A basal dendrite is a
dendrite
Dendrites (from Greek δένδρον ''déndron'', "tree"), also dendrons, are branched protoplasmic extensions of a nerve cell that propagate the electrochemical stimulation received from other neural cells to the cell body, or soma, of the n ...
that emerges from the base of a
pyramidal cell that receives information from nearby neurons and passes it to the soma, or cell body. Due to their direct attachment to the cell body itself, basal dendrites are able to deliver strong depolarizing currents and therefore have a strong effect on
action potential
An action potential occurs when the membrane potential of a specific cell location rapidly rises and falls. This depolarization then causes adjacent locations to similarly depolarize. Action potentials occur in several types of animal cells, ...
output in neurons. The physical characteristics of basal dendrites vary based on their location and species that they are found in. For example, the basal dendrites of humans are overall found to be the most intricate and spine-dense, as compared to other species such as Macaques. It is also observed that basal dendrites of the prefrontal cortex are larger and more complex in comparison to the smaller and simpler dendrites that can be seen within the visual cortex. Basal dendrites are capable of vast amounts of analog computing, which is responsible for many of the different nonlinear responses of modulating information in the
neocortex
The neocortex, also called the neopallium, isocortex, or the six-layered cortex, is a set of layers of the mammalian cerebral cortex involved in higher-order brain functions such as sensory perception, cognition, generation of motor commands, sp ...
. Basal dendrites additionally exist in dentate
granule cell
A granule is a large particle or grain. It can refer to:
* Granule (cell biology), any of several submicroscopic structures, some with explicable origins, others noted only as cell type-specific features of unknown function
** Azurophilic granul ...
s for a limited time before removal via regulatory factors.
This removal usually occurs before the cell reaches adulthood, and is thought to be regulated through both intracellular and extracellular signals.
Basal dendrites are part of the more overarching dendritic tree present on pyramidal neurons. They, along with
apical dendrites, make up the part of the neuron that receives most of the electrical signaling. Basal dendrites have been found to be involved mostly in neocortical information processing.
Dendritic arbor
Basal dendrites are part of sampling dendritic arbors.
These arbors are classified as sampling because they are not completely space filling, but make more than one specific, or selective connection.
For example, at the
CA1 pyramidal cell of a rat, there are 5 basal dendrites at the soma with 30 branch points, while space filling dendritic arbors can contain hundreds of branch points, and selective arbors can contain as few as 0 or 1.
[Figure 2]
is a representation of a CA1 pyramidal cells of a rat, showing many branch points and dendritic length.
Gene expression
In reference to a study on the genes related to basal dendrites, there is proven association with the TAOK2
Serine/threonine-protein kinase TAO2 is an enzyme that in humans is encoded by the ''TAOK2'' gene.
Interactions
TAOK2 has been shown to interact with MAP2K6 and MAP2K3
Dual specificity mitogen-activated protein kinase kinase 3 is an enzyme ...
gene and its interaction with the NPR1
Natriuretic peptide receptor A/guanylate cyclase A (atrionatriuretic peptide receptor A), also known as NPR1, is an atrial natriuretic peptide receptor. In humans it is encoded by the ''NPR1'' gene.
Function
NPR1 is a membrane-bound guanylate ...
-SEMA3A
Semaphorin-3A is a protein that in humans is encoded by the ''SEMA3A'' gene.
Function
The ''SEMA3A'' gene is a member of the semaphorin family and encodes a protein with an Ig-like C2-type (immunoglobulin-like) domain, a PSI domain and a Sema ...
signaling pathway. Research shows growth of basal dendrites when more of the TAOK2 gene is expressed while lower expression decreases the number of dendrites within mice. Additionally, decreasing expression of basal dendrites occurs when the Nrp1 gene is downregulated. Though, the effect can be cancelled through overexpression of TAOK2.
References
Further reading
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Cerebrum
Neurons
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