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. Author manuscript; available in PMC: 2014 Nov 20.
Published in final edited form as: Neuron. 2013 Oct 31;80(4):10.1016/j.neuron.2013.07.047. doi: 10.1016/j.neuron.2013.07.047

Figure 5. The extinction-induced increase in perisomatic parvalbumin reflects new learning.

Figure 5

(A) Design of an experiment with a home cage (HC, n=8) and a fear conditioned group (FC, n=8). (B) Freezing during contextual fear conditioning on day 1. As training progressed, FC mice showed an increase in their level of freezing (p=0.0006). (C) The FC group had a larger number of GFP+ neurons than the HC group in the basal amygdala (BA, p=0.0049). (D) FC mice showed significant freezing during retrieval on day 4 (p=0.0077). (E) The FC group had a larger number of GFP-Zif+ neurons than the HC group (p=0.036). (F) The FC group had a larger number of GFP+Zif+ neurons than the HC group (p=0.0043). Only in the FC group was the percentage of GFP+ZIF+ neurons higher than chance level, confirming that a subset of BA fear neurons was reactivated during retrieval (HC: p=0.23; FC: p=0.016). Chance level was determined by using the % of Zif+ among GFP- neurons as shown in (E). (G-H) Fear conditioning had no effect on perisomatic PV around either type of tagged BA neuron (G: GFP+Zif-, p=0.10; H: GFP+Zif+, p=0.49). Graphs show means ± s.e.m. *P < 0.05, **P < 0.01, ***P < 0.001.