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A typical radiation pattern of phased arrays whose inter-element spacing is greater than half a wavelength, hence the radiation pattern has grating lobes.. For discrete aperture antennas (such as phased arrays) in which the element spacing is greater than a half wavelength, a spatial aliasing effect allows plane waves incident to the array from visible angles other than the desired direction ...
Defining cerebral cytoarchitecture began with the advent of histology—the science of slicing and staining brain slices for examination. [2] It is credited to the Viennese psychiatrist Theodor Meynert (1833–1892), who in 1867 noticed regional variations in the histological structure of different parts of the gray matter in the cerebral hemispheres.
Brain cells make up the functional tissue of the brain. The rest of the brain tissue is the structural stroma that includes connective tissue such as the meninges , blood vessels , and ducts. The two main types of cells in the brain are neurons , also known as nerve cells, and glial cells , also known as neuroglia. [ 1 ]
Adult neurogenesis is the process in which neurons are generated from neural stem cells in the adult. This process differs from prenatal neurogenesis. In most mammals, new neurons are born throughout adulthood in two regions of the brain: [3]
This development section covers changes in brain structure over time. It includes both the normal development of the human brain from infant to adult and genetic and evolutionary changes over many generations. Neural development in humans; Neuroplasticity – changes in a brain due to behavior, environment, aging, injury etc.
In the average adult, the dimensions are as follow: 5-9mm in length, 1-5mm in width and 3-5mm in thickness. Its average weight is 100–180 mg. [40] The pineal gland consists of a central core made up of small lobes and a cortex that possesses a diffuse distribution of neurons. The principal cell type of the pineal is the pinealocyte sensu stricto.
The major sulci and gyri mark the divisions of the cerebrum into the lobes of the brain. The four major lobes are the frontal, parietal, occipital and temporal lobes. Other lobes are the limbic lobe, and the insular cortex often referred to as the insular lobe. There are between 14 and 16 billion neurons in the human cerebral cortex. [2]
The neural crest runs the length of the tube with cranial neural crest cells at the cephalic end and caudal neural crest cells at the tail. Cells detach from the crest and migrate in a craniocaudal (head to tail) wave inside the tube. [67] Cells at the cephalic end give rise to the brain, and cells at the caudal end give rise to the spinal cord ...