Figure 1.

Inhibition of BLA terminals projecting to the vHPC with NpHR increases social interaction in a resident-juvenile intruder procedure. BLA glutamatergic neurons were transduced with either NpHR-eYFP (n = 7) or eYFP alone as a control (n = 8). Yellow light was delivered (3 min, constant) via bilateral optical fibers implanted in the vHPC, after ∼7–8 weeks of viral incubation. A, Left, Coronal brain schematic indicating the site of viral injection into the BLA. Right, Coronal schematic indicating optic fiber location into the vHPC. Top, Experimental timeline. B, Left, Schematic indicating the home-cage resident-juvenile (3–4 weeks) intruder behavioral procedure. Right, Schematic indicating the 3 min epochs with 24 h, counterbalanced between the social tasks. Different intruders were used for each epoch. C, NpHR mice spent significantly more time performing social interaction than eYFP mice during the yellow light illumination epoch. *p = 0.046. D, No significant effect of light stimulation or group was detected on time spent self-grooming compared with eYFP mice. E, NpHR mice spent less time (seconds) exploring their home cage during light stimulation compared with eYFP control mice. *p = 0.035. F, No significant effect of light stimulation or group was detected on freezing behavior in the presence of a juvenile intruder. G, Percentage of total time (3 min), showing social interaction, self-grooming, cage exploration, and freezing. Data are mean values. Error bars indicate SEM.