A small, bluish region on either side of the pons in the brain stem that lies near the lateral wall of the fourth ventricle. It consists of some 20,000 melanin-pigmented cell bodies (hence it is also referred to as the pigmentosus pontis), and contains the generally excitatory catecholamine neurotransmitter norepinephrine (or noradrenaline). Consequently, it is …
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Logical positivism
The name of a philosophical school of thought adopted by members and associates of the Vienna Circle, during the 1920s and 1930s, who included Alfred J. Ayer (1910-1989), Rudolf Carnap (1891-1970), Moritz Schlick (1882-1936), Ludwig Wittgenstein (1889-1951), and the early Bertrand Russell (1872-1970). Its main claim was that only analytical and synthetic statements or propositions …
Locomotion
To move from place to place by changing the body‚was base of support. There are many forms of locomotion in humans. Locomotion that involves moving from one foot to the other is referred to as bipedal locomotion and includes movement patterns such as walking, running, galloping, jumping, and skipping. Quadrupedal locomotion involves moving on …
Lissencephaly
Also referred to as a ‘smooth brain’, it a condition of cortical dysgenesis in which cellular layers are improperly formed and thus the cerebral cortex lacks the typical convolutional pattern formed by gyri and sulci (see figure below). One mutant gene that gives rise to lissencephaly is LIS1 that has been mapped on to chromosome …
Literacy
5nitially, the ability to read and write, but more recently the meaning of literacy has been extended to that of having access to a body of knowledge, such as mathematical, computer or scientific literacy. The initial meaning of reading literacy has also been extended from a straightforward ability to read and write to encompass the …
Liquid
A phonological class of consonants, articulated without friction, that includes the lateral and rhotic consonants (e.g., the initial consonants in the words lay and ray, respectively). They can be prolonged as in ball and shortened in a word like ladder. They are among the most commonly heard sounds in the world’s languages See Bilabial, …
Linguistics
The scientific study of language structure, either the structure of a particular language or the similarities and differences across diverse languages. Linguistics encompasses syntax, morphology, phonology, semantics, and pragmatics, and may focus on either the current state of one or more languages (synchronic linguistics) or on how languages change over time (diachronic linguistics). See Child development, …
Lipids
A diverse group of small organic compounds occurring in living organisms that are insoluble or hydrophobic in water due to the fact they are composed of methylene. They include fats and oils (concentrated means of storing energy), fat-soluble vitamins (e.g. vitamins A, D, E and K), waxes (provide waterproofing of of body surfaces), hormones, phosolipids …
Linguistic anthropology
Originallya branch of anthropology that studied and documented endangered languages,linguistic anthropology now includes the investigation of many differentaspects of language structure and use (see Wortham, 2008). See Anthropology, Emic-etic distinction, Linguistics, Psycholinguistics Wortham, S. (2008). Linguisticanthropology of education. Annual Review of Anthropology, 37,37-51.
Lingua-palatal (or palatal)
Speech sounds formed with a constriction between the blade of the tongue and the hard palate. Creates a narrow opening through which the air passes. There are two lingua-palatal fricatives in English: voiceless (e.g., machine, pressure, shoe) and voiced (e.g., azure, pleasure, rouge). See Bilabial, Clicks, Consonants, Fricative, Glottal, Labio-dental, Lateral sound, Lingua-alveolar (or …