FRONTAL LOBES
   By Claire DeCapua

EARLY STUDIES OF FRONTAL LOBE FUNCTION
	Great strides in Neuropsychology over the last decades have changed how 
we conceive of the localization of functions of the cortex.  The previously 
held tenets of direct localization of complicated neuropsychological function 
were obstacles to continued research and have been supplanted along with its 
opposite tenet, anti localization, with the more useful and comprehensive 
concept of "system localization". System localization states that each mode 
of neuropsychological activity is a functioning system reliant on a complex 
interaction of cooperatively synchronized functioning units, each of which 
plays a part in the neuropsychological activity. 
	 Another concept that has been supplanted by recent work is that of the 
classical concept of the reflex arc.  The concept of "servomechanism" allows 
us now to analyze the brain as a self regulating system, composed of a 
complex interaction between specific and non-specific systems, and between 
mechanisms in the brain stem and differentiated parts of the cortex.  The 
newer theory regarding the workings of the neuron states that one part of the 
neuron exhibits high specificity, and that the other part is composed of very 
complicated units that are sensitive to the incoming signal and can make 
comparisons between present time signal and past experience and resultantly 
regulate brain activity. 	There seems to have always been controversy 
regarding the role of the frontal lobes. Some neurologists who observed 
patients with frontal lobe lesions, failed to find abnormalities in 
"sensitivity or in the motor or reflex function" and therefore concluded 
their patients were symptomless, and that the most recently evolved part of 
the brain had no defined function.  On the other hand, psychiatrists studying 
patient with massive lesions of the frontal lobe, noted "disturbances of 
motives and the absence of criticism" (Mangel and Antrieb).  These 
psychiatrists gave more importance to the frontal lobes, however they were 
unable to specifically distill the nature of the disturbance down to 
neuropsychological terms.
	 Pavlov in 1949, observing dogs with bilateral frontal lobectomies, 
noted that the dogs had not lost their conditioned salivary reflex but 
"general expedient behavior was so affected that the dog was considered a 
mutilated animal, a profound idiot..." In 1907, Bekterev also observed the 
behavior of such animals.  He concluded that the frontal lobes of the dogs 
are responsible for their ability to evaluate the results of their action and 
direct movements 
in alignment with these evaluations.
EARLY STUDIES OF FRONTAL LOBE FUNCTION
	However, even in the above observations, scientists could not 
thoroughly analyze the exact mechanism that had failed to facilitate the 
higher function of the frontal lobe.  This may be due to their reliance of 
the reflex arc schema, instead of the theory of the self regulating system.
	Every human task begins with an intention towards a goal facilitated by 
a program. This process requires a consistent cortical tone that the CNS must 
maintain. When the tone decreased, the cortex is said to be in an "inhibitory 
phase state", and higher order processes tend to wane. The normal occurrence 
of strong stimuli needed to produce a strong reaction, and weak stimuli to 
produce a weak reaction, no longer occurs. In this state, the cortex may 
respond to strong stimuli and weak stimuli with more or less equal reactions, 
which is called the "equalization phase". The weak stimuli might begin to 
cause an even stronger reaction than the strong stimuli caused, which is 
called the "paradoxical phase".  The laws governing the above occurrences 
were thoroughly studied by the Pavlovian school. The behavioral state that 
occurs as a result of the above neural condition could be likened to when an 
individual is asleep or half awake, and exhibits no organized thought. 
Selective connections are replaced by non-selective associations and are 
seemingly purposeless. It is hypothesized that the illogical quality of 
dreams is due to the foregoing  physiological facts.
Neuropsychological research data has elucidated the interrelationship 
between the brain stem mechanisms and the frontal, particularly the medial 
frontal, in maintaining the tone of the frontal lobes for the active state. 
The regulation of the cerebral cortex, particularly the frontal lobe, is 
contingent on the activating system of the brain stem, which in turn is acted 
upon by descending impulses from the frontal lobes. The foregoing 
fundamentals were the subject of the following researchers: Magoun, Moruzzi, 
Jasper, Walter, Levanov, Homskaya, 1966, and Luria, 1972)  
 	Gray Walter found that any expectation elicits characteristic slow 
waves, called "expectancy waves", that begin at the frontal lobe, and then 
spread to other regions.  His research demonstrates that the above diminishes 
if the probability of emergence of the expected signal decreases.
When the instruction that elicited the heightened expectation state is 
negated, the waves cease.
	M.N. Livanov observed similar brain wave phenomena during 
concentration. He found that while trying to solve a complex math problem, 
the subject would produce synchronous wave forms at the frontal cortex. Once 
solution of the problem was complete and concentration terminated, the number 
of synchronous wave forms also decreased. The number of synchronous wave 
forms characterizes certain behavioral and emotional states, i.e., an 
increased number is seen in the acute paranoid state, conversely the number 
decreases under the effects of certain sedative medications.  
