HOME

TheInfoList




In
mammalian brain A brain is an organ that serves as the center of the nervous system In Biology, biology, the nervous system is a Complex system, highly complex part of an animal that coordinates its Behavior, actions and Sense, sensory information by tran ...
anatomy, the prefrontal cortex (PFC) is the
cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of a ...
which covers the front part of the
frontal lobe The frontal lobe is the largest of the four major lobes of the brain in mammals, and is located at the front of each cerebral hemisphere (in front of the parietal lobe and the temporal lobe). It is parted from the parietal lobe by a Sulcus (neur ...

frontal lobe
. The PFC contains the
Brodmann area A Brodmann area is a region of the cerebral cortex, in the human brain, human or other primate brain, defined by its cytoarchitecture, or histological structure and organization of Cell (biology), cells. History Brodmann areas were originally de ...
s
BA8
BA8
,
BA9
BA9
,
BA10
BA10
,
BA11
BA11
, BA12, BA13, BA14, BA24, BA25, BA32, BA44,
BA45
BA45
,
BA46
BA46
, and
BA47
BA47
. The basic activity of this brain region is considered to be orchestration of thoughts and actions in accordance with internal goals. Many authors have indicated an integral link between a person's will to live, personality, and the functions of the prefrontal cortex. This brain region has been implicated in
executive functions Executive functions (collectively referred to as executive function and cognitive control) are a set of cognitive processes Cognition () refers to "the mental action or process of acquiring knowledge and understanding through thought, exper ...
, such as
planning Planning is the process A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include: Business and management *Business process A business p ...

planning
,
decision making In psychology Psychology is the scientific Science () is a systematic enterprise that builds and organizes knowledge Knowledge is a familiarity or awareness, of someone or something, such as facts A fact is an occurrence in ...

decision making
,
short-term memory Short-term memory (or "primary" or "active memory") is the capacity for holding, but not manipulating, a small amount of information in mind The mind is the set of faculties responsible for mental phenomena A phenomenon (; plural phenom ...
, personality expression, moderating social behavior and controlling certain aspects of speech and language. Executive function relates to abilities to differentiate among conflicting thoughts, determine good and bad, better and best, same and different, future consequences of current activities, working toward a defined goal, prediction of outcomes, expectation based on actions, and social "control" (the ability to suppress urges that, if not suppressed, could lead to socially unacceptable outcomes). The frontal cortex supports concrete rule learning. More anterior regions along the rostro-caudal axis of frontal cortex support rule learning at higher levels of abstraction.


Structure


Definition

There are three possible ways to define the prefrontal cortex: * as the granular frontal cortex * as the projection zone of the
medial dorsal nucleus The medial dorsal nucleus (or dorsomedial nucleus of thalamus) is a large nucleus in the thalamus The thalamus (from Greek θάλαμος, "chamber") is a large mass of gray matter located in the wikt:dorsal, dorsal part of the diencephalon ( ...
of the
thalamus The thalamus (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is appr ...

thalamus
* as that part of the frontal cortex whose electrical stimulation does not evoke movements


Granular frontal cortex

The prefrontal cortex has been defined based on
cytoarchitectonics Cytoarchitecture (Ancient Greek language, Greek ''wiktionary:κύτος#Ancient_Greek, κύτος''= "cell" + ''wiktionary:ἀρχιτέκτων#Ancient_Greek, ἀρχιτεκτονική''= "architecture"), also known as cytoarchitectonics, is the ...
by the presence of a cortical granular layer IV. It is not entirely clear who first used this criterion. Many of the early cytoarchitectonic researchers restricted the use of the term prefrontal to a much smaller region of cortex including the gyrus rectus and the
gyrus In neuroanatomy Neuroanatomy is the study of the structure and organization of the nervous system In Biology, biology, the nervous system is a Complex system, highly complex part of an animal that coordinates its Behavior, actions and S ...
rostralis (
CampbellCampbell may refer to: People Surname * Campbell (surname), includes a list of people with surname Campbell Given name * Campbell Brown (footballer), an Australian rules footballer * Campbell Brown (journalist) (born 1968), American television new ...

Campbell
, 1905;
G. E. Smith George Edward Smith ('' né'' Haddad; born January 27, 1952) is an American guitarist. He was the lead guitarist for the duo Hall & Oates Hall & Oates are an American pop rock duo formed in 1970 in Philadelphia. Daryl Hall is generally the lea ...

