麦戈文系列学术讲座
报告题目1：The first-night effect suppresses the strength of slow-wave activity originating in the visual areas during sleep
报告人1：Yuka Sasaki
Associate Professor (Research),
Department of Cognitive, Linguistic & Psychological Sciences, Brown University
摘要1：Our visual system is plastic and adaptive in response to the stimuli and environments we experience. Although visual adaptation and plasticity have been extensively studied while participants are awake, little is known about what happens while they are asleep. It has been documented that sleep structure as measured by sleep stages using polysomnography is altered specifically in the first sleep session due to exposure to a new sleep environment, known as the first-night effect (FNE). However, the impact of the FNE on spontaneous oscillations in the visual system is poorly understood. How does the FNE affect the visual system during sleep? To address this question, the present study examined whether the FNE modifies the strength of slow-wave activity (SWA, 1–4 Hz)—the dominant spontaneous brain oscillation in slow-wave sleep—in the visual areas. We measured the strength of SWA originating in the visual areas during the first and the second sleep sessions. Magnetoencephalography, polysomnography, and magnetic resonance imaging were used to localize the source of SWA to the visual areas. The visual areas were objectively defined using retinotopic mapping and an automated anatomical parcellation technique. The results showed that the strength of SWA was reduced in the first sleep session in comparison to the second sleep session, especially during slow-wave sleep, in the ventral part of the visual areas. These results suggest that environmental novelty may affect the visual system through suppression of SWA. The impact of the FNE may not be negligible in vision research.
报告题目2：Roles of attention and reward in perceptual learning
报告人2：Takeo Watanabe
Professor,
Department of Cognitive, Linguistic & Psychological Sciences, Brown University
摘要2：Perceptual learning (PL) is defined as long-term performance improvement on a perceptual task as a result of perceptual experience. We first found that PL occurs for task-irrelevant and subthreshold features and that pairing task-irrelevant features with rewards is the key to form task-irrelevant PL (TIPL) (Watanabe, Nanez & Sasaki, Nature, 2001; Watanabe et al, 2002, Nature Neuroscience; Seitz & Watanabe, Nature, 2003; Seitz, Kim & Watanabe, 2009, Neuron; Shibata et al, 2012, Science). These results suggest that PL occurs as a result of interactions between reinforcement and bottom-up stimulus signals (Seitz & Watanabe, 2005, TICS). On the other hand, fMRI study results indicate that lateral prefrontal cortex fails to detect and thus to suppress subthreshold task-irrelevant signals. This leads to the paradoxical effect that a signal that is below, but close to, one’s discrimination threshold ends up being stronger than suprathreshold signals (Tsushima, Ssasaki & Watanabe, 2006, Science). We confirmed this mechanism by showing that task-irrelevant learning occurs only when a presented feature is under and close to the threshold (Tsushima et al,2009, Current Biol). From all of these results, we conclude that attention and reward play important but different roles in PL.
时间：2014年4月22日（周二）下午13:00-16:00 PM
地点：新生物楼101报告厅
邀请人：Prof. Fang Fang
欢迎各位老师和同学积极参加！