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REVIEW ARTICLE
Year : 2013  |  Volume : 61  |  Issue : 6  |  Page : 578-580

Not so "silent":The human prefrontal cortex


All India Institute of Medical Sciences, New Delhi; National Brain Research Centre, Nainwal More, Manesar, Gurgaon, Haryana, India

Date of Submission26-Aug-2013
Date of Decision30-Aug-2013
Date of Acceptance31-Aug-2013
Date of Web Publication20-Jan-2014

Correspondence Address:
Prakash Narain Tandon
National Brain Research Centre, Nainwal More, Manesar, Gurgaon, Haryana
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0028-3886.125242

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 » Abstract 

Little was known about the human prefrontal cortex till recently. It was thus labeled as the "silent area," "uncommitted cortex." It not only constitutes the largest component of the human brain but is the latest evolutionary addition to the mammalian brain. It endows the human beings with qualities that differentiate humans from all other animals. During the last couple of decades the advent of modern electrophysiological and imaging (functional magnetic resonance imaging, proton emission tomography, SPECT) techniques have provided a wealth of insight into its role in memory, thought, emotions, moral judgment, social behavior, evaluating rewards, and assessing its fairness or otherwise and above all self-awareness. This brief review summarize the recent significant observations on its functions and connectivity which would interest the cognitive scientists and clinicians alike.


Keywords: Cognition, dorsolateral prefrontal cortex, medial prefrotnal cortex, orbitofrontal cortex, prefrontal cortex


How to cite this article:
Tandon PN. Not so "silent":The human prefrontal cortex. Neurol India 2013;61:578-80

How to cite this URL:
Tandon PN. Not so "silent":The human prefrontal cortex. Neurol India [serial online] 2013 [cited 2019 Dec 12];61:578-80. Available from: http://www.neurologyindia.com/text.asp?2013/61/6/578/125242


Prefrontal cortex (PFC), latest evolutionary addition to the mammalian brain, especially the human, has long been known to endow qualities that differentiate human beings from all other animals. Yet the clinicians considered it "a silent" area in the absence of clinically discernable neurological deficits following its damage. As late as 1975, Penfield [1] who pioneered the mapping of the cortex in conscious, cooperative human beings undergoing surgery for epilepsy, called the PFC as uncommitted cortex. He observed that unlike sensory (which included visual and auditory) and motor convolutions, which are committed to function at birth, "some of the convolutions that are used eventually for what may be called psychical functions are uncommitted to their exact function at the time of birth." Even though as early as 1935, Penfield and Evans [2] had reported that, a major removal of the anterior portion of the frontal lobe results in "a defect in the patient's capacity for planned initiatives." He found that the spontaneous electrical discharges responsible for epilepsy, "if it occurs in the so called silent area of the cortex, there may be no manifestation."

No doubt the motor functions of the prefrontal gyrus and the frontal eye field just anterior to it, the supplementary motor area on the medical surface and the role of the Broca's area in the left inferior frontal gyrus have also been known for a long time. However, the role of frontal lobe, in memory, thought, emotions, judgement and social behavior has been delineated only recently. [3]

The role frontal lobes played in psychical functions elaborated by Fulton led Egaz Moniz to advocate frontal lobotomy for treatment of mental illness. Thus, the important role of the PFC in cognition was suspected for a long time, but its detailed nature and the neural basis responsible for it had remained a mystery. [4]

However, the rapidly accumulating data from electrophysiological, functional magnetic resonance imaging (fMRI), proton emission tomography and other imaging techniques have revealed the role of interconnecting circuits within PFC and with other regions of the brain to be responsible for the integrative function of the PFC. [5] Recent functional imaging studies have revealed that different regions of the frontal cortex are found to be involved in more than one cognitive function and a single cognitive function often involves diverse regions of the brain. [4]

PFC was for some years known to perform executive function, but now it has been demonstrated that its functions include the ability to organize behavioral response to solve a complex problem (including the strategies used in learning new information and systematically searching memory), generating motor programs and using verbal skill to guide behavior. [6],[7]

In addition, PFC has been found to be involved in a variety of other behaviors e.g. moral judgement, laughter and appreciation of jokes, [8] evaluating rewards and judging its fairness or otherwise, [9],[10],[11] awareness, [12] temperament, [13],[14],[15] meditation.

