There Is No Robust Evidence That Neuron Firing in the Brain's Frontal Lobes Is Information Processing

 On the day I am writing this post I see in some news article a typical statement about the brain. Someone states this

"Our brains process information via a vast network containing many millions of neurons, which can each send and receive chemical and electrical signals. Information is transmitted by nerve impulses that pass from one neuron to the next, thanks to a flow of ions across the neuron’s cell membrane. This results in an experimentally detectable change in electrical potential difference across the membrane known as the 'action potential' or 'spike.' "

But is this an accurate description of what is occurring in the frontal lobes of the brain? It would seem not. Neurons are continually firing in the frontal lobes of the brain, but there is no evidence that such firing is information processing or information transmittal in the sense of data or knowledge being passed around. 

It is true that a certain type of information processing is occurring throughout the brain. The chromosomes of all cells (including neurons) contain DNA, and when that DNA is read, it can be considered a form of information processing. But such information processing is something different from the firing of neurons.

Neuron firing may involve some information processing in two areas of the brain: the occipital lobe and the parietal lobe. These two regions are shown below (the parietal lobe in yellow and the occipital lobe in green, at the back). The occipital lobe is connected to the eyes by the optic nerve, so you might say that this lobe at the back of the brain processes information received from the eyes. The parietal lobe receives inputs such as touch sensations and pain sensations, so you might say that this lobe processes such inputs. 

But what about the frontal lobes at the front of the brain? (I will refer to lobes because there is one such lobe in each hemisphere or half of the brain.) The neurons in the frontal lobes are always firing, at a rate of about 1 action potential per second, to as high as 100 or more action potentials per second. Is there any adequate warrant for claiming that such neuron firing is an example of information processing? There is not. 

We might have a reasonable basis for calling such neuron firing in the frontal lobes "information processing" if someone had been able to decipher some kind of code corresponding to such neuron firing. But no one has been able to do any such thing. There has been all kinds of speculation about some kind of coding system that might be used by firing neurons to transmit information. But that has all been mainly  nothing but speculation. No robust evidence has ever been produced that the firing of neurons in the frontal lobe is any kind of real information processing or information transmittal.  When scientists have tried to produce evidence for such a thing, the results are merely pareidolia, like someone claiming to see the face of Jesus in his toast. 

But, it may be claimed, don't we know that the frontal lobes produce human thought, and does not such human thought qualify as information processing? No, we do not actually know that the frontal lobes of the brain or any part of the brain produce human thought. 

When fMRI scans are taken of the brain during cognitive activity, no strong evidence is produced backing up claims that the frontal lobes of the brain are some "seat of thought." Such scans typically show variations from region to region of only about 1 part in 200. The little regions with 1 part in 200 greater difference are scattered around the brain. Such fMRI scans are actually consistent with the claim that the brain is not the source of human thinking or cognition. because the variations are no greater than you might expect from chance variations. But you might think otherwise after looking at one of those "lying with colors" visuals that tries to make regions that differ by only 1 part in 200 look like they differ by some substantial percentage. 

It is part of the dubious folklore of neuroscientists that the prefrontal cortex or frontal lobes are some center of higher reasoning. But the scientific paper here tells us that patients with prefrontal damage "often have a remarkable absence of intellectual impairment, as measured by conventional IQ tests." The authors of the scientific paper tried an alternate approach, using a test of so-called "fluid" intelligence on 80 patients with prefrontal damage. They concluded "our findings do not support a connection between fluid intelligence and the frontal lobes." Table 7 of this study reveals that the average intelligence of the 80 patients with prefrontal cortex damage was 99.5 – only a tiny bit lower than the average IQ of 100. Table 8 tells us that two of the  patients with prefrontal cortex damage had genius IQs of higher than 140.

In a similar vein, the paper here tested IQ for 156 Vietnam veterans who had undergone frontal lobe brain injury during combat. If you do the math using Figure 5 in this paper, you get an average IQ of 98, only two points lower than average. You could plausibly explain that 2 point difference purely by assuming that those who got injured had a very slightly lower average intelligence (a plausible assumption given that smarter people would be more likely to have smart behavior reducing their chance of injury). Similarly, this study checked the IQ of 7 patients with prefrontal cortex damage, and found that they had an average IQ of 101.

It also should be remembered that brain-damaged patients taking standard IQ tests may have higher intelligence than the test score suggests.  A standard IQ test requires visual perception skill (to read the test book) and finger coordination (to fill in the right answers using a pencil). Brain damage might cause reduced finger coordination and reduced visual perception unrelated to intelligence; and such things might cause a subject to do below-average on a standard IQ test even if his intelligence is normal.  

