Center for the Neurobiology of Learning and Memory, Department of Neurobiology and Behavior, University of California, Irvine, CA 92697-3800, United States.
Neuroscience. 2013 Aug 29;246:40-51. doi: 10.1016/j.neuroscience.2013.04.038. Epub 2013 Apr 29.
Neural mechanisms underlying the capacity of memory to be rich in sensory detail are largely unknown. A candidate mechanism is learning-induced plasticity that remodels the adult sensory cortex. Here, expansion in the primary auditory cortical (A1) tonotopic map of rats was induced by pairing a 3.66-kHz tone with activation of the nucleus basalis, mimicking the effects of natural associative learning. Remodeling of A1 produced de novo specific behavioral memory, but neither memory nor plasticity was consistently at the frequency of the paired tone, which typically decreased in A1 representation. Rather, there was a specific match between individual subjects' area of expansion and the tone that was strongest in each animal's memory, as determined by post-training frequency generalization gradients. These findings provide the first demonstration of a match between the artificial induction of specific neural representational plasticity and artificial induction of behavioral memory. As such, together with prior and present findings for detection, correlation and mimicry of plasticity with the acquisition of memory, they satisfy a key criterion for neural substrates of memory. This demonstrates that directly remodeling sensory cortical maps is sufficient for the specificity of memory formation.
记忆能够丰富感官细节的神经机制在很大程度上尚不清楚。一种候选机制是学习诱导的可塑性，它重塑了成年感觉皮层。在这里，通过将 3.66 kHz 的音调与基底核的激活相匹配，诱导大鼠初级听觉皮层 (A1) 的音高拓扑图扩张，模拟自然联想学习的效果。A1 的重塑产生了新的特定行为记忆，但无论是记忆还是可塑性都不一致地处于配对音调的频率，该频率通常在 A1 表示中降低。相反，在每个动物的记忆中最强的情况下，个别主体的扩展区域与音调之间存在特定的匹配，这是通过训练后频率概括梯度来确定的。这些发现首次证明了特定神经代表性可塑性的人工诱导与行为记忆的人工诱导之间的匹配。因此，结合先前和当前关于检测、相关性和可塑性与记忆获取的模拟的发现，它们满足了记忆神经基质的一个关键标准。这表明直接重塑感觉皮层地图足以形成记忆的特异性。
