Max Planck Institute for Biological Intelligence, Martinsried, Germany.
International Max Planck Research School for Molecular Life Sciences, Martinsried, Germany.
Nat Commun. 2024 Oct 23;15(1):9153. doi: 10.1038/s41467-024-53326-x.
Representational drift-the gradual continuous change of neuronal representations-has been observed across many brain areas. It is unclear whether drift is caused by synaptic plasticity elicited by sensory experience, or by the intrinsic volatility of synapses. Here, using chronic two-photon calcium imaging in primary visual cortex of female mice, we find that the preferred stimulus orientation of individual neurons slowly drifts over the course of weeks. By using cylinder lens goggles to limit visual experience to a narrow range of orientations, we show that the direction of drift, but not its magnitude, is biased by the statistics of visual input. A network model suggests that drift of preferred orientation largely results from synaptic volatility, which under normal visual conditions is counteracted by experience-driven Hebbian mechanisms, stabilizing preferred orientation. Under deprivation conditions these Hebbian mechanisms enable adaptation. Thus, Hebbian synaptic plasticity steers drift to match the statistics of the environment.
表象漂移——神经元表象的逐渐连续变化——在许多大脑区域都有观察到。目前尚不清楚漂移是由感觉经验引发的突触可塑性引起的,还是由突触的固有波动性引起的。在这里,我们使用雌性小鼠初级视觉皮层的慢性双光子钙成像,发现单个神经元的最佳刺激方向在数周的时间内缓慢漂移。通过使用圆柱透镜护目镜将视觉体验限制在一个狭窄的方向范围内,我们表明漂移的方向(但不是幅度)偏向于视觉输入的统计数据。一个网络模型表明,最佳取向的漂移主要是由于突触的波动性所致,在正常视觉条件下,这种波动性会被经验驱动的赫布机制所抵消,从而稳定最佳取向。在剥夺条件下,这些赫布机制使适应成为可能。因此,赫布突触可塑性引导漂移以匹配环境的统计数据。