What Is the Frontal Lobe?
Your frontal lobe is one of four different sections (also called lobes) of your brain. The four lobes in your brain are called the frontal, parietal, temporal, and occipital lobes. Each of these lobes controls specific functions of your body.
Your frontal lobe is the largest lobe of your brain. It makes up about 25%-40% of the cortex in your brain, depending upon how researchers define the boundaries of the lobes. Your cortex is the wrinkly surface of your brain that controls higher-level processes, such as language, memory, and reasoning.
As the name suggests, your frontal lobe is in the front of your brain, just behind your forehead. It extends back about halfway through your skull where your parietal lobe starts. It's divided into two major sections, the left hemisphere frontal lobe and the right hemisphere frontal lobe.
Your frontal lobe controls functions such as:
- Motor tasks, such as picking something up, walking around, or forming words
- Judgment, abstract thinking, and creativity
- Social understanding, like what you should and shouldn't say in a given social situation
Frontal Lobe Functions
To help them study the function of the frontal lobe, researchers divide it into four different sections, including:
Precentral gyrus. This section contains your primary motor cortex, which allows you to move specific body parts. Researchers have been able to make a map that shows the body parts that are controlled by specific areas of the primary motor cortex (also called Brodmann area 4). For instance, the areas toward the middle of this section control your lower body, whereas the outer parts control your facial muscles. This section also contains your prefrontal cortex, which is responsible for decision-making, reasoning, personality, picking up social cues, and other complex functions.
Researchers are still working to understand the function of the other three sections of the frontal lobe. Here's what they know so far:
Superior frontal gyrus. The left part of this section is important for your ability to temporarily store and process information you need to learn, reason, and understand language. It also controls your ability to sense and integrate information about where your body is in space. The right part of this section is important to control your impulses and regulate your muscle movements.
Middle frontal gyrus. The left part of this section helps you read and understand text. The right part of this section helps you understand numbers and do mathematical operations. This section also controls your frontal eye fields, which allows you to scan details within a scene or image right in front of you.
Inferior frontal gyrus. This area controls your ability to form words and speak.
Frontal Lobe Development
Around the third week of development, a human embryo goes through a process called gastrulation. Up to this point, the embryo is a hollow ball of cells called a blastula. Gastrulation is when the embryo divides into three cell layers that will eventually form all the different organs of the body. One of these cell layers, called the ectoderm, starts a process called neurulation (pronounced noor-uh-ley-shuhn), around the fourth week of development.
Neurulation is when your central nervous system (your brain and spinal cord) begins to develop. When you're born, your brain is only about 25% of the size your brain will be when you're an adult. So, your entire brain does a lot of growing, changing, and developing throughout your childhood and adolescence, and into young adulthood.
When does your frontal lobe fully develop?
This is a bit hard to pin down because it depends on many different factors, including what you consider "fully developed." A part of your frontal lobe called the prefrontal cortex probably doesn't finish developing until around age 25 for most people. Your prefrontal cortex is the part of your frontal lobe that controls decision-making, reasoning, problem-solving, and some aspects of your personality.
However, the age at which your prefrontal cortex finishes development varies across individuals. This is because it depends on both your genes and what's happening in your environment. It's affected by how much sleep you get, what you eat, whether you've had illnesses, what kind of substances you've been exposed to, when you start sexual development, and just about anything else you can think of. For people who are assigned female at birth (AFAB), the prefrontal cortex tends to finish developing in the late teens and early twenties. For those assigned male at birth (AMAB), it tends to happen in the mid- to late-twenties or even early thirties. The average age, though, is around the mid-twenties.
This doesn't mean that teens and young adults can't or don't reason or solve problems well. Just because your prefrontal cortex is still developing doesn't mean you can't or don't use what's there. It really just means that, until around your mid-twenties, your ability for abstract reasoning and self-regulation hasn't solidified yet. It's probably why teenagers and young adults seem all over the place — rational one minute and clueless the next.
Impact of the Frontal Lobe on Your Health
Your frontal lobe has a dominant side — either left or right — that controls language and speech. The left side tends to be dominant in people who are right-handed, while the right side tends to be dominant in left-handed people. Since most people are right-handed, most people use the left side of their brain more for language and speech. You may store language and speech on the right side of your brain if you are left-handed or sustain an injury to the left side of your brain early in life.
Language involves:
- Semantics or meaning — understanding the differences in words that sound the same
- Developing new words — using one base word to make new words
- Grammar — creating the appropriate sentence structure
- Social context — using language that is appropriate for the setting, such as home vs. school
Speech involves:
- Articulation — pronouncing words correctly
- Voice — using your vocal cords to adjust your sound and tone
- Fluency — using proper rhythm and tone to convey feeling
The frontal lobe controls how you use and process language. You may have a language disorder if you have difficulty understanding other people’s speech or explaining your own ideas, thoughts, or feelings. You may have a speech disorder if you struggle to use the correct word sounds or rhythm of speech.
Three specific areas in the brain control language and speech:
- Broca’s area: This portion is in your brain’s left hemisphere. It produces speech and helps you with articulation.
- Wernicke’s area: This portion is in the posterior superior temporal lobe and helps with comprehension of language. This includes what you hear and what you read.
