Figure 2.

Costimulation of β- and α1-adrenergic receptors enables Hebbian STDP. A, Coapplication of isoproterenol and methoxamine enables bidirectional STDP: tLTP with a pre-then-post pairing (10 ms delay; ○) and tLTD with a post-then-pre pairing (−10 ms delay; ●). B, The magnitude of STDP induced with the agonist mixture depends on the delay between presynapstic and postsynapstic stimulation. C, Developmental changes in the magnitude of tLTP induced (○) and tLTD induced with ± 10 millisecond delays. D, Coapplication of isoproterenol and methoxamine also enables bidirectional STDP in somatosensory cortex. The number of experiments is indicated in parentheses. Superimposed traces in A are averages of 10 consecutive responses recorded right before (thin line) and 30 min after conditioning (thick line) displayed at two time scales. Calibration: 2 mV, 10 and 2 ms. Data are mean ± SEM.