Psychology terms in Biological approach

A neurotransmitter that makes muscles contract and, in the brain, supports attention, learning and the encoding of new memories in the hippocampus.

A brief electrical impulse that travels along the axon when the charge inside a neuron reaches a threshold; it is all-or-none, so the neuron either fires fully or not at all.

A research design that compares adopted people with their biological relatives, who share their genes, and their adoptive relatives, who share their environment, to separate genetic from environmental influences.

An endocrine gland on top of each kidney that releases adrenaline and noradrenaline (from its centre) and cortisol (from its outer layer) in response to stress.

A hormone released by the adrenal glands in response to a threat, which raises heart rate, blood pressure and energy supply as part of the fight-or-flight response.

A substance that increases the effect of a neurotransmitter, by binding to and activating its receptors or by increasing the amount available in the synaptic gap.

One of the different versions of a gene; a person inherits one allele of each gene from each parent.

A small almond-shaped structure inside each temporal lobe that detects threat and triggers fear, and helps to form emotional memories.

A non-human species, or a condition produced in it, that is used to stand in for a human behaviour or disorder so that its causes and treatments can be studied under controlled conditions.

Research that uses non-human animals as participants, either to understand their own behaviour or, more often, to draw conclusions about human behaviour and biology.

A substance that reduces the effect of a neurotransmitter, usually by binding to its receptors without activating them, which blocks the neurotransmitter.

The tendency to describe animals' behaviour in terms of human thoughts, feelings or motives, such as calling a floating rat 'despairing'.

A loss or impairment of the ability to produce or understand language, caused by brain damage, usually to the left hemisphere.

An error in brain imaging data that comes from something other than the brain process being studied, such as head movement, breathing or the scanner itself.

The part of the nervous system that controls involuntary body functions; its sympathetic branch prepares the body for action and its parasympathetic branch returns it to a resting state.

The long fibre of a neuron that carries the action potential away from the cell body towards the axon terminals.

A perspective in psychology that explains behaviour and mental processes through physiological factors such as the brain, neurotransmitters, hormones and genes, and through their evolution.

Explaining a complex behaviour or mental process by breaking it down into its simplest biological parts, such as genes, neurotransmitters or brain areas.

A model proposed by Engel (1977) that explains health and illness through the interaction of biological, psychological and social factors rather than through biology alone.

The blood-oxygen-level-dependent signal measured by fMRI: a change in the magnetic properties of blood as oxygen-rich blood flows to more active brain areas.

A set of techniques that produce pictures of the living brain's structure or activity without surgery, such as MRI, fMRI, PET and EEG.

A region of the left inferior frontal lobe, named after Paul Broca, involved in producing speech and processing grammar; damage to it is linked to slow, effortful speech.

A research design that tests whether one gene, chosen in advance because of its biological role, is associated with a trait or disorder; many such findings have failed to replicate.

The thin, folded outer layer of grey matter covering the two cerebral hemispheres, responsible for perception, language, memory, thinking and voluntary movement.

One of the two halves of the cerebrum, left and right, joined by the corpus callosum; each mainly controls and receives sensation from the opposite side of the body.

A substance released by one cell that carries a signal to other cells by binding to their receptors; the main types are neurotransmitters and hormones.

A structural imaging technique that combines many X-ray images taken from different angles into cross-sectional pictures of the brain.

The percentage of pairs of twins or relatives in which both members show a trait or disorder, given that one of them has it.

A rehabilitation treatment after stroke in which the unaffected arm is restrained so that the patient must practise intensively with the weakened arm, encouraging functional reorganisation.

The arrangement in which each cerebral hemisphere controls movement of, and receives sensation from, the opposite side of the body.

A thick band of nerve fibres that joins the left and right cerebral hemispheres and allows them to share information.

A hormone released by the adrenal glands in response to stress that raises blood sugar, suppresses non-essential functions such as immune responses, and affects memory.

A short, branching extension of a neuron that receives signals from other neurons and carries them towards the cell body.

The growth of new branches on a neuron’s dendrites in response to experience, which allows the neuron to form more synapses with other neurons.

A predisposition or vulnerability to a disorder, which may be genetic, biological, cognitive or psychosocial, and which increases the risk of the disorder without causing it on its own.

A model proposing that a disorder or behaviour develops when an underlying vulnerability (the diathesis) interacts with environmental stress, so that neither alone is sufficient to produce it.

The hypothesis that individuals differ in how strongly they are affected by their environment, so that the most susceptible people do worst in adverse environments and best in supportive ones.

Twins who develop from two eggs fertilised by two different sperm, so, like ordinary siblings, they share on average about 50% of the genes that vary between people.

An epigenetic process in which methyl groups attach to DNA, usually reducing the expression of a gene without changing its sequence.

A neurotransmitter involved in movement, motivation and reward, which signals that an outcome is valuable and strengthens the behaviour that led to it.