G. E. Smith
, 1907;
Brodmann
Brodmann
, 1909; von Economo and
KoskinasKoskinas ( el, Κοσκινάς) is a village in the municipality of Olympia, Greece, Olympia, Elis (regional unit), Elis, Greece. It is 1.5 km northeast of Olympia. Populated places in Elis {{WGreece-geo-stub ...
, 1925). In 1935, however, Jacobsen used the term prefrontal to distinguish granular prefrontal areas from agranular motor and premotor areas. In terms of Brodmann areas, the prefrontal cortex traditionally includes areas 8, 9, 10, 11, 12, 13, 14, 24, 25, 32, 44, 45, 46, and 47, however, not all of these areas are strictly granular – 44 is dysgranular, caudal 11 and orbital 47 are agranular. The main problem with this definition is that it works well only in
primate A primate ( ) (from Latin , from 'prime, first rank') is a eutherian mammal constituting the Taxonomy (biology), taxonomic order (biology), order Primates (). Primates arose 85–55 million years ago first from small Terrestrial animal, ...

primate
s but not in nonprimates, as the latter lack a granular layer IV.


Projection zone

To define the prefrontal cortex as the projection zone of the mediodorsal nucleus of the
thalamus The thalamus (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is appr ...

thalamus
builds on the work of Rose and Woolsey, who showed that this nucleus projects to anterior and ventral parts of the brain in nonprimates, however, Rose and Woolsey termed this projection zone "orbitofrontal." It seems to have been Akert, who, for the first time in 1964, explicitly suggested that this criterion could be used to define homologues of the prefrontal cortex in primates and nonprimates. This allowed the establishment of homologies despite the lack of a granular frontal cortex in nonprimates. The projection zone definition is still widely accepted today (e.g. Fuster), although its usefulness has been questioned. Modern tract tracing studies have shown that projections of the mediodorsal nucleus of the thalamus are not restricted to the granular frontal cortex in primates. As a result, it was suggested to define the prefrontal cortex as the region of cortex that has stronger reciprocal connections with the mediodorsal nucleus than with any other thalamic nucleus. Uylings et al. acknowledge, however, that even with the application of this criterion, it might be rather difficult to define the prefrontal cortex unequivocally.


Electrically silent area of frontal cortex

A third definition of the prefrontal cortex is the area of frontal cortex whose electrical stimulation does not lead to observable movements. For example, in 1890
David Ferrier Sir David Ferrier FRS (13 January 1843 – 19 March 1928) was a pioneering Scottish neurologist Neurology (from el, νεῦρον (neûron), "string, nerve" and the suffix -logia, "study of") is a branch of medicine Medicine is the ...

David Ferrier
used the term in this sense. One complication with this definition is that the electrically "silent" frontal cortex includes both granular and non-granular areas.


