From founding the Amsterdam Psychedelic Research Association (APRA) in 2017 to leading the first-ever neuroimaging study with a classic psychedelic in Amsterdam, this paper represents the closing of a circle and truly means a lot to me. I hope you find it interesting :)

Indeed, we speculate that the butterfly-effect cascading from such a relatively simple, but profound and pervasive computational change, may explain the broad variety and apparent paradoxicality of psychedelic effects.

Now, imagine what could happen to your subjective experience if a fundamental computation for contextual information-processing was altered throughout many, recurrently interacting levels of the brain's functional hierarchy, from visual, to temporal, to semantic processing...

Enter the divisive normalization population receptive field model. The parameter governing surround suppression systematically dropped with psilocybin! This could not be explained by noise or HRF changes alone, which are also included in the model. 🤖

To find out, we scanned participants with 7T fMRI while showing sweeping high-contrast bars. Key result: psilocybin systematically reduced surround suppression, a key mechanism to optimize contextual neural computations, in early visual areas! 🧠

First, we looked at visual perception using the Ebbinghaus illusion, a classic example of how context shapes what we perceive. The contextual surround illusion got systematically stronger! It's not just a figure of speech: we literally see the world differently with psilocybin👁️

Our new paper is out in Nature Communications! nature.com/articles/s41...

We combined psychophysics, 7T fMRI, and computational modeling of vision with placebo, 5mg, and 10mg psilocybin, in the same group of participants, to clarify the computational mechanisms of psychedelics. 🧵

Hello! Psilocybin study results are out as a preprint :)
www.biorxiv.org/content/10.1...