Although there are no absolute boundaries between the different regions of the frontal lobe, on the basis of their structure, connectivity and dominant functions it is best to divide it into three components, e.g. dorsolateral prefrontal cortex (DLPFC), ventromedial prefrontal cortex and basifrontal or orbitofrontal cortex. [16]

Evidence from neuropsychological, electrophysiological and functional neuroimaging suggests a critical role for DLPFC in executive control for goal directed behavior. In addition, its role in short-term or working memory has been known for quite some time. However, recent fMRI studies have revealed its importance in strategies used in learning new information and systematically searching and activation of remote memories. [5],[6],[17],[18] There is growing evidence that LPFC is involved in a number of other cognitive functions like focused and sustained attention, planning and regulation of adaptive behavior, [7] distributive justice. [19]

In contrast, the MPFC, which constitutes an integral part of the "Limbic System" plays an important role in regulation of emotions owing to its bidirectional connections with amygdala. [20],[21],[22] The nucleus accumbens, situated below the genu of the corpus callosum is a significant part of the reward circuit and hence concerned with eating, sex and drug addiction. [11],[23] In addition the PFC plays an important role in social cognition, contributes to the "Theory of Mind," in human awareness and feeling of self. [12],[15],[24]

These observations are not just of academic interest but are being already utilized for therapeutic purpose like deep brain stimulation for depression and obsessive compulsive disorder or cingulotomy for addiction. [16]

Thus, far from being "silent," "uncommitted" or simply responsible for ill-defined "psychical functions," the PFC is comprised of a set of control systems, each with its separate target. [25] As their connectivities indicate, different prefrontal areas control different activities that are separately localized. In the words of Kinsbourne, [26] "human forebrain is exquisitely functionally differentiated and yet quite integrated." Common regions of the human frontal lobe are recruited by diverse cognitive demands. [27]

 
 » References Top

1.Penfield WP. The Mystery of Mind. Princeton: Princeton University Press; 1975.  Back to cited text no. 1
    
2.Penfield WP, Evans J. The frontal lobe in man: A clinical study of maximum removals. Brain 1935;77:1-7.  Back to cited text no. 2
    
3.Frackowiak RS. Art and the brain. Daedalus Spring 1998; p. 71-104.   Back to cited text no. 3
    
4.Miller EK, Cohen JD. An integrated theory of pre-frontal cortex function. Annu Rev Neurosci 2001;24:197-202.  Back to cited text no. 4
    
5.Cabeza R, Nyberg L. Imaging cognition II: An empirical review of 275 PET and fMRI studies. J Cogn Neurosci 2000;12:1-47.  Back to cited text no. 5
[PUBMED]    
6.Mega MS. Amnesia: A disorder of episodic memory. In: D′Esposito M, editor. Neurological Foundations of Cognitive Neuroscience. Cambridge, MA: The MIT Press; 2003. p. 41-54.  Back to cited text no. 6
    
7.Knight RT, D′Espito M. Lateral prefrontal syndrome: A disorder of executive control. In: D′esposito M, editor. Neurological Foundation of Cognitive Control. Cambridge: Cambridge Press; 2003.  Back to cited text no. 7
    
8.Bonyton P. It′s no laughing matter. New Sci 2002; p. 48-51.  Back to cited text no. 8
    