Subdivisions

According to Striedter the PFC of humans can be delineated into two functionally, morphologically, and evolutionarily different regions: the (vmPFC) consisting of the ''ventral prefrontal cortex'' and the ''medial prefrontal cortex'' present in all
mammals Mammals (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the R ...
, and the
lateral prefrontal cortex In human brain anatomy, the lateral prefrontal cortex (LPFC) is part of the prefrontal cortex (PFC). According to Striedter the PFC of humans can be delineated into two functionally, morphologically, and evolutionarily different regions: the Ventr ...
(LPFC), consisting of the ''dorsolateral prefrontal cortex'' and the ''ventrolateral prefrontal cortex'', present only in
primates A primate ( ) (from Latin , from 'prime, first rank') is a eutherian mammal constituting the Taxonomy (biology), taxonomic order (biology), order Primates (). Primates arose 85–55 million years ago first from small Terrestrial animal, ...
. The LPFC contains the
Brodmann area A Brodmann area is a region of the cerebral cortex, in the human brain, human or other primate brain, defined by its cytoarchitecture, or histological structure and organization of Cell (biology), cells. History Brodmann areas were originally de ...
s , , , , , and . Some researchers also include BA44. The vmPFC contains the
Brodmann area A Brodmann area is a region of the cerebral cortex, in the human brain, human or other primate brain, defined by its cytoarchitecture, or histological structure and organization of Cell (biology), cells. History Brodmann areas were originally de ...
s BA12, BA25, BA32, BA33, BA24, , BA13, and BA14. The table below shows different ways to subdivide parts of the human prefrontal cortex based upon Brodmann areas. *The
dorsolateral prefrontal cortex The dorsolateral prefrontal cortex (DLPFC or DL-PFC) is an area in the prefrontal cortex of the brain of humans and other primates. It is one of the most recently derived parts of the human brain. It undergoes a prolonged period of maturation whic ...
is composed of the , , , and . *The
ventrolateral prefrontal cortex File:VLPFC BA regions.tif, Same image, inflated version. The VLPFC is outlined with a red border. The ventrolateral prefrontal cortex (VLPFC) is a part of the prefrontal cortex located on the inferior frontal gyrus, bounded superiorly by ...
is composed of areas , , and BA44. *The medial prefrontal cortex (mPFC) is composed of BA12, BA25, and
anterior cingulate cortex In the human brain The human brain is the central organ Organ may refer to: Biology * Organ (anatomy) An organ is a group of Tissue (biology), tissues with similar functions. Plant life and animal life rely on many organs that co-ex ...
: BA32, BA33, BA24. *The ventral prefrontal cortex is composed of areas , BA13, and BA14. (Also see the definition of the
orbitofrontal cortex The orbitofrontal cortex (OFC) is a prefrontal cortex In mammalian brain anatomy, the prefrontal cortex (PFC) is the cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum ...

orbitofrontal cortex
.) *The dorsolateral prefrontal cortex contains , including the
frontal eye fields The frontal eye fields (FEF) are a region located in the frontal cortex, more specifically in Brodmann area 8 or BA8, of the primate brain A brain is an organ (anatomy), organ that serves as the center of the nervous system in all vertebrate a ...
. *The ventrolateral prefrontal cortex contains BA45 which is part of
Broca's area Broca's area, or the Broca area (, also , ), is a region in the frontal lobe of the dominant hemisphere Hemisphere may refer to: * A half of a sphere As half of the Earth * A hemispheres of Earth, hemisphere of Earth ** Northern Hemisphere ** So ...
. Some researchers also include BA44 the other part of Broca's area.


Interconnections

The prefrontal cortex is highly interconnected with much of the brain, including extensive connections with other cortical, subcortical and brain stem sites. The dorsal prefrontal cortex is especially interconnected with brain regions involved with attention, cognition and action, while the ventral prefrontal cortex interconnects with brain regions involved with emotion. The prefrontal cortex also receives inputs from the brainstem arousal systems, and its function is particularly dependent on its neurochemical environment. Thus, there is coordination between our state of arousal and our mental state. The interplay between the prefrontal cortex and socioemotional system of the brain is relevant for adolescent development, as proposed by the Dual Systems Model. The medial prefrontal cortex has been implicated in the generation of
slow-wave sleep Slow-wave sleep (SWS), often referred to as deep sleep, consists of stage three of non-rapid eye movement sleep. Initially, SWS consisted of both Stage 3, which has 20–50 percent delta wave, delta wave activity, and Stage 4, which has more tha ...
(SWS), and prefrontal
atrophy Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations (which can destroy the gene to build up the organ), poor nourishment, poor circulatory system, circulation, loss of hormone, hormonal sup ...
has been linked to decreases in SWS. Prefrontal atrophy occurs naturally as individuals age, and it has been demonstrated that older adults experience impairments in
memory consolidationMemory consolidation is a category of processes that stabilize a memory trace after its initial acquisition. A memory trace is a change in the nervous system caused by memorizing something. Consolidation is distinguished into two specific processes. ...
as their medial prefrontal cortices degrade. In monkeys, significant atrophy has been found as a result of neuroleptic or
antipsychotic Antipsychotics, also known as neuroleptics, are a class of medication primarily used to manage psychosis Psychosis is an abnormal condition of the mind that results in difficulties determining what is Reality, real and what is not real. Sy ...
psychiatric medication. In older adults, instead of being transferred and stored in the
neocortex The neocortex, also called the neopallium, isocortex, or the six-layered cortex, is a set of layers of the mammalian Mammals (from Latin language, Latin , 'breast') are a group of vertebrate animals constituting the class (biology), class ...