- Angular gyrus: This is near the parietal lobe. It helps process senses that contribute to understanding language as you associate it with images in your mind.
Motor movements. The frontal lobe also helps control your voluntary motor movements. Each side of the frontal lobe controls the opposite side of your body. Cortical neurons radiate to your brain stem and down your spinal cord, telling your body what movement to complete. This includes accurately coordinating movements with correct position and timing.
Conditions Linked to the Frontal Lobe
Because your frontal lobe is necessary for so many functions — voluntary movement, expressive language, and executive functions — any injuries or illnesses that affect your frontal lobes can cause a lot of different signs and symptoms.
Signs of frontal lobe conditions
This list is not exhaustive because you can have many different symptoms, but damage to your frontal lobes may cause:
- Paralysis of some body parts
- Inability to plan and complete a multistep task, such as making coffee (also called sequencing)
- Inability to act spontaneously in social situations
- Difficulty finding and saying the right word (also called Broca's aphasia)
- Loss of flexibility when thinking and persistence of a single idea or behavior (also called perseveration)
- Inability to focus on a task and filter out distractions (also called attention)
- Moods that go up and down (also called emotional lability)
- Trouble with problem-solving
- Trouble inhibiting or controlling your responses or impulses (also called disinhibition)
- Reduced motivation, initiation, and persistence of activities (also called adynamia)
- Reduced awareness or insight into your difficulties
- Changes in your social behaviors
- Changes in your personality
Tests for frontal lobe conditions
To help diagnose any problems with your frontal lobe, your doctor may use lab, imaging, and other diagnostic tests, such as:
- Blood tests to test for heavy metals such as copper, lead, or mercury or your immune system function
- CT scan
- MRI
- PET scan
- Electroencephalogram (EEG)
- Electromyogram (nerve conduction testing)
- Evoked potentials (sensory tests)
- Neuropsychological testing
Frontal lobe dementia
Also known as frontotemporal dementia (FTD), this is a group of neurodegenerative conditions in the frontal and temporal lobes of your brain. Neurodegenerative means that the cells in these areas stop working or die. Unfortunately, neurodegenerative disorders usually get worse over time and have no cure. As the cells in those areas die, you begin to lose the abilities that those areas control.
Based on which parts of the frontal or temporal lobes are affected, there are three main symptom groups:
- Behavioral-variant FTD. This is the most common symptom group. It usually starts with a change in personality, such as socially inappropriate behavior, apathy, loss of empathy, compulsive behavior, hyperorality, and diet changes.
- Semantic-variant primary progressive aphasia. This usually starts with difficulty forming words and grammatically correct phrases. People with this variant may be able to understand single words or simple sentences, but they may get confused by complicated sentences.
- Nonfluent/agrammatic primary progressive aphasia. This usually starts with problems choosing and understanding words. People with this variant may say things that don't make sense or won't understand what other people say to them.
You can also get FTD symptoms when you have other neurodegenerative conditions, such as amyotrophic lateral sclerosis (ALS) and Parkinson's disease.
Risks of Frontal Lobe Damage
Frontal lobe epilepsy. This is a seizure disorder that starts in your frontal lobe. It's often due to problems with your brain development when you were still a fetus. It can also be caused by brain infections, injuries, and tumors.
Seizures. Some seizure disorders are caused by damage to or a malformation in the brain's frontal lobe. Seizures affect your motor abilities and speech. Your doctor will assess your seizures and find out which region of your frontal lobe may be affected.
Personality and social skills. Because the frontal lobe is large and in the front of your skull, it is prone to damage. Any damage may contribute to changes in your social behavior. It may also affect your sense of space and the coordination of your facial muscles.
Frontal lobe stroke. These strokes tend to affect large areas of your frontal lobe because of the way blood vessels are distributed around your brain. Damage from a frontal lobe stroke can cause muscle weakness and sensory loss on the side of your body opposite to the stroke, as well as behavioral changes, memory problems, and trouble with self-care.
Frontal lobe headache. There are no pain receptors inside your brain, so you wouldn't necessarily be able to feel a problem that starts there. Most headaches start in your head, neck, and face. If you have a headache that is right behind your eyes or forehead, it's most likely a tension-type headache. These headaches may feel like a tight band wrapped around your forehead and temples.
Takeaways
Your frontal lobe is the largest section of your brain that allows you to move your muscles, talk, solve problems, and engage with other people in social situations. Some researchers consider this part of the brain the part that makes us different from most other non-human animals. This part of your brain is the last to fully develop; for most people, it doesn't finish developing until you're around 25. Injuries or illnesses that affect your frontal lobes can cause a lot of different signs and symptoms, such as paralysis, inability to speak, and changes in your personality.
Frontal Lobe FAQs
How can I keep my frontal lobe healthy?
Keeping your body healthy is the best way to help keep your brain healthy. In general, this means:
- Eat a balanced diet with plenty of vitamins and minerals. This can help prevent circulatory disorders and decrease your risk for a stroke.
- Stay physically active. This too helps prevent circulatory disorders.
- Reach and maintain a weight that's healthy for you.
- Work with your health care team to manage your health conditions.
- Wear safety equipment to protect your head, such as seat belts and helmets.
