Variety is good for memory
Geneticists have shown how new neurons develop in the adult brain
Scientists from the Salk Institute for Biological Research tracked the development of new neurons in the adult brain and found that the new cells have much more in common with embryonic cells than previously thought, reports RNS. The study was published in the journal Nature Neuroscience (Gonçalves et al., In vivo imaging of dendritic pruning in dentate granule cells).
Billions of brain cells are formed before birth, but in some areas of the mammalian brain, stem cells develop into neurons in adulthood. The authors studied the cells in the dentate gyrus – the area of the brain responsible for the formation of new memories.
As part of the study, scientists monitored the development of mouse brain cells in real time for several weeks. The authors of the work placed animals in different environments that differed in the presence or absence of stimuli. In the case when the animal was in a cage with a large number of objects (running wheels, plastic pipes), brain cells grew faster, sending many branched dendrites to the cells, receiving signals from surrounding neurons. Animals in empty cells showed slower growth of neurons and fewer dendrites.
New neurons and their dendrites fluoresce green
against the background of the blue–colored nuclei of the surrounding cells - VM.
"The surprising thing is that initially the cells grew faster and became larger, but then they shrank and resembled all other cells," the authors of the work say (in a press release from the Salk Institute for Biological Studies Adult brain prunes branched connections of new neurons – VM).
A dendrite is a branched process of a neuron that receives information through synapses from other neurons and transmits it via an electrical signal to the body of the neuron from which it grows. The researchers suggest that the more dendrites a neuron forms, the more plasticity it requires to reduce dendritic branching. "The results obtained indicate that there is a significant biological pressure aimed at preserving or maintaining the dendritic tree of the neuron," the authors explain the results.
Pathology of dendrites is associated with brain disorders. This study will help to understand the mechanisms of many diseases, including autism, schizophrenia and various mental disorders, scientists say.
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11.05.2016