Uncorrected Author Proof Restorative Neurology and Neuroscience xx (20xx) x–xx DOI 10.3233/RNN-140389 IOS Press 1 Specificity and generalization of perceptual learning in low myopia 1 2 Clara Casco a,∗ , Daniela Guzzon b , Monica Moise b , Antonella Vecchies b , Tiziano Testa b and Andrea Pavan c 3 4 a Department of General Psychology, University of Padova, Via Venezia, Padova, Italy 5 b Neuro.Vis.U.S.Laboratory, University of Padova, Via Belzoni, Padova, Italy 6 c Institut f ¨ ur Psychologie, Universit¨ at Regensburg, Universit¨ atsstr., Regensburg, Germany 7 Abstract. 8 Purpose: In this study we investigated in observers with low myopia: (i) the pattern of lateral interactions between stimuli activating early cortical analyzers and its modulation by perceptual learning (PL), and (ii) whether PL transferred to untrained stimuli and tasks and whether it exhibits interocular transfer. 9 10 11 Method: Participants (seven adults with low myopia) performed 12 training sessions. Participants were trained on a contrast detection task of a central Gabor target flanked by two co-oriented and co-aligned high contrast Gabor patches. Target-to-flankers separation along the vertical axis was varied from 2 wavelengths (λ) to 8λ. 12 13 14 Results: The results showed that before PL facilitatory lateral interactions in the myopic eye were reduced in strength, but PL increased contrast sensitivity and improved facilitatory lateral interactions. However, PL did not transfer to different local/global orientations and lower spatial frequencies. On the other hand, PL resulted in an enhancement of the contrast sensitivity function (CSF) and of the uncorrected visual acuity (UCVA) both in the trained and untrained eye. 15 16 17 18 Conclusions: Such improvements seem to be associated to a modulation of lateral interactions between target and flankers and it is likely to take place at a level in which the inputs from the two eyes converge. 19 20 Keywords: Low myopia, perceptual learning, lateral interactions, contrast sensitivity, visual acuity 21 1. Introduction 22 It is well known that performance on perceptual 23 tasks is improved by practice. This practice effect is 24 known as perceptual learning (PL). PL in adult human 25 observers has been shown for several tasks, such as 26 hyper-acuity (McKee and Westheimer, 1978; Poggio, 27 Fahle et al., 1992) phase discrimination in com- 28 pound gratings (Fiorentini and Berardi, 1981), motion 29 discrimination (Ball and Sekuler, 1982, 1987; Ball, 30 Sekuler, et al., 1983), texture discrimination based on 31 ∗ Corresponding author: Clara Casco, Department of General Psychology, University of Padova, Via Venezia 8, 35131, Padova, Italy. Tel.: +39 049 827 6610; E-mail: clara.casco@unipd.it. simple and combined features differences (Ahissar and 32 Hochstein, 1996; Casco, Campana et al., 2004; Casco 33 and Campana, 1999; Campana and Casco, 2003; Karni 34 and Sagi, 1991), and contrast polarity (Grieco, Casco 35 et al., 2006). The finding that the effect of training on 36 simple visual features was highly specific for location 37 in the visual field (Ahissar and Hochstein, 1996; Karni 38 and Sagi, 1991; Grieco, Casco et al., 2006; Fioren- 39 tini and Berardi, 1980), spatial frequency (Fiorentini 40 and Berardi, 1980), contrast polarity (Grieco, Casco 41 et al., 2006), local and global orientation (Ahissar and 42 Hochstein, 1996; Casco and Campana, 1999; Campana 43 and Casco, 2003; Karni and Sagi, 1991; Fiorentini and 44 Berardi, 1980; Casco, Caputo et al., 2001) and in some 45 case even the eye of origin (Karni and Sagi, 1991; 46 0922-6028/14/$27.50 © 2014 – IOS Press and the authors. All rights reserved