One of the most
interesting things about neuroscience is that your brain isn’t restricted to a
certain about of neurons. A neuron is a cell that is part of the body’s nervous
system, which transmits and receives electrical and chemical signals. It has
the ability to send information over a long distance due to its electrochemical
aspect. It has a structure of three main parts: soma, axon and dendrites. The
soma is the body of the cell, it contains the nucleus that holds the majority
of RNA, also in the cell there are ribosomes and endoplasmic reticulum. The
function of the axon is to transmit information to other muscles, organs and
cells through electrical impulses. Some types of neuron have no Axon so they
emit the signals from their dendrites. However the main role of the dendrite is
to process the electrochemical signal received from other neural cells, this
would explain why sensory neurons have dendrites on both end of the cell.
Our brains are made of
around 100 billion neural cells, produced during pre-natal development. However
our brain can create new ones during neurogenesis in the hippocampus and sub
ventricular zone. During this
process neural stem cells are capable to differentiate into brain neurons via
external stimulus. Once these cells have become specialised the brain is
replenished with unspecialised cells, giving them the opportunity to
differentiate in to new neurons providing no limit of the brain’s capacity.
Research has shown for
exercise to cause neurogenesis, due to the production of BDNF
(Brain-Derived-Neurotrophic Factor) proteins. When you exercise it is believed
BDNF is released due to the stress factor, in order to protect current neurons
as well a promote the production of new ones. The other purpose of BDNF
production is to promote the ability of connection between two neurons to
change in strength in response to stimuli, this is known as Synaptic
plasticity. BDNF is secreted due to the influx in calcium (which is due to the
rise in stress levels) because it causes transcription on nerve cells within
the hippocampus and the transcription causes the secretion of BDNF. MK McGovern
on his article about the effect of exercise on the brain he also describes BDNF
as ‘reparative’, during exercise the axons are regenerated by injured neurons
by ‘neutrophin-signalling mechanism’
The hippocampus has an
important job in consolidating long and short-term memory as well as spatial
navigation. It is believed that the hippocampus provides declarative memory,
which is long-term memory using knowledge and facts. So therefore with an
increase in neurons in the hippocampus, more electrical signals can be passed
around, so you’re better at memorising things. For things to be remembered,
there has to be certain strength between the neurons, if two neurons receive an
electrical signal then they will communicate better in the future, this is
known as long-term potentiation.
To conclude, exercise
does have an effect on the brain due to the production of new nerve cells
during neurogenesis which happens in the response to stress.
References
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