Those resembling the slow, involuntary writhing movements characteristic of athetosis, and especially evident in the hands and fingers and sometimes in the feet. First described by William John Little (1810-1894) in 1843. Athetoid cerebral palsy (CP) arises from damage to the basal ganglia or cerebellum, and occurs in about 10% of children with CP. Speech …
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Asymptote
A line on a growth curve that gets increasingly near the ceiling, but does not reach it. An example of an asymptote is the graph of the function f(x) = 1/x, in which two asymptotes are being approached: the line y = 0 and the line x = 0. The curve approaches them, but never …
Astrocyte
One type of a number of different glial cells found in the white and gray matter of the central nervous system (CNS). They are star-shaped, with many processes, and provide mechanical support for neurons by wrapping around them and attaching them to their blood vessels by wrapping around them as well (see figure below). Also, …
Asymmetrical tonic neck posture or response (ATNR)
From the flexed and symmetrical posture of the supine full term newborn, an asymmetry develops in which the upper extremity on the side to which the head is rotated extends, while that on the side of the occiput is flexed , thus being described as a ‘fencing position’ (see figure below). Also, the leg on …
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Assimilation
The process of incorporating new experiences (e.g., a new toy) into an existing scheme or psychological structure. In Piaget‘s theory of genetic epistemology, assimilation must occur in tandem with accommodation, which together form the complementary processes of adaptation. See Accommodation, Adaptation, Cognitive development, Developmental epistemology, Equilibration, Reciprocal assimilation, Scheme
Asperger’s syndrome
Also known as Asperger’s disorder or autistic psychopathy, it is a sub-group on the autistic spectrum. This syndrome and classic autism share the same features, but in Asperger’s language development is normal and cognitive development proceeds on time (in fact, some children with the syndrome display what is known as ‘hyperlexia’, the ability to read …
Asphyxial death
A suffocation wherein the organism is mechanically prevented from breathing sometimes due to being wedged between furniture or being pushed against soft materials or objects blocking the air passages. See Apnea, Sudden infant death syndrome (SIDS, cot or crib death)
Aspartate acid (or aspartic acid)
A non-essential amino acid that is a basic molecule of proteins, and which is an excitatory neurotransmitter like glutamate. Along with glutamate, it is one of the most common neurotransmitters in the brain, some of the others being gamma-amino butyric acid (GABA) and glycine, which are both inhibitory in action. Given that it occurs naturally …
Artificial intelligence (AI)
Also known as machine intelligence, it is problem solving, recognition, and other intelligent-like behavior exhibited by an inanimate device. Computers, and especially programming languages such Lisp, led to an explosion of interest in AI. Examples of the sorts of problems tackled by AI include computer vision, natural language processing and speech recognition. However, the most …
Ascending genital tract infection
One of the most common infectious complications during pregnancy, it occurs when lower genital tract microorganisms (e.g., chlamydia trachomatis, gonorrhoea) from the vagina or cervix ascend to infect or cause inflammation of the amniotic fluid, placenta, choriodecidua, chorioamnion, or uterus. It is associated with an increased risk of preterm labor/delivery. In US women aged 20-65 …