Synapses are the points of communication between neurons and they are subject to adaptations to the extent to which they are used, i.e., synaptic plasticity, which is key to enforce learning or rehabilitation. In this project, we will investigate synaptic plasticity with a novel radioligand 11C-UCB-J and positron emission tomography (PET). This enables neuroimaging of the presynaptic marker, synaptic vesicle glycoprotein 2A (SV2A).

We will examine synaptic plasticity in healthy people exposed to two different antidepressants, i.e., serotonin transporter inhibitors (SSRI) and the psychedelic drug psilocybin, both known to increase synaptic density in animals. Next, in a longitudinal setup in patients, we will follow the regeneration of synapses following stroke.

Specifically, we will investigate the following three research questions/aims:
Aim 1 - Is three weeks of intake of an SSRI associated with higher synaptic density?
Aim 2 - Can a single psychedelic dose of psilocybin increase synaptic density after one week?
Aim 3 - How does synaptic density in the brain change during initial rehabilitation following acute ischemic stroke, and is it related to clinical outcome?