STDP of excitatory (a) and inhibitory (b) synaptic responses recorded in the same cells from slices of young mouse auditory cortex. (Top and middle) Examples of LTP and LTD induced by spike pairings of various timing intervals. Blue symbols in panel b indicate experiments performed with excitation blocked via DNQX. (Bottom) Summary of all cells, showing that spike pairing differentially affects excitation versus inhibition. Excitatory STDP has a Hebbian asymmetric window [short-interval pre-before-postsynaptic pairing (pre→post pairing) induced LTP, and post→pre pairing induced LTD], whereas inhibitory STDP is symmetric (LTP is induced by both pre→post and post→pre pairings). Adapted from D’amour & Froemke (2015). Abbreviations: ACSF, artificial cerebrospinal fluid; DNQX, 6,7-dinitroquinoxaline-2,3-dione; LTD, long-term depression; LTP, long-term potentiation; pA, picoamperes; STDP, spike timing–dependent plasticity.