Abstract
Size perception is influenced by several visual information such as spatial (Murray et al., 2006; Sperandio et al., 2012) and temporal contextual cues (Pooresmaeili et al., 2013), but there is also a functional contribution from other senses, such as audition (Jaekl et al., 2012; Takeshima and Gyoba, 2013). Moreover, we recently demonstrated how auditory information can influence a visual aftereffect, generated using an adaptation paradigm (Tonelli et al., 2017). In this study, we investigated the interaction between audition and size visual adaptation at the neural level. We modified our previous paradigm, presenting an adapter stimulus of constant size and, in the same portion of space, a test stimulus of three different sizes: half, equal and one fifth bigger than the adapter. We had two condition: one just visual and one in which, at the same time of the test, we bilaterally presented a sound at 9000hz. For each condition, we used the ERPs triggered by the adapter stimulus as baseline to obtain a delta for each size of the test stimulus, by subtracting the baseline from the test ERPs. In the posterior channels, we found different activations based on the size of the test stimulus after adaptation in the earliest (20–70ms) component and in the P1/N1 complex (120–170ms and 220–270ms). Interestingly, this modulation is greater in the presence of the sound that seems to boost the visual ERP components these time windows. Results suggest that auditory cues not only contribute to functional estimation of size perception, but can also influence the effect of visual size adaptation, by increasing the posterior activations.