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Pyramidal cells, or pyramidal neurons, are a type of multipolar neuron found in areas of the brain including the cerebral cortex, the hippocampus, and the amygdala. Pyramidal cells are the primary excitation units of the mammalian prefrontal cortex and the corticospinal tract .
The pyramidal tracts include both the corticobulbar tract and the corticospinal tract. These are aggregations of efferent nerve fibers from the upper motor neurons that travel from the cerebral cortex and terminate either in the brainstem ( corticobulbar ) or spinal cord ( corticospinal ) and are involved in the control of motor functions of ...
Layer III, the external pyramidal layer, contains predominantly small and medium-size pyramidal neurons, as well as non-pyramidal neurons with vertically oriented intracortical axons; layers I through III are the main target of commissural corticocortical afferents, and layer III is the principal source of corticocortical efferents.
The pyramidal tracts (corticospinal tract and corticobulbar tracts) may directly innervate motor neurons of the spinal cord or brainstem (anterior (ventral) horn cells or certain cranial nerve nuclei), whereas the extrapyramidal system centers on the modulation and regulation (indirect control) of anterior (ventral) horn cells.
Schematic of a single pyramidal neuron, the primary excitatory neuron of the cerebral cortex, with a synaptic connection from an incoming axon onto a dendritic spine. Neurons are the primary components of the nervous system, along with the glial cells that give them structural and metabolic support. [5]
Neurons are polarised cells that are specialised for the conduction of action potentials also called nerve impulses. [1] They can also synthesise membrane and protein. Neurons communicate with other neurons using neurotransmitters released from their synapses, and they may be inhibitory, excitatory or neuromodulatory. [5]
As many as 95% of neurons in the neocortex, the outermost layer of the mammalian brain, consist of excitatory pyramidal neurons, [2] [3] and each pyramidal neuron receives tens of thousands of inputs from other neurons. [4] Thus, spiking neurons are a major information processing unit of the nervous system.
A place cell is a kind of pyramidal neuron in the hippocampus that becomes active when an animal enters a particular place in its environment, which is known as the place field. Place cells are thought to act collectively as a cognitive representation of a specific location in space, known as a cognitive map . [ 1 ]