A technique that records the brain's electrical activity through electrodes on the scalp, showing changes in activity millisecond by millisecond.

A characteristic of a whole system that comes from the interaction of its parts and cannot be found in, or predicted from, any part on its own.

The network of glands, including the pituitary and adrenal glands and the testes and ovaries, that secrete hormones into the bloodstream to regulate the body and behaviour.

An environment that offers more sensory, physical, social and cognitive stimulation than a standard one; in animal research it is compared with an impoverished environment to study plasticity.

The study of changes in gene expression that do not involve changes to the DNA sequence itself, including changes caused by the environment and experience.

The assumption in twin research that monozygotic and dizygotic twins experience equally similar environments, so that greater similarity in monozygotic twins can be attributed to genes.

Lashley’s proposal that intact areas of the cortex can take over the functions of damaged areas, so that the amount of damage matters more than its location.

A pattern of EEG activity linked in time to a specific stimulus or event, found by averaging the recordings from many repeated trials.

Describes an effect of a neurotransmitter that makes the postsynaptic neuron more likely to fire an action potential.

Brain change that depends on experiences specific to an individual, such as learning a language, a skill or a route, and that can happen at any age.

Brain change that depends on experiences almost every member of a species meets at a predictable age, such as patterned light or speech, which the brain needs to wire its basic systems.

Applying findings from one group or species to another that was not studied, such as using results from rats to draw conclusions about humans.

The extent to which a measure or model appears to show what it claims to, for example how closely an animal's behaviour resembles the human symptom it stands for.

The lobe at the front of each cerebral hemisphere, involved in voluntary movement, speech production, planning, decision-making and self-control.

A functional brain imaging technique that tracks changes in blood oxygenation (the BOLD signal) to show which brain areas are more active during a task.

A form of neuroplasticity in which undamaged brain areas take over functions that were carried out by a damaged area, as in recovery after a stroke.

Gamma-aminobutyric acid: the main inhibitory neurotransmitter in the brain, which makes neurons less likely to fire and is the target of alcohol and anti-anxiety drugs such as benzodiazepines.

A section of DNA on a chromosome that carries the code for making a protein, and that is passed from parents to their children.

A situation in which the effect of an environmental factor on a behaviour or disorder depends on a person’s genotype, or the effect of a genotype depends on the environment.

The tendency for people’s genes and environments to be related, because parents pass on both, because traits evoke reactions, and because people choose environments that suit them.

The transmission of traits from parents to their children through the genes they pass on.

A research method that scans hundreds of thousands of genetic variants across the genome in very large samples to find variants statistically associated with a trait or disorder.

The particular set of alleles that a person carries, either for one gene or across their whole genome.

The main excitatory neurotransmitter in the brain, involved in almost all fast signalling between neurons and in strengthening synapses during learning and memory.

Brain tissue made up mainly of neuron cell bodies, dendrites and synapses, which forms the cerebral cortex; its volume is measured in structural brain scans.

The proportion of the variation in a trait within a population that is associated with genetic differences between its members; it does not apply to individuals and changes with the environment.

A curved structure inside each medial temporal lobe that is essential for forming new declarative memories and for spatial memory.

A chemical messenger secreted by an endocrine gland into the bloodstream, which carries it to target cells throughout the body that have receptors for it.

A small structure at the base of the brain that regulates hunger, thirst, body temperature and sleep, and controls hormone release through the pituitary gland.

Describes an effect of a neurotransmitter that makes the postsynaptic neuron less likely to fire an action potential.

The hypothesis that a first episode of depression usually follows a major stressor, but later episodes are triggered by less and less stress as vulnerability increases.

The specialisation of the two cerebral hemispheres for different functions, such as language being processed mainly in the left hemisphere in most people.

A state of passivity in which an animal or person stops trying to escape or avoid harm after repeated exposure to unpleasant events it could not control.

An area of damaged or destroyed brain tissue, caused by injury, disease or surgery; studying the effects of lesions is a main method of linking brain areas to functions.

The theory that specific areas of the brain are responsible for specific psychological functions, so that damage to one area produces a predictable loss of that function.

A long-lasting strengthening of a synapse that follows repeated stimulation, so that the receiving neuron responds more strongly; it is a leading cellular explanation of learning and memory.

A structural brain imaging technique that uses a strong magnetic field and radio waves to produce detailed images of brain anatomy without radiation.

A functional imaging technique that records the tiny magnetic fields produced by the brain's electrical activity, with millisecond timing and better localisation than EEG.

The gap between the heritability of a trait estimated from twin studies and the much smaller share of variation explained by genetic variants found in genome-wide association studies.

Twins who develop from a single fertilised egg that splits in two, so they share almost 100% of their genes; also called identical twins.

A fatty insulating layer, formed by glial cells, that wraps axons in segments and greatly speeds the conduction of action potentials.

The debate about the relative contribution of inherited factors (nature) and environmental factors (nurture) to behaviour, now usually replaced by the study of how the two interact.

