Surprisingly, this position selectivity was nearly as precise in the regions that displayed a negative BOLD response as in those that displayed a positive BOLD response; regions that display either a positive or a negative BOLD response discriminated objects separated by 0.19 deg.
The recency test group successfully discriminated objects in the first sample phase from those in the more recent, second sample phase, one-sample t test; D1 t(8) = 5.67, p <.001; D2 t(8) = 6.42, p <.001.
This implies that further processing is needed to discriminate object contours from texture edges.
Shotton et al. [7] described a model for discriminating object classes that efficiently incorporates texture, layout, and contextual information.
The whisker somatosensory system is crucial to rodents' ability to discriminate object location and identity.
However, if the ROI can discriminate object position, then the spatial correlation of activity produced by two Gabor stimuli should be higher when the two Gabors are nearer to each other.
Although the regions that display a negative BOLD response clearly have patterns of activity that are capable of discriminating object position (Fig. 7A), how does this compare to regions that display a positive BOLD response?
To address this, we separately defined every possible 5×5×5 cube of voxels in the entire occipital lobe (creating thousands of ROIs), performed the analysis above to obtain a position discrimination slope value for each ROI, and then created a new surface map that shows clusters of voxels that are best able to discriminate object position (see Materials and Methods).
For example, Gori, Del Viva, Sandini and Burr (2008) showed that children younger than 8 10 years did not optimally integrate visual and haptic information to reduce uncertainty when discriminating object size or orientation.
With a short delay between sample and choice phases showed normal discrimination, indicating that perirhinal tauopathy did not lead to a general inability to discriminate objects or assess their familiarity/novelty (Fig. 2E).
