It is generally considered to be involved in a feedback circuit governing the activity of the extrapyramidal motor system, and has long been considered as a error detection device, receiving error signals from the inferior olive and using both efferent copy and sensory feedback to adjust some kind of calibrating signal to correct subsequent movements. …
Category Archives: Uncategorized
Cerebellum (development)
The cerebellum, relative to other brain structures, has a protracted developmental course, such that a considerable portion takes place postnatally. Its origins and those of its associated nuclei begin in week 7 of the embryonic period and its neurogenesis is complete some 6 months after birth. It starts in the embryonic period with neuroblasts located …
Cerebellar cortex
The outer layer of the cerebellum (also known as the corticocerebellum, molecular layer and neocerebellum) with a surface area of 50,000 cm² in the adult human, mainly consisting of parallel fibers and cerebellar interneurons. See Basket cells, Cerebellum (anatomy), Granular layer, Interneurons, Molecular layer, Parallel fibers
Cerebellum (anatomy)
First identified by Herophilus of Chaceldon (355-280 BP), the father of anatomy (who also identified the cerebrum and ventricles in humans), it is commonly referred to as the ‘small brain’, and as the ‘head ganglion’ of the proprioceptive system by Charles Sherrington. The cerebellum is a major structure of the metencephalon (hindbrain), lying above and …
Centromere
Part of a chromosome containing no genes, but controlling chromosome activity, located at the point lying on the equator of the spindle at metaphase during mitosis and which divides at the anaphase (see figure below for its relationships with other components of a chromosome). A chromosome (right) from a cell nucleus (left) showing the position …
Central pattern generator (CPG)
A network of spontaneously active interneurons that emit modulated rhythmical activity. Those situated in the spinal cord are implicated in the coordination rhythmical activities such as locomotion. Some of these neurons are excitatory and others inhibitory. Thus, in the case of locomotion, when the agonist extensor muscles are activated, the antagonist flexors are inhibited. On …
Centrifugal /centripetal
Directed from center/directed to center. A centrifugal or efferent nerve fiber transmits impulses from centers in the nervous system to the parts in which the nerves are distributed, thereby exciting muscle contractions or influencing the processes of nutrition, growth, and secretion. A centrifugal force, a form of inertia, tends to move objects away from the …
Central nervous system (CNS)
That part of the nervous system in vertebrates derived from the neural tube consisting of the brain (prosencephalon, mesencephalon, rhombencephalon) and cerebral ganglia, together with the retina (sometimes considered to be part of the peripheral system), spinal cord, and meninges. Anything else is considered to be the peripheral nervous system. It consists of two regions: …
Central coherence
The ability to integrate information into a gestalt (a perceptual structure possessing qualities that go beyond its constituent elements or parts, and that cannot be described solely in terms of its parts), or to build up a global picture. This particular ability appears to be a particular strength with those individuals diagnosed as autistic (e.g., …
Central dogma of molecular biology
A term coined by Francis H.C. Crick (1916-2004) in 1958, it states the idea that genetic ‘information’ flows in only one direction from DNA -> RNA -> protein. Put another way, it holds that DNA makes (or transcribes) RNA makes (or translates) proteins that in turn facilitate the previous two steps as well as the …