Comparing thoracic and intra-nasal pressure transients to monitor active odor sampling during odor-guided decision making in the mouse

Abstract

Background Recording of physiological parameters in behaving mice has seen an immense increase over recent years driven by, for example, increased miniaturization of recording devices. One parameter particularly important for odorant-driven behaviors is the breathing frequency, since the latter dictates the rate of odorant delivery to the nasal cavity and the olfactory receptor neurons located therein. New Method Typically, breathing patterns are monitored by either measuring the breathing-induced temperature or pressure changes in the nasal cavity. Both require the implantation of a nasal cannula and tethering of the mouse to either a cable or tubing. To avoid these limitations we used an implanted pressure sensor which reads the thoracic pressure and transmits the data telemetrically, thus making it suitable for experiments which require a freely moving animal. Results Mice performed a Go/NoGo odorant-driven behavioral task with the implanted pressure sensor, which proved to work reliably to allow recording of breathing signals over several weeks from a given animal. Comparison to existing Method(s) We simultaneously recorded the thoracic and nasal pressure changes and found that measuring the thoracic pressure change yielded similar results compared to measurements of nasal pressure changes. Conclusion Telemetrically recorded breathing signals are a feasible method to monitor odorant-guided behavioral changes in breathing rates. Its advantages are most significant when recording from a freely moving animal over several weeks. The advantages and disadvantages of different methods to record breathing patterns are discussed.

Bilateral Alignment of Receptive Fields in the Olfactory Cortex

“…The face mask was connected to an airflow sensor (Honeywell AWM3300V, Morris Plains, NJ) to monitor the animal's respiration during the experiments ( Figure S1C) and later align neuronal activity with the sniffs (Figure 3C) (Bolding and Franks, 2017). The accuracy of the face mask in monitoring respiration was tested against intranasal pressure transients (Figures S1E-S1H) as described previously (Reisert et al, 2014).…”

Dynamics of odor sampling strategies in mice

“…The experiments described here use a combination of olfactory psychophysics and measurements of sniffing in a freely moving mouse [19,26] during odor-guided behavior to address how sniff-driven odor-elicited activation patterns in ORNs drive behavioral outputs.…”

Minimally invasive highly precise monitoring of respiratory rhythm in the mouse using an epithelial temperature probe

“…Intranasal pressure measurements have the same drawbacks as they too require invasion of the nasal cavity with a small metal or plastic cannula and, in addition, add considerable weight to the nose and partially obstruct the visual field. Another noteworthy approach employs a pressure sensor implanted into the thoracic cavity to detect changes in pressure associated with respiratory movements (Reisert et al, 2014). This method is advantageous in that it does not cause damage to olfactory tissues.…”

“…Current methods employ the use of temperature or pressure sensors placed within the nasal cavity (Shusterman et al, 2011; Smear et al, 2011; Reisert et al, 2014) or in front of the nares (Ito et al, 2014). However, these methods have significant drawbacks.…”

“…Chronic implantation of sensors allows for the greatest potential mobility for the animal, but current approaches typically penetrate the bone and epithelial tissue overlying the nasal cavity (Shusterman et al, 2011; Smear et al, 2011; Reisert et al, 2014). Pressure changes associated with respiration are measured by placement of a small cannulae into the nasal cavity, allowing for highly accurate readings of respiratory efforts.…”