Executive Function is the major role of DLPFC. It is Important, Very Important:

E = S + WM + Cf

The most important elements of Executive Function are:

Self-control: the aspect of inhibitory control that involves resisting temptations and not acting impulsively or prematurely

Working memory (WM): holding information in mind and mentally working with it (e.g., relating one thing to another, using information to solve a problem)

Cognitive flexibility: changing perspectives or approaches to a problem, flexibly adjusting to new demands, rules, or priorities (as in switching between tasks)

Self control

Self control involves being able to control attention, behavior, thoughts, and/or emotions and somehow not submit to a strong internal urge or temptation, and instead do what’s more appropriate and consistent with long term interests. If we don't develop and use inhibitory control we are controlled by impulses and habits.

So, inhibitory control makes it possible for us to change our behavior, break habits, and to choose how we respond instead of being controlled by our short term feelings and thoughts. 

Our behavior is mostly reflexive: we see this, we think that, someone says this, we do that. But having the skill of self control lets us be aware of our feelings and thoughts without being ruled by them. This takes pause. Inhibition is essentially a form of pause. And this is what the DLPFC does. there is one kind of brain cell in the DLPFC that fires in response to what just happened and another, which fires about what the current choice that could happen next. The learned ability to pause between one and the other let’s us think about what we are about to do, to deliberate. This is the way that we exert delayed gratification. 

The idea of delayed Gratification emerged from the Stanford Marshmallow experiment by Walter Mischel. His group of researchers was trying to understand if and how preschool childrenresisted temptation. They gave a group of four year old children this choice: either eat one marshmallow now, or if they could wait about 15 minutes, get two marshmallows. Some kids could not resist the impulseand ate the marshmallow, but others could delay gratification and win two marshmallows. Mischel interviewed the children when they grew into teenagers and adults. He found some important and consistent patterns. The four year olds who could and would wait, were doing much better later in life. They had better grades, more friends, scored higher on the SAT, had better social skills, self-confidence and self-esteem, were more mature, coped with stress better, had more of a tendency to plan ahead, and were more likely to think about decisions instead of acting on impulse. They also had fewer behavioral problems, were more likely to follow rules instead of breaking them and less likely to be hyperactive. By the time they grew into adults, there was no question of the importance of this skill. Those kids who could wait, were less likely to have alcohol or drug problems, and had more job and relationship satisfaction.

When the DLPFC is not working, or has not been trained, there is usually a self control problem. When this part of the brain is stimulated and strengthened, problems of self control are replaced with successes of self control.

Working Memory

Working Memory (WM) is what lets us hold information in our mind and work with abstract concepts (Baddeley & Hitch 1994, Smith & Jonides 1999). The two kinds of WM are Verbal (words) and Spatial (the relationship of objects in space). WM is required for understanding what happens over time and seeing how things fit together. When we have good WM we ‘get’ the connections between events in past present and future, cause and effect and discerning what things mean. DLPFC is located in front and above the Language Area (Broca’s) which is required for coherent and fluent expression. the two areas cooperate, and DLPFC allows other brain areas to have space to combine, compare and contrast. WM is needed also for attaining goals by organizing sequences of actions to get from beginning, through the middle and achieve completion. Connecting the dots, considering different possibilities, and using the imagination to see patterns among events, ideas, words and objects are WM functions. Without good WM it is hard to see the big picture and see how the parts interact to form the whole. Art, Music and literature all require WM for their creation as well as their appreciation.

When the DLPFC is not working, or has not been trained, there is usually a working memory problem. Meditation and attentional training can help develop this area of brain. When this part of the brain is stimulated and strengthened, problems of working memory are replaced with a wider perspective, increased creativity, better attention and learning. 

Flexible Thinking

Flexible Thinking is learned at a later age than the first two (Davidson et al. 2006, Garon et al. 2008). This is the ability we are using when we look at things from different points of view. We can change perspective in space (“What would this look like in blue?” or “If the couch were over there...”) or in relationships ( “Help me understand this from your perspective”). When we shift the way we look at things, we are able to make creative and useful changes. To do this, however, we need to set aside (inhibit) the way we look at things now, for a different viewpoint, then while setting aside the way things are, we can use our WM as a place to construct a different way of approaching a situation or of understanding an issue.  One can easily see how Flexible Thinking needs and is needed by Self Control as well as WM.  

If at first you don’t succeed, try and try again, but don't do it the same way, try something different. Problem solving often requires us to imagine new possibilities, to think outside of the box.

Being flexible makes it easier to adjust to changed circumstances, to apologize, and to change plans when an obstacle is encountered. There are interesting psychological measures that assess flexibility of thought processing. One is called the Stroop, here is an example

ok, now try this

This sort of tasks shows how challenging it can be and how much slower we go when we have confusing or contradictory inputs. Flexibility is the the ablity to do things a new way in a new situation, but you will notice, that you INHIBIT (Self Control) saying the first thought which may or may not be the correct answer, then, using WM, you recall what the instruction was (or read it again) and only then can you do the different thing. Doing one thing and then doing something else is called Task Switching, it is a form of Flexible Thinking.

Discovery and invention require flexibility. When Fleming came to work at his Bacteria Lab one Monday and saw that his sandwich had grown mold, he also noticed that his strep cultures had weird no growth areas, he put the parts together and concluded that something in the mold had killed the germs, thereby discovering the first antibiotic - penicillin.

An inventor named Anatole was taking a shower, and felt frustrated that if he were holding a bar of soap, he only had one more hand to turn down the cold water and turn up the hot water. It was then he thought of a shower handle that would do both at the same time.

For the first image, can you see white and black arrows? In teh second can you see the faces on the sides of the goblet? How many possibilities can you see in the third?

When the DLPFC is not working, or has not been trained, there is usually a reduction in Flexible Thinking. When this part of the brain is stimulated and strengthened, one would think that Flexible Thinking would improve, but so far, in my experience, brain stimulation does not improve Flexible Thinking as much as it improves Self Control and Working Memory. I'm not sure about this because I have not measured it formally. Feedback from patients who have had brain stimulation for depression routinely includes C students becoming A students, Attention Deficit vanishing and improvement or elimination of impulsivity. Your milage may vary.


Some Recent Articles about Executive Function (Click to download)

Working memory and executive function decline across normal aging, mild cognitive impairment, and Alzheimer's disease.

Advancing understanding of executive function impairments and psychopathology: bridging the gap between clinical and cognitive approaches.

Obesity-associated biomarkers and executive function in children.

Computer-Based Cognitive Programs for Improvement of Memory, Processing Speed and Executive Function during Age-Related Cognitive Decline: A Meta-Analysis.

The neural and genetic basis of executive function: attention, cognitive flexibility, and response inhibition.

Family matters: Intergenerational and interpersonal processes of executive function and attentive behavior.

The emergent executive: a dynamic field theory of the development of executive function.

The early development of executive function and its relation to social interaction: a brief review.

Prefrontal cortex and executive function in young children: a review of NIRS studies.

Behavioral Sleep Problems and their Potential Impact on Developing Executive Function in Children.

Language, executive function and social cognition in the diagnosis of frontotemporal dementia syndromes.

A role for synaptic plasticity in the adolescent development of executive function.

The relationship between executive function and falls and gait abnormalities in older adults: a systematic review.