2014年6月4日水曜日

Novelty Enhances Visual Salience Independently of Reward in the Parietal Lobe

Nicholas C. Foley, David C. Jangraw, Christopher Peck, and Jacqueline Gottlieb
The Journal of Neuroscience, 4 June 2014, 34(23):7947-7957;

刺激の「価値(報酬予測)」と「新規性」はどちらもその刺激に対する注意を増加させることが知られている。
価値と新規性は別々に注意に影響を与えているのか?それとも、お互いに関連するのか?
サルの視線とLIPニューロンの活動を調べたところ、前者っぽい。

Novelty modulates sensory and reward processes, but it remains unknown how these effects interact, i.e., how the visual effects of novelty are related to its motivational effects. A widespread hypothesis, based on findings that novelty activates reward-related structures, is that all the effects of novelty are explained in terms of reward. According to this idea, a novel stimulus is by default assigned high reward value and hence high salience, but this salience rapidly decreases if the stimulus signals a negative outcome. Here we show that, contrary to this idea, novelty affects visual salience in the monkey lateral intraparietal area (LIP) in ways that are independent of expected reward. Monkeys viewed peripheral visual cues that were novel or familiar (received few or many exposures) and predicted whether the trial will have a positive or a negative outcome—i.e., end in a reward or a lack of reward. We used a saccade-based assay to detect whether the cues automatically attracted or repelled attention from their visual field location. We show that salience—measured in saccades and LIP responses—was enhanced by both novelty and positive reward associations, but these factors were dissociable and habituated on different timescales. The monkeys rapidly recognized that a novel stimulus signaled a negative outcome (and withheld anticipatory licking within the first few presentations), but the salience of that stimulus remained high for multiple subsequent presentations. Therefore, novelty can provide an intrinsic bonus for attention that extends beyond the first presentation and is independent of physical rewards.

0 件のコメント:

コメントを投稿