neocortex
during SWS, memories start to remain in the
hippocampus The hippocampus (via Latin from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its popul ...

hippocampus
where they were
encoded In communication Communication (from Latin ''communicare'', meaning "to share" or "to be in relation with") is "an apparent answer to the painful divisions between self and other, private and public, and inner thought and outer world." As ...
, as evidenced by increased hippocampal activation compared to younger adults during
recall Recall may refer to: * Recall (bugle call), a signal to stop * Recall (information retrieval), a statistical measure * ReCALL (journal), ''ReCALL'' (journal), an academic journal about computer-assisted language learning * Recall (memory) * Recal ...
tasks, when subjects learned word associations, slept, and then were asked to recall the learned words. The ventrolateral prefrontal cortex (VLPFC) has been implicated in various aspects of speech production and language comprehension. The VLPFC is richly connected to various regions of the brain including the lateral and medial temporal lobe, the superior temporal cortex, the infertemporal cortex, the perirhinal cortex, and the parahippoccampal cortex. These brain areas are implicated in memory retrieval and consolidation, language processing, and association of emotions. These connections allow the VLPFC to mediate explicit and implicit memory retrieval and integrate it with language stimulus to help plan coherent speech. In other words, choosing the correct words and staying “on topic” during conversation come from the VLPFC.


Function


Executive function

The original studies of Fuster and of Goldman-Rakic emphasized the fundamental ability of the prefrontal cortex to represent information not currently in the environment, and the central role of this function in creating the "mental sketch pad". Goldman-Rakic spoke of how this representational knowledge was used to intelligently guide thought, action, and emotion, including the inhibition of inappropriate thoughts, distractions, actions, and feelings. In this way, working memory can be seen as fundamental to attention and behavioral inhibition. Fuster speaks of how this prefrontal ability allows the wedding of past to future, allowing both cross-temporal and cross-modal associations in the creation of goal-directed, perception-action cycles. This ability to represent underlies all other higher executive functions. Shimamura proposed Dynamic Filtering Theory to describe the role of the prefrontal cortex in
executive functions Executive functions (collectively referred to as executive function and cognitive control) are a set of cognitive processes Cognition () refers to "the mental action or process of acquiring knowledge and understanding through thought, exper ...
. The prefrontal cortex is presumed to act as a high-level gating or filtering mechanism that enhances goal-directed activations and inhibits irrelevant activations. This filtering mechanism enables executive control at various levels of processing, including selecting, maintaining, updating, and rerouting activations. It has also been used to explain emotional regulation. Miller and Cohen proposed an Integrative Theory of Prefrontal Cortex Function, that arises from the original work of Goldman-Rakic and Fuster. The two theorize that “cognitive control stems from the active maintenance of patterns of activity in the prefrontal cortex that represents goals and means to achieve them. They provide bias signals to other brain structures whose net effect is to guide the flow of activity along neural pathways that establish the proper mappings between inputs, internal states, and outputs needed to perform a given task”. In essence, the two theorize that the prefrontal cortex guides the inputs and connections, which allows for cognitive control of our actions. The prefrontal cortex is of significant importance when top-down processing is needed. Top-down processing by definition is when behavior is guided by internal states or intentions. According to the two, “The PFC is critical in situations when the mappings between sensory inputs, thoughts, and actions either are weakly established relative to other existing ones or are rapidly changing”. An example of this can be portrayed in the . Subjects engaging in this task are instructed to sort cards according to the shape, color, or number of symbols appearing on them. The thought is that any given card can be associated with a number of actions and no single stimulus-response mapping will work. Human subjects with PFC damage are able to sort the card in the initial simple tasks, but unable to do so as the rules of classification change. Miller and Cohen conclude that the implications of their theory can explain how much of a role the PFC has in guiding control of cognitive actions. In the researchers' own words, they claim that, “depending on their target of influence, representations in the PFC can function variously as attentional templates, rules, or goals by providing top-down bias signals to other parts of the brain that guide the flow of activity along the pathways needed to perform a task”. Experimental data indicate a role for the prefrontal cortex in mediating normal sleep physiology, dreaming and sleep-deprivation phenomena. When analyzing and thinking about attributes of other individuals, the medial prefrontal cortex is activated, however, it is not activated when contemplating the characteristics of inanimate objects. Studies using fMRI have shown that the medial prefrontal cortex (mPFC), specifically the anterior medial prefrontal cortex (amPFC), may modulate mimicry behavior. Neuroscientists are suggesting that social priming influences activity and processing in the amPFC, and that this area of the prefrontal cortex modulates mimicry responses and behavior. As of recent, researchers have used neuroimaging techniques to find that along with the
basal ganglia #REDIRECT Basal ganglia The basal ganglia (or basal nuclei) are a group of subcortical The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue Nervous tissue, also called neural tissue, is the main tissue ...

