Animal Physiology, Institute of Neurobiology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
Animal Physiology, Institute of Neurobiology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
Curr Biol. 2019 Aug 19;29(16):2616-2624.e4. doi: 10.1016/j.cub.2019.06.060. Epub 2019 Aug 1.
Birds are renowned for their excellent spatial cognition. Corvid songbirds, in particular, rely on explicit representation of spatial cues in memory when caching food and retrieving caches for later consumption. However, the neuronal correlates of flexible spatial memory abilities are largely unknown in birds. We therefore trained carrion crows (Corvus corone) on a spatial delayed-response task in which they had to maintain the variable location of a visual item for a few seconds in working memory. After the crows performed this task with high precision, we recorded single-cell activity from the associative endbrain area Nidopallium caudolaterale (NCL) in the behaving crows. A large fraction of NCL neurons were tuned to individual preferred locations and selectively maintained the spatial location of items in working memory. A comparison of firing rates with reaction times suggested that the majority of delay-selective neurons represented stored location information rather than motor preparation. Almost 30% of all recorded neurons were tuned during both visual presentation and memory delay, and their spatial tuning was significantly correlated. The population of recorded neurons stably maintained spatial information over the course of the working memory period. Importantly, the neural responses of spatially tuned neurons were relevant for the crows' choices and allowed a statistical classifier to predict the subsequently chosen target location in free-choice trials. Our findings demonstrate the pivotal role of the avian NCL in spatial working memory that is reminiscent of the function of the convergently evolved primate prefrontal cortex in spatial working memory.
鸟类以出色的空间认知能力而闻名。特别是鸦科鸣禽，在储存食物和检索以备后用时，依赖于对空间线索的明确记忆表现。然而，鸟类中灵活的空间记忆能力的神经元相关性在很大程度上尚不清楚。因此，我们在空间延迟反应任务中对秃鼻乌鸦进行了训练，在该任务中，它们必须在工作记忆中保持视觉项目的可变位置几秒钟。在乌鸦以高精度执行此任务后，我们记录了在行为乌鸦中与关联端脑区 Nidopallium caudolaterale（NCL）的单细胞活动。NCL 的很大一部分神经元被调整到个体偏好位置，并选择性地保持工作记忆中项目的空间位置。与反应时间的比较表明，大多数延迟选择神经元代表存储的位置信息，而不是运动准备。几乎 30%的记录神经元在视觉呈现和记忆延迟期间被调整，它们的空间调整明显相关。记录神经元的群体在工作记忆期间稳定地维持空间信息。重要的是，空间调整神经元的神经反应与乌鸦的选择有关，并允许统计分类器在自由选择试验中预测随后选择的目标位置。我们的研究结果表明，鸟类 NCL 在空间工作记忆中起着关键作用，这让人联想到趋同进化的灵长类动物前额叶皮层在空间工作记忆中的功能。
