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Principal fissures and lobes of the Cerebrum viewed laterally (Frontal lobe is blue)
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Orbital surface of left frontal lobe
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The is an area in the
Brain of vertebrates. Located at the front of each
Cerebral Hemisphere , frontal lobes are positioned in front of (anterior to) the
Parietal Lobes . The
Temporal Lobes are located beneath and behind the frontal lobes.
On the
Lateral surface of the
Human Brain , the
Central Sulcus separates the frontal lobe from the parietal lobe. The lateral sulcus separates the frontal lobe from the
Temporal Lobe .
The frontal lobe can be divided into a
Lateral , polar (frontalmost), orbital (above the
Orbit ; also called basal or
Ventral ), and
Medial part. Each of these parts consists of particular
Gyri :
The gyri are separated by
Sulci . E.g., the precentral gyrus is in front of the
Central Sulcus , and behind the
Precentral Sulcus . The superior and middle frontal gyri are divided by the
Superior Frontal Sulcus . The middle and inferior frontal gyri are divided by the
Inferior Frontal Sulcus .
In the human brain, the precentral gyrus and the related cortical tissue that folds into the central sulcus comprise the
Primary Motor Cortex , which controls voluntary movements of specific body parts associated with areas of the gyrus.
Frontal lobes have been found to play a part in impulse control, judgment, language, memory, motor function, problem solving, sexual behavior, socialization and spontaneity. Frontal lobes assist in planning, coordinating, controlling and executing behavior. People that have damaged frontal lobes may experience problems with these aspects of cognitive function, being at times impulsive; impaired in their ability to plan and execute complex sequences of actions; perhaps persisting with one course of action or pattern of behavior when a change would be appropriate (perseveration).
Cognitive maturity associated with adulthood is marked by related maturation of cerebral fibers in the frontal lobes between late teenager years and early adult years. Research by Dr. Arthur Toga, UCLA, found increased
Myelin in the frontal lobe gray matter of young adults compared to that of teens, whereas gray matter in parietal and temporal lobes was more fully matured by teen years. Typical onset of schizophrenia in early adult years correlates with poorly myelinated and thus inefficient connections between cells in the forebrain.
A report from the National Institute of Mental Health says a gene variant that reduces dopamine activity in the
Prefrontal Cortex is related to poorer performance and inefficient functioning of that brain region during working memory tasks, and to slightly increased risk for
Schizophrenia .
Dopamine-sensitive neurons in the
Cerebral Cortex are found primarily in the frontal lobes. The
Dopamine system is associated with pleasure, long-term memory, planning and drive. Dopamine tends to limit and select sensory information arriving from the
Thalamus to the forebrain. Poor regulation of dopamine pathways has been associated with schizophrenia.
The so-called
Executive Functions of the frontal lobes involve the ability to recognize future consequences resulting from current actions, to choose between good and bad actions (or better and best), override and suppress unacceptable social responses, and determine similarities and differences between things or events.
The frontal lobes also play an important part in retaining longer term memories which are not task-based. These are often memories with associated emotions, derived from input from the brain's limbic system, and modified by the higher frontal lobe centers to generally fit socially acceptable norms (see
Executive Functions above). The frontal lobes have rich neuronal input from both the alert centers in the brainstem, and from the limbic regions.
Psychological tests that measure frontal lobe function include
Finger Tapping ,
Wisconsin Card Sorting , and measures of verbal and figural fluency.
In the early 20th century, a medical treatment for
Mental Illness , first developed by
Portuguese Neurologist Egas Moniz , involved damaging the pathways connecting the frontal lobe to the
Limbic System . Frontal
Lobotomy (sometimes called frontal leucotomy) successfully reduced distress but at the cost of often blunting the subject's emotions, volition and
Personality . The indiscriminate use of this
Psychosurgical procedure, combined with the severe side effects and dangerous nature of the operation gained it a bad reputation and the frontal lobotomy has largely died out as a psychiatric treatment.
More precise psychosurgical procedures are still occasionally used, although are now very rare occurrences. They may include procedures such as the anterior capsulotomy (bilateral thermal lesions of the anterior limbs of the
Internal Capsule ) or the
Bilateral Cingulotomy (bilateral thermal lesions of the anterior
Cingulate Gyri ) and might be used to treat otherwise untreatable
Obsessional Disorders or
Clinical Depression .
