1. A number of times we have used the idea of ‘executive function’ in explanations of behavior. What does this really mean?
2. Recall that the region of the neocortex forward of the central sulcus is the frontal lobe. The most anterior half of this lobe is commonly referred to as the prefrontal cortex. That region is itself considered to have two major subdivisions, based on function.
3. The ventromedial (bottom-middle) portion is strongly interconnected with brain areas, such as the amygdala and limbic region, that are involved in emotion. The other major subdivision, the dorsolateral portion is the area that seems to be involved in executive function,
4. "The [dorsolateral prefrontal]cortex . . . participates in the initiation and execution of deliberate actions. . . . [Indeed,] a most distinctive disorder arising from prefrontal damage [due to accident or stroke] is the inability to initiate and carry out new and goal-directed patterns of behavior. . . . It has been attributed the so-called executive functions, especially decision making, attention, planning, and working memory. However, [it is crucial to recognize that] most these functions are phenomena of [distributed] neural processing and without a unique location of their own, either in frontal cortex or elsewhere." (The quotes is from the book "The Prefrontal Cortex" by J.M. Fuster)
5. To reiterate the executive functions include:
- initiation of and overall control of the execution of deliberate actions
- initiation of and overall control of goal directed behavior
- attention
- planning
- decision making
Recall the example of Phineas Gage, who lost most of these abilities after his accidental prefrontal lobotomy.
6. Once action is initiated, feedback to the dorsolateral prefrontal cortex allows it to monitor the action at lower levels, so that actions can be matched to intentions and goals. Thus, a continuous feedforward-feedback loop modulates the activity as necessary
7. Inappropriate, or deficient communication between dorsolateral prefrontal cortex and areas where sensation and action are processed and organized is the basis of saying that diseases such as schizophrenia involve impaired executive functioning of the prefrontal cortex.