basal ganglia
, the prefrontal cortex is involved with learning exemplars, which is part of the '' exemplar theory'', one of the three main ways our mind categorizes things. The exemplar theory states that we categorize judgements by comparing it to a similar past experience within our stored memories. A 2014 meta-analysis by Professor Nicole P.Yuan from the University of Arizona found that larger prefrontal cortex volume and greater PFC cortical thickness were associated with better executive performance.


Attention and memory

A widely accepted theory regarding the function of the brain's prefrontal cortex is that it serves as a store of
short-term memory Short-term memory (or "primary" or "active memory") is the capacity for holding, but not manipulating, a small amount of information in mind The mind is the set of faculties responsible for mental phenomena A phenomenon (; plural phenom ...
. This idea was first formulated by Jacobsen, who reported in 1936 that damage to the primate prefrontal cortex caused short-term memory deficits.Jacobsen C.F. (1936) Studies of cerebral function in primates. I. The functions of the frontal associations areas in monkeys. Comp Psychol Monogr 13: 3–60. Karl Pribram and colleagues (1952) identified the part of the prefrontal cortex responsible for this deficit as
area Area is the quantity Quantity is a property that can exist as a multitude or magnitude, which illustrate discontinuity and continuity. Quantities can be compared in terms of "more", "less", or "equal", or by assigning a numerical value in ...
, also known as the
dorsolateral prefrontal cortex The dorsolateral prefrontal cortex (DLPFC or DL-PFC) is an area in the prefrontal cortex of the brain of humans and other primates. It is one of the most recently derived parts of the human brain. It undergoes a prolonged period of maturation whic ...
(dlPFC). More recently, Goldman-Rakic and colleagues (1993) evoked short-term memory loss in localized regions of space by temporary inactivation of portions of the dlPFC. Once the concept of
working memory Working memory is a cognitive system with a limited capacity that can hold information temporarily. Working memory is important for reasoning and the guidance of decision-making and behavior. Working memory is often used synonymously with short-te ...
(see also
Baddeley's model of working memory Baddeley's model of working memory is a model of human memory proposed by Alan Baddeley and Graham Hitch in 1974, in an attempt to present a more accurate model of primary memory (often referred to as short-term memory). Working memory Working ...
) was established in contemporary neuroscience by
Alan Baddeley Alan David Baddeley, is a British psychologist A psychologist is a person who studies normal and abnormal mental states, perceptual, cognitive, emotional, and social processes and behavior by experimenting with, and observing, interpreting, an ...

Alan Baddeley
(1986), these neuropsychological findings contributed to the theory that the prefrontal cortex implements working memory and, in some extreme formulations, only working memory.Baddeley A. (1986) Working memory. Oxford: Oxford University Press. p.289 In the 1990s this theory developed a wide following, and it became the predominant theory of PF function, especially for nonhuman primates. The concept of working memory used by proponents of this theory focused mostly on the short-term maintenance of information, and rather less on the manipulation or monitoring of such information or on the use of that information for decisions. Consistent with the idea that the prefrontal cortex functions predominantly in maintenance memory, delay-period activity in the PF has often been interpreted as a memory trace. (The phrase "delay-period activity" applies to neuronal activity that follows the transient presentation of an instruction cue and persists until a subsequent "go" or "trigger" signal.) To explore alternative interpretations of delay-period activity in the prefrontal cortex, Lebedev et al. (2004) investigated the discharge rates of single prefrontal neurons as monkeys attended to a stimulus marking one location while remembering a different, unmarked location. Both locations served as potential targets of a saccadic eye movement. Although the task made intensive demands on short-term memory, the largest proportion of prefrontal neurons represented attended locations, not remembered ones. These findings showed that short-term memory functions cannot account for all, or even most, delay-period activity in the part of the prefrontal cortex explored. The authors suggested that prefrontal activity during the delay-period contributes more to the process of attentional selection (and
selective attention Attentional control refers to an individual's capacity to choose what they pay attention to and what they ignore. It is also known as endogenous attention or executive Executive may refer to: Role, title, or function * Executive (government), b ...
) than to memory storage.


