Acetylcholine - A neurotransmitter found in the brain, spinal cord, neuromuscular junction and automatic nervous system.
Acetylcholinesterase - The enzyme responsible for the breakdown and inactivation of acetylcholine in the synaptic cleft.

Affective Disorder – Those conditions that affect mood including depressive and bipolar illness.

Alzheimer’s disease (AD) – A progressive dementia caused by destruction of the brain cells (neurones). As the disease advances it may cause changes in personality, disturbing behaviour, loss of physical coordination and increased dependence on a caregiver.

Amygdala - A region of the brain, apparently concerned with mood, feeling instinct and possibly memory for recent events. Dysfunctions of the amygdala are apparently linked to depression, anxiety and panic disorders.
Anhedonia - Anhedonia derived from the Greek: an, meaning not, and hedone, meaning pleasure. So, taken literally anhedonia means the inability to experience pleasure but in psychiatry it means the loss of pleasure in an activity that has previously been enjoyable.

Anti-depressants – Drug treatment for depression (the two main kinds are the tricyclic antidepressants (TCAs) and the selective serotonin reuptake inhibitors (the SSRIs)).

Anti-psychotic drugs – (sometimes called neuroleptics or minor tranquillisers) - Used to alleviate the symptoms of psychosis. In the 1990’s came the launch of atypical antipsychotic drugs. They tend to act on different chemical messengers and are less likely to cause side effects.

Aricept (or donepezil hydrochloride), The first drug licensed in the UK specifically to treat the symptoms of Alzheimer's.

Atrophy - Atrophy occurs when normal tissue or an organ wastes because the cells die. Under nourishment, disease, injury, lack of use or ageing may cause atrophy.

Bilateral dorsolateral prefrontal - Area in the frontal lobe which is of particular interest in schizophrenia.

Bipolar Disorder (Manic Depression) – A form of depression characterised by alternating mood swings - from a very low mood (depression) to a high mood (mania). In between the two mood states people will feel the same as anyone else.

Brain - The brain consists of many parts that are all interconnected and work together. The major parts are the medulla, pons and midbrain (brain stem); cerebellum; hypothalamus; thalamus and cerebrum.

Central Nervous System (CNS) - The CNS consists of the brain and spinal cord, which control the main bodily functions.

Cerebellum - Area of the brain above the pons and medulla that is important for balance and posture. Damage to this area leads to movement or motor difficulties.

Cerebrospinal fluid (CSF) – A clear, colourless tissue fluid that covers the entire surface of the CNS. It has several functions including protection, buoyancy, excretion of waste products and the transportation of hormones to other parts of the brain.

Cognitive enhancers: (acetylcholinesterase inhibitors) - These drugs are intended to increase the effectiveness of the brain damaged by Alzheimer's disease, rather than to halt the degeneration of the brain that characterises the disease. They increase the supply of one of the brain's messenger chemicals, acetylcholine, which is a brain chemical is involved in memory.

Cognition - High level functions carried out by the human brain, including perception, use of speech, memory, concentration, attention (information processing) thinking, executive functions such as planning, problem solving and self-monitoring.

Cognitive impairment (dysfunction) - Changes in cognitive function (memory, concentration, perception etc) caused by trauma or disease. Alzheimer’s disease and schizophrenia are perhaps the most well known conditions where cognition is impaired and the effect on a person is clear to see.

Dementia - Dementia is a gradual decline in mental abilities such as memory, thinking, concentrating and problem-solving. The most common cause of dementia is Alzheimer’s disease, but rarer forms include, Picks disease, Parkinsonism and Lewy body disease.

Depression – A long term lowering of mood and function. Depression is associated with anxiety and panic disorders in many cases

Dopamine - Dopamine is a neurotransmitter in the central nervous system. A deficiency of this chemical is related to Parkinson's Disease, paranoia, memory and concentration problems.

Dorsolateral Prefrontol Cortex - The outer layer of the brain is called the cortex. Increasingly, working memory, a critical function that goes awry in schizophrenia, is being linked to this brain region.

Electroencephalogram (EEG) – A medical device for monitoring the electrical activity of the brain.

Epilepsy - A neurological condition where a brief disruption in the brains chemical messages causes a seizure (fit).

Exelon (rivastigmine) - Available in the UK as a treatment for the symptoms of Alzheimer’s disease.

Extrapyramidal -

Grey matter – A part of the central nervous system (CNS), grey in colour because of the grey nuclei in the cells that make it up. It is the coordination point between the nerves of the CNS.

