Answer:
Piriform cortex
Explanation:
The piriform cortex is located in the cerebrum and is regulates the sense of smell of a person. In humans it is located in between the temporal lobe and the insula.
Here, Dr Watkins is trying to understand how learning is associated with odors. The part of the brain that deals with the sense of smell is the piriform cortex.
Hence, the area of the brain is Dr. Watkins investigating is the piriform cortex.