A control process in which a rise in a hormone’s level acts back on the hypothalamus and pituitary gland to reduce further release, keeping the level stable.

The formation of new neurons; in adult mammals it occurs in only a few regions, such as part of the hippocampus, and how much it happens in adult humans is debated.

A nerve cell that carries information through the nervous system, electrically along its own length and chemically to other cells.

The ability of the brain to change its structure and function in response to experience, learning or injury, throughout life.

The process by which a neuron passes a signal to another cell: an action potential causes release of a neurotransmitter that crosses the synaptic gap and binds to receptors.

A chemical messenger released by a neuron into the synaptic gap that binds to receptors on a neighbouring cell and makes it more or less likely to fire.

A chemical messenger that acts as a neurotransmitter in the brain and as a hormone released by the adrenal glands, increasing arousal, alertness and the body’s readiness for action.

The lobe at the back of each cerebral hemisphere, which contains the visual cortex and processes information from the eyes.

A hormone and brain chemical messenger, released by the pituitary gland and by neurons in the brain, involved in childbirth, breastfeeding and social behaviours such as bonding and trust.

The lobe at the top and back of each cerebral hemisphere, involved in processing touch, body position and spatial information.

The observable or measurable characteristics of a person, such as height or anxiety level, which result from the interaction of their genotype and environment.

A discredited 19th-century theory that personality traits are located in specific brain areas whose size can be read from bumps on the skull.

A small endocrine gland below the hypothalamus that releases hormones controlling most other glands, and releases oxytocin and vasopressin into the blood.

A single number that adds up the effects of many genetic variants a person carries, each weighted by its association with a trait in a genome-wide association study, to estimate genetic tendency towards that trait.

A functional brain imaging technique that detects a radioactive tracer injected into the blood, showing how much glucose or another substance different brain areas use.

The extent to which a measure or model correctly predicts later outcomes, for example whether drugs that work in an animal model also work in humans.

The front part of the frontal lobe, involved in executive functions such as planning, working memory, decision-making, impulse control and social behaviour; it is the last brain region to mature.

A protein on the membrane of a cell with a binding site that fits a particular chemical messenger; when the messenger binds, the receptor changes the activity of the cell.

The reabsorption of a neurotransmitter from the synaptic gap into the presynaptic neuron by transporter proteins, which ends its action and allows it to be reused.

Reasoning backwards from activity in a brain area to the presence of a particular mental process, which is unreliable because most areas take part in many processes.

A network of dopamine pathways, running from the ventral tegmental area to the nucleus accumbens and prefrontal cortex, that is activated by rewards and motivates behaviour that leads to them.

The practice of placing adopted children in families similar to their biological families, which makes genetic and environmental influences harder to separate in adoption studies.

A neurotransmitter involved in regulating mood, sleep, appetite and impulse control, and the main target of SSRI antidepressants.

A gene (5-HTT) coding for the protein that carries serotonin back into the neuron that released it; its short allele was proposed as a genetic vulnerability to depression under stress.

How precisely a brain imaging technique can show where activity or a structure is located, measured as the smallest area it can tell apart.

A person whose corpus callosum has been cut, usually to control severe epilepsy, so that the two hemispheres can no longer share information directly.

The junction between two neurons, or between a neuron and a muscle or gland cell, made up of the presynaptic terminal, the synaptic gap and the postsynaptic membrane.

The tiny space, a few tens of nanometres wide, between the presynaptic terminal and the postsynaptic membrane, across which neurotransmitters diffuse.

A small membrane sac in the axon terminal that stores neurotransmitter and releases it into the synaptic gap when an action potential arrives.

The lobe at the side of each cerebral hemisphere, involved in hearing and language comprehension and, on its inner surface, in memory and emotion through the hippocampus and amygdala.

How precisely a brain imaging technique can show when activity happens, measured as the shortest time between changes it can tell apart.

A hormone, produced mainly by the testes and in smaller amounts by the ovaries and adrenal glands, that influences sexual development, sex drive, competitiveness and dominance.

The mistaken belief that because a treatment relieves a condition, the condition must have been caused by a lack of what the treatment supplies or by the process it acts on.

An economic game in which an investor decides how much money to send to a trustee, the amount is multiplied, and the trustee decides how much to return; the amount sent is used as a measure of trust.

An experimental technique that temporarily lowers brain serotonin by giving a diet and amino acid drink lacking tryptophan, the amino acid from which serotonin is made.

A research design that compares the similarity of monozygotic twins with that of dizygotic twins on a trait, to estimate how far variation in the trait is associated with genetic differences.

A region of the left posterior temporal lobe, named after Carl Wernicke, involved in understanding language; damage to it is linked to fluent but meaningless speech and poor comprehension.

Brain tissue made up mainly of myelinated axons, which carries signals between regions of grey matter; its volume increases through childhood and adolescence.