Hippocampus - Part of the brain responsible for spatial mapping and memory. Probably also involved in mediating personality and anxiety. Important in the study of schizophrenia

Magnetic Resonance Imaging (MRI) - A type of brain scan that creates a picture of the brain using a computer and radio signals. The signals are produced by the body in response to the effects of a very strong magnet contained within the scanner.

Mini-Mental Status Examination - A simple cognitive test that can be used to screen for memory problems. It is short, takes only a few minutes to perform and is commonly used by GPs and geriatricians.

“Negative” symptoms - A group of symptoms in schizophrenia. Negative symptoms are long-lasting - sleep problems, loss of energy and motivation, difficulty in maintaining friendships.

Neurodegeneration - Deterioration of nerve cells in the brain occurring over time. For example, Alzheimer’s disease is a neurodegnerative disease.

Neuropsychology - The study of brain/behaviour relationships and influences on the brain. Neuropsychologist uses objective techniques (tests) to link behaviours to their underlying biological (brain) processes. The aim is to find out whether or not a behavioural abnormality is caused by a biological abnormality in the brain, or an emotional or learned response.

Neuron - A nerve cell vital in the transmission of nerve impulses. Each cell has an enlarged part (the cell body) from which extends the long, thin axon for carrying impulses away. Atached to this structure are dendrites (shorter and more numerous) that receive impulses.

Neurology - The study of the brain, spinal chord and peripheral nerves, their disease and the treatment of those conditions.

Neuropsychology tests - Used to provide a review of a person's mental status, diagnose mental disorders and monitor the effects of treatment.

Neurotransmitter - Any chemical that transmits information from one neuron (brain cell) to another neuron across a very small extracellular space called a synapse. (Neuro refers to the brain cells and transmitter, to sending and receiving information.)

Placebo - A technique or drug that may help to relieve a condition but has no medical or physical benefit. Placebos are often used in trials of new drugs to distinguish between the medical and psychological affects of taking a medication.

“Positive” symptoms - These are abnormal experiences – hallucinations and delusions.

Prepulse Inhibition (PPI) – Inhibition of the startle response to a stimulus (loud noise) caused by the presence of a prepulse (a weaker noise).

Prodromal – Derived from the Greek word prodromos meaning the forerunner of an event. In medicine it refers to the early signs of a illness that precede a fully developed illness.

Psychiatry - A field of medicine concerned with physical and chemical interactions in the brain and how they affect mental and emotional processes.

Psychologist – Specialist in the study of behaviour, not medically qualified.

Psychosis - Mental illness in which people lose touch with reality and may experience hallucinations and delusions. Schizophrenia and bipolar disorder are two important psychoses.

Psychiatrist - A medical doctor who deals with mental disorders including emotional and behavioural problems.

Psychotherapy - A ‘talking therapy’. There are several approaches in this method of treatment of mental health, including psychoanalysis, group therapy and behavioural therapy.

Randomised Controlled Trial (RCT) - An RCT is the accepted way to judge the efficacy of a drug. A drug is allocated randomly to half the trial volunteers, while the other half receive a different treatment or a placebo. By comparing the responses of the two groups, researchers can see just how much difference the treatment under trial makes. Many RCTs are also 'double-blinded’ meaning that neither volunteer nor researcher knows who is getting the real treatment.

Saccadic Eye Movement – A rapid eye movement that directs our gaze to an object. Saccades are followed by a fixed gaze when we take in visual information.

Schizophrenia – A severe mental disorder for which most patients need long-term drug therapy. Symptoms include hallucinations, delusions, apathy and impaired social functioning.

Startle response – Defensive response to a strong sensory stimulus, such as a loud noise.

Substantia nigra - The substantia nigra has been described as the 'gear box' of the brain. When this is not working properly it leads to a movement disorder.

Thalamus - One of a pair of masses of grey matter located in each side of the forebrain. Each is a centre for coordinating and relaying the sensory information concerned with all the senses, (temperature, pain, touch etc.) apart from that of smell.

Ventricles - 4 cavities within the brain, each contains a capillary network that forms cerebrospino fluid from blood plasma.

Voxel – A graphical unit of information in a cross section image that represents a volume of tissue.

White matter – nerve tissue in the central nervous system composed of nerve fibres sheathed in a white fatty insulating protein called myelin. In the brain it occupies the central part of the cerebral cortex.