The orbitalfrontal area is connected to the limbic systems, reticular formation, entorrhinal areas and regulates arousal and biological drives (Russel and Roxanas, 1992). Rolls and Baylis (1994, cited in Martin, 1998) believe the medial orbitofrontal cortex may contain a part of the brain that is responsible for integrating food-related information.
The medial area is a supplementary motor area, which sequences motor behaviour (Russel and Roxanas, 1992).
The dorsolateral area is an integrated post for receiving information from sensory and motor association areas in the temporal and parietal lobes and other frontal areas (Russel and Roxanas, 1992). Stuss and Gow (1992) include all areas anterior to the Rolandic fissure as well as the caudate, anterior putamen and anterior thalamus in frontal lobe functioning.
Stuss & Gow (1992) make a slightly different distinction and divide the frontal lobes into two functionally specific sections (Pandya & Barnes, 1987, cited in Stuss & Gow, 1992). The Dorsal system has strong interconnections with the posterior parietal lobe and cingulate gyrus. It includes the medial surface of the frontal lobe and the superior part of the dorsolateral surface and is responsible for sequential processing of spatially related and motivational information. The ventral system includes the oribital section of the frontal lobes and the ventrolateral regions. It originates near or in the olfactory cortex and mediates emotional tone. These two systems interact and together with the prefrontal cortex which integrates information from all the areas of the brain, result in the frontal lobes being the “final collection point for information related to both the external sensory and the internal limbic (feeling) world” (ibid, p. 350).
While Albeit Strongman (1995, cited in McNaughton, 1995) claims that physiological analysis has not given us psychological insight, McNaughton attempts to show the converse. Stuss and Gow (1992) recognise the confusion of frontal lobe structure as well as functionality and the clearly paradoxical nature of the various symptoms when the frontal lobes dysfuntion and attribute it to three factors.
Firstly, the functional specificity of the different regions of the frontal lobes has not been clearly documented. Secondly, there are inadequate definitions of frontal lobe behaviour. Thirdly, the complexity of the frontal lobes relationship with other parts of the brain must be considered, they do not operate in isolation and in fact the pre-frontal cortex is the only cortical zone to receive information from all sensory regions (Stuss & Gow, 1992, p. 350).
Figure 1. A diagrammatic representation of the brain
The following diagram indicates the relevant parts of the brain. The writer has not found one diagram that comprehensively depicts all relevant areas of the brain under discussion. The parietal, temporal and occipital lobes have been reduced in opacity to focus on the frontal lobe, which is the topic under discussion. Brodmans map is indicated. Connections to and from the frontal lobe to various parts of the brain are depicted.
This diagram focuses on the frontal lobes as well as connections to and from the frontal lobes. Serif fonts (in grey) indicate sub-cortical areas.
Luria’s Model of Brain Function
Luria (1973) divided the brain into three blocks, the frontal lobes being the third block. Luria credits the frontal lobes inextricably intertwined with the brainstem and reticular formation as the primary activator of the brain; they also regulate attention and concentration. Luria states that they are involved “in every complex behavioural process” (1973, p. 70)
The Complex Function of Frontal Lobes
The frontal lobes are described as the “orchestra leader” (Martin, 1998, p. 190) of effective behaviour. Various theories exist that explain frontal lobe functionality, which focus on various aspects of executive functionality such as planning and ability to moderate behaviour, social behaviour, personality and emotion. These theories should all be considered in order to gain a comprehensive picture of frontal lobe functionality.
No single theory has managed to comprehensively explain front lobe functionality. The frontal lobes are complex in their functionality and only a synthesis of the various theories can begin to present a more adequate picture of the various functions of the frontal lobe as well the importance of the various other parts of the brain that are inextricably intertwined with the front lobes in their functionality. “It is clear that every complex form of behaviour depends on the joint operation of several faculties located in different zones of the brain” (Luria, p. 67)
No Longer En-Gage-ing; What Happens When The Frontal Lobes Go Wrong?
