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| Bernt C. Skottun; John R. Skoyles. |
| Conlon at al. (2011, Brain and Cognition, 76, 197-205) studied the responses of dyslexic readers and controls to rapidly presented stimuli. They found that the dyslexic readers showed poorer performance than the controls but only when the interstimulus interval (ISI) was short (150 ms), not when it was long (350 ms). This difference they attributed to a magnocellular or dorsal stream deficiency. However, they did not compute the temporal frequency spectra of the two stimuli. This is done here. It is found that it is very difficult to draw any conclusions with regard to the magnocellular system or the dorsal stream using these stimuli. |
| Tipo: Manuscript |
Palavras-chave: Neuroscience. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/6050/version/1 |
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| John Skoyles; Bernt C. Skottun. |
| Visual stream segregation has been proposed as a method to measure visual attention in dyslexia. Another task proposed to do this is the line-motion illusion. Both tasks, it is observed, can be carried out with spatially distributed stimuli. This, however, appears inconsistent with these tasks being linked speci?cally to attentional processes since this would require them to spatially focus cognitive resources. Also, both line-motion and visual stream segregation involve the perception of movement raising the possibility that what is actually measured by these tasks is not attention but some aspect of motion perception. |
| Tipo: Manuscript |
Palavras-chave: Neuroscience. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/5529/version/1 |
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| John R. Skoyles; Bernt C. Skottun. |
| A number of investigators have found perceptual deficits in schizophrenic subjects. It has also been indicated that those with schizophrenia suffer from reduced attention. This raises the possibility that their perceptual deficits may wholly or in part reflect attentional effects. The present study used computer simulations to examine the potential effects of inattention on performance measures determined with three psychophysical methods: the Two Alternative Forced Choice (2-AFC) Staircase Method, the Two Alternative Forced Choice (2-AFC) Fixed Stimuli Method, and the Yes/No Method. It is shown that both 2-AFC methods are susceptible to attentional effects but, in contrast, the Yes/No Method may allow for the differentiation of attentional effects from... |
| Tipo: Manuscript |
Palavras-chave: Neuroscience. |
| Ano: 2008 |
URL: http://precedings.nature.com/documents/1584/version/1 |
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| John Skoyles; Bernt C. Skottun. |
| Dyslexia and attentional problems are often comorbid. This raises the question whether reading deficits might etiologically follow from attentional difficulties, a hypothesis that has been proposed in regard to visuo-spatial attention deficits. This visuo-spatial attention deficit hypothesis would predict that attention deficits should be specific to dyslexia. However, it is here estimated that at the population level there are more non-dyslexic individuals than dyslexic individuals with visuo-spatial attention deficits. The reason for this is that in the overall population level there are far more individuals without dyslexia than with dyslexia. Thus, a relatively modest percentage presence of attention problems in the non-dyslexic population can result... |
| Tipo: Manuscript |
Palavras-chave: Neuroscience. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/5525/version/1 |
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