Fig. 1: A sparse dual-opsin approach for interval learning in ex vivo cortical circuits.

A Schematic of cortical pyramidal neurons in an organotypic slice culture sparsely transduced with either ChR2 or Chrim (top) and Early vs Late chronic optogenetic training paradigm (bottom). B Sample simultaneous whole-cell patch clamp recordings from two cortical pyramidal neurons expressing ChR2 (blue) or Chrim (red) during the presentation of red or blue light (5 ms, 12 pulses, 25 Hz) in the presence of synaptic blockers [80 μM APV, 40 μM CNQX]. C Sample simultaneous recording from ChR2⁺ (blue) and Chrim⁺ (red) neurons during the presentation of the Early (left) and Late (right) training paradigms. D Image showing non-overlapping expression of ChR2 and Chrim in Layer 2/3 pyramidal neurons in the auditory cortex. Seven independent groups or organotypic slices were prepared at different time periods over the course of a year and trained in identical conditions, yielding consistent results; 3–4 mice per group with 6–8 cortical slices per mouse.