9.Crockett MJ, Clark L, Tabibnia G, Lieberman MD, Robbins TW. Serotonin modulates behavioral reactions to unfairness. Science 2008;320:1739.  Back to cited text no. 9
[PUBMED]    
10.McClure SM, Laibson DI, Loewenstein G, Cohen JD. Separate neural systems value immediate and delayed monetary rewards. Science 2004;306:503-7.  Back to cited text no. 10
[PUBMED]    
11.Richmond BJ, Liu Z, Shidara M. Neuroscience. Predicting future rewards. Science 2003;301:179-80.  Back to cited text no. 11
[PUBMED]    
12.Ehrsson HH, Spence C, Passingham RE. That′s my hand! Activity in premotor cortex reflects feeling of ownership of a limb. Science 2004;305:875-7.  Back to cited text no. 12
[PUBMED]    
13.Whittle S, Allen NB, Lubman DI, Yücel M. The neurobiological basis of temperament: Towards a better understanding of psychopathology. Neurosci Biobehav Rev 2006;30:511-25.  Back to cited text no. 13
    
14.Newberg A, Alavi A, Baime M, Pourdehnad M, Santanna J, d′Aquili E. The measurement of regional cerebral blood flow during the complex cognitive task of meditation: A preliminary SPECT study. Psychiatry Res 2001;106:113-22.  Back to cited text no. 14
[PUBMED]    
15.Craig AD. How do you feel - Now? The anterior insula and human awareness. Nat Rev Neurosci 2009;10:59-70.  Back to cited text no. 15
[PUBMED]    
16.Tandon PN. Human cognition and the frontal lobe. In: Tandon PN, Tripathi RC, Srinivasan N, editors. Expanding Horizons of the Mind Sciences. New York: Nova Science Publishers; 2012. p. 187-200.  Back to cited text no. 16
    
17.Kapur S, Craik FI, Jones C, Brown GM, Houle S, Tulving E. Functional role of the prefrontal cortex in retrieval of memories: A PET study. Neuroreport 1995;6:1880-4.  Back to cited text no. 17
[PUBMED]    
18.Müller NG, Machado L, Knight RT. Contributions of subregions of the prefrontal cortex to working memory: Evidence from brain lesions in humans. J Cogn Neurosci 2002;14:673-86.  Back to cited text no. 18
    
19.Hsu M, Anen C, Quartz SR. The right and the good: Distributive justice and neural encoding of equity and efficiency. Science 2008;320:1092-5.   Back to cited text no. 19
[PUBMED]    
20.Ghashghaei HT, Barbas H. Pathways for emotion: Interactions of prefrontal and anterior temporal pathways in the amygdala of the rhesus monkey. Neuroscience 2002;115:1261-79.  Back to cited text no. 20
[PUBMED]    
21.Murphy FC, Nimmo-Smith I, Lawrence AD. Functional neuroanatomy of emotions: A meta-analysis. Cogn Affect Behav Neurosci 2003;3:207-33.   Back to cited text no. 21
[PUBMED]    
22.Pessoa L. On the relationship between emotion and cognition. Nat Rev Neurosci 2008;9:148-58.  Back to cited text no. 22
[PUBMED]    
23.Abbott A. Neuroscience: Addicted. Nature 2002;419:872-4.  Back to cited text no. 23
[PUBMED]    
24.Frith CD, Singer T. The role of social cognition in decision making. Philos Trans R Soc Lond B Biol Sci 2008;363:3875-86.  Back to cited text no. 24
[PUBMED]    
25.Robbins TW. Dissociating executive functions of the prefrontal cortex. Philos Trans R Soc Lond B Biol Sci 1996;351:1463-70;1470.  Back to cited text no. 25
[PUBMED]    
26.Kinsbourne M. Unity and diversity in the human brain: Evidence form injury. Daedalus Spring 1998; p. 233-56.  Back to cited text no. 26
    
27.Duncan J, Owen AM. Common regions of the human frontal lobe recruited by diverse cognitive demands. Trends Neurosci 2000;23:475-83.  Back to cited text no. 27
[PUBMED]    



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