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


METHODS
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.
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.


CONCLUSIONS
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.
Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA. Electronic address: jreisert@monell.org.
Johannes
J
Reisert
Glen J
GJ
Golden
Koichi
K
Matsumura
Matt
M
Smear
Dmitry
D
Rinberg
Alan
A
Gelperin
D000818:Animals; D003657:Decision Making / Q000502:physiology; D051379:Mice; D009812:Odorants; D009830:Olfactory Bulb / Q000502:physiology*; D055696:Olfactory Perception / Q000502:physiology*; D012119:Respiration; D012903:Smell / Q000502:physiology*; D013686:Telemetry / Q000295:instrumentation / Q000379:methods; D035423:Thoracic Cavity / Q000502:physiology; D014160:Transducers, Pressure
Breathing frequency; Nasal pressure; Odor decisions; Wireless telemetry