Table 1.
Adaptive Myelination and Physical Activity.
| Activity type | Activity method | Duration | Subject | Findings | Timing of findings | Reference |
|---|---|---|---|---|---|---|
| Studies examining adaptive myelination | ||||||
| Motor learning | Reaching task | 15 min/day 11 days | Rats 4–5 months | MRI WM: Increased FA in the external capsule, cingulum, corpus callosum, and internal capsule contralateral to reaching paw | 11 days | Sampaio-Baptista et al. (2013) |
| Increased MBP concentration in areas contralateral to reaching paw | ||||||
| Motor learning | Finger tapping task | 10 min/day 4 weeks | Humans 18–40 years | MRI WM & GM:Increase in FA in the right hemisphere caudate nucleus and corticospinal tract, and tracts linking the middle frontal gyrus to the caudate nucleus | 4 weeks | Reid et al. (2017) |
| MRI GM: Decreased FA in nucleus accumbens | ||||||
| Motor learning | Juggling | 6 weeks | Humans 18–33 years | MRI WM: Significant FAincrease in in the right posterior intraparietal sulcus white matter | 6 weeks | Scholz et al. (2009) |
| Not statistically significant but notable decrease in previously observed increased FA | 10 weeks | |||||
| Motor learning | Running on a complex wheel | 3 weeks Mice were euthanized at various time points | Mice (P60 and P90) | WM: transient increase in OPCs in corpus callosum | 4–6 days | McKenzie et al. (2014) |
| WM: 40% increase in immature and mature OLs in the corpus callosum | 11 days | |||||
| WM: 94% of EdU+ cells were OL lineage cells in the corpus callosum | ||||||
| WM: 50% more mature OLs than controls in the corpus callosum | 3 weeks | |||||
| No increase in OPC proliferation when wheel was removed for a week and reintroduced | ||||||
| Motor learning | Lever-pulling task | 12 days | Mice (6 weeks) | GM: Increase in MBP mRNA expression in the left primary motor cortex | 12 days | Kato et al. (2019) |
| GM: More mature OLs in the left primary motor cortex in WT mice than in PLP-tg mice following motor learning | ||||||
| WM: More mature OLs in the subcortical white matter in WT mice than in PLP-tg mice following motor learning | ||||||
| Motor learning | