Using state-trace analysis to dissociate the functions of the human hippocampus and perirhinal cortex in recognition memory
Using state-trace analysis to dissociate the functions of the human hippocampus and perirhinal cortex in recognition memory
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DOI：
10.1073/pnas.1215710110
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发表时间：
2013-02-19
影响因子：
11.1
通讯作者：
Henson, Richard N.
中科院分区：
文献类型：
--
作者：
Staresina, Bernhard P.;Fell, Juergen;Henson, Richard N.
神经科学中一个反复出现的问题是关于两个或更多大脑区域是否执行本质上不同的功能的证据。在这里，我们介绍了状态跟踪分析在神经活动测量中的应用，说明了这种分析如何为定性不同的功能提供令人信服的证据，即使在功能和大脑测量之间的精确“神经测量”映射未知的情况下也是如此。通过这样做，我们解决了关于支持人类记忆的大脑系统的长期争论：海马体和大脑周围皮质，内侧颞叶记忆系统的两个关键组成部分，是否对识别记忆提供了定性不同的贡献。另一种解释是，这两个区域支持单一的共享功能，如记忆强度，而之前的神经成像研究获得的明显分离只是反映了不同区域之间不同的、非线性的神经测量映射。为了在这些情景之间做出判断，我们分析了在识别范式中直接从人的海马体和周围皮质获得的颅内脑电数据，并对作为不同类型记忆判断函数的检索线索引起的反应进行状态跟踪分析。只要假设每个区域的神经测量映射是单调的，任何一维理论(如记忆强度帐户)都会产生单调状态轨迹。关键的是，结果显示了一个非单调的状态轨迹；也就是说，在不同的记忆条件下，这两个区域的活动水平并没有显示出相同的相对顺序。这种非单调的状态轨迹表明，至少有两种不同的功能在海马体和周边皮质中实现，允许正式拒绝内侧颞叶对再认记忆的贡献的单过程解释。
A recurring issue in neuroscience concerns evidence as to whether two or more brain regions implement qualitatively different functions. Here we introduce the application of state-trace analysis to measures of neural activity, illustrating how this analysis can furnish compelling evidence for qualitatively different functions, even when the precise "neurometric" mapping between function and brain measure is unknown. In doing so, we address a long-standing debate about the brain systems supporting human memory: whether the hippocampus and the perirhinal cortex, two key components of the medial temporal lobe memory system, provide qualitatively different contributions to recognition memory. An alternative account has been that both regions support a single shared function, such as memory strength, with the apparent dissociations obtained by previous neuroimaging studies merely reflecting different, nonlinear neurometric mappings across regions. To adjudicate between these scenarios, we analyze intracranial electroencephalographic data obtained directly from human hippocampus and perirhinal cortex during a recognition paradigm and apply state-trace analysis to responses evoked by the retrieval cue as a function of different types of memory judgment. Assuming only that the neurometric mapping in each region is monotonic, any unidimensional theory (such as the memory-strength account) will produce a monotonic state trace. Critically, results showed a nonmonotonic state trace; that is, activity levels in the two regions did not show the same relative ordering across memory conditions. This nonmonotonic state trace demonstrates that there are at least two different functions implemented across the hippocampus and perirhinal cortex, allowing formal rejection of a single-process account of medial temporal lobe contributions to recognition memory.