Temporal-prefrontal cortical network for discrimination of valuable objects in long-term memory
Temporal-prefrontal cortical network for discrimination of valuable objects in long-term memory
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DOI：
10.1073/pnas.1707695115
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发表时间：
2018-02-27
影响因子：
11.1
通讯作者：
Hikosaka, Okihide
中科院分区：
文献类型：
--
作者：
Ghazizadeh, Ali;Griggs, Whitney;Hikosaka, Okihide
根据先前学到的价值记忆和区分对象对于目标导向行为至关重要。虽然我们知道大脑皮层有助于物体识别，但令人惊讶的是，人们对它在保持长期物体-价值关联方面的作用知之甚少。为了解决这个问题，我们训练猕猴将小或大的奖励与许多随机分形对象（>100）任意关联，然后使用fMRI研究大脑中基于价值的反应选择性的长期保留。我们发现，在颞叶和前额叶皮层的核心子区域中，训练后几个月，与低奖励（“坏”刺激）相比，先前与高奖励（“好”刺激）相关的分形引起了升高的fMRI反应。在纹状体、杏仁核和屏状核的子区域也观察到类似的长期基于值的调制，但在海马体中没有。值调制的颞-前额叶子区域表现出很强的静息态功能相互连接。此外，对于这个核心以外的地区，长期价值反应的幅度预测的休息状态功能连接到核心次区域的强度。在单独的测试中，自由观看的凝视行为表明猴子对物体价值保持了稳定的长期记忆。这些结果表明，在颞叶-前额叶回路及其相关的皮层下区域中存在一种内隐和高容量的记忆机制，用于长期保留可以指导价值取向行为的对象-价值记忆。
Remembering and discriminating objects based on their previously learned values are essential for goal-directed behaviors. While the cerebral cortex is known to contribute to object recognition, surprisingly little is known about its role in retaining long-term object-value associations. To address this question, we trained macaques to arbitrarily associate small or large rewards with many random fractal objects (>100) and then used fMRI to study the long-term retention of value-based response selectivity across the brain. We found a pronounced long-term value memory in core subregions of temporal and prefrontal cortex where, several months after training, fractals previously associated with high reward ("good" stimuli) elicited elevated fMRI responses compared with those associated with low reward ("bad" stimuli). Similar long-term value-based modulation was also observed in subregions of the striatum, amygdala, and claustrum, but not in the hippocampus. The value-modulated temporal-prefrontal subregions showed strong resting-state functional connectivity to each other. Moreover, for areas outside this core, the magnitude of long-term value responses was predicted by the strength of resting-state functional connectivity to the core subregions. In separate testing, free-viewing gaze behavior indicated that the monkeys retained stable long-term memory of object value. These results suggest an implicit and high-capacity memory mechanism in the temporal-prefrontal circuitry and its associated subcortical regions for long-term retention of object-value memories that can guide value-oriented behavior.