Cell death, axon retraction and synapse elimination in development. See Apoptosis (or cell death), Axon retraction (or pruning), Quantitative and qualitative regression, Synapse elimination
Category Archives: Uncategorized
Regular words
printed words that contain consistent grapheme-phoneme correspondences (e.g., bridge) . See Irregular words
Register
A list of individuals with a defined condition that enables the burden of disease to be measured in a given population over a given period of time. See Epidemiology
Reflexivity
Oftenconsidered to be a central aspect of ethnography, reflexivity is self-awarenessand self-criticism on the part of the researcher (see Smith, 1999). Emphasis on reflexivity ispart of the rejection of the notion that impartial and unbiased objectivity isthe ideal for any scientific investigation. Since research with humanparticipants requires interaction and establishing a relationship, the concernsand interests …
Reflexology
The doctrine that behavioral mechanisms reside in the chaining of reflexes that is triggered by external stimulation. Closely allied to stimulus-response theory, it led to the human newborn being regarded as nothing more than a bundle of reflexes, and thus a passive rather than an active organism. See Cortical inhibition hypothesis, Hierarchical models of motor …
Reflexive (vegetative) vocalizations
Non-speech sounds such as cries, grunts, sneezing and hiccoughs during the first two months after birth. One characteristic of these vocalizations is referred to as quasi-resonant nucleic (faint, low-pitched grunt-like sounds with muffled resonance, with a lack of energy above 2000Hz). These sounds give way those that indicate an increase in the control of phonation (e.g., cooing, babbling). See Babbling, …
Reflex
Reflex arcA reflex should be distinguished from an action as it is a stereotyped response or movement (e.g., an eye blink to a specific external stimulus such as a puff of air) involving little or no cortical mediation. As such, it lacks the hallmark features of an action such as motor equivalence, which allow movements …
Reflex arc
A simple model of the neural circuit that includes an afferent fiber conveying sensory information in the central nervous system and an efferent fiber to an end-organ (muscle, blood vessel, gland). See Monosynaptic and polysynaptic reflexes, Reflex
Reflective abstraction
A termintroduced by Piaget; reflective abstraction is any personal activity thatderives knowledge by reflecting on one’s own operations are activities, forinstance by reflecting on action-result relationships, or relationships betweenvarious actions or operations performed in a particular context. Reflective abstraction may be triggered bycognitive conflict (e.g., the experience that the application of a particularoperation leads to …
Reelin
Derived from an abnormal reeling gate, it is a protein in the brain. Originally found in reeler mice who manifest this gait, they were shown to have to have deficiency in this protein and were homozygous for the reel in gene. In contrast, mice heterozygous for the gene had no obvious neuroanatomical defects, but those …