Cellular membrane potential plays a key role in the formation and retrieval of memories in the metazoan brain, but it remains unclear whether such memory can also be encoded in simpler organisms like bacteria. Here, we show that single-cell-level memory patterns can be imprinted in bacterial biofilms by light-induced changes in the membrane potential. We demonstrate that transient optical perturbations generate a persistent and robust potassium-channel-mediated change in the membrane potential of bacteria within the biofilm. The light-exposed cells respond in an anti-phase manner, relative to unexposed cells, to both natural and induced oscillations in extracellular ion concentrations. This anti-phase response, which persists for hours following the transient optical stimulus, enables a direct single-cell resolution visualization of spatial memory patterns within the biofilm. The ability to encode robust and persistent membrane-potential-based memory patterns could enable computations within prokaryotic communities and suggests a parallel between neurons and bacteria.

细胞膜电位在后生动物脑中记忆的形成和恢复中起着关键作用，但是尚不清楚这种记忆是否还可以在细菌等较简单的生物体中编码。在这里，我们显示了单细胞水平的记忆模式可以通过光诱导的膜电位变化被印在细菌生物膜中。我们证明，短暂的光学扰动会在生物膜内细菌的膜电位中产生持久而强大的钾通道介导的变化。相对于未曝光的细胞，已曝光的细胞以反相的方式对细胞外离子浓度的自然振荡和诱导振荡做出响应。这种反相响应在瞬态光学刺激后会持续几个小时，使生物膜内空间记忆模式的直接单细胞分辨率可视化成为可能。编码健壮和持久的基于膜电位的记忆模式的能力可以在原核社区内进行计算，并暗示神经元和细菌之间存在相似之处。