Department of Neurobiology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
Front Neural Circuits. 2020 Jan 28;13:82. doi: 10.3389/fncir.2019.00082. eCollection 2019.
Associative learning of pure tones is known to cause tonotopic map expansion in the auditory cortex (ACx), but the function this plasticity sub-serves is unclear. We developed an automated training platform called the "Educage," which was used to train mice on a go/no-go auditory discrimination task to their perceptual limits, for difficult discriminations among pure tones or natural sounds. Spiking responses of excitatory and inhibitory parvalbumin (PV) L2/3 neurons in mouse ACx revealed learning-induced overrepresentation of the learned frequencies, as expected from previous literature. The coordinated plasticity of excitatory and inhibitory neurons supports a role for PV neurons in homeostatic maintenance of excitation-inhibition balance within the circuit. Using a novel computational model to study auditory tuning curves, we show that overrepresentation of the learned tones does not necessarily improve discrimination performance of the network to these tones. In a separate set of experiments, we trained mice to discriminate among natural sounds. Perceptual learning of natural sounds induced "sparsening" and decorrelation of the neural response, consequently improving discrimination of these complex sounds. This signature of plasticity in A1 highlights its role in coding natural sounds.
已知纯音的联想学习会导致听觉皮层（ACx）中的音调图扩张，但这种可塑性的功能尚不清楚。我们开发了一个名为“Educage”的自动化训练平台，用于在听觉辨别任务中对老鼠进行训练，使其达到感知极限，以便对纯音或自然声音进行困难的辨别。兴奋性和抑制性小脑蛋白（PV）L2/3 神经元在小鼠 ACx 中的尖峰反应显示出学习引起的所学习频率的过度表达，这与以前的文献一致。兴奋性和抑制性神经元的协调可塑性支持 PV 神经元在回路中兴奋-抑制平衡的自动维持中的作用。使用一种新的计算模型来研究听觉调谐曲线，我们表明，所学习音调的过度表达不一定会提高网络对这些音调的辨别性能。在一组单独的实验中，我们训练老鼠辨别自然声音。自然声音的感知学习诱导了神经反应的“稀疏化”和去相关，从而提高了对这些复杂声音的辨别能力。A1 中的这种可塑性特征突出了其对自然声音编码的作用。
