Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA.
Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA.
Cereb Cortex. 2021 Jul 29;31(9):4206-4219. doi: 10.1093/cercor/bhab079.
Working memory, the ability to maintain and transform information, is critical for cognition. Spatial working memory is particularly well studied. The premier model for spatial memory is the continuous attractor network, which posits that cells maintain constant activity over memory periods. Alternative models propose complex dynamics that result in a variety of cell activity time courses. We recorded from neurons in the frontal eye fields and dorsolateral prefrontal cortex of 2 macaques during long (5-15 s) memory periods. We found that memory cells turn on early after stimulus presentation, sustain activity for distinct and fixed lengths of time, then turn off and stay off for the remainder of the memory period. These dynamics are more complex than the dynamics of a canonical bump attractor network model (either decaying or nondecaying) but more constrained than the dynamics of fully heterogeneous memory models. We speculate that memory may be supported by multiple attractor networks working in parallel, with each network having its own characteristic mean turn-off time such that mnemonic resources are gradually freed up over time.
工作记忆是维持和转化信息的能力，对认知至关重要。空间工作记忆是研究得特别多的。空间记忆的主要模型是连续吸引子网络，它假设细胞在记忆期间保持恒定的活动。替代模型提出了导致各种细胞活动时间过程的复杂动力学。我们在 2 只猕猴的额眼区和背外侧前额叶皮层记录神经元，在长时间（5-15 秒）的记忆期间。我们发现记忆细胞在刺激呈现后早期开启，持续固定的时间长度，然后关闭并在记忆期间的其余时间保持关闭。这些动力学比经典的凸起吸引子网络模型（衰减或非衰减）的动力学更复杂，但比完全异构记忆模型的动力学更受约束。我们推测，记忆可能是由多个吸引子网络并行工作支持的，每个网络都有自己的特征平均关闭时间，因此记忆资源随着时间的推移逐渐释放。
