ARCHAIC INHERITANCE

refers to the presumed phylogenetic influences inherent in the development of the individual

ARCUATE ZONE OF THE BRAIN

the bow-shaped portion of the reticular formation on the back of the brain that extends from the spinal cord to the pons. This also...

ARIPIPRAZOLE

n. an atypical antipsychotic agent that is thought to bind to the presynaptic D2 dopamine autoreceptor, and thereby inhibit the release of dopamine from...

AROMATASE

n. an enzyme that works to convert many of the male sex hormones (androgens) into female sex hormones (estrogens). See also aromatization hypothesis.

AROUSAL-REDUCTION MECHANISM

any stimulus or reaction that decreases the degree of arousal within an individual after arousal has reached an uncomfortably high level. According to British-born...

ARTERIOVENOUS MALFORMATION (AVM)

an abnormal, congenital tangle of arteries and veins that are directly connected and lack any intervening capillaries. Such malformations may have no apparent symptoms,...

ARTIFACT

n. 1. an error caused by improper statistical manipulation of experimental data or a logical flaw in experimental design that causes the changes that...

ASCENDING RETICULAR ACTIVATING SYSTEM (ARAS)

refers to the pathways that transmit nervous impulses from the reticular formation of the midbrain in an ascending manner through the thalamus, and then...

ASPERGER'S DISORDER

a pervasive developmental disorder associated with varying degrees of deficits in social, emotional and conversational skills, difficulties with set-shifting, and a preference for the...

ASSESSMENT INSTRUMENT

an instrument that is typically used in the evaluation of ability, achievement, interests, personality, psychopathology, or some other factor.

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