A system in the brain stem that controls arousal of other parts of the brain and is closely tied to sustained attention and associated functions. It is that part of the reticular activating system (RAS) emanating from the mesencephalic nucleus in the mesenecephalon sitting atop of the brain stem (the main structure of the system …
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The midbrain, part of the brain stem, divided in two structures: the tectum and tegmentum. The tectum (or ‘roof’) forms the dorsal surface of the midbrain, and is made up of the (posterior) inferior and (anterior) superior colliculi (the former having auditory functions, the latter visual functions). The tegmentum, lying anterior to the tectum, consists …
Relatively fixed, assumed to be innate, mental systems that have unique inputs and processes that operate on those inputs. The claim for innateness probably stemmed from regarding mental modules as having evolved from natural selection pressures, a view evident in the evolutionary psychology of the husband-wife partnership of Lea Cosmides and John Tooby. The concept of …
A condition of significantly below average intellectual development (IQ<70) and adaptive functioning in, for example, self-care, that is manifested before 18 years of age. An IQ between 50 and 70 is taken to signify mild mental retardation, 35 to 50 the moderate form, 20 to 35 the severe manifestation, and below 20 profound mental retardation. …
In Piagetian theory, the reconstruction of action on concrete objects in the absence of those objects (cf. object permanence). Mental images are formed as a result of the abbreviation and internalization of action on objects. To construct a mental image (or mental imagery) is to engage in abbreviated actions that are similar to the actions …
The meninges (singular meninx) are a three-part system of membranous layers or lamellae (see figure below) that form a bag-like envelope surrounding the central nervous system (brain and spinal cord), and which contain cerebrospinal fluid (CSF). Together, the cardinal function of the meninges is to protect the central nervous system (CNS) from mechanical damage and …
Inflammation of the membranes (the meninges) covering the brain and spinal cord. If the blood vessels in the brain become inflamed, the brain becomes starved of oxygen. It can be caused by bacterial infection, viral infection and infection due to the microorganism meningococcus. The infection occurs in the cerebrospinal fluid surrounding the membranes. Individuals with …
The theory of inheritance originally outlined by Gregor Mendel (1822-1884) in 1866 and formulated in two laws. The law of segregation states that each hereditary characteristic is controlled by two factors (now referred to as alleles) that segregate and pass into separate reproductive (or germ) cells. The law of independent assortment holds that pairs of …
The encoding of information, its storage and retention, and subsequent retrieval. The information can range from stimuli, events and images through to ideas. Many different memory systems have been identified such as perceptual memory, working memory and the distinctions between long-term memory (of which perceptual memory is a part), sensory and short-term memory (of which working …
12.6 Age at menarche in a selection of countries. Adapted from Parent et al. (2003). Average menarcheal age is younger in France and other Mediterranean countries compared to other countries in western European countries, differences that might involve not only genetic factors, but the effects of geographical location such as altitude, day light hours, humidity, …