Circuits in the Ventral Medulla That Phase-Lock Motoneurons for Coordinated Sniffing and Whisking

Figure 5

Facial motoneurons and nose motion. (a) Muscle nasi deflector (ND) is located laterally to the premaxillary bone (PM). It takes origin at the orbital edge of the maxilla and its long tendon inserts over the nasal cartilage (stars, attachment sites). (b) Electromyographic recordings in alert head-restrained rats reveal that muscle ND is active during the late phase of expiration during basal respiration (upper traces) and during the early phase of expiration during sniffing (lower traces); black traces, smoothed rectified EMGs. (c) Experimental setup to measure nose motion and nasal airflow in head-restrained rats; IR, infrared light. (d) Blockade of the right naris with a polymer compound abolishes respiratory signals from the right thermocouple and biases nose deflection towards the left side of the face. (e) Upper traces show normalized respiratory signals recorded from the left and right nostrils. Lower traces show that change in lateral nose position is associated with change in airflow through the left and right nostrils as estimated from difference in the amplitude of thermocouple signals. (f) Spectral coherence between lateral displacement of the nose and air flow difference between the left and right nostrils. Black line, 95% confidence level based on Gaussian approximation; light red area, 95% confidence interval based on boot-strap. All data in this figure are unpublished results.

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