Berton and colleagues (2006) found that the regulation of avoidance behavior in mice confronted by an aversive social target requires BDNF (brain-derived neurotrophic factor) from the:

Berton and colleagues (2006) found that the regulation of avoidance behavior in mice confronted by an aversive social target requires BDNF (brain-derived neurotrophic factor) from the: B. vental tegmental area (VTA).

Explanation:

The vental tegmental area (VTA) is located in the midbrain, this section of the brain contanins different type of neurons. This area is in charge of the reward system, that has to do with the reinforcement behavior.  

can you explain a little further maybe give multiple choice? ?

the branch of biology that deals with the normal functions of living organisms and their parts.

the way in which a living organism or bodily part functions.