The Use of Olfaction by Neonatal Mice for Navigation During the Blind Stage of Development Nicholas Corbin Hilker Distance Traveled With Eyes Open Department of Biological Sciences, York College of Pennsylvania 500 Introduction: Test 1 Test 2 Control Test 4 A preference for home nesting material has been observed in the early development of many rodent Results: 400 Mean Time of Travel by Pup Mice with Eyes Closed or Opened species. Distance (cm) 300 600 b Eyes Closed Eyes Opened Pup mice are born without functional eyes and rely 500 b Time of Travel (s) 200 mostly on olfaction for sensory signals for the first 14 400 a days after birth 300 a x 100 Locomotion in neonatal mouse pups is observed 200 xz yz around 9 days after birth while still in their blind stage of 100 y 0 development 0 0 100 200 300 Time (s) 400 500 600 ol 1 2 4 st st st tr on The odors of the mother and other siblings act as a Te Te Te C Figure 4. The distance of travel by pups and the time taken to find the home Figure 1. The mean time of travel by pup mice in different test nest with their eyes open. Pups were given10 min to find the nest in each test. scent source for pups, but their use on traveling long conditions, during eyes open and eyes closed stages of life. Bars that share a letter are considered not significantly different. Data were If the nest was not found after 10 min, a score of 600 seconds was given. distances back to the nest is unknown statistically tested using a Kruskal-Wallis Test. Eyes closed and eyes open were statistically tested separately Table 2. Analysis of speed data comparing eyes closed and open tests.____ Mean StDeva Nb Min-Max Test 1 0.26 – 1.17 Questions: Distance Traveled with Eyes Closed Eyes Closed Eyes Open 0.82 1.78 0.246 0.671 17 17 0.86 – 3.22 Test 2 The aim of this experiment is to test olfaction use by pups 600 Eyes Closed 0.38 0.188 16 0.02 – 0.71 Test 1 returning to their home nest. This lead to two research Eyes Open 1.87 0.853 15 0.59 – 4.22 Test 2 500 Control questions. Test 4 Control Eyes Closed 0.95 0.53 33 0.07 – 2.15 Eyes Open 2.71 0.968 32 1.33 – 4.83 400 Distance (cm) Is scent an important part of a pup’s ability to traverse an Test 4 Eyes Closed 0.51 0.273 29 0.02 – 1.22 open area under different conditions? 300 Eyes Open 3.14 1.701 26 0.57 – 7.18 a. Standard Deviation b. Number of individuals tested 200 Does the addition of sight affect how the pups traverse the environment? 100 Conclusion: Nest finding at days 10-13 seems to be highly reliant 0 Methods: 0 100 200 300 400 500 600 on olfaction. Time (s) Figure 2. The distance of travel by mouse pups compared to the time taken to find Mice pups aged 10-13 days were each tested in three out of four the home nest with their eyes closed. Pups were given 10 min to find the nest in Control test differed significantly from tests 2 and 4 each test. If the nest was not found after 10 min, a score of 600 seconds was experiments. Pups were then tested again with eyes open (14-15 days) given. showing that replacing of the nest, or a strip from the Test 1. environment affect navigation due to olfaction. Environmentalbedding was fresh unscented bedding, nest bedding was old soiled bedding Faster nest finding at days 14-15 may be a Test 2. combination of vision & olfaction as well as increased Environmental bedding was old and soiled, nest bedding was fresh strength. and unscented Literature Cited: Test 3 Control. Schoenfeld, T A., and Corwin, J V. Maturation of Olfactory Exploration in Golden Hamsters. Developmental Psychobiology 1985; 18: 515-528. Environmental bedding and nest were old and soiled. This was done Szerzenie, V, Hsiao, S. Development of Locomotion toward Home Nest Material in Neonatal Rats. Developmental as a control test Psychobiology 1976; 10: 315-321. Test 4. Wiedenmayer, C P, Myers, M M, Mayford, M, and Barr, G A. Olfactory Based Spatial Learning in the Neonatal Nice and its Dependence on CaMKII. Learning and Memory 2000; 2: 1051-1055. Table 1. Mean weight of pups on test days______ __ Control conditions are used but a strip of environmental bedding was removed and replaced with fresh bedding Eyes Closed Eyes Open Acknowledgment: Tank 4 5.45 g 4.23 g I would like to thank Dr. Rehnberg for his support in the development and testing and presentation Tank 5 6.10 g 4.48 g processes. I would also like to thank the Biology staff for their help and interest in this thesis Tank 6 6.21 g 6.30 g experiment.