A Noninvasive Method for Monitoring Breathing Patterns in Nonhuman Primates Using a Nasal Thermosensor

Differences in the respiration signals from the two measurements. A, Left, A representative trace of the respiratory signal from monkey P was monitored with a temperature sensor (red) and movement sensor (blue). The nasal air temperature increased and decreased with the expiration and inspiration, respectively. The red triangles indicate the peaks of the respiratory phase waveform monitored by the temperature sensor. Right, Enlarged view of the area indicated by the solid box. The blue triangle indicates the peak of the respiration signal monitored with the chest band method. B, Each plot indicates the difference in the peak timing of respiration signal monitored by the thermosensor and chest band in three monkeys (red square, monkey M; black circle, monkey P; blue triangle, monkey S). The temperature was measured from three positions [−5 mm (out), 0 mm (just), and 5 mm (in) from the entrance of the nasal cavity] in the three monkeys. Each line indicates the regression line. C, The differences in peak timing depend on the body weight. The mean of the peak timing recorded from the three probe positions was plotted.

Effect of licking on respiration monitoring. A, Schedule of the music stimuli and reward delivery. One sound stimulus was chosen pseudo-randomly from three candidates and was presented for 3 min at 1-min intervals. The monkeys received six rewards irregularly during the sound stimulation. B, The example of licking (above) and respiration (bottom) after rewarding monkey M. The triangles indicate the timing of single licking. C, The mean and SD of the temperature aligned on the licking during one session (monkey M, 84 licks; monkey P, 214; monkey S, 90).