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Chizuru T. Homma and Hiroshi Ashida

Abstract

Cognition of space and time affect each other; a line with longer length appears to be longer in exposure duration (space on time), and a line with longer exposure duration appears to be longer in length (time on space). This cognitive interaction is known to be asymmetric; the effect of space on time is larger than that of time on space. We conjectured that this asymmetry is not intrinsic but may depend on the saliency of relevant signals. Participants were asked to judge the visual exposure duration of lines that varied in length or the lengths of the lines with different exposure times. The ranges of task-relevant and -irrelevant stimulus values were the same in the spatial and temporal tasks. Task difficulty was also evaluated by subjective rating. We found that duration affected the judgment of length more than vice versa, when the spatial task was significantly more difficult than the temporal task. Together with our previous results that showed the opposite effect, our conjecture is supported that the saliency of stimuli should affect the balance of interactions.

Jonathan T. W. Schubert, Jonathan T. W. Schubert, Tobias Heed, Jonathan T. W. Schubert, Tobias Heed, Julia Föcker, Jonathan T. W. Schubert, Tobias Heed, Julia Föcker and Brigitte Röder

Sighted individuals seem to represent skin locations automatically in anatomical and external reference frames (Shore et al., 2002; Yamamoto and Kitazawa, 2001), which are reflected in lateralized oscillatory activity in the beta and alpha range, respectively (Buchholz et al., 2013). Congenitally blind individuals do not seem to automatically activate external reference frames suggesting a crucial contribution of developmental vision for touch localization.

We recorded EEG while sighted and congenitally blind participants directed attention to one hand in order to detect rare tactile targets at this hand only. In each trial, the relevant hand was indicated by an auditory cue (S1) which preceded the tactile stimulus (S2) by 1000 ms. Participants either adapted an uncrossed or a crossed hand posture. Attention- and posture-related power modulations in the alpha band were analyzed.

In the sighted orienting attention to one uncrossed hand (S1–S2 interval) was accompanied by an alpha reduction over contralateral parietal cortex and an alpha increase over ipsilateral cortex. With hands crossed a contralateral alpha decrease (relative to the anatomical hand) was still observed, but the ipsilateral alpha increase was less pronounced.

In the blind orienting attention to one of the hands was accompanied by a contralateral alpha decrease over parietal cortex which extended towards the ipsilateral hemisphere as well. By contrast, an alpha increase was not observed. This pattern of alpha activation in the congenital blind remained unchanged when they adopted a crossed hand posture.

These findings complement ERP evidence about deployment of attention in sighted and blind (Eardley and van Velzen, 2011) and extend previous evidence that alpha activity related mechanisms of attention control depend on developmental vision.

Stephen T. Hammett and Andrei Gorea

Anne Giersch and Jennifer T. Coull

Mark T. Wallace, Mark T. Wallace, Andrea Hillock-Dunn, Mark T. Wallace, Andrea Hillock-Dunn, Dipanwita Ghose, Mark T. Wallace, Andrea Hillock-Dunn, Dipanwita Ghose, Juliane Krueger-Fister, Mark T. Wallace, Andrea Hillock-Dunn, Dipanwita Ghose, Juliane Krueger-Fister, Diana Sarko, Mark T. Wallace, Andrea Hillock-Dunn, Dipanwita Ghose, Juliane Krueger-Fister, Diana Sarko and Ryan Stevenson

The talk will compare and contrast results from animal neurophysiological and human psychophysical studies that have focused on characterizing the maturation of temporal factors that are critical determinants in the integration of audiovisual stimuli. In the animal model realm, individual neurons in both cortical and subcortical structures progress through a series of developmental stages. During this maturational progression, neurons first transition from having temporal tuning profiles that are quite narrow to having tuning functions that are very broad. This initial period of broadening is then followed by a more protracted developmental period in which these temporal tuning profiles gradually narrow to achieve adult-like values. In human development, where we have studied children from ages 6–18, a gradual narrowing of multisensory temporal function, specifically in the width of the multisensory temporal binding window, is observed. Our evidence suggests that this window is not fully mature until late adolescence, highlighting a surprisingly long period during which multisensory temporal function is changing. These results will be discussed in the context of their implications for both behavioral and perceptual development.

Frederick A.A. Kingdom and Kathy T. Mullen