Using the term "neoplasms" to refer to brain tumors, the 1966 study here states, "Taken as a whole, the mean I.Q. of 95.55 for the 31 patients with lateralized frontal tumors suggests that neoplasms in either the right or left frontal lobe result in only slight impairment of intellectual functions as measured by the Wechsler Bellevue test."  

In the paper "Neurocognitive outcome after pediatric epilepsy surgery" by Elisabeth M. S. Sherman, we have some discussion of the effects on children of hemispherectomy, surgically removing half of their brains to stop seizures. Such a procedure involves a 50% reduction in the total volume of the frontal lobes of the brain, and a 50% reduction of the prefrontal cortex. We are told this:

Cognitive levels in many children do not appear to be altered significantly by hemispherectomy. Several researchers have also noted increases in the intellectual functioning of some children following this procedure....Explanations for the lack of decline in intellectual function following hemispherectomy have not been well elucidated. 

Referring to a study by Gilliam, the paper states that of 21 children who had parts of their brains removed to treat epilepsy, including 10 who had surgery to the frontal lobe, none of the 10 patients with frontal lobe surgery had a decline in IQ post-operatively, and that two of the children with frontal lobe resections had "an increase in IQ greater than 10 points following surgery." 

The paper here gives precise before and after IQ scores for more than 50 children who had half of their brains removed in a hemispherectomy operation.  For one set of 31 patients, the IQ went down by an average of only 5 points. For another set of 15 patients, the IQ went down less than 1 point. For another set of 7 patients the IQ went up by 6 points. 

A writer at Slate.com states the following: 

"And victims of prefrontal injuries can still pass most neurological exams with flying colors. Pretty much anything you can measure in the lab—memory, language, motor skills, reasoning, intelligence—seems intact in these people."

In 1930 a patient listed as Joe A. in the medical literature underwent a bilateral frontal lobectomy performed by Dr. Walter Dandy, who removed almost all of his frontal lobes. An autopsy in 1949 confirmed that "both frontal lobes had been removed." The paper describing the autopsy said that from 1930 to 1944 Joe A.'s behavior was "virtually unchanged." On page 236 of this source, we read that Dandy said this of three patients including Joe A.: "These three patients with the extirpation of such vast areas of brain tissue without the disclosure of any resulting defect is most disappointing." I could see how it would be disappointing for someone hoping to prove a connection between some brain area and intellectual function. Page 237 of the same source tells us that on casual meeting Joe A. appeared to be mentally normal.  Page 239 of this source states this about Joe A, summarizing the findings of Brickner.:

"Nor was intellectual disturbance primary. The frontal lobes played no essential role in intellectual function; they merely added to intellectual intricacy, and ' were not intellectual centers in any sense except, perhaps, a quantitative one.' " 

A 1939 paper you can read here was entitled "A Study of the Effect of Right Frontal Lobectomy on Intelligence and Temperament." A patient C.J was tested for IQ before and after an operation removing his right frontal lobe. He had the same IQ of 139 before and after the operation. Page 9 says the lobectomy "produced no modification of intellectual or personality functions."  On page 10 we are told this about patients having one of their frontal lobes removed:

"Jefferson (1937) reported a series of eight frontal lobectomies in which the patients were observed for intellectual and emotional deficits following operation. There were five cases of right frontal lobectomy, three of whom were living and well when the article was written. It could be stated definitely that in two of the three cases there were no abnormalities which could be noted by the surgeon, patient, or family, and while the third case showed a mild memory defect, the operation had been too recently performed to judge whether or not the loss would be permanent. The three cases of left frontal excision likewise showed no significant changes, but comment was made that one patient was slightly lacking in reserve, another remained slightly facetious, and the third, who suffered a transient post-operative aphasia, appeared a trifle slow and diffident."

The following excerpt from a scientific paper tells us of additional cases of people who did not seem to suffer much mind damage after massive damage to the frontal lobes or prefrontal cortex. Resection is defined as "the process of cutting out tissue or part of an organ."

"Several well-documented patients have been described with a normal level of consciousness after extensive frontal damage. For example, Patient A (Brickner, 1952) (Fig. 2A), after extensive surgical removal of the frontal lobes bilaterally, including Brodmann areas 8–12, 16, 24, 32, 33, and 45–47, sparing only area 6 and Broca's area (Brickner, 1936), 'toured the Neurological Institute in a party of five, two of whom were distinguished neurologists, and none of them noticed anything unusual until their attention was especially called to A after the passage of more than an hour.'  Patient KM (Hebb and Penfield, 1940) had a near-complete bilateral prefrontal resection for epilepsy surgery (including bilateral Brodmann areas 9–12, 32, and 45–47), after which his IQ improved. Patients undergoing bilateral resection of prefrontal cortical areas for psychosurgery (Mettler et al., 1949), including Brodmann areas 10, 11, 45, 46, 47, or 8, 9, 10, or 44, 45, 46, 10, or area 24 (ventral anterior cingulate), remained fully conscious (see also Penfield and Jasper, 1954; Kozuch, 2014; Tononi et al., 2016b). A young man who had fallen on an iron spike that completely penetrated both frontal lobes, affecting bilateral Brodmann areas 10, 11, 24, 25, 32, and 45–47, and areas 44 and 6 on the right side, went on to marry, raise two children, have a professional life, and never complained of perceptual or other deficits (Mataró et al., 2001)."

