A Barnes maze for juvenile rats delineates the emergence of spatial navigation ability.

ABSTRACT: The neural bases of cognition may be greatly informed by relating temporally defined developmental changes in behavior with concurrent alterations in neural function. A robust improvement in performance in spatial learning and memory tasks occurs at 3 wk of age in rodents. We reported that the developmental increase of spontaneous alternation in a Y-maze was related to changes in temporal dynamics of fast glutamatergic synaptic transmission in the hippocampus. We also showed that, during allothetic behaviors in the Y-maze, network oscillation power increased at frequency bands known to support spatial learning and memory in adults. However, there are no discrete learning and memory phases during free exploration in the Y-maze. Thus, we adapted the Barnes maze for use with juvenile rats. Following a single platform exposure in dim light on the day before training (to encourage exploration), animals were trained on the subsequent 2 d in bright light to find a hidden escape box and then underwent a memory test 24 h later. During escape training, the older animals learned the task in 1 d, while the younger animals required 2 d and did not reach the performance of older animals. Long-term memory performance was also superior in the older animals. Thus, we have validated the use of the Barnes maze for this developmental period and established a timeline for the ontogeny of spatial navigation ability in this maze around 3 wk of age. Subsequent work will pair in vivo recording of hippocampal oscillations and single units with this task to help identify how hippocampal maturation might relate to performance improvements.

SUBMITTER: McHail DG 

PROVIDER: S-EPMC5817281 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature