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Confocal microscope image of cerebellar Purkinje cells expressing tdTomato. These cells are some of the largest neurons in the human brain (Betz cells being the largest), [5] with an intricately elaborate dendritic arbor, characterized by a large number of dendritic spines. Purkinje cells are found within the Purkinje layer in the cerebellum.
The human cerebellum is located at the base of the brain, with the large mass of the cerebrum above it, and the portion of the brainstem called the pons in front of it. It is separated from the overlying cerebrum by a layer of tough dura mater called the cerebellar tentorium; all of its connections with other parts of the brain travel through the pons.
The human brain is primarily composed of neurons, glial cells, neural stem cells, and blood vessels. Types of neuron include interneurons, pyramidal cells including Betz cells, motor neurons (upper and lower motor neurons), and cerebellar Purkinje cells. Betz cells are the largest cells (by size of cell body) in the nervous system. [40]
Purkinje cells receive more synaptic inputs than any other type of cell in the brain—estimates of the number of spines on a single human Purkinje cell run as high as 200,000. [11] The large, spherical cell bodies of Purkinje cells are packed into a narrow layer (one cell thick) of the cerebellar cortex, called the Purkinje layer.
Plasticity of the synapse between a parallel fiber and a Purkinje cell is believed to be important for motor learning. [11] The function of cerebellar circuits is entirely dependent on processes carried out by the granular layer. Therefore, the function of granule cells determines the cerebellar function as a whole. [12]
There are four paired deep cerebellar nuclei embedded in the white matter centre of the cerebellum. The nuclei are the fastigial , globose , emboliform , and dentate nuclei. In lower mammals the emboliform nucleus appears to be continuous with the globose nucleus, and these are known together as the interposed nucleus .
Embryonic vertebrate subdivisions of the developing human brain hindbrain or rhombencephalon is a developmental categorization of portions of the central nervous system in vertebrates. It includes the medulla, pons, and cerebellum.
Cerebellar granule cells form the thick granular layer of the cerebellar cortex and are among the smallest neurons in the brain. (The term granule cell is used for several unrelated types of small neurons in various parts of the brain.) Cerebellar granule cells are also the most numerous neurons in the brain: in humans, estimates of their total ...