Persichetti Andrew S, Aguirre Geoffrey K, Thompson-Schill Sharon L
University of Pennsylvania.
J Cogn Neurosci. 2015 May;27(5):893-901. doi: 10.1162/jocn_a_00760. Epub 2014 Nov 12.
A central concern in the study of learning and decision-making is the identification of neural signals associated with the values of choice alternatives. An important factor in understanding the neural correlates of value is the representation of the object itself, separate from the act of choosing. Is it the case that the representation of an object within visual areas will change if it is associated with a particular value? We used fMRI adaptation to measure the neural similarity of a set of novel objects before and after participants learned to associate monetary values with the objects. We used a range of both positive and negative values to allow us to distinguish effects of behavioral salience (i.e., large vs. small values) from effects of valence (i.e., positive vs. negative values). During the scanning session, participants made a perceptual judgment unrelated to value. Crucially, the similarity of the visual features of any pair of objects did not predict the similarity of their value, so we could distinguish adaptation effects due to each dimension of similarity. Within early visual areas, we found that value similarity modulated the neural response to the objects after training. These results show that an abstract dimension, in this case, monetary value, modulates neural response to an object in visual areas of the brain even when attention is diverted.
学习与决策研究中的一个核心关注点是识别与选择选项的价值相关的神经信号。理解价值的神经关联的一个重要因素是物体本身的表征,它与选择行为是分开的。如果一个物体与特定价值相关联,那么视觉区域内该物体的表征会发生变化吗?我们使用功能磁共振成像适应技术来测量参与者学会将货币价值与一组新物体关联前后这些物体的神经相似性。我们使用了一系列正值和负值,以便能够区分行为显著性的影响(即大值与小值)和效价的影响(即正值与负值)。在扫描过程中,参与者进行了与价值无关的感知判断。至关重要的是,任何一对物体的视觉特征相似性并不能预测它们价值的相似性,因此我们能够区分由于相似性的每个维度而产生的适应效应。在早期视觉区域内,我们发现训练后价值相似性调节了对物体的神经反应。这些结果表明,在这种情况下为货币价值的一个抽象维度,即使在注意力分散时,也会调节大脑视觉区域对物体的神经反应。