response times were acquired. The results revealed that the regular/irregular contrast yields similar patterns in Hungarian, for both nominal and verbal inflection, as in previous studies of non-agglutinative Indo-European languages: the production of irregular inflected forms was both less accurate and slower than of regular forms, both for plural and past-tense inflection. The results replicate and extend previous findings to an agglutinative language with complex morphology. Together with previous studies, the evidence suggests that the regular/irregular distinction yields a basic behavioral pattern that holds across language families and linguistic typologies. Finally, the study sets the stage for further research examining the neurocognitive substrates of regular and irregular morphology in an agglutinative non-Indo-European language