One of the earliest reported cases of damage to the frontal lobes was that of the railway supervisor Phineas Gage in 1848 (Harlow, 1868, cited in Banich, 2004; Stuss & Gow, 1992). An explosion projected an iron rod through his head leaving considerable damage to his frontal lobes. From a previously capable supervisor, Gage was no longer able to follow through on his supervisory tasks, lacking motivation and drive; and he was now short-tempered and irritable, albeit his physical and cognitive facilities remained intact, so much so that his friends complained that he was “no longer Gage”.
Several theorists have ascertained functionality of the frontal lobes by working retrospectively in assessing the symptoms that appear or the functioning that change or disappear with damage to the frontal lobes.
There is ordinarily not a neat lesion or frontal lobe disease is a progressive one, and a single linear cause an effect explanation is insufficient to explain these changes. As a part of the brain is damaged or degenerates which includes the frontal lobes as well as contiguous areas, a variety of symptoms ensue. It is important to embrace an integrated approach and recognise that we cannot view certain symptoms in isolation – they are in fact entwined.
Damage to the frontal lobes has variable and wide reaching consequences. Ironically intellectual impairment is seldom the case and frontal lobe patients will perform normally on IQ tests. The consequences of frontal lobe damage are often not adequately described by looking at single sets of cognitive, emotional, social or personality symptoms. It is important to embrace an integrated approach and recognise that we cannot view certain symptoms in isolation – they are in fact entwined. It is imperative not to oversimplify the complexity of the consequences of frontal lobe damage to these areas of the brain by viewing only isolated consequences.
A further problem with isolating functions of the frontal lobes and the dysfunction that manifests with their damage is the heterogeniality of terminology used.
The Frontal Lobes and Personality
This writer is amenable to the theory presented by Stuss, Gow and Heatherington (1992) who note the heterogeneous nature of symptoms with frontal lobe dysfunction as well as their clearly paradoxical extremes in these symptoms. They conclude that the frontal lobe is responsible for personality, which includes mood, affect and drive. They maintain that these four constructs present a comprehensive explanation of frontal lobe functionality and dysfunction.
Mood is defined as the subjective internal experience, which is usually a constant internal disposition, but may change. Affect is defined as the externalised expression of mood. Drive is defined as a force which motivates human behaviour, this is not the psychodynamic term, but is better seen as “autoactivation” (Stuss & Gow., 1992, p. 350). Emotion is a term that is all inclusive of mood, affect and drive and is more cognitively orientated the experience or conscious awareness of internal feelings.
Stuss & Gow (1992) define personality as the combination of qualities or characteristics that make a person unique. They note that these characteristics are stable and result in predictable behavioural responses to the external environment. Personality is inclusive of emotion or mood, affect and drive, as well as the other qualities such as self-reflectiveness. Personality maintains “a dynamic balance between internal drive, needs and desires, and internal or external forces that regulate the expression of these internal states in conformity with culturally given norms” (Stuss & Gow., 1992, p. 350).
There are a variety of symptoms when the frontal lobes dysfunction that are clearly paradoxical in nature and may be a result of several factors. Firstly, the functional specificity of the different regions of the frontal lobes has not been clearly documented. Secondly, there are inadequate definitions of frontal lobe behaviour. Thirdly, the complexity of the frontal lobes relationship with other parts of the brain must be considered, they do not operate in isolation and in fact the pre-frontal cortex is the only cortical zone to receive information from all sensory regions (Stuss & Gow, p. 350).
Stuss and Gow (1992) define the frontal lobes as all structures anterior to the Rolandic Sulcus and including the caudate, anterior putamen and anterior thalamus. They divide the frontal lobes into two functionally specific sections (Pandya & Barnes, 1987, cited in Stuss & Gow, 1992). The Dorsal system has strong interconnections with the posterior parietal lobe and cingulate gyrus. It includes the medial surface of the frontal lobe and the superior part of the dorsolateral surface and is responsible for sequential processing of spatially related and motivational information. The ventral system includes the oribital section of the frontal lobes and the ventrolateral regions. It originates near or in the olfactory cortex and mediates emotional tone. These two systems interact and together with the prefrontal cortex which integrates information from all the areas of the brain, result in the frontal lobes being the “final collection point for information related to both the external sensory and the internal limbic (feeling) world” (ibid, p. 350).
