November 23, 2008
hallucinogen, human
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“At first there are violet and green spots which are not well defined, then come images of carpet patterns, ribbed vaulting, etc. From time to time single dots with the most brilliant colors float across the field of vision. The phenomena are generally not as clear as those in the two preceding experiments. Later on landscapes, halls, architectural scenes (e.g. pillars decorated with flowers) also appear…” –Arthur Heffter, November 23 1897 (quoted by Holmstedt and Liljestrand 1963 via heffter.org)
On this day in 1897, Arthur Heffter ingested 150 mg mescaline sulfate, proving its psychoactivity. In doing so, he became the first person ever to experience a trip from a purified hallucinogen.
Heffter, a prominent pharmacologist, carried out his heroic self-experimentation as part of a careful scientific study of the peyote cactus and its alkaloid components.
A short biographical sketch and quotes from the relevant pages of his lab notebook can be found at the Heffter Research Institute website.
August 4, 2008
consciousness, human
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Perceptual rivalry is one of the neatest ways to study the neural correlates of the contents of consciousness. If you’re not familiar with this phenomenon, you can read Olivia Carter’s online tutorial on binocular rivalry, one commonly studied type of perceptual rivalry. (There’s also some nice images in a Figure from Blake & Logothetis’ 2002 Nature Reviews Neuroscience article here).
Perceptual rivalry should fascinate anyone with an interest in consciousness research. It is also a rare area where scientific studies of consciousness and hallucinogens converge. Carter has done groundbreaking studies (links below) of how psilocybin and possibly LSD affect perceptual rivalry, including some research using the amazing phenomenon of motion-induced blindness (demo here), my favorite visual illusion. Carter’s research is consistently inspiring: She uses rigorous quantitative tools to measure the effects of pharmacological manipulations on consciousness. Her work is one reason I consider perceptual rivalry among the most interesting directions to pursue in future human hallucinogen research, even if (as Carter and Dittrich’s data suggest) hallucinogens do not affect rivalry through a 5-HT2A mechanism.
Two noteworthy developments in non-hallucinogenic rivalry research are a paper by Jakob Hohwy and colleagues giving an elegant theory for why rivalry occurs and a great paper by Joel Pearson and colleagues showing that mental imagery influences rivalry.
Read the rest…
