Reply to comment

I just wanted to briefly introduce an interesting article from the May 2001 issue of Nature titled Decisions, decisions.  This article discusses a possible locus of brain decision – a master box for the ultimate convergence of sensible input into motor output.  William Newsome working with Michael Shadlenn and colleagues have located what they believe to be “decision neurons,” first located in a brain region linking visual processing and eye movement, the LIP, and later in the prefrontal cortex.  Discovered in monkeys while monitoring the activation of specific neurons in response to left/right movements of dots, Newsome and Shadlenn believe that decision neurons monitor the activity of cells that respond to left or right movements (through corollary discharge?) and then send signals to the superior colliculus, which controls movements.  Eventually, these men were able to predict the direction of a monkey’s eye movement based on the firing of a single neuron. 

Ranulfo Romo of the University of Mexico has continued studies on these neurons and proposes that there are decision neurons within the prefrontal cortex that act independent of sensory input.  While highly speculative, this would be the central locus of decision making.  Decision neurons could also be involved with deciding what simplifications to make during visual processing from visual input to form the image in our brain.  I recommend that you read this article for much more detailed information.