Final answer:
Gastric secretions are greater during parasympathetic stimulation due to the 'rest-and-digest' response which increases GI secretion and motility, unlike the sympathetic 'fight-or-flight' response that decreases these functions.
Step-by-step explanation:
The greater gastric secretions would be observed when parasympathetic neurons are stimulated. The autonomic nervous system, which includes sympathetic and parasympathetic fibers, regulates the extrinsic innervations of the alimentary canal. While sympathetic activation prepares the body for 'fight-or-flight' by decreasing gastrointestinal secretion and motility, parasympathetic activation enhances digestion during 'rest-and-digest' by increasing gastrointestinal secretion and motility. Therefore, the gastric secretions would be greater during parasympathetic stimulation compared to sympathetic stimulation.