Neurological Glossary
Neurological terms are often complicated and difficult to understand. The following glossary defines a variety of terms to help you understand neurological terminology:
NAD
No Abnormality Detected
Narcolepsy
Sleep disorder characterized by excessive daytime sleepiness and dysregulated REM sleep
Negative symptom
Reduction (weakness
Neglect (left or right-sided neglect)
Ignoring or not being aware of being touched on one side
Negri body
A viral body found in the cytoplasm of certain nerve cells containing the rabies virus
Neologism
Made-up word
Neonatal
Newly born [first four weeks of life]
Nerve conduction velocity study
Method of diagnosing the type and location of nerve injury using application of electrical stimulation to the nerve
Network inhibition hypothesis
Proposed pathophysiological mechanism for complex behavioural phenomena and impaired consciousness in complex partial seizures; theory is that the seizures induce excitation in the temporal lobe that propagates to the dorsomedial thalamus and upper brainstem reticular formation
Neuralgia
Pain that follows the paths of specific nerves
Neuraxis
Often used synonymously with central nervous system (even though some suggest that it represents only the unpaired portions of the CNS)
Neurilemma
Thin membrane surrounding the axons and myelin of peripheral nerves; outermost layer of nerve fibres
Neurite
Terminal axon or dendrite
Neuritic plaque
mature plaque composed of a) silver-positive swollen neurites engorged with aggregates of paired helical filaments and round dense bodies and b) an amyloid core; seen in Alzheimer's disease
Neurofibrillary tangles
Flame-shaped intracytoplasmic inclusions in cortical neurons consisting of paired helical filaments; characteristic of
Neurogenic bladder
Bladder dysfunction associated with a lesion in the brain
Neuroglia
see glia
Neuroleptic
Drug that blocks dopamine receptors; antipsychotic drug
Neuroleptic malignant syndrome
Rare
Neurologist
A doctor who specialises in diseases of the brain and nervous system
Neurology
The study of the structure
Neuroma
Tumour composed of nerve tissue
Neuromelanin
Dark brown pigment seen in selected neuronal populations (most characteristically in the substantia nigra and locus ceruleus) that represents the residua of catecholamine metabolism
Neuromuscular junction
Junction (synapse) between the terminal of a motor neurons and a muscle fibre; myoneural junction
Neuron
Main functional cell of the brain and nervous system
Neuropathy
Medical term describing disorders of the nerves of the peripheral nervous system
Neuropil
Unmyelinated neuronal processes (axons and dendrites) in the gray matter of the central nervous system
Neuroplasticity
The brain's ability to reorganise itself
Neuro-protective agents
Medications developed to protect the brain from secondary injury.
Neurotransmitter
Chemical substance that transmits electrical impulses between neurons
Night Splints
Splints to hold good position overnight
Night terror
Sleep disorder (usually of children) involving abrupt awakening from sleep in a terrified state; affected individual is usually confused and does not remember details of the event
Nociceptive
Painful
Nodulus
Posterior part of the cerebellar vermis; medial portion of the vestibulocerebellum
Non-communicating hydrocephalus
Blockage of CSF flow along one or more of the narrow pathways connecting the ventricles (most commonly the cerebral aqueduct)
Non-fluent aphasia (Broca's or expressive aphasia)
Selective impairment of language production including impaired repetition due to a lesion of the left inferior frontal lobe (Brodmann areas 44 and 45)
Non-REM sleep
Sleep stages 1 through 4; characterized by a slowing of brain waves and some physiological functions
Normal pressure hydrocephalus (NPH)
Clinical symptom complex characterized by abnormal gait
Nothnagel Syndrome
Ipsilateral oculomotor palsy and contralateral ataxia due to a midbrain tegmental lesion affecting the III nerve fascicle and superior cerebellar peduncle
Notochord
Embryological predecessor of the vertebral column
Nuchal rigidity
Stiff neck
Nucleus
Collection of neuronal cell bodies
Nucleus ambiguus
Motor nucleus in the dorsolateral medulla that innervates striated muscle in the neck and thorax
Nucleus cuneatus
Nucleus located in the lower medulla containing the second-order sensory neurons that relay mechanosensory information from peripheral receptors in the upper body to the thalamus via the medial lemniscus
Nucleus gracilis
Nucleus located in the lower medulla containing the second-order sensory neurons that relay mechanosensory information from peripheral receptors in the lower body to the thalamus via the medial lemniscus
Nystagmus
Involuntary jerking of the eyes. It occurs in disorders of the part of the brain responsible for eye movements.