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Children and adults can approximate numbers of items, compare these approximations, and perform approximate arithmetic operations via a non-symbolic, pre-linguistic system called the Approximate Number System (ANS). Studies using neuroimaging techniques demonstrated the role of the parietal cortex in decoding both non-symbolic and symbolic quantity. Although it has been proven that the parietal regions are involved also in visual processing such as coherence motion perception, little is known about the relationship between these visual processes and the ANS. The aim of this study is to investigate whether the acuity in the ANS is related to dorsal and/or ventral visual functions. A sample of sixty-five typical development children (age 6-10 years; 42 males and 23 females) took part in the experiment. ANS acuity was measured using a numerical discrimination task (Halberda et al., 2008) in which participants were briefly shown arrays of yellow and blue dots and had to identify the more numerous array; a motion coherence test and a form coherence test were applied to evaluate dorsal and ventral stream functions respectively. In the motion test participants were asked to detect the direction of moving dots, in the form test participants had to recognize a form created by spatially aligned dots. We found significant correlations between ANS acuity and motion perception ability (p=0.014) as well as form discrimination ability (p=0.047). More specifically, higher performance in the motion and form tests are related to higher ANS acuity. The effect size values show that the magnitude of the relationship with the ANS was higher for the motion (partial η2=0.09) than for the form coherence test (partial η2=0.06). These results demonstrate that both dorsal and ventral visual processing influence ANS acuity but that the association between ANS and dorsal stream processing is slightly stronger.

Perceptual learning has been studied as a mechanism by which people automatically and implicitly learn. Alternatively, learning can occur explicitly mediated by conscious feed-back which controls and guides the subjects'(tm) performance. The aim of this study was to examine whether the explicit and implicit learning could produce different patterns of results in a visual motion discrimination task. We exposed 12 participants to four different sessions. A preliminary training session consisted of 120 trials of motion discrimination task repeated three times in different days to measure the explicit learning. The subject had to discriminate among 4 directions in motion test presented at 10% of coherence (considered as parathreshold). A pre-test in which the baseline was evaluated by the correct responses average in the motion discrimination task for each direction. The implicit learning session was tested using the classic paradigm of task-irrelevant perceptual learning (TIPL) (Seitz and Watanabe, 2003) in which learning was mediated by subliminally pairing one selected direction with specific targets of an unrelated training task. This phase consisted of 120 trials repeated 7 times in three days. After that a post-test similar to the pretest indicated the implicit learning effect. In the explicit learning the improvement is relatively poor and not significant. In the implicit learning the effect was clearly significant for the trained direction, while the subjects did not improve their performances in the other directions. These results of the stronger learning effect obtained in TIPL suggest that visual motion learning can benefit more from direct lower level processing then from mediated attention mechanisms related to explicit learning.