Neurological Glossary
GABA (Gamma Aminobutyric Acid)
Chemical produced by the brain to relax muscles - lacking in those with spasticity
Gadolinium-enhancing lesion
Abnormality on MRI that becomes bright after injection of the chemical compound gadolinium; implies breakdown in the blood-brain barrier
Gait
The characteristics of walking particular to an individual
Gait Trainers
Walking Aids
Gaiters
Splints to help keep knees and elbows straight.
Gamma motor neurons
Neurons that contract the ends of the muscle spindle so that spindle sensitivity to passive stretch is kept constant throughout muscle shortening
Ganglia
Aggregations of nerve cell bodies
Gastroscopy
Investigation of the interior of the stomach through special cameras at the end of a fibreoptic tube.
Gemistocyte
Reactive astrocyte having increased glial filaments and glassy eosinophilic cytoplasm
Generalised seizure
Seizure that affects both cerebral hemispheres simultaneously and causes unconsciousness
Geniculate ganglion
Sensory ganglion of the facial nerve that innervates taste buds on the anterior 2/3 of the tongue
Genu
Knee-like bend in the anterior part of the corpus callosum or internal capsule
Germinal matrix
A highly vascular, metabolically active area of the brain located just beneath the ependymal lining of the ventricular walls, which is the source of neurons and glial cells that will later migrate to cerebral cortex. It involutes in the second trimester. Germinal matrix vessels are fragile and are believed to have impaired autoregulation, making them prone to rupture in premature infants, resulting in intraventricular hemorrhage.
Gerstmann syndrome
A neurological disorder that includes a writing disability (agraphia or dysgraphia), a lack of understanding of the rules for calculation or arithmetic (acalculia or dyscalculia), an inability to distinguish right from left, and an inability to identify fingers (finger agnosia) that is due to a lesion of the angular gyrus of the dominant parietal lobe
Glasgow Coma Scale (GCS)
Most widely used scoring system to quantify level of consciousness following traumatic brain injury; scores range from 3 to 15, based on the sum of the best eye opening response, the best verbal response, and the best motor response
Glia
Supporting cells of the nervous system that provide structural and metabolic support for the neurons; includes astrocytes, oligodendrocytes, ependymal cells, and microglia
Glioblastoma multiforme
WHO grade IV astrocytoma characterized by hemorrhagic necrosis, endothelial proliferation, ± crossing of the corpus callosum, ring-enhancement on imaging, and poor survival
Gliosis
Scar or dense fibrous network of glial processes in an area of CNS injury
Global aphasia
Impairment of language production, comprehension, and repetition due to lesion of entire perisylvian region; usually associated with right hemi-paresis
Globus pallidus
Most medial component of the basal ganglia and generator of most basal ganglionic output
Glossopharyngeal nerve (cranial nerve IX)
Nerve containing motor, sensory, and parasympathetic fibres; motor fibres originate in the nucleus ambiguus and innervate the stylopharyngeus to elevate the palate; sensory fibers originate in the superior and petrosal ganglion and supply taste to the posterior third of the tongue and tactile sensation to the posterior tongue, pharynx, middle and external ear, and eustacian tube; parasympathetic fibres originate in the inferior salivatory nucleus and carry secretory and vasodilatory fibers to the parotid gland
Goal setting
The process whereby the professionals and the patient decide on the main objectives for rehabilitation
Golgi tendon organs
Sense active stretch and via inhibitory inter-neurons inhibit the motor neurons to provide protection against hurtful contractile forces
Gower’s sign
Manoeuvre used by patients with proximal muscle weakness (as in myopathy) in order to arise from the floor or from a kneeling or squatting position; the hands are used to “walk up” the thighs
Gradenigo Syndrome
Ipsilateral lateral rectus palsy, peripheral facial palsy, decreased hearing, and upper facial pain due to a lesion in the apex of the temporal bone
Graphesthesia
Ability to recognize letters or numbers drawn on the finger or palm
Gray matter
Part of the CNS consisting of neuronal cell bodies and dendrites
Guillain-Barre syndrome (acute inflammatory demyelinating polyneuropathy)
Acute, ascending, and progressive neuropathy believed to result from an autoimmune response triggered by an antecedent illness or various medical conditions and characterized by weakness, parenthesis, hyporeflexia, and labile autonomic dysfunction; most patients exhibit absent or profoundly delayed conduction in nerve fibres resulting from demyelination, but in a subset of patients, there is a direct cellular immune attack on the axon itself
Gyrus
Convoluted ridge on the outer surface of the brain caused by infolding of the cerebral cortex and bound by sulci
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