Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA; Tianqiao and Chrissy Chen Brain-Machine Interface Center, California Institute of Technology, Pasadena, CA, USA.
Neuron. 2018 Jan 3;97(1):209-220.e3. doi: 10.1016/j.neuron.2017.11.029. Epub 2017 Dec 14.
The human posterior parietal cortex (PPC) is thought to contribute to memory retrieval, but little is known about its specific role. We recorded single PPC neurons of two human tetraplegic subjects implanted with microelectrode arrays, who performed a recognition memory task. We found two groups of neurons that signaled memory-based choices. Memory-selective neurons preferred either novel or familiar stimuli, scaled their response as a function of confidence, and signaled subjective choices regardless of truth. Confidence-selective neurons signaled confidence regardless of stimulus familiarity. Memory-selective signals appeared 553 ms after stimulus onset, but before action onset. Neurons also encoded spoken numbers, but these number-tuned neurons did not carry recognition signals. Together, this functional separation reveals action-independent coding of declarative memory-based familiarity and confidence of choices in human PPC. These data suggest that, in addition to sensory-motor integration, a function of human PPC is to utilize memory signals to make choices.
人类顶后皮质（PPC）被认为有助于记忆检索，但对于其具体作用知之甚少。我们记录了两名患有四肢瘫痪的植入微电极阵列的人类主体的单个 PPC 神经元，他们执行了识别记忆任务。我们发现了两组以记忆为基础做出选择的神经元。记忆选择神经元更喜欢新颖或熟悉的刺激，根据信心程度调整其反应，并在不考虑真相的情况下发出主观选择信号。信心选择神经元无论刺激熟悉度如何都发出信心信号。记忆选择信号出现在刺激出现后 553 毫秒，但在动作出现之前。神经元还编码了口语数字，但这些调谐数字的神经元没有携带识别信号。总的来说，这种功能分离揭示了人类 PPC 中与动作无关的陈述性记忆熟悉度和选择信心的独立编码。这些数据表明，除了感觉运动整合之外，人类 PPC 的功能之一是利用记忆信号做出选择。
