Plain-language definitions of the neuroscience terms used throughout NeuroMap.
Action potential
A brief electrical signal that travels along a neuron's axon, forming the basic unit of information transmission in the nervous system.
Amygdala
An almond-shaped structure in the medial temporal lobe central to fear, threat detection, and emotional memory. See the full Amygdala article.
Aphasia
A language disorder, usually caused by stroke or brain injury, that impairs the ability to produce or understand speech and writing.
Astrocyte
A star-shaped type of glial cell that supports neurons structurally and metabolically, helps regulate the blood-brain barrier, and assists in repairing brain tissue.
Autonomic nervous system
The part of the peripheral nervous system that regulates involuntary functions such as heart rate, digestion, and breathing.
Axon
The long, slender projection of a neuron that carries electrical signals away from the cell body toward other neurons.
Basal ganglia
A group of deep brain structures involved in initiating and smoothing voluntary movement; central to Parkinson's disease pathology.
Bilateral
Occurring on, or affecting, both sides of the brain or body.
Brain stem
The stalk connecting the brain to the spinal cord, controlling vital functions like breathing and heart rate. See the full Brain Stem article.
Broca's area
A region typically in the left frontal lobe responsible for producing fluent, grammatically organised speech.
Central nervous system (CNS)
The brain and spinal cord together, which process and coordinate information for the entire body.
Cerebral cortex
The brain's outer layer of grey matter, responsible for higher-order functions like thought, perception, and voluntary movement.
Cerebrospinal fluid (CSF)
A clear fluid that cushions the brain and spinal cord, removes waste, and helps regulate pressure within the skull.
Cerebrum
The largest part of the brain, made up of the left and right hemispheres and encompassing the cerebral cortex.
Cognitive function
Mental processes such as attention, memory, language, and reasoning that together enable thinking and understanding.
Consciousness
The state of being aware of and able to perceive one's surroundings, thoughts, and existence; thought to depend heavily on the thalamus, brain stem, and cortex working together.
Contralateral
Relating to the opposite side - for example, the left motor cortex controls movement on the contralateral (right) side of the body.
Corpus callosum
A dense band of nerve fibres connecting the brain's two hemispheres. See the full Corpus Callosum article.
Cortex
A general term for the brain's outer layer of tissue; usually refers to the cerebral cortex.
Dementia
A general term for a decline in memory, thinking, and reasoning severe enough to interfere with daily life; Alzheimer's disease is its most common cause.
Dendrite
A branching extension of a neuron that receives signals from other neurons and relays them toward the cell body.
Dopamine
A neurotransmitter involved in movement, motivation, and reward; its loss in the midbrain underlies the motor symptoms of Parkinson's disease.
Electroencephalography (EEG)
A technique that records the brain's electrical activity via electrodes on the scalp, commonly used to detect and study seizures.
Executive function
A set of higher-order cognitive processes - planning, impulse control, working memory, and task-switching - largely governed by the prefrontal cortex.
Frontal lobe
The brain's largest lobe, involved in decision-making, personality, and voluntary movement. See the full Frontal Lobe article.
Glia (glial cells)
Non-neuronal support cells in the nervous system that provide structural support, insulation, nutrients, and immune defence for neurons.
Grey matter
Brain tissue made up mostly of neuron cell bodies, found in the cortex and various deep nuclei.
Hemisphere
One of the two symmetrical halves of the cerebrum (left and right), connected by the corpus callosum.
Hippocampus
A seahorse-shaped structure in the temporal lobe essential for forming new memories and spatial navigation. See the full Hippocampus article.
Homunculus
A distorted map of the body used to illustrate how much cortical territory the motor or sensory cortex devotes to each body part.
Ipsilateral
Relating to the same side - the opposite of contralateral.
Limbic system
A group of interconnected structures, including the hippocampus and amygdala, involved in memory and emotion.
Magnetic resonance imaging (MRI)
A non-invasive imaging technique using magnetic fields to produce detailed images of brain structure, widely used in both research and diagnosis.
Medulla oblongata
The lowest part of the brain stem, controlling essential functions such as breathing, heart rate, and blood pressure.
Motor cortex
A strip of cortex at the back of the frontal lobe that initiates voluntary movement, organised as a body map (the motor homunculus).
Myelin
A fatty insulating layer wrapped around many axons that dramatically speeds up electrical signal transmission.
Neurodegeneration
The progressive loss of structure or function of neurons, underlying conditions such as Alzheimer's and Parkinson's disease.
Neuron
A specialised nerve cell that transmits information via electrical and chemical signals; the basic building block of the nervous system.
Neuroplasticity
The brain's ability to reorganise itself - forming new connections or strengthening existing ones - in response to learning, experience, or injury.
Neurotransmitter
A chemical messenger released by neurons to transmit signals across a synapse to another neuron, muscle, or gland.
Occipital lobe
The brain's primary visual processing centre, located at the back of the cerebral cortex. See the full Occipital Lobe article.
Parietal lobe
A cerebral lobe that integrates sensory information and supports spatial awareness. See the full Parietal Lobe article.
Peripheral nervous system (PNS)
All nerves outside the brain and spinal cord, connecting the central nervous system to the limbs and organs.
Prefrontal cortex
The foremost part of the frontal lobe, central to planning, judgment, impulse control, and personality.
Proprioception
The sense of the body's own position and movement in space, relying heavily on the parietal lobe and cerebellum.
Semantic memory
Long-term memory for general facts and concepts about the world, as distinct from memory for personal experiences.
Somatosensory cortex
A strip of the parietal lobe that processes touch, temperature, and pain signals from across the body.
Synapse
The junction between two neurons where electrical signals are converted to chemical signals (via neurotransmitters) and back again.
Temporal lobe
A cerebral lobe responsible for hearing, language comprehension, and memory. See the full Temporal Lobe article.
Thalamus
A central relay structure that routes nearly all sensory and motor signals to the cerebral cortex. See the full Thalamus article.
Vestibular system
The sensory system, based in the inner ear, that detects balance and spatial orientation, working closely with the cerebellum.
Wernicke's area
A region typically in the left temporal lobe essential for language comprehension.
White matter
Brain tissue made up mostly of myelinated axons, which connect different grey matter regions; the corpus callosum is a major white matter structure.
