Effects of category learning on the stimulus selectivity of macaque inferior temporal neurons
Effects of category learning on the stimulus selectivity of macaque inferior temporal neurons
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DOI：
10.1101/lm.1040508
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发表时间：
2008-09-01
影响因子：
2
通讯作者：
Vogels, Rufin
中科院分区：
文献类型：
--
作者：
De Baene, Wouter;Ons, Bart;Vogels, Rufin
灵长类动物可以学习对复杂的形状进行分类，但目前还不清楚这种分类学习如何影响视觉皮层对形状的表征。以往关于分类学习对猕猴下颞叶（IT）皮层形状表征的影响的研究已经产生了不同且相互矛盾的结果，由于设计上的不足，这些结果难以解释。本研究通过记录分类学习前后的信息技术反应来克服这些问题。我们使用沿两个形状维度变化的参数化形状。猴子被广泛地训练来根据两个维度中的一个对形状进行分类。与以前的研究不同，我们的范式在动物之间平衡了相关的分类维度。我们发现，分类学习增加了对类别相关刺激维度（即训练维度的扩展表示）的选择性，并且在相关维度（即类别调整）中，类别内反应相似性与类别间反应相似性的比率增加。只有当习得的类别相关效应与预先习得的刺激选择性分离时，这些小影响才明显。这些结果表明，形状分类学习可以诱导成人IT神经元的形状调谐发生轻微的类别相关变化，表明习得的、类别相关的神经元反应变化主要发生在IT的下游。
Primates can learn to categorize complex shapes, but as yet it is unclear how this categorization learning affects the representation of shape in visual cortex. Previous studies that have examined the effect of categorization learning on shape representation in the macaque inferior temporal (IT) cortex have produced diverse and conflicting results that are difficult to interpret owing to inadequacies in design. The present study overcomes these issues by recording IT responses before and after categorization learning. We used parameterized shapes that varied along two shape dimensions. Monkeys were extensively trained to categorize the shapes along one of the two dimensions. Unlike previous studies, our paradigm counterbalanced the relevant categorization dimension across animals. We found that categorization learning increased selectivity specifically for the category-relevant stimulus dimension (i.e., an expanded representation of the trained dimension), and that the ratio of within-category response similarities to between-category response similarities increased for the relevant dimension (i.e., category tuning). These small effects were only evident when the learned category-related effects were disentangled from the prelearned stimulus selectivity. These results suggest that shape-categorization learning can induce minor category-related changes in the shape tuning of IT neurons in adults, suggesting that learned, category-related changes in neuronal response mainly occur downstream from IT.