Unsupervised changes in core object recognition behavior are predicted by neural plasticity in inferior temporal cortex.
Unsupervised changes in core object recognition behavior are predicted by neural plasticity in inferior temporal cortex.
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DOI：
10.7554/elife.60830
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发表时间：
2021-06-11
期刊：
影响因子：
7.7
通讯作者：
DiCarlo JJ
中科院分区：
文献类型：
--
作者：
Jia X;Hong H;DiCarlo JJ
物体识别的时间连续性是自然视觉输入的一个特征，并可能被腹侧视觉流以一种无监督的方式利用，在颞下皮层（IT）中建立神经表征。在这里，我们研究了个体IT神经元的可塑性是否在无监督视觉经验诱导的人类核心物体识别行为变化的基础上。我们建立了一个单神经元可塑性模型，结合先前建立的IT人口-识别-行为联系模型来预测人类的学习效果。我们发现，在神经生理学数据的约束下，我们的模型在很大程度上预测了人类表现变化的平均方向、幅度和时间过程。我们还发现了先前未报道的观察到的人类表现变化对初始任务难度的依赖性。这一结果支持了一种假设，即人类和非人类灵长类动物的容忍核心物体识别是由自然发生的无监督的时间连续经验指导的——至少部分是这样。熊就是熊，不管它有多远，也不管我们从什么角度看它。事实上，在不同环境中识别物体的能力是我们视觉的重要组成部分。大脑中一个被称为颞下皮层（简称IT）的区域在这一壮举中起着关键作用。在灵长类动物中，IT皮质神经细胞群的活动与对不同物体的识别有关——相反，抑制IT皮质活动会损害物体识别行为。尽管物体的大小、位置或方向发生了变化，但这些细胞仍对其保持选择性，因此人们认为，无论物体的视觉特性如何变化，IT皮层都具有识别物体的能力。这种宽容是如何产生的？一种被称为“时间连续性”的特性被认为与此有关——换句话说，物体不会瞬间出现或消失。对非人类灵长类动物的研究表明，时间连续性确实可以重塑IT皮层神经细胞的活动，而对人类的行为实验表明，它会影响识别物体的能力。然而，这两组研究使用了不同的视觉任务，因此尚不清楚在猴子身上观察到的细胞过程是否真的支持人类的行为效应。因此，Jia等人开始研究这两者之间的联系。在最初的实验中，人类志愿者以一种无人监督的方式接受了一组视觉任务，这些任务的设计与之前在非人类灵长类动物身上进行的测试类似。研究人员向参与者展示了不同大小的相同或不同物体的连续视图，然后进行了物体识别测试。随着时间的推移，这些操作导致志愿者的尺寸容忍度发生了变化。为了测试哪种细胞机制支持这种行为效应，Jia等人建立了一个模型，模拟了个体IT细胞和IT网络的可塑性，以预测志愿者观察到的物体识别的变化。该模型的高可预测性表明，IT皮层的可塑性确实解释了志愿者的行为变化。这些结果让我们对时间连续性在视觉中的作用有了新的认识，使我们对信息技术皮层帮助我们评估周围世界的方式有了更深入的了解。
Temporal continuity of object identity is a feature of natural visual input and is potentially exploited – in an unsupervised manner – by the ventral visual stream to build the neural representation in inferior temporal (IT) cortex. Here, we investigated whether plasticity of individual IT neurons underlies human core object recognition behavioral changes induced with unsupervised visual experience. We built a single-neuron plasticity model combined with a previously established IT population-to-recognition-behavior-linking model to predict human learning effects. We found that our model, after constrained by neurophysiological data, largely predicted the mean direction, magnitude, and time course of human performance changes. We also found a previously unreported dependency of the observed human performance change on the initial task difficulty. This result adds support to the hypothesis that tolerant core object recognition in human and non-human primates is instructed – at least in part – by naturally occurring unsupervised temporal contiguity experience. A bear is a bear, regardless of how far away it is, or the angle at which we view it. And indeed, the ability to recognize objects in different contexts is an important part of our sense of vision. A brain region called the inferior temporal (IT for short) cortex plays a critical role in this feat. In primates, the activity of groups of IT cortical nerve cells correlates with recognition of different objects – and conversely, suppressing IT cortical activity impairs object recognition behavior. Because these cells remain selective to an item despite changes of size, position or orientation, the IT cortex is thought to underly the ability to recognise an object regardless of variations in its visual properties. How does this tolerance arise? A property called ‘temporal continuity’ is thought to be involved – in other words, the fact that objects do not blink in and out of existence. Studies in nonhuman primates have shown that temporal continuity can indeed reshape the activity of nerve cells in the IT cortex, while behavioural experiments with humans suggest that it affects the ability to recognize objects. However, these two sets of studies used different visual tasks, so it is still unknown if the cellular processes observed in monkey IT actually underpin the behavioural effects shown in humans. Jia et al. therefore set out to examine the link between the two. In the initial experiments, human volunteers were given, in an unsupervised manner, a set of visual tasks designed similarly to the previous tests in nonhuman primates. The participants were presented with continuous views of the same or different objects at various sizes, and then given tests of object recognition. These manipulations resulted in volunteers showing altered size tolerance over time. Aiming to test which cellular mechanism underpinned this behavioural effect, Jia et al. built a model that simulated the plasticity of individual IT cells and the IT networks, to predict the changes of object recognition observed in the volunteers. A high predictability of the model revealed that the plasticity in IT cortex did indeed account for the behavioral changes in the volunteers. These results shed new light on the role that temporal continuity plays in vision, refining our understanding of the way the IT cortex helps to assess the world around us.