Effects of environmental enrichment on mouse nasal cavity development

Abstract

Rodents in their olfactory environment are encountered by a wide variety of chemical stimuli that vary in their physico-chemical properties. Different olfactory subsystems help rodents process this array of sensory stimuli making odor perception an exciting and efficient phenomenon. A vast majority of non-pheromonal odour molecules carried by airflow-associated odour plumes travel through the airways of the nasal cavity and end up in the cilia where olfactory sensory neurons express their receptors. The structure of the nasal cavity is highly intricate which may play a role in strengthening the encoding of the airflow and odorant molecules. Olfactory sensory neurons are also known to process the mechanical stimulus provided by the airflow. It remains elusive how sensing the mechanical stimulus aids the olfactory perception and decision-making processes. Is it possible that a dynamic environment can play a crucial role in the development of intricate nasal cavity structures as well? In my thesis work, we tried to investigate the development of murine nasal cavity structure under different conditions of the environment. We provided olfactory and mechanical stimuli to the animals during their early postnatal period starting from birth, using a custom-built enrichment cage. The development of nasal turbinates during this period was probed using the computerized tomography (CT) scanning machine. Different parameters such as turbinate surface area, length, breadth, volume were analyzed in comparison with that of normally reared animals. To analyze these parameters, we developed a deep neural network model based on encoder-decoder architecture to segment the images for processing and analysis. The statistical analysis showed that there was a significant difference in the acquired parameters between the groups of rodent pups that were reared in different environments - normal cage and environment enriched cage. Overall, we provide a comparison of nasal cavity development under different sensory environments and a deep learning model-based methodology to extract the relevant parameters. Further experiments are being carried out to probe the changes at the cellular level in olfactory epithelium from sensory enriched and normally reared animals.