1. Optogenetic inhibition of Te1→ PL cortex axons caused fear generalization.
Optogenetic inhibition of Te1→ PL cortex axons caused fear generalization. A, Schematic representation of virus injections in the Te1 (AAV5-CaMKIIα:eNpHR3.0-mCherry or control AAV5-CaMKIIα-mCherry) and optic fibers implanted in the PL cortex. The anti-mCherry antibody revealed a specific injection in the Te1 and the colocalization between mCherry and the synaptic protein bassoon-specific Te1→ PL cortex labeled terminals. Scale bars: 500 and 25 μm. B, Virus infection of the Te1 of a representative rat (left) and atlas reconstruction of the minimal and maximal spreading of the virus along different stereotaxical coordinates (right). C, D, Schematic representation of the optic fiber tracks in the PL cortex and relative Nissl staining. Scale bar, 500 μm. E, Experimental design for the optogenetic experiments. F, eNpHR3.0-mCherry and mCherry discriminator rats showed low levels of freezing to the new 15 kHz tone. When the same tone was delivered during optogenetic inhibition of Te1 terminals, eNpHR3.0-mCherry rats showed an increase in the freezing response. G, Generalizer rats exhibited similar level of freezing during the optogenetic inhibition and not. H, I, During CS presentation, discriminators and generalizers exhibited high rates of freezing, and optogenetic manipulation did not affect conditioned freezing. J, Optogenetic manipulations did not affect fear-odor discrimination. K, A subgroup of discriminators was tested in the open-field apparatus. Animals spent most time in the periphery either during light-on and light-off conditions. ***p < All data are mean and SEM.
Giulia Concina et al. J. Neurosci. 2018;38:
©2018 by Society for Neuroscience