Prefrontal Cortex

Prefrontal cortex

The prefrontal cortex is a part of the brain located at the front of the frontal lobe. It is implicated in a variety of complex behaviors, including planning, and greatly contributes to personality development.

Role of the prefrontal cortex

The prefrontal cortex helps people set and achieve goals. It receives input from multiple regions of the brain to process information and adapts accordingly. The prefrontal cortex contributes to a wide variety of executive functions, including:

  • focusing one’s attention
  • predicting the consequences of one’s actions; anticipating events in the environment
  • impulse control; managing emotional reactions
  • planning for the future
  • coordinating and adjusting complex behaviors (“i can’t do a until b happens”)

For an example of how these functions are tied together, let’s look at a man in a job interview. During the conversation, he has to focus on the interviewer and keep track of details the interviewer mentions. If the interviewer asks him a tough question, the man may get nervous. But the man can predict that running away will not get him the job, so he rejects that fearful impulse and asks for clarification around the question. The man can plan out his answers as he gets more information. Hopefully he can then ace the interview and get the job.

The prefrontal cortex also plays a big role in personality development. It helps people make conscious decisions according to their motivations. Over time, this can lead to certain tendencies in behavior, such as a person acting friendly toward others because they want to be popular. While the prefrontal cortex does not house a person’s entire self, it does contribute to the complex attitudes and choices that form a personality.

Development of the prefrontal cortex

The brain develops in a back-to-front pattern, and the prefrontal cortex is the last portion of the brain to fully develop. This does not mean that children do not have functional prefrontal cortices. Rather, they do not develop the complex decision-making and planning skills adults have until they are older.

During adolescence, the brain’s network of neurons develops many more synapses. These connections increase communication between parts of the brain and allow the individual to learn complex skills. However, this growth may happen unevenly.

For example, most fifteen-year-olds can assess hypothetical risk as well as adults. However, a teen’s prefrontal cortex has not grown many connections with the limbic system yet. In other words, the part of the brain that provides self-control can’t communicate well with the part of the brain that controls the fight or flight response. Thus, the same fifteen-year-old may act rashly under stress, even if they technically “know better.”

experience plays a role in the development of the prefrontal cortex. Teens exposed to a variety of stimuli and challenges may “mature” more quickly. However, most neurologists agree that the prefrontal cortex is not fully developed until around the age of 25.

Parts of prefrontal cortex

The prefrontal cortex is located at the very front of the brain. It is part of the brain’s wrinkled outer layer called the cortex. In adults, the prefrontal cortex takes up nearly a third of this outer layer.

There are competing theories about how best to categorize the parts of the prefrontal cortex. The brain is very interconnected, both physically and functionally. It is difficult to point to a specific part of the brain and say that this section alone controls a certain ability.

In general, though, the prefrontal cortex can be divided into three parts according to which functions they serve.

  • The medial prefrontal cortex: Contributes to attention and motivation. It can be thought of as a metaphorical start button, allowing people to begin an activity when it is time to do so. Lesions (i.e. Injuries) in this area cause people to become apathetic and unfocused. They may have trouble acting spontaneously or initiating speech. They could also have trouble concentrating on a task once it has started.
  • The orbital prefrontal cortex: Helps people control their impulses and ignore distractions. It helps them keep strong emotions in check in order to follow social rules. In one famous case, a man named phineas gage got an iron rod blown through his skull, injuring this area. Gage survived but displayed significant changes to his personality. He became irritable and reckless, growing prone to inappropriately crude humor. Research shows such changes are common when the orbital prefrontal cortex is injured.

The lateral prefrontal cortex: Allows people to create and execute plans. This region also helps individuals organize actions in a certain sequence, such as when a person needs to follow a recipe. Injuries to this region can interfere with people’s abilities to switch between tasks, recall where an instruction came from, or adapt to changes in rules.

References:

arain, m., haque, m., johal, l. Mathur, p. Nel, w. Rais, a., sandhu, r., & sharma, s. (2013). Maturation of the adolescent brain. Neuropsychiatric disease and treatment, 9(1), 449-461. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/pmc3621648

fuster, j. M. (2001, may 1). The prefrontal cortex—an update. Neuron, 30(2), 319-333. Retrieved from https://www.cell.com/neuron/fulltext/s0896-6273(01)00285-9

hathaway, w. R., & newton, b. W. (2019, april 8). Neuroanatomy, prefrontal cortex. Retrieved from https://www.ncbi.nlm.nih.gov/books/nbk499919

twomey, s. (2010). Phineas gage: neuroscience’s most famous patient. Smithsonian magazine. Retrieved from https://www.smithsonianmag.com/history/phineas-gage-neurosciences-most-famous-patient-11390067

last updated: 09-4-2019

Last Updated: 09-12-2023