Juvenile soft-diet feeding disrupts cerebellar timing and impairs balance in mice

Sensorimotor experience shapes developing neural circuits. Whether diet texture-dependent oral sensorimotor experience influences cerebellar population activity, and if so in what way, remains unclear. Here we tested whether reducing oral sensorimotor experience by soft-diet feeding during the juvenile post-weaning period was associated with motor performance beyond mastication and with Purkinje-cell population activity in cerebellar vermis lobules VI-VII. Soft diet feeding from 3 to 6 weeks of age was associated with impaired rotarod performance and swimming postural balance, without a reduction in body-weight gain. In vivo one-photon calcium imaging from cerebellar lobules VI-VII revealed reduced synchrony of Purkinje-cell dendritic calcium transients, whereas individual calcium events were unchanged. Soft-diet feeding from 6 to 9 weeks produced milder and assay-dependent behavioral effects and did not reduce Purkinje-cell calcium synchrony in the same region. Fixed-frequency optogenetic activation of Purkinje cells improved motor performance in juvenile soft-diet mice. These findings suggest that reduced oral sensorimotor experience during the juvenile period is associated with altered cerebellar population timing and impaired balance control.