The proportion of SPNs with stable DA responses is compared after local injection of aCSF, LY235959, or NBQX. More than 90% of SPNs with LY235959 or NBQX injection exhibited stable DA responses (activity increase or decrease), but fewer than 50% of SPNs with aCSF injection. Total SPNs, 117; stable responses, 39 of 43 in LY235959 tests, 43 of 45 in NBQX tests, and 12 of 29 in aCSF tests (see complementary data on unstable DA responses in Figure S3).