Objectives: Nasal breathing has many health benefits, especially in exercise. Airflow through the nose stimulates the Olfactory Bulb (OB) during the breathing cycle, associated with the airflow intensity. This information reaches the OB and causes oscillations that transfer to other brain areas. Brain rhythms have been associated with different cognitive states and play functional roles in network computation, such as memory. Accordingly, this study investigates the effect of olfactory sensory neurons (OSNs) in improving working memory following aerobic exercise training in rats.
Methods and Materials: In this study, we used sixteen male Wistar rats (12-14 weeks, weighing 250-300 g). After implanting an electrode in the OB and HIP for Local field potentials recording, animals were divided into two exercises and two control groups. At the beginning of each week, one exercise group and one control group, to destroy the OSNs, received 300 mg/kg methimazole. After completing the exercise protocol (7 weeks/ 5 Days/week), we simultaneously recorded LFPs from rat Hip and OB during a Y-maze working memory task. Two-way variance analysis was used for statistical analysis.
Results: Our results showed that destroying olfactory sensory neurons significantly reduces the working memory capacity (P=0.04). On the other hand, the power of the delta and theta frequency bands increased and working memory improved in exercise groups (P=0.01).
Conclusions: We propose that the non-invasive stimulation of OSNs during nasal breathing may be a mechanism for improving working memory through exercise.