The three components of personality are aligned with these anatomical regions:
- Drive is aligned to the dorsal system, which is related to motivation and initiation of behaviour)
- Mood is aligned to the ventral system, which is related to emotional tone
- Affect is the motor expression of feeling and the observable output of an initiated behaviour managed by the premotor cortex.
To this Stuss and Gow (1992) add the ability to be self-reflective as a final necessary component of personality.
The Frontal Lobes and Executive Function / Drive
Executive functions include a range of functions that are essential to daily living. These include the ability to initiate, control or discontinue actions; to use information flexibly; to respond to new situations and information; to think abstractly, to sort and sequence information; and to direct behaviour in a goal directed way (Lezak, 1995).
In order for behaviour to be effective, it must meet environmental conditions. It must be appropriate, modifiable, energised or motivated and be free from disruptive internal influences. Effective behaviour requires an anticipatory relationship to the goal in the form of planning. It requires the ability to monitor ongoing actions as to effect change, should deviations from the plan occur, and the effectiveness of action must finally be checked against the anticipated outcomes and any necessary adjustments made.
(Walsh, 1991, p. 170)
Endogenous damage to the frontal lobes disrupts these processes. “Loss of drive has been considered one of the major deficits of frontal system damage as it underlies the efficient functioning of other abilities” (Stuss & Benson, 1986 cited in Stuss & Gow, 1992). Loss of drive, interest and motivation are commonly reported after frontal lobe damage (Blumer & Benson, 1975, cited in Stuss & Gow., 1992). Stuss & Gow. (1992) attribute this to the dorsal system.
Executive dysfunction, is often characterised by psychological inertia which is the inability to initiate, change or discontinue actions (Banich, 2004). Once engaged in an activity frontal lobe patients seem to get caught in a behavioural loop where they engage in repetitive behaviour called perseveration. These patients are also unable to make changes in goal directed behaviour should a change in the in the process be required, they become locked in one method of solving the problem even if this does not bring them closer to a solution. For example a traffic jam might require a new route which would involve a change in switching sets which would be difficult for these patients.
Other goal directed behaviours that are affected by frontal lobe damage are an inability to stay on task and self-monitor their performance. Patients have difficulty maintaining an attentional set for information that is most task-relevant, struggle to remember the sequence of events or to order their own behaviour to reach the final goal.
Pseudodepression, which includes apathy and indifference, is actually a disorder of self-activation (Laplane, 1990 cited in Stuss & Gow., 1992).
“Often what is needed to perform is available or within these patients’ capacity but it does not occur to them to use what is there or to anticipate future needs” (Lezak, 1995, p. 187). Patients lose control of their destinies and become more socially dependent the more incapacitated they become. This may contribute to social isolation as they become over-dependent.
Damage to areas connected to the frontal lobes such as the striatum, cingulate and thalamus also bring about lowered drive and motivation (Damasio & van Hoesen, 1983; Habib & Poncet, 1988; Laplane, 1990; Stuss, Guberman, Nelson & LaRochelle, 1988, all cited in Stuss and Gow., 1992). This highlights the fact that the frontal lobes do not function in isolation.
Theories of frontal lobe function
Working memory
A theory of working memory points to the dorsolateral pre-frontal cortex in working memory (Goldman-Rakic, 1987, cited in Lezak, 1995; Banich, 2004) and suggests that damage to this area might impede the ability to keep a goal in mind and may thus hinder goal directed behaviour. Secondly, difficulty in keep information available may interrupt the patient’s understanding of temporal relations between objects and events (Lezak, 1995; Banich, 2004).
