Complex sentence: Kelso's main thesis is that the real-life coordination of neurons in the brain and the real-life coordinated actions of people and animals are linked by virtue of sharing a common coordination dynamics.
Split into simpler sentences: Kelso's main thesis is that the real-life coordination of neurons in the brain and the real-life coordinated actions of people and animals are cut from the same dynamic cloth. That is, brain, mind and behavior are linked by virtue of sharing a common underlying coordination dynamics.