* Katrin H. Preller et al., “The Fabric of Meaning and Subjective Effects in LSD-Induced States Depend on Serotonin 2A Receptor Activation,” Current Biology 27, no. 3 (2017): 451–57. The work was done in Franz Vollenweider’s lab. When the serotonin 5-HT2A receptors were blocked with a drug (ketanserin), “the LSD-induced attribution of personal relevance to previously meaningless stimuli” was also blocked, leading the authors to conclude that these receptors play a role in the generation and attribution of personal meaning.