Welcome to part two of _On the brain, a Conversation series by people whose job it is to know as much as there is to know about the body’s most complex organ. Here, Malcolm Horne, deputy director of the Florey Neuroscience Institutes, explores the brain’s role in our capacity to move and, through our understanding of this, the way we might treat brain disorders._
The 2003 Rugby World Cup final between Australia and England was a tense match with scores level through each team scoring penalty goals.
Under the scrutiny of a 100,000 strong crowd and the millions around the world watching on TV, the players had to step up and strike the kick accurately to keep their team in the game.
Kicking (well) is a highly learned and practiced skill but one that easily disappears under cognitive pressure.
It also exemplifies the way human movement differs from that of other animals by showing the capacity of humans to learn and modify their movement to achieve specific outcomes.
The capacity to move so as to capture food or engage in reproduction was a very early step in human evolutionary history. Traces of this ancient history are reflected in the structure and workings of the human spinal cord, which controls movement in the same way as almost all other animals including reptiles.
With time, the mammalian brain has evolved extra neural equipment, layered over these basic spinal reflex paths, to achieve more complex control of the spinal systems.
These neural systems coordinate the four limbs and trunk with information from the eyes, ears and balance system: this function is well exemplified in the silky movements of the cat.