A 36 year old man walks into a restaurant and immediately starts salivating at the smell of grilled meat. He hasn’t eaten yet but begins to feel mild abdominal gurgling. A few hours later, he experiences a small release of digestive enzymes. The physician explains that the pancreas has already started preparing enzymes due to neural signals before food even entered his digestive tract.

Which phase of pancreatic secretion is most likely active in this case?