Those who claim that the brain makes the mind keep trying to push the silly idea that you are just a bunch of neural signals passing around inside your head. The scientists who make such claims typically are members of a belief community, a kind of sect of the ivory towers. When we hear such claims we are observing the speech customs of such a community. The members of belief communities often keep repeating the same old claims, which often are not justified by any robust evidence.
(1) If minds are produced by firing neurons, we would expect that neurons would fire much more frequently during conscious awareness than during unconscious sleep.
(2) If minds are produced by firing neurons, we would expect that neurons would fire much more frequently during heavy mental activity such as deep concentration, heavy calculation or rapid memory recall, than during a passive awake condition involving a mental resting state.
(3) If minds are produced by firing neurons, we would expect that when neurons fire most rapidly, that would produce the highest state of consciousness or mental activity.
None of these predictions turns out to be true. To investigate this matter, you should ignore the type of visual shown below, a misleading visual that open appears in articles about the brain. The reality is that all of these types of brain waves occur during each of the listed states.
A misleading diagram recurring in neuroscience articles
Figure 1 of the paper here ("Firing rates of hippocampal neurons are preserved during subsequent sleep episodes and modified by novel awake experience") shows two scatter plots showing neural firing rates in the hippocampus of rats. One scatter plot is marked "Awake" and the other scatter plot is marked "Sleep." The two scatter plots look pretty identical. They both show rates of neuron firing varying from about once every ten seconds to ten times per second.
Judging from such graphs, neurons do not seem to fire more often in rats when they are awake. Some people claim that neurons fire less frequently during sleep, but they typically fail to give us specific figures as to how much less frequently they fire.
Referring to readings from an EEG (a device that reads brain waves), we read this on an expert answers site:
"In REM sleep, the EEG is remarkably similar to that of the awake state (Purves et al., 2001). Although the EEG represents the synchronized activity of many neurons in the cortex, it does give us a clue whether they are firing faster or not. Wakefulness is mainly dominated by beta and gamma waves (source: Scholarpedia), i.e. 12 - 100 Hz. REM sleep is characterized by low-amplitude mixed-frequency brain waves, quite similar to those experienced during the waking state - theta waves, alpha waves and even the high frequency beta waves more typical of high-level active concentration and thinking, i.e. 4-30 Hz (table 1) (source: Sleep)."
When I ask Google "how much do average neuron neuron firing rates vary between sleep and wakefulness," I get the AI overview answer below:
"Average neuron firing rates decrease by approximately 30-40% during non-REM (NREM) sleep compared to wakefulness, largely driven by the appearance of 'OFF' periods (silence)...Similar to active wakefulness, neural firing rates in REM are generally higher than in NREM and often match awake levels."
This is an indication of only a small difference in neuron firing rates between sleep and wakefulness. We are told that during one type of sleep (NREM sleep) firing rates decrease by 30%, but that is a gradual decrease occurring over an hour or two. So if you had a gradual decrease to a 30% lower firing rate during NREM sleep, this would be something like an average neuron firing rate of 15% less than during wakefulness. And during the other type of sleep (REM sleep) neurons seem to fire about as often as when you are awake.
Diving into this AI overview by doing more scrolling or clicking, I find the story changes. Later in the same AI overview I am told that "average neuron firing rates vary significantly between sleep and wakefulness, typically characterized by a 10%–20% decrease during sleep, though these shifts depend heavily on the specific brain region and sleep stage."
The type of graph that gives you the most information when analyzing brain waves is a type of graph called the EEG multitaper spectrogram. Someone unfamiliar with it may have to take a minute or two studying how the graph works before he can understand it. The graph can show up to 10 hours of brain activity. Each column of pixels shows the activity for a particular short time unit such as a minute or a few minutes. The higher rows on the graph represent the higher-frequency brain waves. A red color represents a high intensity; a yellow or green color represents a medium intensity; and a blue color represents a lower intensity.
We are sometimes shown versions of this graph which will suggest that lower-frequency brain waves are much more common during sleep. However, in Figure 7 of the paper here, we are shown multitaper EEG spectrograms that are called representative of sleep, and those diagrams seem to depict theta, alpha and beta waves occurring almost as frequently as delta waves.
The paper "Sleep Neurophysiological Dynamics
Through the Lens of Multitaper Spectral
Analysis" by Prerau et. al. seems like the best paper I can find giving data comparing brain waves during sleep and brain waves when awake. The paper has many examples of EEG multitaper spectrograms plotting the differences between brain waves during sleep and brain wave when awake. The graphs show no strong evidence of greater electrical activity in the brain while you are awake.
Here is figure 1 of the paper, showing electrical activity in a brain from midnight to 10:00 AM. Roughly the first hour and the last hour are wakefulness.
(1) The graph plots brain waves that occurred over about 10 hours that included 8 hours of sleep and 2 hours of being awake.
(2) The left edge of the graph plots brain waves occurring during an hour of being awake, before the 8 hours of sleep occurred.
(3) The right edge of the graph plots brain waves occurring during an hour of being awake, after the 8 hours of sleep occurred.
(4) The middle 80% of the graph plots brain waves occurring during sleep.
(5) With this type of graph, the redder the color and the higher up on the graph the colors occurs, the greater the indication that more electrical activity was occurring. For any given frequency, blue represents the lowest power; green represents a higher power than blue; yellow represents a higher power than green; and red represents a higher power than yellow.
So what do we see in the graph above? Overall, there is little difference between the amount of electrical activity occurring during sleep and while being awake. According to the graph, while awake there is a slightly greater power in the higher frequency band (about 15 Hz), because the top left corner and the top right corner are a little more green than blue. But according to the same graph while the person is awake there is slightly less power in the lower frequency band (about 7 Hz), because in the bottom left and the bottom right of the graph we see more green and yellow than red. Overall, we seem to see no evidence of much greater electrical activity in the brain when a person is awake, compared to when he is asleep.
What we see here is evidence suggesting that brains are not much more electrically active when you are awake as opposed to when you are asleep. This isn't what we would expect under the dogma that the brain is the source of the mind.
Another interesting comparison to make is to compare brain waves during wakefulness and brain waves during anesthesia. The average person might think that the firing rate of neurons slows down greatly during the unconsciousness produced by anesthesia. That is not true, however.
The diagram below is from the paper " Electroencephalographic dynamics of etomidate‐induced loss of consciousness" that you can read here. At the bottom we see an EEG multitaper spectrogram showing brain waves during both a conscious awake state and unconsciousness produced by anesthesia. The first third of the bottom visual shows the awake and conscious state. According to the diagram, loss of consciousness (LOC) occurs at around the 300 second mark, about the middle of the colored visual.
This is just as we would expect under the idea that your brain is not the source of your mind.
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