Skip to main content
. 2025 Sep 15;28(9):pyaf065. doi: 10.1093/ijnp/pyaf065

Figure 5.

Figure 5

Acquisition of trace fear conditioning in rats without functional RE did not require VH NMDA receptor activation. The upper and middle panels showed the immobility levels of the RE-intact animals (upper panels) and the RE inactivation animals (middle panels) during the BL and each of the 10 tones (CS) during the conditioning and test sessions, and the lower panels summarized the overall immobility level across the BL and tones for respective groups. VH NMDA receptor blockade resulted in a slower increase in immobility level during acquisition in both RE-intact (upper left panel) and RE inactivation (middle left panel) animals. During test session, RE-intact animals (upper right panel) showed lower freezing response to the tone if conditioned under VH NMDA receptor blockade. However, RE inactivation animals (middle right panel) showed a high level of fear expression regardless of VH NMDA receptor blockade during conditioning. BL, baseline; CS, conditioned stimulus; RE, nucleus reuniens; VH, ventral hippocampus. *, P < .05.