Neurotransmitters and brain function

Although I’ve taken a general interest in brain function and states of consciousness, until the last few years I really only paid much attention to the relationship between brain waves and states of consciousness, and in particular the use of brainwave entrainment methods to facilitate certain states (see earlier post here). Only in the last few years have I looked more closely into the complex and interacting roles of brain waves, neurotransmitters and various brain networks.

By Thomas Splettstoesser (,

Neurons (nerve cells) in the brain form elaborate networks, with each neuron having up to 15,000 connections with neighbouring neurons at contact points called synapses. While the nerve impulse travel through the neuron as an electrical impulse, it does not cross the gap known as the synaptic cleft but rather stimulates the release of a chemical messenger: a neurotransmitter. This crosses the synaptic cleft and is received by neurotransmitter receptors on the target cell. A neurotransmitter with increase (excitatory) or decrease (inhibitory) the probability that the target cell will produce a nerve impulse.

There are three main types of neurotransmitters in the brain: small molecules used for fast signal transmission between neurons, small used for slower modulation of network activity, and large molecules (peptides) used for even slower modulation of cell circuit functions. Most neurons have receptors for most of the neurotransmitters in all three of these categories.

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Psychedelics and the health risks of drugs, alcohol and tobacco

In the last decade or so, there has been a renaissance of interest in the therapeutic potential of psychedelics. While natural psychedelic substances have been used by humans for many thousands of years, psychedelics had a massive cultural impact on the West in the 1950s and 1960s. Albert Hoffman, a research scientist working for the Swiss pharmaceutical company Sandoz, accidentally invented LSD (lysergic acid diethylamide) in 1938 and discovered its psychedelic properties five years later. In 1955, a New York banker named Gordon Wasson sampled the psilocybe (magic) mushroom in Mexico and published an article on his experience in Life magazine.

Scientists discovered the role of neurotransmitters in the brain in the 1950s, and psychedelics inspired scientists to search for the neurochemical origins of mental disorders previously thought to be psychological. Psychedelics were also used in psychotherapy to treat various disorders, including alcoholism, anxiety and depression, with some promising results, although these studies generally did not reach modern standards of research design.

However, psychedelics were also embraced by the counterculture and became linked in the mind of authorities with youth counterculture and the anti-Vietnam war protests. By the end of the 1960s, most Western governments had outlawed and forced underground the psychedelic drugs which had been legal in most places previously, and also shut down all scientific research.

In the 1990s small groups of scientists managed to start conducting various trials of the therapeutic uses of psychedelics and this has led to the so-called psychedelic “renaissance” in which larger well-designed trials of psychedelic use for treating a range of mental disorders are being carried out by research groups at institutions such as Imperial College London, Johns Hopkins University and New York University. Just today, it was announced that the Australian government will be providing $15 million funding for clinical trials into the use of psilocybin and other psychedelics for the treatment of mental illnesses, including depression and PTSD. Michael Pollan’s book How to Change Your Mind gives an excellent account of the history of psychedelics, both above ground and underground, and the psychedelic renaissance, and was a best seller. See also this article by Michael Pollan on the “Psychedelic Renaissance”.

As part of my work on the global burden of disease for the World Health Organization (WHO), I carried out several assessments of the direct and indirect health impacts of the use of drugs, alcohol and tobacco. I recently did an approximate update to year 2019 for deaths directly due to drug use disorders (overdoses and directly toxic effects) and indirect deaths from road injury, suicide and infectious diseases attributable to drug use. A proportion of HIV, hepatitis B and hepatitis C deaths can be attributed to injecting drug use with contaminated needles. The great majority of direct and indirect deaths due to drug use are due to the use of opioids, both illicit and pharmaceutical opioids. Very few deaths are associated with psychedelic drug use, but I was curious to get a ballpark estimate for comparison with other drug deaths. I will present a brief summary of the broad estimates of drug-attributable deaths, then review evidence on the likely contribution of psychedelic drugs.

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Is ASMR an altered state of consciousness?

A few days ago, I was watching Would I Lie to You (WILTY), a BBC panel show in which contestants have to bluff about their deepest secrets…and the opposing team have to find out which ones are true. One of the best things on TV.  On this particular episode, a mystery guest Charlotte came onto the show, and each member of one team had to explain how they knew Charlotte.  Joe Lycett claimed that “In the evenings, I like to relax by watching videos of her wrapping gifts on YouTube. “

It turned out to be true. Afterwards, I looked up Charlotte on YouTube and found a video of her wrapping presents.

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