The cell distributions estimated from the data suggested that the neurons in the fovea tends to prefer higher spatial frequency than in the parafovea, which is consistent to the physiological insight in animal cortex. ❋ Satohiro Tajima Et Al. (2010)
It has not been explained by previously proposed computational frameworks why there is such a qualitative disparity between the fovea and the parafovea, and why the sensitivity in the parafovea forms an N-shaped curve Empirically and theoretically obtained thresholds for discriminating falloff parameters ❋ Satohiro Tajima Et Al. (2010)
Hess RF (2006) Discrimination of amplitude spectrum slope in the fovea and parafovea and the local amplitude distributions of natural scene imagery. ❋ Satohiro Tajima Et Al. (2010)
Note the slightly different result between fovea and parafovea when considering gain control among neurons, because the distribution of cell number doi: 10.1371/journal. pone.0009704.g006 ❋ Satohiro Tajima Et Al. (2010)
Figure 5d depicts the neuronal distributions in fovea and parafovea estimated by fitting the data to the model with gain control. ❋ Satohiro Tajima Et Al. (2010)
The inset figures show the spatial frequency tuning curves of each of seven neurons, illustrating the difference in the distributions of the peak preferred frequencies between the fovea and the parafovea. ❋ Satohiro Tajima Et Al. (2010)
The model suggested that the differences between performance in fovea and parafovea could be explained by taking into account the distributional difference of cortical neurons over preferred frequencies. ❋ Satohiro Tajima Et Al. (2010)
To get an intuitive understanding of how the qualitative difference between the fovea and the parafovea arises in the model, it is illustrative to follow the process by which the Fisher information is derived from the Figure 3 depicts the procedure for computing the Fisher information from the neuronal tuning curves. ❋ Satohiro Tajima Et Al. (2010)
We have found that the expected fovea-parafovea difference in the cell distribution over the preferred spatial frequency would cause a qualitative disparity among the psychophysical skills in the fovea and the parafovea, which was not demonstrated previously. ❋ Satohiro Tajima Et Al. (2010)
The difference between the fovea and the parafovea is most apparent for stimuli with relatively small ❋ Satohiro Tajima Et Al. (2010)
Of particular interest, a reported qualitative disparity between performance in fovea and parafovea can be explained based on the distributional difference over preferred frequencies of neurons in the current model. ❋ Satohiro Tajima Et Al. (2010)
This is because the model with gain control more precisely locates the peaks and dips of the plot, although both models can reproduce the qualitative structures (fovea-parafovea difference and N-shaped threshold curve in the parafovea) of the subject's sensitivity. ❋ Satohiro Tajima Et Al. (2010)
Distribution of neurons explains fovea-parafovea difference ❋ Satohiro Tajima Et Al. (2010)
This indicates that the neuronal interaction need not be primarily considered for explaining the human sensitivity to the changes in value, especially when we focus on the origin of its qualitative structures such as the fovea-parafovea difference and N-shaped sensitivity curve seen in the parafovea. ❋ Satohiro Tajima Et Al. (2010)
The model parameters were set to be the same for both conditions except that the fovea had a broader distribution of the unit's preferred spatial frequency, covering a relatively higher frequency domain than the parafovea; this assumption is in qualitative agreement with an electrophysiological study that intensively investigated the spatial frequency selectivity of Macaque striate cells with various loci of receptive fields ❋ Satohiro Tajima Et Al. (2010)
For the parafovea, the discrimination threshold peaks at a small whereas no peak is observed for foveal presentation, as the data show in ❋ Satohiro Tajima Et Al. (2010)
Brown and red curves show the thresholds for fovea and parafovea, respectively. doi: 10.1371/journal. pone.0009704.g002 ❋ Satohiro Tajima Et Al. (2010)
The model explains the reported qualitative and quantitative differences in human performance between the fovea and the parafovea. ❋ Satohiro Tajima Et Al. (2010)
The panels a-c and d-f in the figure show the cases for the fovea and the parafovea, respectively. ❋ Satohiro Tajima Et Al. (2010)
We show that the neuronal distribution profile plays an important role in the emergence of the fovea-parafovea difference. ❋ Satohiro Tajima Et Al. (2010)
