Combining ultra-flexible electrodes with two-photon imaging to illuminate brain-wide neural dynamics

Brain activity consists of neural signals dynamically coordinated across spatial and temporal scales. To sample distributed brain-wide activity, we combine chronically implanted ultra-flexible electrodes for subcortical recordings with simultaneous two-photon calcium imaging in mouse neocortex. Flexible electrodes preserve optical access even at steep insertion angles and enable weeks-long single-neuron tracking. With these combined recordings, we demonstrate how subcortical-cortical coupling is modulated across slow brain states and around fast ripple events.