Speech production and language

Various areas of the prefrontal cortex have been implicated in a multitude of critical functions regarding speech production, language comprehension, and response planning before speaking. Cognitive neuroscience has shown that the left ventrolateral prefrontal cortex is vital in the processing of words and sentences. The right prefrontal cortex has been found to be responsible for coordinating the retrieval of explicit memory for use in speech, whereas the deactivation of the left is responsible for mediating implicit memory retrieval to be used in verb generation. Impaired recollection of nouns (explicit memory) is impaired in some amnesic patients with damaged left prefrontal cortices, but verb generation remains intact because of its reliance on left prefrontal deactivation. Many researchers now include BA45 in the prefrontal cortex because together with BA44 make up an area of the frontal lobe called Broca's Area. Broca's Area is the widely considered the output area of the language production pathway in the brain (as opposed to Wernike's area in the medial temporal lobe, which is seen as the language input area). BA45 has been shown to be implicated for the retrieval of relevant semantic knowledge to be used in conversation/speech. The right lateral prefrontal cortex (RLPFC) is implicated in the planning of complex behavior, and together with bilateral BA45, they act to maintain focus and coherence during speech production. However, left BA45 has been shown to be activated significantly while maintaining speech coherence in young people. Older people have been shown to recruit the right BA45 more so than their younger counterparts. This aligns with the evidence of decreased lateralization in other brain systems during aging. In addition, this increase in BA45 and RLPFC activity in combination of BA47 in older patients has been shown to contribute to “off-topic utterances.” The BA47 area in the prefrontal cortex is implicated in “stimulus-driven” retrieval of less-salient knowledge than is required to contribute to a conversation. In other words, elevated activation of the BA47 together with altered activity in BA45 and the broader RLPFC has been shown to contribute to the inclusion of less relevant information and irrelevant tangential conversational speech patterns in older subjects.


Clinical significance

In the last few decades,
brain imaging Neuroimaging or brain imaging is the use of various techniques to either directly or indirectly image the structure, function, or pharmacology of the nervous system. It is a relatively new discipline within medicine Medicine is the Art (ski ...
systems have been used to determine brain region volumes and nerve linkages. Several studies have indicated that reduced volume and interconnections of the frontal lobes with other brain regions is observed in patients diagnosed with
mental disorders A mental disorder, also called a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitting, or o ...
and prescribed potent
antipsychotic Antipsychotics, also known as neuroleptics, are a class of medication primarily used to manage psychosis Psychosis is an abnormal condition of the mind that results in difficulties determining what is Reality, real and what is not real. Sy ...
s; those subjected to repeated
stressor A stressor is a chemical or biological agent, environment (biophysical), environmental condition, Stimulus (physiology) , external stimulus or an event seen as causing Stress (biology), stress to an biological organism, organism. Psychologically sp ...
s; those who excessively consume sexually explicit materials;
suicide Suicide is the act of intentionally causing one's own death Death is the permanent, irreversible cessation of all biological functions that sustain a living Living or The Living may refer to: Common meanings *Life, a condition t ...

suicide
s; those incarcerated;
criminal In ordinary language, a crime is an unlawful act punishable by a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper ...

criminal
s;
sociopath Psychopathy, sometimes considered synonymous with sociopathy, is traditionally a personality disorder characterized by persistent Anti-social behaviour, antisocial behavior, impaired empathy and remorse, and Boldness, bold, Disinhibition, disi ...
s; those affected by lead poisoning; and daily male cannabis users (only 13 people were tested). It is believed that at least some of the human abilities to feel
guilt Guilt may refer to: *Guilt (emotion) Guilt is a moral emotion that occurs when a person believes or realizes—accurately or not—that they have compromised their own standards of conduct or have violated universal moral A moral (from ...
or remorse, and to interpret
reality Reality is the sum or aggregate of all that is real or existent within a system, as opposed to that which is only imaginary Imaginary may refer to: * Imaginary (sociology), a concept in sociology * The Imaginary (psychoanalysis), a concept by ...

