Figure 3. Chronic stress increases burst and tonic firing of LHb→VTA neurons.
(A) Experimental design.
(B) Top: Injection-site of EIAV-Cre (red) in the VTA (left) and expression of ChR2-eYFP (green) in LHb→VTA neurons (right) (IP: interpeduncular nucleus, 3V: 3rd ventricle, MHb: medial habenula; DAPI: blue; Scale bars: 300 μm (left), 250 μm (right)). Bottom: Localizations of optrodes in LHb for CTRLD0–1 (green) and CMSD2–3 (blue) mice (fr: fasciculus retroflexus, DG: dentate gyrus).
(C) Left: Action potential waveforms for LHb→VTA neurons in CTRLD0–1 (green) and CMSD2–3 (blue) mice (Scale bars: 20 μV/0.5 ms (CTRLD0–1), 30 μV/0.5 ms (CMSD2–3)). Right: Mean action potential width for LHb→VTA neurons in CTRLD0–1 (green) and CMSD2–3 (blue) mice (data represent means ± SEM).
(D) Normalized frequencies of interspike intervals for LHb→VTA neurons in CTRLD0–1 (green) and CMSD2–3 (blue) mice.
(E) Mean percentage of spikes in bursts recorded for LHb→VTA neurons in CTRLD0–1 (green) and CMSD2–3 (blue) mice (* p < 0.05, data represent means ± SEM).
(F) Mean number of spikes per burst for LHb→VTA neurons in CTRLD0–1 (green) and CMSD2–3 (blue) mice (* p < 0.05, data represent means ± SEM).
(G) Mean interburst frequencies for LHb→VTA neurons in CTRLD0–1 (green) and CMSD2–3 (blue) mice (* p < 0.05, data represent means ± SEM).
(H) Mean intraburst frequencies for LHb→VTA neurons in CTRLD0–1 (green) and CMSD2–3 (blue) mice (data represent means ± SEM).
(I) Mean tonic firing frequencies for LHb→VTA neurons in CTRLD0–1 (green) and CMSD2–3 (blue) mice (** p < 0.01, data represent means ± SEM).
(J) Mean firing frequencies for LHb→VTA neurons in CTRLD0–1 (green) and CMSD2–3 (blue) mice (** p < 0.01, data represent means ± SEM).
