Final answer:
The statement is false. During quiet breathing, action potentials primarily activate inspiratory motor neurons, as quiet exhalation is a passive process that generally does not involve active expiratory motor neuron activation.
Step-by-step explanation:
The statement that action potential bursts occur first in inspiratory, then in expiratory motor neurons during quiet breathing is false. During quiet breathing, action potentials are generated cyclically in neurons called the respiratory rhythm generator within the brainstem. These action potentials are primarily directed at inspiratory muscles, such as the diaphragm, through inspiratory motor neurons during the inspiration phase. Expiratory motor neurons are generally not active during quiet exhalation, as this process is often passive and does not require the active contraction of expiratory muscles. The expiratory muscles become more active and thus receive more action potentials during forced breathing, not quiet breathing.