Pavlovian associative learning. (a) Schematic diagram of Pavlov’s dog experiment. (b) Electrical pulses as conditioned stimulus (CS) with EPSC < 500 nA (no salivation). (c) Optical pulses as unconditioned stimulus (US) with EPSC > 500 nA (salivation). (d) Imitation of Pavlovian conditioning. Reprinted with permission from Ref. [82], Copyright 2018 Wiley-VCH.