Anderson and his colleagues discovered two intermingled but distinct populations of neurons in the amygdala, a part of the brain that is involved in innate social behaviors. One population promotes social behaviors, such as mating, fighting, or social grooming, while the other population controls repetitive self-grooming -- an asocial behavior.That is not at all what I would expect... need to think about that some more.
Interestingly, these two populations are distinguished according to the most fundamental subdivision of neuron subtypes in the brain: the "social neurons" are inhibitory neurons (which release the neurotransmitter GABA, or gamma-aminobutyric acid), while the "self-grooming neurons" are excitatory neurons (which release the neurotransmitter glutamate, an amino acid).
But I am guessing the switch has something to do with immune response.
Healthy animals are social, unhealthy animals are not.
