anencephaly (aprosencephaly) CNS malformation involving failure of closure of the cephalic end of the neural tube, resulting in absence of the forebrain and cerebrum; rudimentary brainstem may be present so that reflex actions such as breathing and responses to sound or touch may occur
atonic seizure (drop attack) generalized seizure characterized by sudden loss of muscle tone and strength; may cause the head to drop suddenly, objects to fall from the hands, or the legs to lose strength, with falling and potential injury
An invasive study in which a catheter (a small tube) is placed in the artery and contrast material is injected to which makes the blood vessels visible on an X-Ray image. The catheter is inserted in the groin into the femoral artery (the artery to the leg) through a needle, and is guided into the arteries in the neck and head.
agnosia inability to recognize and interpret objects, people, sounds, or smells despite intact primary sense organs (e.g., inability to identify a sound despite intact hearing); typically results from damage to the occipital or parietal lobe
aseptic meningitis syndrome characterized by headache, neck stiffness, low grade fever, and Cerebro Spinal Fluid lymphocytic pleocytosis in the absence of an acute bacterial pathogen; often used synonymously with viral meningitis, but also incudes meningeal inflammation due to various drugs (e.g., NSAIDs) or diagnostic procedures (e.g., angiography); atypical bacterial, fungal, parasitic, or parameningeal infection; neoplastic processes; and various systemic disorders
The intervertebral disc - cartilaginous cushion found between the vertebrae of the spinal column. It may bulge beyond the vertebral body and compress the nearby nerve root, causing pain. The terms "slipped disc", "ruptured disc" and "herniated disc" are often used interchangeably even though there are subtle differences.
alpha motor neurons large motor neurons that innervate extrafusal skeletal muscle fibers alpha-synuclein protein expressed predominantly in the CNS that when aggregated, can result in neurodegenerative diseases such as Parkinson disease, dementia with Lewy bodies, and multisystems atrophy
Slight dilatation on the common carotid artery at its bifurcation containing nerve cells sensitive to blood pressure. Stimulation can cause slowing of the heart, vasodilatation and a fall in blood pressure.
Anton's syndrome form of cortical blindness in which the patient is unaware of/denies the visual impairment; due to a lesion of the occipital lobe extending from primary visual cortex into visual association cortex