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Psychedelics and the “Default Mode Network”

April 28, 2013

MAPS logoOne of the more interesting aspects of the MAPS (Multi-disciplinary Association for Psychedelic Studies) conference held in Oakland over 19-21 April was attending sessions led by hard-core neuroscientists presenting their work about the effects of psychedelics on brain functioning.

This work by neuroscientists is part of the renaissance of clinical studies on psychedelics, which has undergone a long hiatus for three decades following the classifying of LSD and other psychedelics as illegal in the sixties. Rick Doblin, founder and executive director of MAPS, said in his opening address that: “there is now more psychedelic research than at any other time in last 40 years.”

Sophisticated techniques of mapping brain functioning through Functional Magnetic Resonance Imagery (fMRI) – which measures brain activity by detecting associated changes in blood flow – and the use of Magnetoencephalogy (MEG) – which measures brain oscillations – allow detailed observations of what happens in the brain as a result of taking psychedelics. What particularly seems to be exciting the researchers in this field is the effect of psychedelics on what is called the ‘default mode network’ (DMN) in the brain.

Wandering_and_wondering_Raichle first used this term in 2001 to describe the nature of brain activity when it is not engaged in any specific, externally focused task. It appears to be a densely connected network linking together different parts of the brain, which is activated during autobiographical memory, future planning, mind-wandering, thinking about thinking, day-dreaming, or in general, any self-referential mental activity.

Robin Carhart-Harris, a researcher working at Imperial College London, referred to the DMN as an important integration center and common convergence zone that gives coherence to cognition. He likened it metaphorically to the “capital city of a country”.

What is especially significant is that a number of separate studies of different psychedelics – MMDA, ayahuasca and psilocybin – conducted by researchers in different countries, all show that a common effect of these different psychedelics on the brain is to reduce DMN activity. This is also found with experienced meditators,

Furthermore, these studies have shown that, through the use of psychedelics, sensory and emotional impulses, which are normally repressed, are able to reach consciousness. Difficult memories are more easily and less painfully accessed. This has important implications for the treatment of post-traumatic stress disorder, which is now being explored in clinical studies with control groups, in which MMDA is given to patients simultaneously with psychotherapeutic treatment.

In contrast, people who are depressed show an increase in DMN activity. This is likely to be precisely because what characterizes depression is a sense of constant rumination and negative self-referential mental activity – in neurological terms being stuck in the DMN. This is now suggesting the possibility of the use of psychedelics in the treatment of depression.

Sigmund-FreudThere is still not yet consensus within the neuroscientific community over what exactly the function of the DMN network is. Raichle, the discoverer of the DMN, has referred to it as “the orchestrator of the self”.

Robin Carhart-Harris puts forward the hypothesis that the DMN is the neurological basis of the ego and sees it as helping recuperate Freud and give his ideas a foundation in neuroscience – which is what Freud always wanted.

I find these studies interesting for two reasons:

1.  They seem to suggest empirically what Terence McKenna said, and what myself and many others experience, that psychedelics “dissolve the boundaries of the ego.”

2. These studies generally exist within the traditional scientific paradigm in which consciousness is reduced to and located within brain functioning. In his talk, Robin Carhart-Harris said explicitly that: “science has found no evidence to suggest consciousness exists outside the brain”.

Interestingly, the same day, I went to an evening talk by Stan Grof who said exactly the opposite that: “there is no proof that consciousness is generated in the brain.” Grof compared the brain to a TV set and said the fact we can watch programs does not therefore imply that the programs are generated inside the TV set. Besides, consciousness does things that the brain is not capable of.

The clinical studies presented at MAPS, as can be seen here, imagine the ego within the theoretical perspective of neuroscientific science. In the next post, I want to look at the ego from a more personal perspective offered by Madre Ayahuasca.


This stark opposition of views about the nature of consciousness is also reflected in a very recent controversy where Graham Hancock’s and Rupert Sheldrake’s TED talks were taken down from the main TED Youtube channel and moved to their blog.

On his Facebook page, Graham Hancock wrote:

“The controversy has brought to light a fundamental fault-line that is emerging in the science of consciousness between the OLD PARADIGM of materialist reductionism (represented by people like Richard Dawkins, Daniel Dennett and others) and a NEW PARADIGM of non-local conscious. The new paradigm, represented by all the major scientific figures who wrote to the Huffington post on 19 April is open to the revolutionary possibility at the center of both my talk and Rupert’s talk, namely that consciousness may not be generated by the brain but rather “transceived” by the brain (I address this specifically in my talk between 10:18 and 10:42) — i.e. that consciousness may be a fundamental “non-local” property of all dimensions of the universe and that rather than being an”epiphenomenon of brain activity” it may instead be that the brain acts as an interface that allows consciousness to manifest “locally” on the material plane.”

  1. Peggy Langdon permalink

    I would assume (?) all thing in moderation applies to these hypothesis also. I had a dear artist friend who in the 60’s painted some of the most published psychedelic posters in the SF area. He also took some of the most LSD at that time. His brain was completely frazzled and burned but of course he added alcohol to the mix later in life. He became a complete hermit living in AZ where I met him. He would go wacko ever so often and contributed all these difficulties to his use of drugs. He finally died of a stroke alone..very sad..

    • Chris permalink

      @ peggy, how is this even remotely relevant……

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