reality
, are dependent on a well-functioning prefrontal cortex. The advanced neurocircuitry and self-regulatory function of the human prefrontal cortex is also associated with the higher
sentience Sentience is the capacity to experience feeling Feeling was originally used to describe the physical sensation of touch through either experience or perception. The word is also used to describe other experiences, such as "Emotion, a feeling of ...
in humans, as the prefrontal cortex in humans occupies a far larger percentage of the brain than in any other animal. And it is theorized that, as the brain has tripled in size over five million years of human evolution, the prefrontal cortex has increased in size sixfold. A review on executive functions in healthy exercising individuals noted that the left and right halves of the prefrontal cortex, which is divided by the
medial longitudinal fissure Medial may refer to: Mathematics * Medial magma, a mathematical identity in algebra Geometry * Medial axis, in geometry the set of all points having more than one closest point on an object's boundary * Medial graph, another graph that repre ...
, appears to become more interconnected in response to consistent aerobic exercise. Two reviews of structural neuroimaging research indicate that marked improvements in prefrontal and hippocampal gray matter volume occur in healthy adults that engage in medium intensity exercise for several months. A
functional neuroimaging Functional neuroimaging is the use of neuroimaging Neuroimaging or brain imaging is the use of various techniques to either directly or indirectly Medical imaging, image the neuroanatomy, structure, function, or pharmacology of the nervous syst ...
review of meditation-based practices suggested that practicing
mindfulness Mindfulness is the practice of purposely bringing one's attention in the present moment without evaluation,Mindfulness Training as a Clinical Intervention: A Conceptual and Empirical Review, by Ruth A. Baer, available at http://www.wisebrain.or ...

mindfulness
enhances prefrontal activation, which was noted to be correlated with increased well-being and reduced anxiety; however, the review noted the need for
cohort studies A cohort study is a particular form of longitudinal study A longitudinal study (or longitudinal survey, or panel study) is a research design Research design refers to the overall strategy utilized to carry out research Research is "creati ...
in future research to better establish this. Treatments with
anti-cancer drugs Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (list of chemotherapeutic agents, chemotherapeutic agents) as part of a standardized chemotherapy regimen. ...
often are toxic to the cells of the brain, leading to
memory Memory is the faculty of the brain A brain is an organ Organ may refer to: Biology * Organ (anatomy) An organ is a group of Tissue (biology), tissues with similar functions. Plant life and animal life rely on many organs that co-exis ...

memory
loss and
cognitive dysfunction Cognitive disorders (CDs), also known as neurocognitive disorders (NCDs), are a category of mental health disorders that primarily affect cognitive abilities including learning, memory, perception, and problem solving. Neurocognitive disorders incl ...
that can persist long after the period of exposure. Such a condition is referred to as chemo brain. To determine the basis of this condition, mice were treated with the chemotherapeutic agent
mitomycin C Mitomycin C is a mitomycin The mitomycins are a family of aziridine Aziridine is an organic compound consisting of the three-membered heterocycle (CH2)2NH. It is a colorless, toxic, volatile liquid that is of significant practical interest. It ...

mitomycin C
. In the prefrontal cortex, this treatment resulted in an increase of the oxidative DNA damage , a decrease in the enzyme OGG1 that ordinarily , and epigenetic alterations. Chronic intake of alcohol leads to persistent alterations in brain function including altered decision making ability. The prefrontal cortex of chronic alcoholics has been shown to be vulnerable to oxidative DNA damage and neuronal
cell death Cell death is the event of a biological cell The cell (from Latin ''cella'', meaning "small room") is the basic structural, functional, and biological unit of all known organisms. Cells are the smallest units of life, and hence are often refe ...

cell death
.


History

Perhaps the seminal case in prefrontal cortex function is that of
Phineas Gage Phineas P. Gage (18231860) was an American railroad construction foreman remembered for his improbable survival of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal lobe ...

