Temporal Components in the Parahippocampal Place Area Revealed by Human Intracerebral Recordings
Temporal Components in the Parahippocampal Place Area Revealed by Human Intracerebral Recordings
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DOI：
10.1523/jneurosci.4646-12.2013
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发表时间：
2013-06-12
影响因子：
5.3
通讯作者：
Epstein, Russell A.
中科院分区：
文献类型：
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作者：
Bastin, Julien;Vidal, Juan R.;Epstein, Russell A.
许多高级视觉区域表现出复杂的刺激选择模式，这使得它们的反应很难用单一的认知机制来解释。例如，在fMRI研究中，海马旁区（PPA）对环境场景的反应最大，但对非场景地标性物体（如具有完全不同几何结构的建筑物）的反应也很强烈。我们假设PPA对场景和建筑物的反应可能由不同的潜在机制和不同的时间剖面驱动。为了验证这一点，我们检查了人类脑内脑电图记录的宽带伽玛（50-150 Hz）反应，这是一种与人口峰值活动密切相关的测量方法。我们发现，PPA在大约80毫秒的时间内区分了场景和非场景刺激，这表明这是一个自下而上的过程，编码了特定场景的视觉或几何特征。相比之下，PPA对建筑物和非建筑物的不同反应发生得较晚（类似于170毫秒），这可能反映了对场景和物体可定义的空间或语义特征的延迟处理，可能结合了来自其他皮层区域的信号。虽然高级视觉区域的反应偏好通常被解释为单一认知机制的运作，但这些结果表明，当考虑到识别的动态时，会出现更复杂的画面。
Many high-level visual regions exhibit complex patterns of stimulus selectivity that make their responses difficult to explain in terms of a single cognitive mechanism. For example, the parahippocampal place area (PPA) responds maximally to environmental scenes during fMRI studies but also responds strongly to nonscene landmark objects, such as buildings, which have a quite different geometric structure. We hypothesized that PPA responses to scenes and buildings might be driven by different underlying mechanisms with different temporal profiles. To test this, we examined broadband gamma (50-150 Hz) responses from human intracerebral electroencephalography recordings, a measure that is closely related to population spiking activity. We found that the PPA distinguished scene from nonscene stimuli in similar to 80 ms, suggesting the operation of a bottom-up process that encodes scene-specific visual or geometric features. In contrast, the differential PPA response to buildings versus nonbuildings occurred later (similar to 170 ms) and may reflect a delayed processing of spatial or semantic features definable for both scenes and objects, perhaps incorporating signals from other cortical regions. Although the response preferences of high-level visual regions are usually interpreted in terms of the operation of a single cognitive mechanism, these results suggest that a more complex picture emerges when the dynamics of recognition are considered.