Sense organs are often actively controlled by motor processes and such active sensing
profoundly shapes the timing of sensory information flow. The temporal coordination
between different active sensing processes is less well understood but is essential
for multisensory integration, coordination between brain regions, and energetically
optimal sampling strategies. Here we studied the coordination between sniffing and
whisking, the motor processes in rodents that control the acquisition of smell and
touch information, respectively. Sniffing, high-frequency respiratory bouts, and whisking,
rapid back and forth movements of mystacial whiskers, occur in the same theta frequency
range (4-12 Hz) leading to a hypothesis that these sensorimotor rhythms are phase
locked. To test this, we monitored sniffing using a thermocouple in the nasal cavity
and whisking with an electromyogram of the mystacial pad in rats engaged in an open
field reward foraging behavior. During bouts of exploration, sniffing and whisking
showed strong one-to-one phase locking within the theta frequency range (4-12 Hz).
Interestingly, we also observed multimode phase locking with multiple whisks within
a sniff cycle or multiple sniffs within a whisk cycle-always at the same preferred
phase. This specific phase relationship coupled the acquisition phases of the two
sensorimotor rhythms, inhalation and whisker protraction. Our results suggest that
sniffing and whisking may be under the control of interdependent rhythm generators
that dynamically coordinate active acquisition of olfactory and somatosensory information.
