Which group primarily influences normal respiration control?

The apneustic center is primarily involved in the control of normal respiration by regulating the depth and duration of breathing. It is located in the pons and plays a critical role in stimulating inspiratory neurons, promoting prolonged inhalation, and modulating the respiratory rhythm. The apneustic center provides a continuous output to the inspiratory neurons of the medulla, which helps establish a steady breathing pattern.

The pneumotaxic center, also located in the pons, influences the switch from inhalation to exhalation but does not primarily control the basic rhythm of breathing. The ventral respiratory group (VRG), located in the medulla, is important in generating the rhythm of respiration but is not the primary influence. The corticobulbar tract is involved in the voluntary control of skeletal muscles, including those used for respiration, but does not specifically dictate the rhythm or control of normal, automatic respiration.

Thus, the apneustic center's role in promoting and regulating inspiratory activity makes it the key influence for normal respiration control.