Department of Biology, Brandeis University, Waltham, United States.
Volen Center for Complex Systems, Brandeis University, Waltham, United States.
Elife. 2020 Jul 23;9:e58509. doi: 10.7554/eLife.58509.
Modifications of synaptic inputs and cell-intrinsic properties both contribute to neuronal plasticity and development. To better understand these mechanisms, we undertook an intracellular analysis of the development of direction selectivity in the ferret visual cortex, which occurs rapidly over a few days after eye opening. We found strong evidence of developmental changes in linear spatiotemporal receptive fields of simple cells, implying alterations in circuit inputs. Further, this receptive field plasticity was accompanied by increases in near-spike-threshold excitability and input-output gain that resulted in dramatically increased spiking responses in the experienced state. Increases in subthreshold membrane responses induced by the receptive field plasticity and the increased input-output spiking gain were both necessary to explain the elevated firing rates in experienced ferrets. These results demonstrate that cortical direction selectivity develops through a combination of plasticity in inputs and in cell-intrinsic properties.
突触输入的改变和细胞内在特性的改变都有助于神经元的可塑性和发育。为了更好地理解这些机制，我们对内侧膝状体神经元在视觉皮层中的方向选择性的发育进行了细胞内分析，这种发育在睁眼后几天内迅速发生。我们发现了简单细胞的线性时空感受野在发育过程中发生改变的有力证据，这表明了回路输入的改变。此外，这种感受野的可塑性伴随着接近峰电位阈值的兴奋性和输入-输出增益的增加，导致在有经验的状态下尖峰反应显著增加。感受野可塑性引起的亚阈值膜反应的增加和输入-输出尖峰增益的增加，对于解释有经验的雪貂中升高的放电率都是必要的。这些结果表明，皮层方向选择性的发展是通过输入和细胞内在特性的可塑性的结合来实现的。
