2,701 articles
Mirror neuron
Mirror neurons, discovered by Rizzolatti's Parma group in macaque area F5, fire both when an animal performs and observes an action; their proposed role in action understanding is heavily contested.
Mirror-touch synesthesia
Mirror-touch synesthesia is a synesthesia variant in which seeing another person touched produces a felt touch on one's own body; prevalence about 1.6%, explained by threshold and self-other theories, and linked variably to empathy.
Misophonia
Misophonia is a disorder of intense anger or disgust triggered by specific sounds like chewing or breathing, first named in 2001, defined by a 2022 Delphi consensus, and treatable with cognitive behavioral therapy.
Mitomycin C
Mitomycin C (MMC, NSC 26980) is an antitumor antibiotic activated by quinone reduction into a DNA-cross-linking bis-electrophile; FDA-approved 1974 for cancers and widely used off-label as an antiscarring agent in glaucoma trabeculectomy surgery.
Mitral cell
Mitral cell: principal excitatory projection neuron of the vertebrate olfactory bulb, named for its miter-shaped soma. One primary dendrite reaches a single glomerulus; axons form the lateral olfactory tract to olfactory cortex.
Mitral valve
Mitral valve (left atrioventricular valve): the two-leaflet heart valve between left atrium and left ventricle; disorders include prolapse, regurgitation, and stenosis; treated by repair, replacement, or TEER.
Mitral valve annuloplasty
Mitral valve annuloplasty: suturing a prosthetic ring or band around the mitral annulus during valve repair. Introduced by Carpentier in 1968; rigid, flexible, and semirigid rings exist, with no proven outcome difference between types.
Moderate and severe traumatic brain injury
Moderate and severe traumatic brain injury (moderate-severe TBI) is head trauma more severe than mild TBI, defined by GCS below 13 or prolonged loss of consciousness or amnesia.
Molar (tooth)
Molar, the multi-cusped posterior grinding tooth (third molar = wisdom tooth). Humans have 12 permanent molars, typically three-rooted with 4–5 cusps; first molars erupt at 6–7 years, third at 17–21, and are prime targets for fissure sealants.
Monomelic amyotrophy
Monomelic amyotrophy (Hirayama disease) is a rare juvenile lower motor neuron disorder causing unilateral distal upper limb atrophy sparing the brachioradialis, from flexion-induced cervical cord ischemia; collar or surgery, self-limiting course.
Mons pubis
Mons pubis (mons veneris): rounded fatty eminence over the pubic bone, the most anterior part of the female external genitalia; hair-bearing after puberty, cushions intercourse, and may be reduced surgically by monsplasty.
Morning glory disc anomaly
Morning glory disc anomaly (MGDA) is a rare congenital optic nerve malformation with a funnel-shaped, flower-like optic disc, usually affecting one eye and impairing vision.
Moro reflex
Moro reflex, also called the startle or embrace reflex (Umklammerungsreflex), is a primitive newborn reflex elicited by sudden head drop, with arm extension-abduction then flexion; it disappears by 2–5 months and signals clavicle fracture, brachial plexus palsy, or brain injury when absent or asymmetric.
Morphogen
Morphogen: a signaling molecule forming a concentration gradient that gives cells positional information during embryonic development. Term coined by Turing (1952); French Flag model by Wolpert (1969); examples include Bicoid, Shh, Dpp, BMP, and Nodal.
Morton's neuroma
Morton's neuroma, or interdigital neuroma, is a thickening of tissue around an irritated common plantar digital nerve between the toes, usually the third web space. Treated first with footwear changes, then steroid injections or neurectomy; not a true nerve tumor.
Mosaic schwannomatosis
Mosaic schwannomatosis (MNF3, mosaic SWN) is a rare mosaic form of schwannomatosis caused by postzygotic SMARCB1 or LZTR1 variants, producing multiple schwannomas with a milder phenotype; ORPHA:634492, ICD-11 LD2D.1Y.
Motilin
Motilin is a 22-amino-acid peptide hormone secreted by M cells of the duodenal and jejunal mucosa that stimulates gastrointestinal motility; erythromycin mimics it, launching prokinetic drug development.
Motion sickness
Motion sickness (seasickness, car sickness) is nausea, vomiting, dizziness, pallor, and cold sweating from real or perceived motion conflicting vestibular, visual, and proprioceptive inputs; treated with habituation, scopolamine, and sedating antihistamines.
Motor Activity
Motor Activity (MeSH D009043, introduced 1968): body movements of a human or animal as a behavioral phenomenon; also IUPAC neurotoxicology term for animal physical activity, measured by actigraphy and accelerometry.
Motor control
Motor Control (ISSN 1087-1640) is a peer-reviewed quarterly Human Kinetics journal, official journal of the International Society of Motor Control since 1997, publishing multidisciplinary research on human movement control and motor disorders; MEDLINE-indexed, 2024 impact factor 1.4.
Motor cortex
Motor cortex: frontal lobe region for voluntary movement, comprising primary motor cortex (M1, Brodmann area 4), premotor cortex, and supplementary motor area; somatotopic map, Betz cells, corticospinal output, discovered by Fritsch and Hitzig in 1870.
Motor neuron
A motor neuron, also called an efferent neuron or motor nerve cell, carries command signals from the central nervous system to muscles and glands, forming the final common path.
Motor neuron diseases
Motor neuron diseases (MNDs) are progressive neurological disorders destroying upper and lower motor neurons, causing weakness, wasting, and fasciculations. Main types are ALS (80–90% of cases), progressive bulbar palsy, primary lateral sclerosis, and progressive muscular atrophy; ALS is usually fatal within 3–5 years.
Motor neuroprosthetics
Motor neuroprosthetics: devices restoring movement after stroke or spinal cord injury by stimulating muscles, nerves, spinal cord, or brain, or decoding brain signals (BCIs), from Liberson's 1961 foot-drop stimulator to Utah-array robotic arm control.
Motor skill
Motor skill: learned ability to perform movements efficiently, assessed by retention and transfer. Covers Fitts-Posner stages, contextual interference (random vs blocked practice, SMD 0.55), implicit vs explicit learning, and cortex-basal ganglia-cerebellum mechanisms.
Motor unit number estimation
Motor unit number estimation (MUNE), including MUNIX, MScanFit, and MPS variants, estimates the number of functioning motor units in a muscle from surface EMG, mainly to track lower motor neuron loss in ALS.
Moyamoya disease
Moyamoya disease, a rare progressive cerebrovascular disorder causing bilateral intracranial carotid occlusion with puff-of-smoke collaterals; RNF213 p.R4810K susceptibility gene, Suzuki staging, DSA diagnosis, surgical revascularization treatment.
MRIMLD study
MRIMLD (NCT07155135) is a completed retrospective single-center study by Ryka Tashakkor of Socal Heart evaluating 1.5 Tesla MRI safety in 16 patients with non-MRI-conditional, mixed-manufacturer cardiac implantable electronic devices, reporting 23 scans with no adverse events or device parameter changes.
Mucociliary Clearance
Mucociliary clearance, also called mucociliary transport, is the lung's primary innate defense: cilia beating in metachronal waves propel a mucus layer trapping inhaled particles and pathogens out of the airways.
Mucocutaneous venous malformations
Mucocutaneous venous malformations, formally VMCM, are a rare hereditary vascular malformation causing small venous lesions of the skin and mucosa, inherited in an autosomal dominant pattern.