Aerobic
exercise and its effect on the Brain
Earlier
in the semester, Dr. Art Kramer of the Beckman Institute for Advance Science and
Technology at the University of Illinois presented his work on the effects of
aerobic exercise on the brain. Over the course of his lecture, Dr. Kramer
offered compelling evidence that moderate habitual can increase cognitive
abilities like memory, executive function, attention, and motor skills. However,
most of the studies that suggest this relationship are longitudinal in nature
in which various characteristics of the person are measured at the onset of the
experiment and then measured again after a long period of time. In regards to
the effect of exercise on these cognitive functions, individuals were tested
before and after they adopted an exercise regimen in order to determine effect.
However, Dr. Kramer offered additional fMRI images to corroborate the data in
these studies. Specifically, these images showed an increased size of the
hippocampus – and the vascular areas surrounding it – when comparing the before
and after images. This growth in the region associated with memory supports the
overall conclusion of these long term studies. Dr. Kramer explained that it is
a well-known fact that aerobic exercise spurs angiogenesis and neurogenesis – that
is capillary growth and growth of neurons respectively. However, the period of exercise
required to bring about substantial structural change to the brain was a wide
margin ranging anywhere from 3 months to a year.
In
an experiment conducted by Christie et al. 2013, a systematic approach is used
to find a threshold value for the point at which structural changes to the
brain become observable. Using Sprague-Dawley rats, researchers looked for long
term potentiation of neurons of the Dentate Gyrus as a marker. The running periods
exhibited by the rats were 3, 7, 14, 28, and 56 days respectively. The researchers
discovered that both long term and short periods of exercise resulted in cell
proliferation at the Dentate Gyrus. However, increases in neurogenesis were
found to take much longer than short term periods. It was observed that “Increases
in immature neurons did not occur until the animal had been running for a minimum
of 14 days” (Christie et al 2013)[1].
Though, reliable long term potentiation did not occur until 56 days of running.
They concluded that the neurons produced
in response to exercising – those that appeared after 14 days – did not ‘contribute
significantly’ until the rat had matured. This study
could potentially lead to a more accurate indication of the amount of exercise
needed to induce the cognitive benefits of exercise.
[1] Patton,
., Sickmann, ., Hryciw, ., Kucharsky, ., Parton, ., & Christie, . (2013,
October 16). Long-term exercise is needed to enhance synaptic plasticity in the
hippocampus [abstract]. In www.pubmed.gov. Retrieved December 12,
2013, from pubmed (DOI: 10.1101/lm.030635.113).
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