Psychedelic Research

My pace of posting has slowed as I am deep in dissertation writing.  So I have been remiss in failing to celebrate several good new articles, including a study of MDMA-cannabis interactions from Dumont and colleagues and an exciting article that considers one of my favorite topics: hallucinogens from a Bayesian perspective.  However, my primary motivation for this entry is to note the death of psychedelic researcher Abraham Hoffer.
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The philosophically inclined may be interested to know that Jerry Fodor has published a review of Andy Clark’s Supersizing the Mind: Embodiment, Action and Cognitive Extension in the London Review of Books. A response to Fodor’s article can be found on David Chalmers’ blog. Chalmers also makes available a pdf of the introduction he wrote to Clark’s book.

Many users of cannabis believe that some strains are more likely to make people feel anxious than others. Why is this? A new fMRI study shows different effects of THC and another psychoactive component in cannabis that may partly explain this.
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Richard Yensen, author of “Hacia una medicina psiquedélica”, earned his PhD studying the effects of MDA-assisted psychotherapy in neurotic people at Maryland Psychiatric Research Center (MPRC) in the 1970s. Below he remembers MPRC’s director, psychedelic researcher Albert Kurland.
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Giuseppe Pagnoni and colleagues have published an fMRI study looking at neural activity during Zen meditation. They compared experienced Zen practitioners (versus meditation-naive controls) when their meditation was intermittently interrupted by a task (in which participants had to distinguish words from nonwords). The paper particularly focuses on what happens after the interrupting task is done and people (theoretically at least) returned to their meditation. The researchers subtracted the neural response to words and nonwords to isolate brain regions that were specifically associated with semantic processing and they found their participant groups differed in the time course of this difference. As you might expect, the experienced Zen practitioners “displayed a reduced duration of the neural response linked to conceptual processing in regions of the default network, suggesting that meditative training may foster the ability to control the automatic cascade of semantic associations triggered by a stimulus and, by extension, to voluntarily regulate the flow of spontaneous mentation.” [The default network is an empirically defined set of brain areas that tend are more active ('by default') before one starts on a task and then decrease activity when one focuses on something.]
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Today is the birthday of Richard Spruce (September 10, 1817 – December 28, 1893), the pioneering botanist who explored the Amazon and Andes in the mid 1800s, collecting tens of thousands of botanical specimens and recording the vocabularies of over twenty cultures previously unknown to western civilization. Among many other accomplishments, Spruce identified for western culture the botanical make-up of ayahuasca. His wikipedia entry is here.
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Cognitive neuroscience has learned a lot by having participants perform tasks. By engaging specific brain networks with a well-chosen task, we can make the relevant networks stand out against the background activity of the brain. In recent years, some smart scientists have begun to focus on the background activity itself. They’ve shown that low-frequency (i.e., <0.1 Hz) fluctuations in the fMRI signal have coherent patterns. These coherent patterns appear to pick out different networks in the brain and scientists have begun to use resting-state fMRI to study how different diseases affect brain networks.
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These only appear off-topic at first — if they ain’t the real topic, I don’t know what is.
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