The reaction of an animal’s salivary glands to a stimulus (measured in drops of saliva). Normally, the stimulus is the presence of food in the mouth.

A state of loss of motivation as a result of completing a session of a particular behaviour. For example, after food deprivation an animal might be given food and then achieve a state of satiety as a result of free ingestion.

The nature of the relationship between an animal’s behaviour and the reinforcing agent that is contingent upon it. This might be continuous reinforcement or partial reinforcement.

Regular structure within a polypeptide chain. There are two main types: the α-helix and the β-sheet.

A family of enzymes involved in the processing/proteolysis of APP.

A term that refers to the capacity of an individual to set goals and to meet them. A capacity to obtain satisfaction in realising ambitions.

Memory that includes general knowledge of the world acquired through education and experience, including the use of language.

Extracellular structures composed of complex and incompletely characterised molecular and cellular constituents. Amyloid β peptide, produced by proteolytic cleavage of APP, and ApoE are the major components of the plaques.

Neurons that convey information to the central nervous system.

An adjective describing a neuron that synthesises, stores and releases serotonin or a synapse at which serotonin is the neurotransmitter.