Eous structure 14 that innervates the VTA5,15?8, and aversive and rewarding stimuli activate a subset of these BNSTv projection neurons19?1. To identify and record the activity of BNSTvVTA neurons employing antidromic photostimulation in vivo, we targeted ChR2-eYFP22 beneath the handle of a CaMKIIa promoter for the BNSTv of adult mice. four ?six weeks later, ChR2-eYFP was observed in BNSTv cell bodies and projection fibers that innervate the VTA (Fig. 1a). Below anesthesia, optical fibers for antidromic photostimulation have been positioned above the VTA, even though recording electrodes and optical fibers for orthodromic photostimulation were positioned inside the BNSTv (Fig. 1b). We recorded from BNSTv units that displayed reputable spiking to both orthodromic and antidromic-photostimulation. By systematically decreasing the interval in between orthodromic- and antidromic-photostimulation, the fidelity of antidromic spikes was significantly attenuated (Fig. 1c,d), demonstrating spike collision23. Also, antidromic spike latencies were drastically greater and showed significantly less variability in comparison to orthodromic spikes (Fig. 1e,f), and antidromic spike fidelity was considerably higher than orthodromic spike fidelity to 40 Hz photostimulation (Fig. 1g ). As a result, photostimulation of BNSTvVTA projections benefits in antidromic spiking that’s reliably distinguishable from putative trans-synaptic circuit activation. To examine the neurophysiological dynamics of identified BNSTvVTA neurons in behaving mice we implanted 16-channel multielectrode arrays within the BNSTv too as optical fibers above the VTA for antidromic identification of neurons24 (Fig. 1h; Supplementary Fig. 1). Delivery of single five ms, 473 nm light pulses to the VTA resulted in time-locked firing in several BNSTv neurons. Photostimulation of BNSTvVTA fibers resulted within a bimodal firing pattern in BNSTv neurons because of distinguishable antidromic and polysynaptic activity (Supplementary Fig. 2, Supplementary Strategies). Principle component and correlation evaluation comparing waveform shapes demonstrated that spontaneous waveforms have been very correlated with light-evoked waveforms (average r = 0.N-Cyano-2-pyridinecarboximidamide custom synthesis 950 ?0.1215071-17-2 In stock 008; Supplementary Fig.PMID:23756629 2; Supplementary Table 1)7. Light-evoked spike latencies revealed that a subset of recorded units regularly displayed time-locked spiking on 11.21 ?0.68 out of 20 trials (56 ) using a imply latency of 7.31 ?0.32 ms (Fig. 1i,j), comparable with our anesthetized recording information (Fig. 1e), plus a previous study working with electrical antidromic stimulation of BNST projections in rodents25. Accordingly, neurons that have been identified as antidromic-responsive displayed spike fidelity of 81 ?15 in response to 20 Hz photostimulation (Supplementary Fig. 2). Making use of these criteria (Supplementary Procedures), we identified 53/137 units as BNSTvVTA projection neurons. BNSTv neurons display heterogeneous responses following aversive stimuli exposure19,20. Therefore, we classified the firing patterns of identified BNSTvVTA neurons in response toAuthor Manuscript Author Manuscript Author Manuscript Author ManuscriptNature. Author manuscript; offered in PMC 2013 October 11.Jennings et al.Pageunpredictable foot shocks and related contextual cues (Supplementary Approaches). Identified BNSTvVTA neurons segregated into three functionally distinct classes primarily based on adjustments in their normalized firing rates all through the foot-shock session (Supplementary Fig. three), demonstrating that BNSTvVTA neurons differentially encode informa.