Stellate cells are

neuron A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...

s in the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...

, named for their star-like shape formed by dendritic processes radiating from the cell body. These cells play significant roles in various brain functions, including inhibition in the

cerebellum The cerebellum (: cerebella or cerebellums; Latin for 'little brain') is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as it or eve ...

and excitation in the

cortex Cortex or cortical may refer to: Biology * Cortex (anatomy), the outermost layer of an organ ** Cerebral cortex, the outer layer of the vertebrate cerebrum, part of which is the ''forebrain'' *** Motor cortex, the regions of the cerebral cortex i ...

, and are involved in

synaptic plasticity In neuroscience, synaptic plasticity is the ability of synapses to Chemical synapse#Synaptic strength, strengthen or weaken over time, in response to increases or decreases in their activity. Since memory, memories are postulated to be represent ...

and neurovascular coupling.

Morphology

Stellate cells are characterized by their star-shaped dendritic trees. Dendrites can vary between neurons, with stellate cells being either spiny or aspinous. In contrast, pyramidal cells, which are also found in the cerebral cortex, are always spiny and pyramid-shaped. The classification of neurons often depends on the presence or absence of dendritic spines: those with spines are classified as spiny, while those without are classified as aspinous.

Types and locations

Cerebellar

Many stellate cells are GABAergic and are located in the molecular layer of the

. Most common stellate cells are the

inhibitory An inhibitory postsynaptic potential (IPSP) is a kind of synaptic potential that makes a Chemical synapse, postsynaptic neuron less likely to generate an action potential.Purves et al. Neuroscience. 4th ed. Sunderland (MA): Sinauer Associates, Inc ...

interneurons found within the upper half of the molecular layer in the cerebellum. These cells synapse onto the dendritic trees of Purkinje cells and send inhibitory signals. Stellate cells are derived from dividing progenitor cells in the white matter of the postnatal cerebellum.

Cortical

Stellate neurons are also found in the cortex. Cortical spiny stellate cells are located in layer IVC of the

primary visual cortex The visual cortex of the brain is the area of the cerebral cortex that processes visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalamus ...

, and in the somatosensory barrel cortex of mice and rats, glutamatergic (excitatory) spiny stellate cells are organized in layer 4 of the barrel cortex. These cells receive excitatory synaptic fibers from the thalamus and process feed-forward excitation to layers 2/3 of the primary visual cortex to pyramidal cells. Cortical spiny stellate cells exhibit a 'regular' firing pattern.

Other locations

GABAergic aspinous stellate cells are also found in the somatosensory cortex. These cells can be immunohistochemically labeled with glutamic acid decarboxylase (GAD) due to their GABAergic activity, and they occasionally colocalize with neuropeptides.

Development

Stellate and basket cells originate from the cerebellar ventricular zone (CVZ) along with Purkinje cells and Bergmann glia. These cells follow a similar pathway during migration, starting in the deep layer of the white matter, moving through the internal granular layer (IGL) and the Purkinje cell layer (PCL) until reaching the molecular layer. In the molecular layer, stellate cells change orientation and positioning until they reach their final placement, guided by Bergmann glial cells.

Function

Stellate cells receive Excitatory Post Synaptic Potentials (EPSCs) from parallel fibers. The characteristics of these EPSCs depend on the pattern and frequency of presynaptic activity, influencing the extent and duration of inhibition within the cerebellar cortex. Synapses between parallel fibers and stellate cells exhibit plasticity, allowing for long-term changes in synaptic efficacy. This

can occur at both parallel fiber-stellate cell synapses and parallel fiber-Purkinje cell synapses, suggesting a role in cerebellar motor learning.

Neurovascular Coupling

Cerebellar stellate cells also play a crucial role in neurovascular coupling. Electrophysiological stimulation of single stellate cells is sufficient to release nitric oxide (NO) and induce dilation of blood vessels.

References

External links

NIF Search - Stellate Cell
via the Neuroscience Information Framework {{Cortex types Cerebellum Human cells Central nervous system neurons