Pathway-specific drive of action potential in identified NAc core MSNs. A, Left, Comparison of the probability of AP firing versus pulse number shows that PFC inputs preferentially drive the firing of D2 MSNs compared with D1 MSNs (D1 MSNs n = 6, D2 MSNs n = 6, pulse 1: p = 0.0005, pulse 2–5: p < 0.0001, Fisher's exact test). Right, Example traces of APs evoked in D1 and D2 MSNs in response to trains of optical stimulation of PFC inputs (2 ms light pulses, 5 pulses at 10 Hz). B, Left, Comparison of the probability of AP firing versus pulse number shows that BLA inputs preferentially drive the firing of D1 MSNs compared with D2 MSNs (D1 MSNs n = 7, D2 MSNs n = 6, pulse 1–3: p < 0.0001, pulse 4: p = 0.0027, pulse 5: p = 0.0445, Fisher's exact test). Right, Example traces of APs evoked in D1 and D2 MSNs in response to trains of optical stimulation of BLA inputs. C, Left, Comparison of the probability of AP firing versus pulse number shows no difference at vHipp inputs of the firing of D1 MSNs and D2 MSNs (D1 MSNs n = 6, D2 MSNs n = 6, pulse 1: p = 0.0357, pulse 2: p = 0.1997, pulse 3–5: p = 1.0000, Fisher's exact test). Right, Example traces of APs evoked in D1 and D2 MSNs in response to trains of optical stimulation of vHipp inputs. Blue dots indicate time of stimulation. All experiments were performed in the presence of picrotoxin to prevent from feedforward inhibition. All data are shown as mean ± SEM or geometric mean ± CI. *p < 0.05.