American Psychological Association.

General medical term used to describe a disturbance of speech caused by damage to the brain; strictly, an absence of speech.

The purified protein component of a lipoprotein particle. In mammals, a group of eight apolipoproteins will most often be present in a set ratio. This complex molecule serves a wide variety of functions in the blood, including transport of fat from tissue to tissue.

Amyloid precursor protein.

Something unnatural that arises as a result of an experimental intervention. For example, a structure that is seen when a cell preparation is examined under the microscope may appear to be a natural cell component, but may actually be the result of an alteration in the cell’s structure caused by the procedures used to prepare the specimen for microscopy.

Derived from a history of associations, as in Pavlovian conditioning.

The process by which an organism forms an association between two events. The term covers both classical and instrumental conditioning. In either case, one event owes its strength to its pairing with some other event.

Learning by experience to associate two events that have been paired (e.g. the sight of a needle with the effect of heroin).

The smallest particle of an element, consisting of a core of protons and neutrons (the nucleus) surrounded by electrons.

Adenosine triphosphate. Each molecule of ATP is made up of a nucleotide base, a sugar unit and a chain of three phosphate groups.  ATP is the energy currency of the cell.  Energy is stored as ATP in the reaction between ADP (adenosine diphosphate) and P_i (inorganic phosphate):

ADP + P_i ATP

and is made available as required via the breakdown of ATP to ADP and P_i.