Phonological activation in pure alexia

International audiencePure alexia is a reading impairment in which patients appear to read letter-by-letter. This disorder is typically accounted for in terms of a peripheral deficit that occurs early on in the reading system, prior to the activation of orthographic word representations. The peripheral interpretation of pure alexia has recently been challenged by the phonological deficit hypothesis, which claims that a postlexical disconnection between orthographic and phonological information contributes to or is responsible for the disorder. Because this hypothesis was mainly supported by data from a single patient (IH), who also has surface dyslexia, the present study re-examined this hypothesis with another pure alexic patient (EL). In contrast to patient IH, EL did not show any evidence of a phonological deficit. Her pattern of performance in naming was not qualitatively different from that of normal readers; she appeared to be reading via a mode of processing resulting in strong serial and lexical effects, a pattern often observed in normal individuals reading unfamiliar stimuli. The present results do not obviously support the phonological hypothesis and are more consistent with peripheral interpretations of pure alexia. The peripheral and the phonological accounts of pure alexia are discussed in light of two current models of visual word recognition

Nuclear and electronic contributions to the third-order nonlinearity in different glasses

Using, a time resolved optical heterodyne Kerr effect experiment along with a Raman light diffusion experiment, we have measured the nuclear (non-instantaneous) and electronic (instantaneous) contributions to the nonlinear index of refraction in tellurite niobium-doped and silicate lead-doped glasses. The experimental set-up and the procedure used to measure the nuclear and electronic contribution are detailed. Our experimental results clearly indicate that the ratio between the instantaneous and the non-instantaneous contribution remain constant while the doping concentration or the temperature of the sample vary. These ratios are ˜5 and ˜10 in tellurite niobium-doped and silicate lead glasses, respectively

Visual phonology: The effects of orthographic consistency on different auditory word recognition tasks

International audienceIn this study, we investigated orthographic influences on spoken word recognition. The degree of spelling inconsistency was manipulated while rime phonology was held constant. Inconsistent words with subdominant spellings were processed more slowly than inconsistent words with dominant spellings. This graded consistency effect was obtained in three experiments. However, the effect was strongest in lexical decision, intermediate in rime detection, and weakest in auditory naming. We conclude that (1) orthographic consistency effects are not artifacts of phonological, phonetic, or phonotactic properties of the stimulus material; (2) orthographic effects can be found even when the error rate is extremely low, which rules out the possibility that they result from strategies used to reduce task difficulty; and (3) orthographic effects are not restricted to lexical decision. However, they are stronger in lexical decision than in other tasks. Overall, the study shows that learning about orthography alters the way we process spoken language

Phonology Matters: The Phonological Frequency Effect in Written Chinese

Does phonology play a role in silent reading? This issue was addressed in Chinese. Phonology effects are less expected in Chinese than in alphabetical languages like English because the basic-units of written Chinese (the characters) map directly into units of meaning (morphemes). This linguistic property gave rise to the view that phonology could be bypassed altogether in Chinese. The present study, however, shows that this is not the case. We report two experiments that demonstrate pure phonological frequency effects in processing written Chinese. Characters with a high phonological frequency were processed faster than characters with a low phonological frequency, despite the fact that the characters were matched on orthographic (printed) frequency. The present research points to a universal phonological principle according to which phonological information is routinely activated as a part of word identification. The research further suggests that part of the classic word-frequency effect may be phonological.link_to_subscribed_fulltex

MR imaging assessment of myocardial edema with T2 mapping

International audienceCardiac magnetic resonance (CMR) provides a high signal-to-noise ratio, high spatial and temporal resolutions, as well as a delayed-enhancement sequence and is therefore considered a reference technique in the field of cardiac imaging. However, currently available sequences are not adequate to assess some pathologic conditions, such as myocardial edema. T2 mapping sequences generate parametric images that are based on the transverse relaxation time (T2) for each voxel. In case of edema, the T2 relaxation time is longer. This review summarizes current knowledge on CMR T2 mapping for assessing myocardial edema