Agonist
A molecule that interacts with and activates a receptor.
Amphetamine
A synthetic drug that has a stimulant effect. Used to treat attention deficit and hyperactivity as well as and narcolepsy.
Analgesia
Relief of pain or state of being insensitive to pain.
Antagonist
A molecule that interacts with and deactivates or inhibits a receptor.
Blinding
Concealing group assignment or some other feature of treatment (i.e., whether patients are randomized to a placebo or active treatment) that might influence the outcomes from the participants.
Carfentanil
A strong synthetic opioid. In PET studies, radioactively tagged carfentanil ([11C]-carfentanil) can be used to track mu-opioid receptor activity in the brain.
Conditioning
Training, consciously or unconsciously, a person or animal to associate a certain stimulus with a certain response.
Connectivity
Connectivity in neuroimaging refers to temporal correlations between two structures that suggest that these structures directionally or bidirectionally influence each other.
Dopamine
A neurotransmitter that is associated with signaling in reward, motivation, and motor pathways. Dopamine pathway dysfunction is implicated in multiple diseases and illnesses, including substance misuse or addiction, schizophrenia, attention deficit and hyperactivity, Parkinson’s disease, and others.
Double-blind
In a clinical trial, concealing the group assignment or some other feature of treatment (i.e., whether patients are randomized to a placebo or active treatment) that might influence the outcomes from both participants and experimenters.
Endogenous opioids
Opioid peptides that naturally occur in the brain and interact with opioid receptors to relieve pain and signal reward.
Functional magnetic resonance imaging (fMRI)
An imaging technique that utilizes the magnetic properties of hemoglobin to generate images of the brain based on blood flow. An fMRI can be used to create contrasts that show differences in brain activity at different times.
Hawthorne effects
Effects that occur simply because a subject is being observed in a study.
Hyperalgesia
Increase of pain or state of being hypersensitive to pain.
Meta-analysis
An analysis of results from multiple studies.
Naloxone
An opioid antagonist that is commonly used to block the effects of opioids during an overdose.
Natural history
The natural course of a disease or illness in an individual, starting from onset, peaking, and then resolving.
Nocebo effects
Negative or adverse events or effects that occur in response to an inert or placebo treatment.
Nociceptive pain
Short-term pain that originates from the activation of nociceptors with damage of tissue.
Nociceptor
A sensory receptor that responds to painful stimuli.
No treatment control
A control group in which the participants receive no treatment at all to serve as a neutral comparison to other treatments.
Open-label placebo (OLP)
Placebos that are administered openly or without deception.
Perkins’s tractors
Small metal rods patented by Elisha Perkins as a “cure-all.”
Pharmacogenomics
The study of how genome variation is associated with an individual drug treatment response with the aim of improving the development of safer and more efficacious drugs. Pharmacogenomics is a key field of study in the pursuit of personalized or precision medicine.
Placebo effects
Events or effects that occur in response to an inert or placebo treatment.
Placebome
The group of genome-related or genome-derived molecules that are hypothesized to affect an individual’s placebo response. Some of these molecules may include genes, proteins, and microRNAs, among others.
Positron emission tomography (PET)
An imaging technique that utilizes the properties of radioactive particles to create images of the human body. A PET scan be used to differentiate between tissue types, and in neuroscience, it can be used to observe cerebral blood flow or receptor activity.
Prediction error
The mismatch between what was expected and what actually happens. The prediction error is encoded by dopamine signaling and is instrumental to learning. The prediction error is instrumental to learning and, in reward processing, is encoded by dopamine.
Randomized placebo-controlled clinical trial
A clinical trial in which the participants are randomly assigned to active or inert treatment arms in order to test the effectiveness of the active intervention. In a double-blind randomized placebo-controlled clinical trial, the participants are not aware of which treatment arm they have been assigned in order to reduce bias in the reporting outcomes.
Remifentanil
A short-acting synthetic opioid used to relieve pain.
Side effect
An effect, whether positive or negative, that is not the primary intended outcome of a treatment.
Single nucleotide polymorphisms (SNPs)
A site in the genome at which a single nucleotide differs in the DNA nucleotide sequence, causing genetic variability.
Social observational learning
Learning, either conscious or subconscious, that occurs when the observation of behavior of a demonstrator modifies the behavior of the observer.
Statin
A drug used to lower cholesterol levels in the body.