Chemical Senses Advance Access originally published online on September 12, 2008
Chemical Senses 2009 34(1):63-76; doi:10.1093/chemse/bjn051
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A Method for Generating Natural and User-Defined Sniffing Patterns in Anesthetized or Reduced Preparations
1 Departments of Biology 2 Biomedical Engineering, Boston University, 5 Cummington Street, Boston, MA 02215, USA
Correspondence should be sent to: Man Ching Cheung, Department of Biology, Boston University, Boston, MA 02215, USA. e-mail: mccheung{at}bu.edu
| Abstract |
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Sniffing has long been thought to play a critical role in shaping neural responses to odorants at multiple levels of the nervous system. However, it has been difficult to systematically examine how particular parameters of sniffing behavior shape odorant-evoked activity, in large part because of the complexity of sniffing behavior and the difficulty in reproducing this behavior in an anesthetized or reduced preparation. Here we present a method for generating naturalistic sniffing patterns in such preparations. The method involves a nasal ventilator whose movement is controlled by an analog command voltage. The command signal may consist of intranasal pressure transients recorded from awake rats and mice or user-defined waveforms. This "sniff playback" device generates intranasal pressure and airflow transients in anesthetized animals that approximate those recorded from the awake animal and are reproducible across trials and across preparations. The device accurately reproduces command waveforms over an amplitude range of approximately 1 log unit and up to frequencies of approximately 12 Hz. Further, odorant-evoked neural activity imaged during sniff playback appears similar to that seen in awake animals. This method should prove useful in investigating how the parameters of odorant sampling shape neural responses in a variety of experimental settings.
Key words: active sensing, artificial sniffing, behavior, imaging, neural coding, respiration
Accepted 6 August 2008