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Diversity of the dendritic tree, functional consequences
Rab Nóra, 2016. 09. 29.
The word ‘dendrite’ originates from the Greek déndron, which means ‘tree’.
These neuronal structures propagate the electrochemical stimulation
received from other neural cells to the cell body. Furthermore, they integrate
synaptic potentials and generate the output of the cell.
Dendrites are highly branched projections - the emergence of the dendritic
tree is called arborization. The most significant morphological feature of
neuron is the dendritic tree. Different neuron types have different patterns of
dendritic arborizations, which are so characteristic that we can unmistakably
identify the class of the given neuron. Using this criterion alone, hundreds of
neuron types have been described. These arborizations extend over
hundreds, sometimes thousands of microns, and they are precisely arranged.
The shape of the dendrites reflects both the necessity of accommodating
inputs from specific locations and the requirement that these inputs be
processed in a specific way.
The characteristic shape of dendrites is often clue to the way neurons process
information. For example, the horizontal cell in the retina has two separate
regions of dendritic arborization. It is believed that potentials are transformed
separately in the two regions, with little information passing between them.
They integrate and regulate the input from multiple photoreceptor cells. One
of their function is allowing eyes to adjust to see well under both bright and
dim light condition.
The dendritic tree takes part in neuronal plasticity and remodeling. Dendrites
themselves are capable of plastic changes during the adult life of living
beings, even in invertebrates. There are changes in the dendrite structure,
even in adults (e.g. as a result of physiological conditions induced by
hormones in females). These changes affect communication and signal
processing in the cell.
Sources:
https://users.itk.ppke.hu/neurobiologia/LECTURES_20162017_SEMESTER_1/3.%20WEEK/3.%20LITERATURE/Dendrites.pdf
https://en.wikipedia.org/wiki/Dendrite
https://en.wikipedia.org/wiki/Retina_horizontal_cell