The complex neural system provides the biophysical basis for advanced cognitive function, with interconnected neurons exhibiting intricate activity patterns to encode external stimuli. Simultaneously recording these patterns at high temporal and spatial resolutions from a large set of cells is a daunting task given the complexity of in vivo neural networks.
To explore the biophysical feasibility of population temporal coding, we used neuronal cultures that exhibit reverberatory activity. Our findings demonstrated that interconnected neurons can self-organize into recurrent networks through activity-dependent synaptic plasticity and maintain information in precise spatiotemporal firing patterns.
To further investigate neural coding, we developed and optimized a novel genetically-encoded voltage indicator (GEVI) ASAP4 to record fast and direct neural electrical activity with subthreshold membrane potential fluctuations. The new ASAP4 series have a positively sloped fluorescence-voltage relationship with enhanced photostability for long-duration in vivo voltage recordings.