Imagine that you have stumbled across a secret laboratory where an evil scientist is conducting unauthorized brain research. By altering brain structures, he has created superheroes who have specialized powers or abilities. One of these superheroes seldom feels hungry or thirsty and can go for days without feeling the need to eat or drink. In this case, the scientist MOST likely altered the

Amygdala.

Explanation:

Brain is one of the important organ of the body that control and coordinates the other system of the body. The three main divisions of the brain are fore brain, midbrain  and hind brain.

The amygdala region is located in the temporal lobe of the brain. The maygdala region of the brain is involved in the learning and memory of the individual. This brain structure is involved in controlling the functions and regulates the thinking as well. The scientists has made change specifically in this region ti create superheroes.

Thus, the correct answer is amygdala.