Final answer:
The central region of the left amygdala is likely stimulated, as it is associated with processing emotions, particularly feelings of fear and anxiety.
Step-by-step explanation:
When surgeons stimulated a particular part of Lisa's brain, resulting in feelings of hopelessness and dread, they were most likely stimulating the central region of the left amygdala. The amygdala is a structure within the limbic system known for its role in processing emotions, particularly fear and anxiety. Stimulation of the amygdala has been associated with various emotional responses and is critical for classical conditioning as well as the attachment of emotional value to learning processes and memory.