	Neurophysiological research over the last few decades has elucidated 
the "orienting reaction" which is the vegetative and electrophysiological 
reaction which consists of the following: constriction of the vascular system 
to the arms, dilatation to the vascular system to the head, galvanic skin 
changes and alpha rhythm decrease. Sokolov and his colleagues in 1958, and 
1960 showed that despite the tendency of new stimuli to initiate the 
orienting reaction, there is a habituation to the stimulus where the 
orienting reaction decreases, but resurges with any introduction of new 
stimulus.   
	Vinogradova (1959) and Homskaya (1960, 1961, 1965, 1966, 1972) proved 
that the orienting reaction could be increased and stabilized, and made 
inextinguishable over time, if the patient was given a verbal instruction 
that linked meaning to the stimulus.  The increasing and stabilizing of the 
orienting reaction by linking meaning to the stimulus could be achieved by 
telling the subject to watch for changes in the stimulus, (i.e. force, 
duration, or quality).  Also the above could be achieved by telling the 
subject to count the number of presented stimuli, or to perform an action 
when the stimulus changes to a signal.  
	Even with lesions to the extra-frontal structures, such as the post 
central, temporal, or parietoccipital parts of the brain where lesioning 
resulted in significant kinesthetic, auditory, and visual impairment, the 
meaningful verbal link to stimulus, functioned to stabilize the orienting 
reaction. The disorders in the above lesioned patients were the following: 
gnosis, praxis, and speech problems, as well as deficits in spatial 
orientation and intellectual function. However these extra frontal lesions 
left the attention span of the frontal lobe intact.
	In contrast when the lesions were found in the polar, medial, or 
mediobasal section of the frontal cortex, the attachment of meaningful verbal 
instruction to the stimulus did not lead to the stabilization of the 
orienting reflex. In the cases of patients with frontal lesions, the 
attachment of a verbal instruction to the stimulus merely resulted in re-
eliciting the orienting reaction briefly, and sometimes not at all.  The 
patients had mixed results with completion  of the task in the absence of the 
stable increased tone of the cortex. The data of the above study correlates 
with clinical observation of these patients who have difficulty with 
sustained attention, and active state. They lose the assigned problem as well 
as the intention, and manifest other difficulty with purposeful activity.  
Electrophysiological studies done by Baranovskaya and Homskaya in 1966, where 
alpha rhythms were monitored, there is corroboration of the above.   
	Several more electrophysiological studies validate the tenet that when 
frontal lobe lesions affect the polar, medial, and mediobasal section of the 
frontal lobe, the physiological requirements necessary for regulation of 
attention are deranged due to the fact that aforementioned structures 
communicate in a descending mode with the reticular system, and interact in a 
most complex mode to regulate the neural activity.
TESTS TO MEASURE FRONTAL LOBE DYSFUNCTION
Magda Arnold in his review of his predecessors' work emphasizes the motor 
component which in addition to the required sensory discrimination is 
essential to every learned performance He suggest that the frontal lobe 
serves movement, movement impulses and motor memory, and that therefore, 
frontal lesions should interrupt learned responses, and sensory 
discrimination that entails more then approach or avoidance.   
	Arnold again cautions against faulty interpretation of the effects of 
frontal lobe lesions in disease, accident and surgery due to the possibility 
that more then one functional unit was damaged.  Also misinterpretation must 
be guarded against by considering the possibility of connecting tracts that 
have been damaged in addition to the area of circumscribed lesion.    
	Arnold criticizes the Russian school following Pavlov, as well as their 
Western colleagues for not trying to find the motor engrams, while they hold 
tenets that the prefrontal area is the third area of the motor analyzer 
capable of the highest synthesis and discrimination.  He attributes this to 
their acceptance of motor learning as mainly kinesthetic.  Luria's work is 
cited as validating the motor and motor memory function of the frontal lobe, 
especially in the case of a particular patient who had sustained frontal lobe 
damage and was untrainable in occupational work shops even though he did not 
demonstrate any paresis or apraxia.  This particular patient continued to 
plane a plank until he had planned it completely through and started to plane 
the bench. This group of patients could understand and repeat the verbal 
commands, so their auditory memory would be presumed to be intact.  However 
if the examiner were to tell this type of patient to tap three times, the 
patient could not perform the task the specified number of times. This would 
indicate a lack of self performance evaluation required to cease activity at 
the correct time.  Arnold attributes this disorder to the disconnection 
between the cingulate gyrus and the anterior insula, which are the motor 
appraisal areas the lesion had interrupted.    