Phineas Gage
, whose left frontal lobe was destroyed when a large iron rod was driven through his head in an 1848 accident. The standard presentation (e.g.) is that, although Gage retained normal memory, speech and motor skills, his personality changed radically: He became irritable, quick-tempered, and impatient—characteristics he did not previously display — so that friends described him as "no longer Gage"; and, whereas he had previously been a capable and efficient worker, afterward he was unable to complete tasks. However, careful analysis of primary evidence shows that descriptions of Gage's
psychological Psychology is the scientific Science () is a systematic enterprise that Scientific method, builds and organizes knowledge in the form of Testability, testable explanations and predictions about the universe."... modern science is ...

psychological
changes are usually exaggerated when held against the description given by Gage's doctor, the most striking feature being that changes described years after Gage's death are far more dramatic than anything reported while he was alive. Subsequent studies on patients with prefrontal injuries have shown that the patients verbalized what the most appropriate social responses would be under certain circumstances. Yet, when actually performing, they instead pursued behavior aimed at immediate gratification, despite knowing the longer-term results would be self-defeating. The interpretation of this data indicates that not only are skills of comparison and understanding of eventual outcomes harbored in the prefrontal cortex but the prefrontal cortex (when functioning correctly) controls the mental option to delay immediate gratification for a better or more rewarding longer-term gratification result. This ability to wait for a reward is one of the key pieces that define optimal executive function of the human brain. There is much current research devoted to understanding the role of the prefrontal cortex in neurological disorders. Clinical trials have begun on certain drugs that have been shown to improve prefrontal cortex function, including
guanfacine Guanfacine, sold under the brand name Tenex among others, is an oral medication used to treat attention deficit hyperactivity disorder (ADHD) and high blood pressure. It is not considered a first-line treatment for either indication. Common si ...

guanfacine
, which acts through the
alpha-2A adrenergic receptor The alpha-2A adrenergic receptor (α2A adrenoceptor), also known as ADRA2A, is an α2 adrenergic receptor, and also denotes the human gene This article is an index of lists of human genes. By chromosome Below is a list of articles on human chrom ...
. A downstream target of this drug, the HCN channel, is one of the most recent areas of exploration in prefrontal cortex pharmacology.


Etymology

The term "prefrontal" as describing a part of the brain appears to have been introduced by
Richard Owen Sir Richard Owen (20 July 1804 – 18 December 1892) was an English biologist, comparative anatomist and paleontologist. Despite being a controversial figure, Owen is generally considered to have been an outstanding naturalist with a remark ...

Richard Owen
in 1868. For him, the prefrontal area was restricted to the anterior-most part of the frontal lobe (approximately corresponding to the frontal pole). It has been hypothesized that his choice of the term was based on the
prefrontal bone The prefrontal bone is a bone separating the lacrimal bone, lacrimal and frontal bones in many tetrapod skulls. It first evolution, evolved in the sarcopterygian clade Rhipidistia, which includes lungfish and the Tetrapodomorpha. The prefrontal is ...
present in most amphibians and reptiles.


Additional images

File:Prefrontal cortex (left) animation.gif, Animation, prefrontal cortex of left
cerebral hemisphere The vertebrate cerebrum (brain) is formed by two cerebral hemispheres that are separated by a groove, the longitudinal fissure. The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres ...
(shown in red) File:Prefrontal cortex (left) - anterior view.png, Front view File:Prefrontal cortex (left) - lateral view.png, Lateral view File:Prefrontal cortex (left) - medial view.png, Medial perspective


See also

*
Lobotomy A lobotomy, or leucotomy, was a form of psychosurgery, a Neurosurgery, neurosurgical treatment of a mental disorder that involves severing connections in the brain's prefrontal cortex. Most of the connections to and from the prefrontal cortex, ...
*
Interference theory The interference theory is a theory regarding human memory. Interference occurs in learning. The notion is that memories encoded in long-term memory (LTM) are forgotten and cannot be retrieved into short-term memory (STM) because either memory inte ...
* Self-model theory of subjectivity * Dorsomedial prefrontal cortex *
Ventromedial prefrontal cortex The ventromedial prefrontal cortex (vmPFC) is a part of the prefrontal cortex in the mammalian brain. The ventral medial prefrontal is located in the frontal lobe at the bottom of the cerebral hemispheres and is implicated in the processing of r ...

Ventromedial prefrontal cortex


References


External links


Diagram (ua.edu)

Diagram (universe-review.ca)
* {{Prosencephalon Cerebral cortex Frontal lobe