Institution: Stanford University
Talk Title: Effect of Attentional State on Experience Dependent Visual Cortical Neuroplasticity: Contrast Response Function Changes as a Result of Attention to Visual Stimulus Across Days
Abstract: Passive viewing of a flickering checkerboard has been shown to induce potentiation of EEG visual evoked responses in both rodents and humans, providing a noninvasive technique for measuring experience-dependent visual cortical neuroplasticity sometimes referred to as stimulus-specific response potentiation (SSRP). The most robust form of SSRP identified in humans is a 10-minute presentation of a full field high-contrast checkerboard stimulus that contrast-reverses at 2 Hz (See, e.g. Norman et al Biological Psychiatry 2007). It is well known that attention has a powerful effect on perceptual learning and memory, but how attention regulates experience-dependent neuroplasticity, if at all, is little studied and has not been tested in the context of SSRP. Here we decided to test if attentional state affects the neuroplasticity measured with SSRP. We hypothesize that attentional deployment to the induction stimulus enhances response potentiation specifically within the retinotopic extent of the induction stimulus, while attending away from the induction stimulus may suppress response potentiation. This would be evidenced by a larger leftward shift and/or increased slope of the Contrast Response Function when attention is directed to the potentiated stimulus. Our preliminary data (n=27) suggests that post-induction neural activity increased regardless of attentional deployment. Interestingly, when analyzing the potentiated hemifield data across days, our results preliminarily demonstrate a greater SSRP induced response enhancement on the second day compared to the first day. Additionally, response potentiation occurred in both the potentiated (left) and control non-potentiated (right) hemifield, suggesting that SSRP effects can extend beyond the retinotopic extent of the induction stimulus.