	Arnold cites Luria's work with patients sustaining massive lesions of 
the frontal convexity for whom carrying out a complex program is problematic, 
and results in perseveration.  One patient in particular was asked to draw 
spectacles and completed that task.  Then when asked to draw a watch seemed 
compelled to continue drawing spectacles despite his attempts to follow the 
examiners commands.  the patient then began to draw figures and watch hands 
on to the spectacles lens, which Arnold interprets as his inability to use 
motor imagination.  If the lesion is pervasive, the motor registration area 
and the imagination circuit is interrupted as it spreads out to the 
dorsomedial nucleus in the frontal lobe.  The patient needed the ability to 
visualize each object to draw each.  As he draws the first item, he lays down 
a motor engram, which is reactivated in the drawing of the second item. 
Lacking the "motor" imagination" required to plan and guide his movements, 
his second drawing attempt follows the facilitated path, and he repeats the 
drawing of the first item. The above type of patient does not look around, or 
look for significant features of a picture even when instructed to do so, due 
to the same inability to imagine or plan.  
	Arnold cites Luria's recognition of the affects of damage to the 
imagination circuit and disconnection to the motor appraisal area, but 
criticizes Luria's unwillingness to pinpoint the structures involved.  Luria 
describes the problem these patients have in memorizing series of words or 
numbers.  For example, an unimpaired person pays special attention to the 
words he has missed on the first presentation and slowly increases the number 
of words learned. The patient with damage to aforementioned structures of the 
frontal lobes learns and repeats three or four of these, no matter how many 
times the series is presented and does not improve.  These patients prove 
unable to correct mistakes, and may go on repeating the mistake.  they seem 
unable to evaluate their performance, and are incapable of correcting because 
they cannot imagine what to do.   
TESTS TO MEASURE FRONTAL LOBE DYSFUNCTION
	Russian researchers report that premotor lesions disturb the 
comprehension of complex sentences.  One Russian researcher reports that 
premotor lesions disturb  the comprehension of complex sentences.  One 
patient reported that he could only grasp a few words after silent reading 
and could not understand it.  He described having to read it several times to 
pick out the ideas and put them together.  this process was made even harder 
if he was not allowed to read it out loud, which utilizes the visual memory 
as well as the auditory both of which may be unimpaired.  Reading aloud also 
focuses the attention which is another area of deficit in frontal lobe 
disorders.  These same deficits make arithmetic solution difficult because 
the patient does not know how to plan and then convert the plan into action.  
Disconnection of the imagination circuit affects the ability to plan or 
imagine, and the premotor lesion prevents the setting of intention.  
	Despite impaired functioning the following researchers found intact 
intelligence, in patients with prefrontal lobotomy or frontal lesions 
(Mettler, 1949. Hebb, 1950; LeBeav, 1954; Ghent et al.,1962) Luria sites this 
as a contradiction. However, Magda Arnold points out that in the above cases 
the motor appraisal areas were still intact.
Arnold also points out that mass I.Q. tests do not require motor 
imagination. One of the few tests that require motor imagination is the "open 
field" segment of the Binet. Other tests that require motor imagination are 
the Porteus maze test, and the Kohs block test. In these tests lobotomized 
patients and patients with frontal damage are deficient.  
	Arnold cites psychologists who have tried to devise special tests that 
are more sensitive to frontal lobe damage and go a step beyond general 
intelligence testing which require intact visual and auditory memory which 
may be intact in frontal lobe patients, but fail to test motor memory or 
motor imagination., Ghent in 1962 attempted to devise tasks for humans that 
would demonstrate impairment in delayed response tasks which correlated with 
frontal lesion in test animals.  The following is Arnold's appraisal of those 
tasks and the flaws inherent.  
	The line test consisted of a patient attempting to ascertain the pint 
at which the tilt of a fluorescent tube, matched the original tilt as the 
examiner turn the tube.  Arnold critiques this test as requiring visual 
memory and appraisal, which are served by visual memory areas 18 and 19 and 
the posterior hippocampal gyrus, but which a prefrontal lobotomy would not 
affect.  
	Ghent devised the Tactual Point Localization test which consisted of a 
patient silting with eyes closed, hands resting on knees, palms turned up. 
The examiner would touch a spot on the palm with a blunt stylus for two 
seconds. The 
TESTS TO MEASURE FRONTAL LOBE DYSFUNCTION
examiner would then either immediately afterwards, or 15 seconds later 
contact the palm with the stylus several times.  the patient need to 
determine which of the subsequent contacts matched the original. This task 
required touch memory and appraisal, mediated by the somesthetic memory of 
the parietal lobe and the somesthetic appraisal area of the posterior 
cingulate appraisal area of the posterior cingulate gyrus and posterior 
insula.
