Attentional Modulation of Early Visual Activity during Visual Short-Term Memory Encoding

• Main Authors: Hsin-Ya Fan, 范馨亞
• Other Authors: Ching-Po Lin
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/41589655875064170844

碩士 === 國立陽明大學 === 神經科學研究所 === 101 === Previous evidence has revealed that top-down attention biases neural responses in early visual areas to favor the perceptual analysis of the attended visual field at the corresponding retinotopic location. Recently, similar effects of attentional modulation have been shown to occur in visual short-term memory (VSTM) (Harrison &; Tong, 2009; Jehee, Brady, &; Tong, 2011; Serences, Ester, Vogel, &; Awh, 2009). However, the neural mechanisms by which attention facilitates the encoding of VSTM events remain unclear. In this study, we used functional magnetic resonance imaging (fMRI) to investigate whether attentional biasing of the corresponding retinotopic visual activity modulates VSTM encoding by manipulating spatial-based attention with two levels of VSTM load in a delay-response task. We observed greater overall BOLD responses with spatial attention in V1-V3 cortices, and the same was observed with high VSTM load and with higher order of early visual areas. It was revealed that attentional modulation in these areas reduced when VSTM load increased, however, this effect was not statistically significant. These results lend support to the assumption that early visual activity can be modulated by attention in VSTM encoding stage.