[show abstract][hide abstract] ABSTRACT: Neurobiology of reading research has yet to explore whether reliance on the ventral-lexical stream during word reading can be enhanced by the instructed reading strategy, or whether it is impervious to such strategies. We examined Instructions: name all vs. name words (based on spelling), Word Type: regular words vs. exception words, and Word Frequency (WF) in print (log(10) HAL WF) in an experiment while measuring fMRI BOLD and overt naming reaction time (RT) simultaneously. Instructions to name words increased overall reliance on the ventral-lexical stream, as measured by visible BOLD activation and the WF effect on RT, with regular words showing the greatest effects as a function of this reading strategy. Furthermore, the pattern of joint effects of these variables on RT supports the notion of cascaded, not parallel, processing. These results can be accommodated by dual-stream cascaded models of reading, and present a challenge to single-mechanism parallel processing models.
[show abstract][hide abstract] ABSTRACT: The aim of this study is to evaluate the data from a participant in a reading study who had a diagnosis of Meares-Irlen syndrome/visual stress (MISViS). MISViS is characterised by visual distortions and somatic issues, which are remediated using coloured filters. The authors present a case study providing descriptive neurobiological comparisons of MISViS versus a control group. The study involved eleven English language speakers who participated in behavioural and neuroimaging versions of a language experiment with varied proportions of regular and exception words. Behavioural measures included accuracy and response times. Neuroimaging was conducted using a 1.5T Siemens Sonata MRI. The MISViS participant's data were removed from the overall experiment and analysed as a case study. Impulse response functions (IRFs) and percentage of active voxels were extracted from four regions of interest: BAs 17, 18, 19, and the postcentral gyrus (PG) and two control regions (BA6 and left BA45). The results indicated that significant differences existed between the control group and the MISViS participant for IRF intensity in two regions (BA6 and PG) and percentage of active voxels in four regions (BA17, BA19, PG, and BA6). No significant differences occurred in left BA45 for either variable of interest. No significant differences were found for behavioural measures. In conclusion, our findings offer one of the first neurobiological descriptions of differences in IRF intensity and percentage of active voxels in visual and somatosensory cortex during a language experiment for a participant with MISViS in the absence of migraine compared to controls.
[show abstract][hide abstract] ABSTRACT: The Frequency (high vs. low) × Regularity (regular vs. exception) interaction found on naming response times is often taken as evidence for parallel processing of sub-lexical and lexical systems. Using a Go/No-go naming task, we investigated the effect of nonword versus pseudohomophone foils on sub-lexical processing and the subsequent Frequency × Regularity interaction. We ran two experiments: (1) a Go/No-go naming task with nonword foils (e.g., bint) and (2) a Go/No-go naming task with pseudohomophone foils (e.g., pynt). Experiment 1 replicated the Frequency × Regularity interaction on naming response times supporting the notion of parallel sub-lexical and lexical processing. Experiment 2 eliminated the Frequency × Regularity interaction providing evidence for the modulation of sub-lexical information. These results indicate that using pseudohomophones in the Go/No-go naming task minimized information provided from sub-lexical processing and maximized information provided from the lexical system.
Journal of Psycholinguistic Research 09/2011; 40(5-6):367-78. · 0.59 Impact Factor