Martinovic Jasna, Gruber Thomas, Hantsch Ansgar, Müller Matthias M
Institut für Psychologie I, Universität Leipzig, Germany.
Brain Res. 2008 Mar 10;1198:93-106. doi: 10.1016/j.brainres.2007.12.050. Epub 2008 Jan 3.
Object recognition is subserved by mechanisms that seem to rely on the activity of distributed neural assemblies coordinated by synchronous firing in the gamma-band range (>20 Hz). The present study relied on a novel EEG-compatible plane-rotation paradigm to elicit view-dependent processing leading to delays in the recognition of disoriented objects. The paradigm involved a covert naming task (grammatical gender decision). The task's suitability was first evaluated through a control experiment that contrasted covert with overt naming. The plane-rotation paradigm was subsequently employed in an EEG experiment. It was found that recognition delays for disoriented objects were accompanied by induced gamma-band activity's (GBA) peak latency delays, replicating Martinovic, Gruber and Müller (2007, Journal of Cognitive Neuroscience). Brain electrical tomography was performed to obtain further information on the intracranial current density distributions underlying the latency shifts. Induced GBA was found to be generated by a set of distributed prefrontal, temporal and posterior sources committed to representational processing. Their relative contribution differed between upright and disoriented objects, as prefrontal activity became more prominent with increased disorientation. Together these findings indicate that adaptive changes in dynamic coding of object identity occur during recognition of disoriented objects. Induced GBA is a marker of pronounced sensitivity to these changes and thus a robust neural signature of representational activity in high-level vision.
物体识别由一些机制所支持，这些机制似乎依赖于由伽马波段范围（>20赫兹）的同步放电所协调的分布式神经集合的活动。本研究依赖于一种新型的与脑电图兼容的平面旋转范式，以引发视图依赖加工，从而导致对方向错乱物体的识别延迟。该范式涉及一个隐蔽命名任务（语法性属判定）。该任务的适用性首先通过一项将隐蔽命名与公开命名进行对比的对照实验进行评估。随后，平面旋转范式被用于一项脑电图实验。研究发现，对方向错乱物体的识别延迟伴随着诱发伽马波段活动（GBA）的峰值潜伏期延迟，重复了马尔蒂诺维奇、格鲁伯和米勒（2007年，《认知神经科学杂志》）的研究结果。进行了脑电断层扫描，以获取关于潜伏期变化背后颅内电流密度分布的更多信息。发现诱发的GBA是由一组致力于表征加工的分布式前额叶、颞叶和后部源产生的。它们的相对贡献在直立物体和方向错乱物体之间有所不同，随着方向错乱程度的增加，前额叶活动变得更加突出。这些发现共同表明，在对方向错乱物体的识别过程中，物体身份的动态编码会发生适应性变化。诱发的GBA是对这些变化显著敏感性的一个标志，因此是高级视觉中表征活动的一个强大神经特征。
