A frontal typically refers to the frontal lobe, the largest of the brain’s four main lobes and the region responsible for everything from planning and decision-making to movement and speech. It sits at the front of each hemisphere, directly behind your forehead, and makes up roughly one-third of the brain’s total surface area. Because it controls so many higher-level functions, the frontal lobe plays an outsized role in shaping personality, behavior, and everyday thinking.
Where the Frontal Lobe Sits
The frontal lobe occupies the most forward part of each cerebral hemisphere. Its rear boundary is the central sulcus, a deep groove running roughly ear to ear across the top of the brain that separates the frontal lobe from the parietal lobe behind it. Along the side, the lateral (Sylvian) fissure marks the border between the frontal lobe and the temporal lobe below. Everything in front of these landmarks belongs to the frontal lobe.
The term “frontal” also shows up in anatomy outside the brain. The frontal bone forms the lower part of your forehead and extends over the eye sockets. Inside that bone sit two frontal sinuses, air-filled cavities lined with mucus-producing cells that help keep your nasal passages moist. But when most people search “what is a frontal,” they’re asking about the brain region, and that’s where the real complexity lies.
Executive Functions: Planning, Focus, and Self-Control
The front-most section of the frontal lobe, called the prefrontal cortex, is the brain’s command center for what neuroscientists call executive functions. These are the mental skills you use to manage your own behavior: staying focused on a task, weighing options before making a decision, setting goals based on past experience, and stopping yourself from acting on impulse. Working memory, the ability to hold a piece of information in mind just long enough to use it (like remembering a phone number while you dial), also depends heavily on this area.
A specific sub-region called the orbitofrontal cortex, located just above the eye sockets, handles impulse control and helps you link actions to their likely consequences. It’s the part of your brain that lets you resist grabbing food off someone else’s plate or blurting out something inappropriate. It does this by connecting what you see and feel to predictions about outcomes and rewards.
Movement and Motor Control
A strip of brain tissue running along the back edge of the frontal lobe, just in front of the central sulcus, forms the primary motor cortex. This is where voluntary movement begins. Neurons here send electrical signals down through the spinal cord to motor neurons that contract specific muscles. Adjacent areas, the premotor cortex and the supplementary motor area, help plan and coordinate those movements before they happen. When you reach for a cup of coffee, the motor planning regions fire first, then the primary motor cortex sends the signal that actually moves your arm and hand.
Speech and Language Production
On the left side of the frontal lobe in most people sits Broca’s area, a region critical for producing speech. It occupies the lower rear portion of the frontal lobe and influences the motor movements needed to form words. But its role goes beyond simply moving your mouth. The front part of Broca’s area helps process word meaning, while the back part handles how words sound. The area also contributes to sentence grammar, language fluency, and the ability to repeat what you’ve heard. Damage here typically produces halting, effortful speech, even though the person may understand language perfectly well.
Personality and Behavior Changes After Damage
Because the frontal lobe governs so much of what makes a person “themselves,” damage to it can cause dramatic shifts in personality. The specific changes depend on which part is injured.
Damage to the orbitofrontal area tends to produce what’s sometimes called the orbitofrontal syndrome: disinhibition, impulsivity, emotional outbursts, poor judgment, tactlessness, and social inappropriateness. In severe cases, these changes can lead to behavior so extreme that a previously law-abiding person begins engaging in criminal acts. People with this type of damage often lack insight into how much they’ve changed.
Injury to a deeper midline structure called the anterior cingulate produces the opposite pattern. Rather than becoming disinhibited, these patients become withdrawn, quiet, and profoundly apathetic, sometimes losing motivation to do almost anything. Damage to the outer upper portion of the frontal lobe, the dorsolateral prefrontal cortex, tends to impair organization and planning while leaving social skills relatively intact. The person may seem scattered or disorganized rather than socially inappropriate.
These personality shifts are also a hallmark of traumatic brain injury. Post-concussion syndrome can include irritability, aggression triggered by minor provocations, anxiety, depression, sexual inappropriateness, and emotional swings. Family members and caregivers often describe it as living with a different person.
Frontal Lobe Maturation
The prefrontal cortex is one of the last brain regions to fully develop. It matures primarily during adolescence and doesn’t reach full development until around age 25. This timeline is the biological reason teenagers are more prone to impulsive decisions, risk-taking, and difficulty planning ahead. It’s not that adolescents lack intelligence; the hardware for weighing consequences and controlling impulses simply isn’t finished yet. This fact has influenced legal and policy discussions about everything from the drinking age to juvenile sentencing.
Conditions Linked to the Frontal Lobe
Several neurological conditions target the frontal lobe specifically. Frontotemporal dementia (FTD) is one of the most significant. Unlike Alzheimer’s disease, which typically starts with memory loss, FTD often begins with personality and behavior changes because it attacks the frontal and temporal lobes first. Early signs of the behavioral variant include acting impulsively, losing interest in family or hobbies, repeating the same actions or phrases, displaying emotions that don’t match the situation, difficulty reading social cues, and compulsive eating. Because these symptoms look more like a psychiatric problem than a neurological one, FTD is frequently misdiagnosed in its early stages.
FTD also includes language-dominant forms called primary progressive aphasias, where people gradually lose the ability to speak fluently, understand words, or find the right term during conversation. Movement problems like muscle stiffness, difficulty with balance, and unexplained falls can also appear, particularly in related conditions like progressive supranuclear palsy and corticobasal syndrome.
Frontal lobe epilepsy is another condition worth noting. It accounts for an estimated 10 to 20 percent of epilepsy surgery cases, though its true prevalence in the general epilepsy population is likely higher. Seizures originating in the frontal lobe can look unusual, sometimes producing brief episodes of thrashing, cycling leg movements, or strange vocalizations during sleep, which can be mistaken for psychiatric episodes or sleep disorders.