Apparently patient KM got smarter after they took out most of his prefrontal cortex. That's a case helping to show that brains don't make minds. The book here discusses intelligence tests done on patients who underwent surgery on the frontal lobes:

"It was natural that the effect of an injury on the frontal lobes, said to be concerned with the higher functions of men, should be measured by these tests of intelligence. The absence of marked effects on mental ability, as measured by these intelligence tests, was, not surprisingly, felt to be puzzling." 

This paper here describes a case of a "modern Phineas Gage": a patient C.D. who suffered massive prefrontal  damage after a penetrating head injury. But C.D's IQ after the injury was measured at 113, well above average.  His verbal IQ after the injury was 119, in the 90th percentile. We read:

"C.D. reported that he did not have any cognitive or emotional problems following the accident. In describing how his thinking skills were completely unaffected, C.D. stated that, 'all the shattered bone was caught in the gray matter in front of the brain.' " 

The paper also tells us, "C.D.’s performances on memory tests were all in the average to above-average ranges in terms of the traditional measure of level of correct responses." 

There is another case of this type. The case is particularly interesting because it helps to discredit the claim that the frontal lobes of the brain are necessary for language and thinking.  The case is reported in the paper "Early bilateral and massive compromise of the frontal lobes."  We read about an amazing case of an 8-year-old girl with good mental skills despite having basically no frontal lobes of the brain. We see an MRI scan showing a gigantic black empty region in the brain corresponding to missing frontal lobes.

We read that a brain scan at age three revealed this:

"GC's first report of frontal compromise at age three. MRI scans revealed no structures in the frontal lobe, covered with cerebrospinal fluid. Weighed-T1 MRI scans showed no recognizable frontal structures, expect for a small portion of the ventral frontal cortex. The mesencephalon, pons, and medulla oblongata were present, and so were all other lobes and the cerebellum."  

We read that a brain scan of the girl at age 8 showed basically the same results, with at most only a tiny of the frontal lobes existing. 

Under a heading of "Neurological and neuropsychological assessment" we read that "she could describe sensory and affective experiences, and reacted to environmental events with apparent emotional and cognitive congruency (e.g., pleasure, tiredness, playfulness, anger, and basic symbolization  Supplementary Video 1, Supplementary Video 2)." The links take us to a page of videos of the young girl. We see her seeming to act pretty much like a normal girl of her age. I recommend watching all of the short videos on the page. The girl with basically no frontal lobes stands, dances, seems to speak normally, and responds to requests to touch parts of her body, and show how she brushes her teeth. The person asking the questions to the girl speaks very rapidly, but the girl seems to have no difficulty understanding the questions, and the girl makes appropriate verbal and manual responses.  Asked to point to the questioner's thumb, the girl points to the right spot. Asked to point to the girl's eyes, the girl points to the right spot. Asked where she would wear a pair of glasses, the girl points to her eyes. Asked where she would wear a pair of shoes, she points to her feet. The girl is able to distinguish between herself and a fantasy character (Minnie Mouse), and says that she is not Minnie (Video 9). 

We see below a visual of the girl's brain, from Supplementary Video 11:

A much better title for the paper would have been "Good cognitive performance despite loss of the frontal lobes."

In this post I have taken selected excerpts from my much longer post "Reasons for Doubting Thought Comes from the Frontal Lobes or Prefrontal Cortex," which you can read here. The post includes most of the evidence discussed above, along with a discussion of many other papers and cases that collectively provide a very strong basis for rejecting common claims that thought or cognition comes from the frontal lobes or prefrontal cortex of the brain. Other posts of mine very relevant to this discussion are my posts discussing how all parts of the brain have an abundance of many types of severe signal noise. 

The truth is that we have no basis for claiming that the neurons firing in the brain's front lobes are either any type of information processing or any type of computation or any type of thinking. What we know is consistent with the idea that the firing of neurons in the frontal lobes is mere noise, no more examples of information processing than the arising of bubbles on the surface of a boiling soup.