Animal research has revealed a general reward system that triggers the release of the neurotransmitter.

Dopamine

Explanation:

Dopamine is a type of neurotransmitter. It is made by the brain and used in the brain in the nervous system by nerve cells. It is also called a chemical mass-anger. Dopamine is a neurotransmitter that helps us to understand how we feel happiness. It is a unique ability. It helps us in thinking, planning, focus and to find the things interesting.  

Many parts affected by dopamine such as:

on the first day of new student week, amber revealed to her roommate that she is a lesbian. this is an example of self-disclosure.

the packers and the chiefs played in the first super bowl, which was held in los angeles in 1967. -is the sentence that would stand out the most when scanning a paragraph.