Bridging the translational neuroscience gap: Development of the ‘shiftability’ paradigm and an exemplar protocol to capture psilocybin-elicited ‘shift’ in neurobiological mechanisms in autism

Clinical trials for drugs targeting core autism features have failed, despite evidence linking various neurochemical systems to brain function in autism. The field has relied on association studies, but the only way to directly establish a neurotransmitter's role in a brain function is to experimentally change it and observe a shift. There is little direct experimental evidence on how neurochemical systems modulate information processing in the living human brain, limiting translation from animal studies. The authors introduce a "shiftability" paradigm to bridge this gap, using psilocybin as a pharmacological probe of the serotonin system in vivo. They present the protocol for 'PSILAUT', a study testing whether the serotonin system functions differently in autistic and non-autistic adults.

Study at a glance

Abstract

Abstract Clinical trials of pharmacological approaches targeting the core features of autism have failed. This is despite evidence from preclinical studies, genetics, post-mortem studies and correlational analyses linking peripheral and central markers of multiple candidate neurochemical systems to brain function in autism. Whilst this has in part been explained by the heterogeneity of the autistic population, the field has largely relied upon association studies to link brain chemistry to function. The only way to directly establish that a neurotransmitter or neuromodulator is involved in a candidate brain function is to change it and observe a shift in that function. This experimental approach dominates preclinical neuroscience, but not human studies. There is very little direct experimental evidence describing how neurochemical systems modulate information processing in the living human brain. As a result, our understanding of how neurochemical differences contribute to neurodiversity is limited and impedes our ability to translate findings from animal studies into humans. Here, we begin by introducing our “shiftability” paradigm, an approach to bridge the translational gap in autism research. We then provide an overview of the methodologies used and explain our most recent choice of psilocybin as a pharmacological probe of the serotonin system in vivo . Finally, we provide a summary of the protocol for ‘PSILAUT’, an exemplar “shiftability” study which uses psilocybin to directly test the hypothesis that the serotonin system functions differently in autistic and non-autistic adults.