Executive Functions, The New Homunculus

Remember that little guy inside the brain of a character in some cartoon of long ago, Disney sticks in mind, that was working the elaborate machinery that made the guy go.  It was pointed out to us that nothing was explained when you explained human activity by saying there was just another little human inside generating all the human behavior.

That little guy was called a Homunculus.

 But the problem of explaining human behavior remains–is it really just a manner of stimulus, response, consequence as argued by mainstream Psychology since 1913? (John Watson’s original article)?

Over the last 30 or so years a replacement for the homunculus has been developed and we call it the Executive Functions of the brain.  People (Psychologists) have been using the term to mean all kinds of human behaviors, from problem solving to self regulation in general.

Slowly but surely consensus has been converging on the basic componenets of the Executive Functions and, in fact, Russell Barkley has proposed a simple model that provides a nice map for directing assessment and rehabilitation strategies for those with Broken Brains.

He argues that the foundation of the EFs is the inhibition system.  Until an individual is able to stop his ongoing behavior(s) (or, prepotent responses as they say), and resist distractions, the executive functions can not begin to develop.

Immediately, one asks:  Well, how does inhibition occur?  Barkley focuses on the fact that Ritalin, a Dopamine re-uptake inhibitor, facilitates inhibition and promotes EF development in children and adults.  But where does inhibition come in the first place?  Grey, a personality theorist argues that one of the five main neuronal circuits in the frontal lobes is in fact a Behavioral Inhibition System that can be under-activated (ADHD) or over-activated (Depression.)  I will talk about that model in another post.

Another model that I will talk about in another post is Anthony Damasio’s notion of the somatic marker as the key for triggering the BIS.  Stay tuned,

When inhibiton is activated, according to Barkley, a sensory memory system begins to develop (visual memory and auditory memory.)  He calls this system the Working Memory.  The working memory is the palette upon which everything else is constructed and translated into action.

As language develops, it can use the WM palette to construct longer and longer strings of words and symbols, self talk, to make plans and delay gratification.

And as self talks develops, the individual learns to control emotions more effectively.

He then argues that with self talk, working memory and emotional controls in place, problem solving skills can be practiced covertly.

Of course, my description does not do the model justice and I refer the reader to Barkley’s work.  He is a very good writer and if you get the chance to see him speak, I wouldn’t miss it–he is an excellent speaker.

The most recent version of his Handbook came out in ‘05 and you can review at Amazon.  (I can’t seem to get the link in my post yet.)

In case you think I am a starry eyed grad student who is enamored with a new find, well I have been interested in the problem of consciousness and attention since I was a graduate student in 1968 and I am pretty dry eyed now.  I am enthused because I have been working with the developmentally disabled and traumatically brain injured for my whole professional career (34 years) and I am finally starting to see real results in cognitive rehabilitation, especially in attention training (the other way of saying inhibition training) and memory training. 

Comment on!  I am just getting started!

Teaser:  What do you think of computer rehabilitation programs?