OBJECTIVES: The cerebral cortex contains neurons that play a pivotal role in controlling rhythmic masticatory jaw movements. However, the population characteristics of individual cortical neuronal activity during mastication and the impact of tooth loss on these characteristics remain unclear. Thus, in this study, we aimed to determine the activity patterns of mastication-related motor cortical neurons elicited during mastication and examine the effects of tooth extraction on neuronal activity using two-photon Ca METHODS: GCaMP6f-expressing adeno-associated virus serotype 1 was injected into the left motor cortex (centered 2 mm anterior and 2 mm lateral to the bregma) and electromyography (EMG) electrodes were implanted into the right masseter and digastric muscles of 6-8-week-old C57BL/6j mice. Three weeks after surgery, in vivo two-photon Ca RESULTS: Mastication induced a remarkable increase in the power and frequency of Ca CONCLUSIONS: Our in vivo imaging study provides new insights into the neuronal basis of tooth loss-induced cortical neuroplasticity, and suggests a possible therapeutic approach for oral sensorimotor dysfunction.