Controlled vs Automatic processes
According to Stuss and Benson (1986, cited in Stuss & Gow, 1992; Banich, 2004) frontal lobe damage disturbs the “super-ego personified” or supervisory attention system. This leaves contentional scheduling in control, which may result in the patient being able to perform on routine tasks, but not voluntary tasks. The writer is reminded of the man who was unable to say “no” at the instruction of his doctor. After several attempts he blurted out in frustration: No, doctor, I cannot say no!”
Use of Scripts
Managerial knowledge units (MKUs) are scripts or memories that are stored in the prefrontal cortex. MKUs maintain information on how to use, perform or manage simple actions that have a similar or unifying theme. Organised hierarchically, MKUs specify information about the setting in which an event occurs, the set of events that must happen in order to achieve the goal, and the end-event that must terminate the action. MKUs are connected through learning and behaviour is reinforced the more the MKU is used (Banich, 2004).
Guidance of Behaviour towards a Goal
It seems that frontal lobe damage affects the ability to maintain a goal list – a list of behaviours or strategies necessary in order to achieve a goal. Usually a variety of behaviours or strategies must be examined as to how well they will aid the end point in mind. Loss of a goal list affects behaviour across several domains; these include difficulty with abstract thinking, perceptual analysis and verbal output, difficulty staying on task and environmental dependency syndrome (that is being excessively influenced by environmental stimuli as there is no internal goal directing behaviour).
The Frontal Lobes and Emotion / Mood and Affect
Emotional changes after frontal lobe damage are antithetical and may result in blunted or exaggerated affective experience (mood) and expression (affect). This includes depression, aggression, mania, hypermania, anxiety, obsessive compulsive disorder, psychosis and schizophrenia.
Depression was observed in patients with right frontal lobe damages, while euphoria was observed in patients with left frontal lobe damage. (Damasio & Anderson, 1993)
“Several different brain regions or more complex cerebral networks are responsible for the production of the complete clinical profile of mood disorders” (Guze & Gitlin, 1994, p. 118). The frontal cortex as well as the basal ganglia and the temporal lobe are implicated in the production of mood disorder symptoms (Guze & Gitlin, 1994).
Laplane attributes pseudodepression, which includes apathy and indifference, to a disorder of self-activation (1990 cited in Stuss & Gow, 1992).
Several degenerative conditions such as Parkinsons disease, Huntington’s disease, Multiple Sclerosis may evoke depression as well as trauma and head injury, stroke and brain tumours (Guze & Gitlin, 1994).
McNaugton (1995) suggests anxiety may be a memory disorder and attributes anxiety to certain biases in the processing of information, which impacts what is stored. He credits the septo-hippocampal of the limbic system in generating this bias.
A “limbic-frontal loop” (Stuss & Gow, 1992, p. 351) may cause obsessive and other anxiety disorders. The observed repetitiveness and fixedness of OCD patients is also similar to frontal lobe patients (Stuss & Gow, 1992).
Anxiety, OCD, paranoia cannot be isolated to any one centre. They “are reciprocally interconnected in a neural network where any particular psychological state is probably best represented by a pattern of activity distributed across many centres in the network” (McNaughton, 1995, p. 17)
The Frontal Lobes and Self Reflectiveness
Self-reflectiveness is important for social interaction as well as insight and empathy. “Reasonably accurate self-awareness is a pre-condition to accepting the need for rehabilitation and thereby cooperating with it” (Ben-Yishay and Diller, 1993; Kay and Silver, 1989; Prigatano, 1991b; cited in Lezak, 1995, p. 187). Lack of insight can also result in a failure to examine whether behaviour is socially appropriate. The writer thinks of the frontal lobes as the “super-ego personified”. Hyperfrontality seems to result in obsessive-compulsive behaviour (Baxter, 1987, cited in Schulz, 1999) which could be viewed as excessive internal regulation. Hypofrontality seems to result in Attention Deficit Hyperactivity Disorder (Schulz, 1999), which results in less self-regulated and often socially inappropriate behaviour.
