, 2010). GABAergic cells in the BLA are comprised of several groups (McDonald, 1982 and Sosulina et al., 2010), with diverse neurochemical expression profiles (Jasnow et al., 2009, Mascagni and McDonald, 2003, Rainnie et al., 2006 and Smith et al., 2000). These might play specific GS-7340 cell line physiological roles. However, GABAergic cell types of the BLA have not been fully characterized, and there is a pressing need to define the nature and function of such cellular diversity (Ehrlich et al., 2009). A division of labor between

GABAergic cell types in controlling local network activities is exemplified in hippocampus, where cells innervating distinct neuronal compartments fire at specific oscillation phases (Klausberger et al., 2003 and Tukker et al., 2007). We hypothesized that BLA GABAergic cells contribute in a type-specific manner to the coordination of θ oscillatory interactions with the hippocampus and local responses to salient sensory stimuli. We investigated this by recording the spontaneous and noxious stimulus-driven firing of anatomically-identified BLA interneurons in vivo. Our findings demonstrate that distinct types of BLA GABAergic cell fulfill specialized and complementary roles in regulating behaviorally relevant network activities. We simultaneously recorded learn more spontaneous single-neuron activity in BLA (comprised

of the lateral and basal nuclei) and hippocampal θ oscillations in dorsal CA1 (dCA1) LFPs of urethane-anesthetized rats. Prominent θ oscillations (4.15 ± 0.23 Hz, mean ± SD) occurred during cortical activated states in dCA1 (Klausberger et al., 2003), but not in BLA LFPs. Gamma (γ) oscillations were also detected in dCA1 LFPs (42.1 ± 1.60 Hz, mean ± s.d.). We recorded interneuron responses to noxious stimuli by delivering electrical shocks and pinches to the hindpaw controlateral to the recording sites. We also examined the firing of BLA glutamatergic principal neurons in relation to dCA1 θ. After recordings, neurons were juxtacellularly filled with Neurobiotin, allowing for their unambiguous identification. Interneurons with somata in the BLA were recorded and labeled (Figure S1, available online, shows cell locations). These were

GABAergic, as all tested cells expressed the vesicular GABA transporter (VGAT) and/or glutamate decarboxylase (GAD; Figures 3F and Carnitine palmitoyltransferase II 4I), and all synapses examined with electron microscopy were symmetric. Interneuron types were distinguished according to the combination of their postsynaptic targets, neurochemical markers and axo-dendritic patterns. Twenty eight GABAergic cells could be classified in four types: axo-axonic, parvalbumin-expressing basket, calbindin-expressing dendrite-targeting, and “AStria-projecting” cells. Axo-axonic cells (n = 6) were recorded and anatomically indentified. During dCA1 θ, they spontaneously fired action potentials at a mean frequency of 12.4 Hz (range 6.5–15.9 Hz; Table 1; Figure 1A). The firing of 4 of 6 cells was significantly modulated in phase with dCA1 θ (p < 0.