Locating the Dorsolateral Prefrontal Cortex
The dorsolateral prefrontal cortex (DLPFC) is a distinct region in the frontal lobe of the brain. It occupies the upper and outer parts of the prefrontal cortex. Specifically, it encompasses Brodmann areas 9 and 46, and sometimes parts of area 8 and 10, which are numerical classifications of brain regions. This area is positioned just above and slightly to the side of the eyes, extending backward towards the top of the head.
The DLPFC receives and integrates information from various other brain areas. Its anatomical boundaries are not always sharply defined, yet its functional role is distinct.
How the Dorsolateral Prefrontal Cortex Works
The dorsolateral prefrontal cortex plays a role in working memory, which is the ability to temporarily hold and manipulate information. This allows individuals to keep track of details during a conversation or remember steps in a complex task. For instance, when you recall a phone number to dial it, the DLPFC helps manage that information until it is no longer needed. It helps maintain a mental workspace where thoughts can be actively processed and updated.
This brain region is involved in planning and problem-solving. It enables individuals to organize a sequence of actions to achieve a goal, such as preparing a meal or mapping out a travel itinerary. The DLPFC helps in breaking down complex problems into manageable steps and anticipating potential outcomes. Its activity increases when faced with novel situations requiring strategic thought.
Decision-making processes also rely on the DLPFC, particularly when choices involve complex information or require evaluating multiple options. It helps in weighing the pros and cons of different alternatives and selecting the most appropriate course of action. This function extends to financial decisions or choosing between different educational paths. The DLPFC supports the rational evaluation of potential outcomes.
Cognitive flexibility, the ability to adapt to new situations or shift between different tasks or thought patterns, is another function supported by the DLPFC. For example, when switching from one project to another, this region helps adjust mental gears. It allows individuals to discard old rules that no longer apply and adopt new ones quickly. This adaptability is important for navigating unpredictable environments.
The DLPFC also contributes to inhibitory control, which is the capacity to suppress inappropriate thoughts or actions. This enables individuals to resist distractions and focus on a specific task, or to refrain from impulsive behaviors. For instance, it helps prevent blurting out an answer before being called upon or resisting the urge to check a phone during a lecture. This function is important for self-regulation and goal-directed behavior.
The Dorsolateral Prefrontal Cortex and Cognitive Health
Dysfunction in the dorsolateral prefrontal cortex is implicated in various neurological and psychiatric conditions, affecting how individuals think and behave. In schizophrenia, for example, individuals often exhibit deficits in executive functions, such as working memory, planning, and cognitive flexibility. These impairments are linked to abnormal activity and connectivity within the DLPFC, contributing to symptoms like disorganized thought. Brain imaging studies show reduced activation in this area during cognitive tests in people with schizophrenia.
Major depressive disorder also shows connections to DLPFC function, particularly concerning mood regulation and cognitive control. Individuals with depression may experience difficulties with attention, decision-making, and emotional processing, which are functions associated with the DLPFC. Research suggests altered connectivity and reduced gray matter volume in this region in depressed individuals, impacting their ability to regulate negative emotions and engage in goal-directed behavior. These changes can contribute to symptoms like anhedonia and psychomotor retardation.
Attention-Deficit/Hyperactivity Disorder (ADHD) is characterized by impairments in attention, impulse control, and planning, all of which are managed by the DLPFC. Children and adults with ADHD often show reduced activity or structural differences in this brain region. These neurobiological differences contribute to the core symptoms of inattention and hyperactivity-impulsivity, making it challenging to sustain focus or inhibit immediate responses. Understanding these links helps explain the cognitive profile of ADHD.
Neurodegenerative diseases, such as Parkinson’s disease and early-stage Alzheimer’s disease, can also affect DLPFC function as the conditions progress. In Parkinson’s disease, while primarily a movement disorder, patients often develop cognitive impairments, including executive dysfunction, due to the degeneration of dopamine pathways that project to the DLPFC. Similarly, in early Alzheimer’s disease, before widespread memory loss, individuals may experience subtle difficulties with planning and problem-solving, indicating early DLPFC involvement. These cognitive changes can impact a person’s independence and quality of life.