The Frontal Lobes and Speech, Language and Motor Symptoms
Several motor symptoms may become evident after frontal lobe damage. These include disturbances in speech and language; abnormal reflexes, muscle tone, gait and posture, olfactory disturbances, disturbances in eye and head movements and sphincter control resulting in incontinence (Damasio & Anderson, 1993). Motor symptoms do not seem to fall into Stuss and Gow’s (1992) theory of personality unless one considers that the functionality is available without the inclination to use it.
Conclusion
The writer concurs with Walsh (1991) that effective behaviour includes motivated, modifiable and appropriate behaviour that is free from disturbing internal influences such as disease and brain trauma. The frontal lobes are the part of the brain that effect such appropriate behaviour in that they control the executive functions of planning and initiating behaviour, changing the plans to be spontaneous and flexible or discontinue action in order to respond to familiar and new situations appropriately.
Stuss and Gow (1992) attribute these functions to drive, and alongside mood and affect, they incorporate these three functions to define personality. They attribute frontal lobe damage to a disorder of personality, which includes an inability to be self-reflective and ascertain whether behaviour is appropriate, motivated or effective.
Several other theories have described the reason and rhyme for effective behaviour. No one theory is comprehensive and a synthesis of all is necessary to explain frontal lobe anatomy and physiology. However, the frontal lobes alone cannot explain behaviour as they interact with practically every other part of the brain. While the frontal lobes might maintain executive control, they do not operate in isolation; rather it is the rich interconnection of the frontal lobes alongside other cortical structures as well as sub-cortical structures that effect efficient behaviour.
It is usually by assessing damage to the frontal lobes that theorists have been able to ascertain the functionality of the frontal lobes by working retrospectively in assessing the symptoms that appear or the functioning that change or disappear with damage to the frontal lobes. Damage to the frontal lobes has variable and wide reaching consequences. The consequences are often not adequately described by looking at single sets of cognitive, emotional, social or personality symptoms. It is important to embrace an integrated approach and recognise that we cannot view certain symptoms in isolation – they are in fact entwined. It is imperative not to oversimplify the complexity of the consequences of frontal lobe damage to these areas of the brain by viewing only isolated consequences.
References
Banich, M.T. (2004). Cognitive Neuroscience and Neuropsychology (2nd ed). USA: Houghton Mifflin.
Damasio A.R & Anderson, S.W. (1993). The Frontal Lobes in Heilman, K. & Valenstein, E (eds) Clinical Neuropsychology (3rd ed) pp 409-460 New York: Oxford
Guze, B. H. & Gitlin, M. (1994). The neuropathologic basis of Major Affective Disorders: Neuroatatomic Insights. The Journal of Neuropsychiatry and Clinic Neurosciences, 6 (2), 114-121.
Lezak, M. (1995). Neuropsychological assessment (2nd ed.). New York: Oxford. Pp. 187-191.
Luria, A.R. (1970). The functional organisation of the brain. Scientific American, 222, 66-78.
Martin, G. N. (1998). Neuropsychology. England: Prentice Hall
McNaughton, N. (1995). Brain mechanisms of anxiety. New Zealand Journal of Psychology, 24(20, 11-18.
Russel, J. D & Roxanas, M. G. (1990). Psychiatry and the frontal lobes. Australian and New Zealand Journal of Psychiatry, 24 113-132.
Schultz, M.L. (1999). Awakening Intuition. Great Britain: Bantam Books.
Stuss, D. T. & Gow, C. A. (1992) No longer Gage”: Frontal lobe dysfunction and emotional changes. Journal of Consulting and Clinical Psychology, 60 (3), 349-359.
Walsh, K. W. (1991) Understanding Brain Damage. A primer of neuropsychological evaluation. (2nd Ed). Edinburgh: Churchill Livingstone
