Search results
Results From The WOW.Com Content Network
The medium spiny neurons are medium-sized projection neurons with extensively branched dendrites. The cell body is 15–18 μm and has five primary dendrites that become branched. At first the dendrites are without spines but at about the first branch point they become densely spined.
Projection fibers consist of efferent and afferent fibers uniting the cortex with the lower parts of the brain and with the spinal cord. In human neuroanatomy, bundles of axons (nerve fibers) called nerve tracts , within the brain, can be categorized by their function into association tracts , projection tracts , and commissural tracts .
The substantia nigra is located in the ventral midbrain of each hemisphere. It has two distinct parts, the pars compacta (SNc) and the pars reticulata (SNr). The pars compacta contains dopaminergic neurons from the A9 cell group that forms the nigrostriatal pathway that, by supplying dopamine to the striatum, relays information to the basal ganglia.
The output neurons of the nucleus accumbens send axonal projections to the basal ganglia and the ventral analog of the globus pallidus, known as the ventral pallidum (VP). ). The VP, in turn, projects to the medial dorsal nucleus of the dorsal thalamus, which projects to the prefrontal cortex as well as back to the ventral and to dorsal stri
Dendritic spines on medium spiny neuron of striatum. Types of cells in the striatum include: Medium spiny neurons (MSNs), which are the principal neurons of the striatum. [2] They are GABAergic and, thus, are classified as inhibitory neurons. Medium spiny projection neurons comprise 95% of the total neuronal population of the human striatum. [2]
Dopaminergic pathways (dopamine pathways, dopaminergic projections) in the human brain are involved in both physiological and behavioral processes including movement, cognition, executive functions, reward, motivation, and neuroendocrine control. [1] Each pathway is a set of projection neurons, consisting of individual dopaminergic neurons.
Dendritic spines serve as a storage site for synaptic strength and help transmit electrical signals to the neuron's cell body. Most spines have a bulbous head (the spine head), and a thin neck that connects the head of the spine to the shaft of the dendrite. The dendrites of a single neuron can contain hundreds to thousands of spines.
Golgi cell circuit functions also seem to be regulated by metabotropic glutamate receptors. Golgi cells possess mGluR2 receptors, [ 12 ] and when these receptors are activated, an inward rectifier K current is enhanced, aiding in the Golgi cell's silencing after a period of intensive granule cell-Golgi cell transmission. [ 13 ]