Does the brain have one last mental hurrah before it dies?

There are many voices in the scientific community (perhaps most voices) who believe that accounts of near-death experiences including the consistently reported out-of-body experiences, transcendental perceptions and panoramic life reviews are simply the result of a final burst of chemical and electrical activity in the dying brain.

These materialist views have been supported by studies performed on rodents that demonstrated end-of-life electrical surges (ELES) in their brains.

The EEG of a dying man.

In 2022, a paper was published looking at the only case up to that date where an electroencephalograph (EEG) was recorded during the transition to death.

An 87-year-old male had sustained a serious head injury following a fall. His CT scan subsequently confirmed a large bleed into his brain (bilateral subdural haematomas) and he underwent surgery to remove the clots.

Postoperatively his initial recovery declined after two days with a worsened right hemiparesis (increased weakness on the right side of the body) and seizure activity.

He was commenced on anti-seizure medications and underwent an EEG, which showed non-convulsive status epilepticus in the left hemisphere of the brain.

During this EEG, the patient developed ventricular tachycardia (VT), a life-threatening heart arrhythmia, and respiratory arrest.

In consideration of his ‘Do Not Resuscitate’ order and in consultation with his family, the decision was made to withdraw treatment.
Shortly afterwards, the man died.

This gave researchers a unique opportunity, and later analysis of the man’s EEG showed the electrical activities in this mans brain during the transition to death.

The published results are dense and complex and require a good technical understanding of the principles of EEG and their interpretation, which I do not have.
But my understanding is that they found increased (relative to other waveforms) gamma wave activity and coupling of gamma and alpha wave activity.

In normal brains, increased gamma activity is associated with conscious perception.
Alpha waves are associated with information processing, especially in the visual cortex.

The researchers speculated that as this cross-coupling of alpha and gamma wave activity is associated with cognitive processes and memory recall in healthy individuals, perhaps such activity could explain a last hurrah “recall of life” or out of body experience as death becomes imminent.

Read the original article: Enhanced Interplay of Neuronal Coherence and Coupling in the Dying Human Brain

But not so fast….

A few months after this paper, a rebuttal was published in the same journal.

Bruce Greyson, Pim van Lommel and Peter Fenwick made some important clarifications on the data in the original study:

• The EEG did not show an increase in absolute gamma activity. It actually showed a decrease. The increase was only relative compared to the decrease in alpha, beta, and delta waves.
• There were many variables that could have confounded any EEG findings. Including the traumatic brain injury, and the use of dissociative & anticonvulsive drugs, to control his seizures.
• The possibility that the EEG may have been, at least in part, recording the electrical activity of muscle contractions.
• At the time of data collection that was marked as “cardiac arrest,” the patient was actually in VT (ventricular tachycardia). This is an arrhythmia that is technically not a “cardiac arrest” and can still produce cardiac output and cerebral perfusion.
  

The authors also cite a study from 2021 in which continuous EEG recordings of 19 ICU patients at the time of death (following cardiac arrest) showed brief EEG activity (<5 min) followed by decreased EEG activity & increased entropy (disorganised activity) across the spectrum.

Read the full commentary on the article: Commentary: Enhanced Interplay of Neuronal Coherence and Coupling in the Dying Human Brain

My ten cents worth:

More studies are needed to explore the near-death experience including electrophysiological responses at the time of death. The AWARE II study is perhaps the most robust to date.

We must not forget that correlation is not causation.
Increases in EEG activity may cause the perceptions and experiences of a NDE (material view)… but it may also be what the experience of non-local consciousness looks like reflected in the physiology of the brain.

Just like the electrical activity measured in a circuit is what Beethoven’s 9th looks like reflected in the workings of an FM radio.

The very same people who argue so strongly that NDEs emerge from a hallucinating or confabulating brain are unable to tell us exactly how that brain produces consciousness in the first place.