Differential involvement of the dorsal hippocampus in passive avoidance in C57bl/6J and DBA/2J mice

Abstract

The inferior performance of DBA/2 mice when compared to C57BL/6 mice in hippocampus-dependent behavioral tasks including contextual fear conditioning has been attributed to impaired hippocampal function. However, DBA/2J mice have been reported to perform similarly or even better than C57BL/6J mice in the passive avoidance (PA) task that most likely also depends on hippocampal function. The apparent discrepancy in PA versus fear conditioning performance in these two strains of mice was investigated using an automated PA system. The aim was to determine whether these two mouse strains utilize different strategies involving a different contribution of hippocampal mechanisms to encode PA. C57BL/6J mice exhibited significantly longer retention latencies than DBA/2J mice when tested 24 h after training irrespective of the circadian cycle. Dorsohippocampal NMDA receptor inhibition by local injection of the selective antagonist DL-2-amino-5-phosphonovaleric acid (AP5, 3.2 microg/mouse) before training resulted in impaired PA retention in C57BL/6J but not in DBA/2J mice. Furthermore, nonreinforced pre-exposure to the PA system before training caused a latent inhibition-like reduction of retention latencies in C57BL/6J, whereas it improved PA retention in DBA/2J mice. These pre-exposure experiments facilitated the discrimination of hippocampal involvement without local pharmacological intervention. The results indicate differences in PA learning between these two strains based on a different NMDA receptor involvement in the dorsal hippocampus in this emotional learning task. We hypothesize that mouse strains can differ in their PA learning performance based on their relative ability to form associations on the basis of unisensory versus multisensory contextual/spatial cues that involve hippocampal processing.

Neurotrophin receptor p75NTR mediates Huntington’s disease–associated synaptic and memory dysfunction

“…Finally, we examined associative memory in the passive avoidance task, based on the association formed between an aversive stimulus (electrical foot shock) and a specific environmental context (light-dark) ( Figure 4D), which relies on cortical and hippocampal circuits (48)(49)(50). Latency to step-through during the training session was found to be similar between genotypes.…”

GABA-mediated presynaptic inhibition is required for precision of long-term memory

“…This is because we observe a loss of memory precision in both the contextual fear task as well as novel object recognition and novel object location tasks in GABA B(1a) knockout mice. Both of these novel object tasks are independent of fear responses and rely heavily on hippocampal functioning (Best and Orr 1973;Lorenzini et al 1996;Ambrogi Lorenzini et al 1997;Baarendse et al 2007). Moreover, dysfunction of presynaptic inhibition and synaptic potentiation within the mossy fiber pathway and Schaffer commissural pathway is well documented in these mice (Vigot et al 2006;Guetg et al 2009;Gassmann and Bettler 2012), as is the importance of the mossy fiber pathway in memory precision (Ruediger et al 2011;Jasnow et al 2012).…”

ENU Mutagenesis Screening for Dominant Behavioral Mutations Based on Normal Control Data Obtained in Home-Cage Activity, Open-Field, and Passive Avoidance Tests

“…D2 and DBF 1 mice showed no significant differences in night and total activities of males, and in max for 15 min. For the percent of night activity, D2 showed significantly higher values than B6 or DBF 1 (Table 2).…”

“…For PA performance, D2 mice were the worst learners among the groups at both shock intensities for males and at 0.3 mA for females, whereas B6 mice were the worst learners at 0.15 mA for females in this study. Some previous studies also indicate that D2 mice are poorer performers than B6 mice [1,29], although one study has indicated that the performance of B6 was poorer than that of D2 mice [18]. These inconsistent results for strains in the PA test may arise from differences in experimental conditions such as shock intensity [25].…”