Unpredictable and seemingly random behavior occurring in a non-linear system and governed by deterministic laws. In fact chaos, despite being incorrectly associated with randomness, is fully deterministic. Two hallmarks of chaos are that its behavior never cross the same path twice and that a chaotic system has a sensitive dependence on initial conditions, which means …
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Cerebral palsy
The cerebral palsies are a heterogenous collection of motor disorders, best defined as a group of non-progressive, but often changing, motor impairment syndromes secondary to lesions or abnormalities of the brain arising in the early stages of its development. What is ‘non-progressive’ (i.e., permanent) is the cerebral lesion, while its functional manifestations change with age …
Cerebrospinal fluid (CSF)
Clear, colorless fluid that fills the neural tube and later circulates through the four ventricles of the brain, within which it is secreted and then propelled by ependymal cells that line the walls of the ventricles. The fluid is absorbed into the bloodstream and re-circulated. It contains some white blood cells and supplies nutrients to …
Cerebral cortex (or pallium)
The six-layered, 1.4 to 4 mm convoluted sheet or mantle of neural tissue (unmyelinated neurons or tray matter), supported by deep white matter and separated by a prominent, longitudinal central fissure dividing it into in two hemispheres, that dominates the outside view of the human brain and forming the cerebrum. In fact, while it makes …
Cerebral cortex (disorders)
Common examples are aphasia, apraxia, agnosia and one-side (or contralateral) neglect. One of the most widely studied disorders in cortical structure is lissencephaly resulting from the arrest in migration of all cortical neurons before they reach their normal expected destinations. See Agnosia, Aphasia, Apraxia, Cell migration, Cerebral cortex (development), Cerebral cortex (functions), Cerebral cortex (or …
Cerebral cortex (functions)
Broadly speaking, the cerebral cortex is responsible for so-called ‘higher-order’ functions such as thought, voluntary movements, reasoning and perception. One way of accounting for its functions is by means of considering those ascribed to the four lobes: • frontal lobe: associated with reasoning, planning, parts of speech, voluntary movement, emotions and problem solving. Specific parts …
Cerebral cortex (development)
The first neurons that go to form the human cerebral cortex are generated during the first half of gestation in the proliferative ventricular zone close to the cavity of the cerebral ventricle. They undergo a complicated form of migration, termed the ‘inside-out’ pattern, in which the later born neuroblasts travel past those born earlier to …
Cerebellum and basal ganglia
Both share a number of similarities in terms of structure (i.e., hodology) and function. With regard to structure, both have projections to and back from the premotor cortex via the thalamus, and both function together to process information from the association cortex in the service of organizing and executing movements (see figure below). The differences …
Cerebral (or intracerebral) hemorrhage
Also called a hemorrhagic stroke, it is a haemorrhage or bleeding into the substance of the cerebrum, usually in one hemisphere and in the region of the internal capsule through the rupture of the lenticulostriate artery (one of the branches of the middle artery that supply structures in the basal ganglia where most hemorrhages due …
Cerebellum (disorders)
Staccato-like speech with pauses in the wrong places Signs associated with lesions to the neocerebellum See Ataxia, Athetoid (or athetotiform) movements, Basal ganglia (disorders), Brain damage studies, Cerebellum (anatomy), Cerebellum (development), Cerebellum (functions), Cerebellum (development), Chiari II malformation, Dandy Walker malformation