How are different dopamine receptors related to episodic memory in humans? Protocol for a Systematic Review

Here we present a protocol for a systematic review of studies investigating the role of dopamine receptors in episodic memory in humans. We will search for studies assessing how episodic memory tests are affected by pharmacological interventions targeted at specific subsets of dopamine receptors, or whether memory performance is associated with dopamine receptor density/occupancy (though molecular imaging methods) or genetic variations of dopamine receptor genes. Searches will be conducted on PubMed, Web of Science, Scopus, and EMBASE. Study selection will follow predefined eligibility criteria and will be performed by two independent investigators. Methodological quality will be assessed using JBI critical appraisal tools as appropriate (specific JBI tools will be selected based on the studies’ design). We plan to perform a narrative synthesis, organizing studies according to their approach (pharmacological studies, molecular imaging, or genetic studies), the receptor targeted (which depends on the drug administered, radioligand employed, or gene variant assessed), the brain region of interest (if applicable), and the memory test used, and then look for patterns, trying to identify more robust findings at the intersection of these different sources of evidence.