Wednesday, February 6, 2013

Exercise and the Brain


This is a study I stumbled across that I found intriguing which shows changes in the structure and density of hippocampal astrocytes in rats undergoing an exercise program.  The references included in the introduction also seem noteworthy for those wishing to delve deeper into the subject of the effect of exercise on the brain and how this may relate to mental health issues.

"There is a considerable evidence to show that physical
exercise has a positive effect on brain function in both
humans (Hillman et al. 2008; Laurin et al. 2001) and animals
(Albeck et al. 2006; Farmer et al. 2004; Stranahan
et al. 2010). Physical exercise improves cognitive functions
(Kashihara et al. 2009; Kramer et al. 2006) and memory
(Alaei et al. 2008; de Senna et al. 2011), reduces anxiety
and depression (Martinsen 2008), and has protective
properties on a wide variety of neurological diseases,
such as Parkinson’s disease (Smith and Zigmond 2003),
Alzheimer’s disease (Mirochnic et al. 2009) and ischemic
stroke (Stummer et al. 1994).
Studies designed to shed light on the neurobiological
bases of these benefits have demonstrated that physical
exercise is involved in cerebral plasticity. Exercise can
induce neurogenesis (Kim et al. 2003; van Praag et al.
1999a, b, 2005) and increase the release of neurotrophic
factors such as: brain-derived neurotrophic factor (BDNF),
nerve growth factor (NGF), fibroblast growth factor (FGF)
and their mRNAs (Berchtold et al. 2010; Go´mez-Pinilla
et al. 1997; Neeper et al. 1996). Physical exercise can also
induce long-term potentiation (LTP) (van Praag et al. 1999a)
and angiogenesis (van der Borght et al. 2009). In addition,
physical activity can increase the most common markers of
hippocampal synaptic and structural plasticity, such as
synapsin I, neurofilaments, microtubule-associated protein 2
(Ferreira et al. 2011).
Nevertheless, there are only a few studies that have
investigated the effects of exercise in astrocytes in animals
and humans. Some of these studies report that physical
exercise was able to increase the glial fibrillary acidic
protein (GFAP) expression as well as the number of GFAPpositive
astrocytes in the frontoparietal cortex and striatum
(Li et al. 2005), and stimulate the proliferation of the
astrocytes in the subgranular zone of the hippocampus of
rodents (Uda et al. 2006).
Thus, the goal of our study was to analyze the effects of
physical exercise in the morphology of GFAP-positive
hippocampal astrocytes, more specifically, in the stratum
radiatum within the CA1 (Interaural 6.70 mm/Bregma
-2.30 mm to Interaural 4.70 mm/Bregma -4.30 mm), a
region that contains numerous astrocytes and is involved in
important functions including learning and memory
(Catalani et al. 2002; Squire et al. 2004)."

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