Current Biology:数字在大脑中的表现形式
作者: 心理学 / 3825次阅读 时间: 2011年4月04日
来源: 转载








心理学之家 推荐原文原始出处:

Current Biology, 24 September 2009 doi:10.1016/j.cub.2009.08.047

Deciphering Cortical Number Coding from Human Brain Activity Patterns

Evelyn Eger1, 2, 3, , , Vincent Michel2, 3, 4, Bertrand Thirion2, 4, Alexis Amadon2, 5, Stanislas Dehaene1, 2, 3 and Andreas Kleinschmidt1, 2, 3

1 INSERM U562, F-91191 Gif/Yvette, France

2 NeuroSpin, Institut d'Imagerie Biomédicale, Direction des Sciences du Vivant, Commissariat à l'énergie Atomique, F-91191 Gif/Yvette, France

3 Université Paris-Sud, F-91405 Orsay, France

4 Parietal Team, Institut National de Recherche en Informatique et en Automatique (INRIA) Saclay-?le-de-France, F-91893 Orsay, France

5 Laboratoire de Résonance Magnétique Nucléaire, F-91191 Gif/Yvette, France

Neuropsychology and human functional neuroimaging have implicated human parietal cortex in numerical processing, and macaque electrophysiology has shown that intraparietal areas house neurons tuned to numerosity. Yet although the areas responding overall during numerical tasks have been well defined by neuroimaging, a direct demonstration of individual number coding by spatial patterns has thus far been elusive.We used multivariate pattern recognition on high-resolution functional imaging data to decode the information content of fine-scale signals evoked by different individual numbers. Parietal activation patterns for individual numerosities could be accurately discriminated and generalized across changes in low-level stimulus parameters. Distinct patterns were evoked by symbolic and nonsymbolic number formats, and individual digits were less accurately decoded (albeit still with significant accuracy) than numbers of dots. Interestingly, the numerosity of dot sets could be predicted above chance from the brain activation patterns evoked by digits, but not vice versa. Finally, number-evoked patterns changed in a gradual fashion as a function of numerical distance for the nonsymbolic notation, compatible with some degree of orderly layout of individual number representations.Our findings demonstrate partial format invariance of individual number codes that is compatible with more numerous but more broadly tuned populations for nonsymbolic than for symbolic numbers, as postulated by recent computational models. In more general terms, our results illustrate the potential of functional magnetic resonance imaging pattern recognition to understand the detailed format of representations within a single semantic category, and beyond sensory cortical areas for which columnar architectures are well established.

«Nature:关于大脑决策机制的一个新理论 认知心理学