cerebral blood flow

We also have some really interesting new thinking around photobiomodulation and oral health, especially the idea of red light possibly influencing the oral microbiome indirectly by improving the environment that the bacteria are living in.

We also have new human urolithin A data, which sounds interesting, A data, and involving cerebral blood flow, along with research showing that urolithin A and urolithin B may actually have very different biological personalities.

We have new molecular hydrogen pharmacokinetic data.

We have a brand new human study looking at aging neurons.

Neurons depend continuously on oxygen and glucose delivered by blood, not because consciousness is somehow stored in oxygen, but because maintaining the electrical gradients that make neural signaling possible is metabolically expensive.

Within seconds of abrupt circulatory arrest, cerebral blood flow collapses, oxygen delivery falls, glucose delivery falls with it, and the biochemical machinery that normally keeps sodium, potassium, calcium, and other ions separated across neuronal membranes begins losing the energy required to do its job.

In most human and animal studies, ordinary scalp EEG activity and clinical consciousness disappear within roughly 30 seconds of sudden circulatory arrest, although the exact timing varies with the circumstances and with what is being measured.

Cortical evoked responses can sometimes persist longer, which is an early hint that the brain is not crossing one perfectly synchronized threshold all at once.

This also explains why saying that near-death experiences are simply caused by lack of oxygen does not get us very far.

A major 2025 review in Nature Reviews Neurology proposed something far more complicated.

Impaired cerebral blood flow produces systematic hypotension, hypoxia, rising carbon dioxide, and acidosis, why neuronal excitability and multiple neurotransmitter systems become altered at the same time.

Psychological threat responses, dissociation, memory, expectation, and attempts by the brain to construct a coherent experience may interact with those physiological changes.

CMRO2 is the cerebral metabolic rate of oxygen consumption.

Cerebral blood flow, or CBF, describes how much blood reaches the brain.

MAC is an anesthetic potency measurement based on immobility.

These are the three different concepts.