Figure 2. Hyperactivity of LHb neurons is associated with projection target and behavioral phenotype.
(A) Experimental design.
(B) Injection site of beads (red) in the VTA (IPN: interpeduncular nucleus; Scale bar: 300 μm).
(C) Firing in response to +150 pA depolarizing current injection in LHb→VTA neurons from CTRL and CMS mice with different D-scores: CTRLD0–1 (top left), CMSD0–1 (top right), CTRLD2–3 (bottom left) and CMSD2–3 (bottom right) mice (Scale bars: 20 mV/0.5 s).
(D) Mean number of action potentials in response to injection of different depolarizing ramp currents recorded in LHb→VTA neurons from CTRLD0–1 (light green), CTRLD2–3 (dark green), CMSD0–1 (pink) and CMSD2–3 (blue) mice (* p < 0.05, ** p < 0.01, data represent means ± SEM).
(E-G) Mean number of action potentials in response to injection of a +150 pA depolarizing current in LHb→VTA neurons from CTRL or CMS mice that were pooled according to whether they were positive or negative for specific behavioral phenotypes (i.e. anxiety assessed in EPM (E), anhedonia assessed in SPT (F), immobility assessed in TST (G)). Animals were considered positive if they scored below the corresponding cutoff value defined in Figures 1A–1C (* p < 0.05, ** p < 0.01; data represent means ± SEM).
(H) Experimental design.
(I) Injection site of beads (red) in the DR (AQ: cerebral aqueduct; Scale bar: 400 μm).
(J) Firing in response to +150 pA depolarizing current injection in LHb→DR neurons from CTRL and CMS mice with different D-scores: CTRLD0–1 (top) and CMSD2–3 (bottom) mice (Scale bars: 20 mV/0.5 s).
(K) Mean number of action potentials in response to injection of different depolarizing ramp currents recorded in LHb→DR neurons from CTRLD0–1 (light green) and CMSD2–3 (blue) mice (data represent means ± SEM).
(L) mEPSCs recorded in LHb→DR neurons from CTRLD0–1 (top) and CMSD2–3 (bottom) mice (Scale bars: 10 pA/1 s).
(M) Mean mEPSC frequencies (left) and mEPSC amplitudes (right) recorded in LHb→DR neurons from CTRLD0–1 and CMSD2–3 mice (data represent means ± SEM).