Better fathers have smaller testicles When men were shown photos of their own children, those rated as better fathers by their female partners had more activity in the ventral tegmental area (VTA) of the brain, part of its reward system. Men with larger testes were rated lower in surveys of their parenting involvement and had less activity in the VTA. Because testes size is correlated with sperm count, Rilling and his team took the size as a measure of mating effort
Ventral Tegmental Area (VTA) is the area that synthesizes dopamine, which then sends to nucleus accumbens. Nucelus accumbens is the pleasure center, and it is stimulated by the neurotransmitter dopamine from VTA. VTA also sends dopamine to prefrontal cortex which regulates and controls these impulses. The locus coeruleus is the area packed with norepinephrine; and when stimulated by a lack of the addictive substance, will drives the person to do anything necessary to obtain a fix.
The ventral tegmental area (VTA), a group of neurons at the very centre of the brain, plays an especially important role in this circuit. The VTA receives information from several other regions that tell it how well various fundamental needs, and more specifically human needs, are being satisfied.
WELL CONNECTED Neurons (green) in the lateral hypothalamus connect with those in the ventral tegmental area of mice’s brains to contribute to compulsive sugar consumption. ~~ Courtesy of Edward Nieh/MIT