Department of Epileptology, University Hospital Bonn, Bonn, Germany.
Epilepsy Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Nat Neurosci. 2024 Mar;27(3):587-599. doi: 10.1038/s41593-023-01550-x. Epub 2024 Feb 16.
Associative memory enables the encoding and retrieval of relations between different stimuli. To better understand its neural basis, we investigated whether associative memory involves temporally correlated spiking of medial temporal lobe (MTL) neurons that exhibit stimulus-specific tuning. Using single-neuron recordings from patients with epilepsy performing an associative object-location memory task, we identified the object-specific and place-specific neurons that represented the separate elements of each memory. When patients encoded and retrieved particular memories, the relevant object-specific and place-specific neurons activated together during hippocampal ripples. This ripple-locked coactivity of stimulus-specific neurons emerged over time as the patients' associative learning progressed. Between encoding and retrieval, the ripple-locked timing of coactivity shifted, suggesting flexibility in the interaction between MTL neurons and hippocampal ripples according to behavioral demands. Our results are consistent with a cellular account of associative memory, in which hippocampal ripples coordinate the activity of specialized cellular populations to facilitate links between stimuli.
联想记忆使不同刺激之间的关系得以编码和检索。为了更好地理解其神经基础，我们研究了是否联想记忆涉及表现出刺激特异性调谐的内侧颞叶（MTL）神经元的时间相关尖峰。使用癫痫患者在进行联想物体-位置记忆任务时的单个神经元记录，我们确定了代表每个记忆的单独元素的特定物体和特定位置的神经元。当患者编码和检索特定记忆时，相关的特定物体和特定位置的神经元在海马回波期间一起激活。这种随着患者联想学习的进展而出现的与涟漪锁相的特定刺激神经元的共激活是随着时间的推移而出现的。在编码和检索之间，共激活的涟漪锁定时间发生了变化，这表明根据行为需求，MTL 神经元和海马回波之间的相互作用具有灵活性。我们的结果与联想记忆的细胞解释一致，其中海马回波协调专门细胞群体的活动，以促进刺激之间的联系。
