The Bigger Their Brain Cortex Injuries, the Better the Mice Performed

Scientists lack any coherent explanation for how a brain could generate thought or intellect. Thoughts are immaterial things, so how could they possibly be generated by material things such as neurons? We know how physical things can generate other physical things (such as a meteor producing a crater), and we know how mental things can generate other mental things (such as one idea leading to a similar idea). But nobody can give a coherent explanation as to how a physical thing such as a brain could produce a mental thing such as a thought or idea.

Scientists often fall back on localization claims to try to hide this shortfall. A scientist who cannot explain the how of a brain making an idea or decision will often try to make up for this shortfall by trying to convince us that at least he knows where the brain makes some idea. A common claim is that thought comes from the cortex of the brain, particularly the frontal cortex.

It is part of the dubious folklore of neuroscientists that the prefrontal cortex is 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.  Similarly, this study checked the IQ of 7 patients with prefrontal cortex damage, and found that they had an average IQ of 101.

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 this paper (page 276), scientist Karl Lashley noted that you can remove 50% of the cortex of an animal without having any effect on the retention of mazes learned by the animal.  Lashley noted on page 270 of this paper something astonishing, that the smartest animal he had tested was one in which the fibers of the cortex had been severed:

"The most capable animal that I have studied was one in which the cortex and underlying association fibers had been divided throughout the length of each hemisphere. His I.Q., based on ten tests, was 309."

In an article last year on the site of Forbes magazine, we hear about a rather similar result. After stating the standard dogma that the cortex is the center of learning, thinking and memory, the article states some experimental findings completely inconsistent with such a conclusion. The article discussed some experiments in which scientists made lesions or gashes in the brain cortex of mice, like someone cutting into a slab of beef. We read the following:

"One more bizarre thing the researchers noticed was the bigger the lesions on the cortex, the better the mice performed. 'It was a strange result…' says Hong, who hesitates before adding: 'I wouldn't say that we're confident that if we [tested] a lot more animals we would see it. It was sort of a trend that we noticed. I guess the answer is, we don't know. Basically, it implied that the less the cortex is active, the better the animal is doing and the cortex was somehow interfering with the animal's ability to learn.' "

This result is entirely inconsistent with the claim that the cortex is the seat of learning, and what generates thinking. But such a result is very consistent with the idea that the brain is kind of like a valve that restricts our minds, rather than something that generates our minds. Such a result is also consistent with what Lashley reported, that the smartest animal he had ever seen was one in which the fibers of the brain cortex had been severed. Such a result is also consistent with the fact that brain signals are known to be transmitted with particularly low reliability in the cortex. As a scientific paper says, "In the cortex, individual synapses seem to be extremely unreliable: the probability of transmitter release in response to a single action potential can be as low as 0.1 or lower." If the cortex is transmitting signals so unreliably, we should not be terribly surprised by a "less cortex, better thinking" result. 

The paper here states, “O'Connor and colleagues reported that after diffuse brain injury, female rats performed better than males on the rotarod test of motor coordination and also incurred a slight advantage on the Barnes maze test of learning and memory.” At the post here, we read of another case in which a removal of brain tissue yielded an improvement that lasted for at least 13 years:

"In a strange case, a woman developed 'hyper empathy' after having a part of her brain called the amygdala removed in an effort to treat her severe epilepsy, according to a report of her case. Empathy is the ability to recognize another person's emotions. The case was especially unusual because the amygdala is involved in recognizing emotions, and removing it would be expected to make it harder rather than easier for a person to read others' emotions, according to the researchers involved in her case."

Schematic depiction of someone with "hyper-empathy"

So we have not just one but four neuroscience results suggesting that mental function can be increased by damaging the brain. Will future humans have brain surgery to increase their intelligence, not by surgeons adding brain tissue, but by surgeons removing brain tissue?

Of course, it will be more easy for you to find a scientific paper that may report decreased cognitive performance from a mouse or rat after damage to the brain. This is because there are many thousands of neuroscientists doing experiments eagerly hoping to find such results, to back up their dogmatic belief that the brain is what produces the mind. Similarly, if we had countless thousands of researchers convinced that hair length affects a human's ability to think, we would have very many scientific papers purporting to show that people with shorter hair are not as smart as people with longer hair.