灵活而目标明确的行为能力要求在短时间内保持积极记忆和控制多种类型的信息，这种能力称为“工作记忆（WM）”。大脑接受的信息会自动保存在工作记忆中，如何描述和控制这些信息对了解大脑如何指导行为至关重要。
通常情况下，人们通过具体信息的刺激物来进行研究，如地点或文字。然而最近，研究人员一直在强调规则的重要性，即在刺激因素与等待回应之间建立联系。在7月10日《神经元》（Neuron）杂志发表的一篇文章中，Montojo和 Courtney 等人将心算与功能磁共振成像进行关联研究，测试在WM区控制下更新的数字（即刺激物）和更新的数学运算（即规则）是否依赖于相同的神经系统。
结果表明，虽然一个共同的神经网络激活这两种类型的更新，但更新规则却优先激活大脑皮层前额叶，而更新数字则优先激活大脑皮层顶叶。新研究结果说明，数字和运算规则同时在WM中储存，但它们却具有两种不同的神经激活机制。（科学网 武彦文/编译）
（《神经元》（Neuron），Vol 59, 173-182, 10 July 2008，Caroline A. Montojo and Susan M. Courtney）
更多阅读（英文）
Neuron, Vol 59, 173-182, 10 July 2008
Article
Differential Neural Activation for Updating Rule versus Stimulus Information in Working Memory
Caroline A. Montojo1 and Susan M. Courtney1,2,3,
Differential Neural Activation for Updating Rule versus Stimulus Information in Working Memory
Caroline A. Montojo1 and Susan M. Courtney1,2,3,
1 Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD 21218-2686, USA
2 Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21218-2686, USA
3 F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21218-2686, USA
2 Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21218-2686, USA
3 F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21218-2686, USA
Summary
Establishing what information is actively maintained in working memory (WM) and how it is represented and controlled is essential to understanding how such information guides future behavior. WM has traditionally been investigated in terms of the maintenance of stimulus-specific information, such as locations or words. More recently, investigators have emphasized the importance of rules that establish relationships between those stimuli and the pending response. The current study used a mental arithmetic task with fMRI to test whether updating of numbers (i.e., stimuli) and updating of mathematical operations (i.e., rules) in WM relies on the same neural system. Results indicate that, while a common network is activated by both types of updating, rule updating preferentially activates prefrontal cortex while number updating preferentially activates parietal cortex. The results suggest that both numbers and rules are maintained in WM but that they are different types of information that are controlled independently.
