Unitized representation of paired objects in area 35 of the macaque perirhinal cortex
Unitized representation of paired objects in area 35 of the macaque perirhinal cortex
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DOI：
10.1111/j.1460-9568.2010.07320.x
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发表时间：
2010-08-01
影响因子：
3.4
通讯作者：
Miyashita, Yasushi
中科院分区：
文献类型：
--
作者：
Fujimichi, Ryoko;Naya, Yuji;Miyashita, Yasushi
鼻周皮层对于长期刺激-刺激联想记忆至关重要，由两个细胞结构不同的分区组成：35 区 (A35) 和 36 区 (A36)。先前的电生理学研究表明，猕猴 A36 在视觉成对联想任务中参与联想和检索过程。 However, the neuronal properties of macaque A35 have never been examined because A35 is located in a very narrow region, which makes it difficult to systematically record single-unit activity from there.在本研究中，我们通过将磁共振成像引导的体内定位与死后组织学定位相结合，克服了靶向 A35 的技术难题。这种双轨方法使我们能够在两只猕猴执行成对关联任务时记录它们的 181 个 A35 神经元。在这些神经元中，64 个在提示期表现出刺激选择性反应（提示选择性神经元），而 18 个在延迟期表现出刺激选择性反应（延迟选择性神经元）。与 A36 一样，A35 中线索选择性神经元对配对伙伴的反应是相关的。在这两个区域中，显示延迟选择性的神经元中的这些相关性比没有延迟选择性的神经元中的相关性更强。值得注意的是，A35 中的延迟选择性神经元对最佳刺激及其配对刺激的反应类似，而 A36 中的延迟选择性神经元则对它们进行区分。然而，这两个区域中的这些神经元都将由最佳刺激及其配对关联组成的主要对与其他对区分开来，表明两个区域之间保持了对之间的选择性。这些结果表明 A35 中的延迟选择性神经元将这些配对刺激表示为单个统一项目而不是两个相关项目。
The perirhinal cortex, which is critical for long-term stimulus-stimulus associative memory, consists of two cytoarchitectonically distinct subdivisions: area 35 (A35) and area 36 (A36). Previous electrophysiological studies suggested that macaque A36 is involved in both association and retrieval processes during a visual pair-association task. However, the neuronal properties of macaque A35 have never been examined because A35 is located in a very narrow region, which makes it difficult to systematically record single-unit activity from there. In the present study, we overcame this technical difficulty for targeting A35 by combining magnetic resonance imaging-guided in-vivo localization with postmortem histological localization. This two-track approach enabled us to record from 181 A35 neurons in two macaque monkeys while they performed a pair-association task. Among these neurons, 64 showed stimulus-selective responses during the cue period (cue-selective neurons), whereas 18 did during the delay period (delay-selective neurons). As in A36, the responses of cue-selective neurons in A35 to paired associates were correlated. In both areas, these correlations were stronger in neurons showing delay selectivity than in those without delay selectivity. Notably, delay-selective neurons in A35 responded similarly to the optimal stimulus and its paired associate, whereas delay-selective neurons in A36 discriminated between them. However, these neurons in both areas discriminated the primary pair, consisting of the optimal stimulus and its paired associate, from other pairs, indicating that selectivity across pairs was maintained between the two areas. These results suggest that delay-selective neurons in A35 represent these paired stimuli as a single unitized item rather than two associated items.