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The development of the nervous system in humans, or neural development, or neurodevelopment involves the studies of embryology, developmental biology, and neuroscience.These describe the cellular and molecular mechanisms by which the complex nervous system forms in humans, develops during prenatal development, and continues to develop postnatally.
Examples of neural inducers are the molecules noggin and chordin. When embryonic ectodermal cells are cultured at low density in the absence of mesodermal cells they undergo neural differentiation (express neural genes), suggesting that neural differentiation is the default fate of ectodermal cells.
The diencephalon encloses a cavity called the third ventricle. The thalamus serves as a relay centre for sensory and motor impulses between the spinal cord and medulla oblongata, and the cerebrum. It recognizes sensory impulses of heat, cold, pain, pressure etc. The floor of the third ventricle is called the hypothalamus.
The theory of Michael Commons' model of hierarchical complexity is also relevant. The description of stages in these theories is more elaborate and focuses on underlying mechanisms of information processing rather than on reasoning as such. In fact, development in information processing capacity is invoked to explain the development of reasoning.
During embryonic development, neural crest cells from each neuromere prompt the development of the nerves and arteries, helping to support the development of craniofacial tissues. If gene expression goes wrong, it can have severe effects on the developing embryo, causing abnormalities like craniofacial clefts, also known as cleft palates . [ 1 ]
The parts of the brainstem are the midbrain, the pons, and the medulla oblongata; the diencephalon is sometimes considered part of the brainstem. [ 2 ] The brainstem extends from just above the tentorial notch superiorly to the first cervical vertebra below the foramen magnum inferiorly.
[52] [53] The development of the thalamus can be subdivided into three steps. [54] The thalamus is the largest structure deriving from the embryonic diencephalon , the posterior part of the forebrain situated between the midbrain and the cerebrum.
In 1968, three years after the introduction of the gate control theory, Ronald Melzack concluded that pain is a multidimensional complex with numerous sensory, affective, cognitive, and evaluative components. Melzack's description has been adapted by the International Association for the Study of Pain in a contemporary definition of pain. [1]