	In "the visual point localization" procedure the task of the patient 
was to match the position of a target moving on the perimeter with the 
original positions. As with the line test, visual memory and appraisal areas 
are required.  
	In the "digit span" test auditory memory and appraisal served by the 
temporal association area, and posterior insula, facilitated the patients 
performance, as the examiner read digits orally. Damage to the frontal lobe 
would not interfere with performance of this test. 
	In the "Form Span" test ten forms from the Seguinn Goddard form board 
had to be memorized with eyes closed. The blocks were then randomly 
repositioned either immediately or 15 seconds later. The patient was asked to 
find the original blocks and rearrange in the original positions. This 
procedure can be accomplished by using visual memory and appraisal. In the 
"body tilt" test, a blind folded patient sat in a chair which was tilted 20 
degrees for five seconds. The patient was instructed to remember the tilt.  
The chair was relocated to its original upright position and then slowly 
retitled, until the patient could signal when the chair resumed the tilt. To 
accomplished this "spatial orientation task", kinesthetic memory and 
appraisal were the required functions. The question the patient needed to ask 
himself was "is this familiar or unfamiliar".  
	The patients who participated in the Body Tilt test were male veterans 
who had sustained penetrating wounds to the frontal lobes. The control group 
was composed of veterans with leg wounds. The third group was composed of 
veterans with extra frontal injury. None of these tests showed any difference 
in the three above groups. Due to the fact that, delayed response impairment 
in animals was seen as a defect in short term memory, the intention of the 
tests was to sample short term memory in various dimensions. Short term 
memory in these frontal lobe damage patients was not apparent via the above 
testing strategies. The authors of the test maintain that defect in recall 
was mediated by kinesthetic-orientation cues, however the last two tests 
showed no impairment among the three groups in this realm.
	Arnold reiterates that memory is not a unitary function, but is 
modality specific. Defects to visual, auditory, tactual or kinesthetic memory 
do not necessarily occur with lesioning of the frontal lobes.  The delayed 
response impairment in animals with frontal lobe damages not a defect in 
generalized short term memory or in kinesthetic recall but the result of 
impaired motor memory. When there is time delay between stimulus and required 
response, the animal is unable to remember his intention. If the time delay 
is subtracted, the intention is formed and carried out immediately via the 
action circuit and its connection with the premotor and motor areas of the 
frontal lobe. 

         
Pribam, K.H. and Luria, A.R. (1973)  Physiology of the Frontal Lobes pp. 3-4. 
Academic Press, New York.
Pribam, K.H. and Luria, A.R. (1973)  Physiology of the Frontal Lobes pp. 3-4. 
Academic Press, New York.
Pribam, K.H. and Luria, A.R. (1973)  Physiology of the Frontal Lobes pp. 3-4. 
Academic Press, New York.
Pribam, K.H. and Luria, A.R. (1973)  Physiology of the Frontal Lobes pp. 4. 
Academic Press, New York.
Pribam, K.H., and Luria, A.R. (1973). Physiology of the Frontal Lobes pp. 3-4 
Academic P;ress, New York. 
Pribam, K.H. and Luria, A.R. (1973)  Physiology of the Frontal Lobes pp.8 
Academic Press, New York.
Pribam, K.H. and Luria, A.R. (1973)  Physiology of the Frontal Lobes pp. 4. 
Academic Press, New York.
Pribam, K.H. and Luria, A.R. (1973)  Physiology of the Frontal Lobes pp. 6. 
Academic Press, New York.
Pribam, K.H. and Luria, A.R. (1973)  Physiology of the Frontal Lobes pp. 6. 
Academic Press, New York.
Pribam, K.H. and Luria, A.R. (1973)  Physiology of the Frontal Lobes pp. 6. 
Academic Press, New York. 
Pribam, K.H. and Luria, A.R. (1973)  Physiology of the Frontal Lobes pp. 4. 
Academic Press, New York.
Arnold, M. (1984). Memory and the Brain pp. 183. Lawrence Earlbaum 
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Arnold, M. (1984). Memory and the Brain pp. 184. Lawrence Earlbaum 
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Arnold, M. (1984). Memory and the Brain pp. 184-185. Lawrence Earlbaum 
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Arnold, M. (1984). Memory and the Brain pp. 185. Lawrence Earlbaum 
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Arnold, M. (1984). Memory and the Brain pp. 185. Lawrence Earlbaum 
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Arnold, M. (1984). Memory and the Brain pp. 186. Lawrence Earlbaum 
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Arnold, M. (1984). Memory and the Brain pp. 186. Lawrence Earlbaum 
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Copyright © 1999, Dr. John M. Morgan, All rights reserved - This page last edited 19 - November, 1999
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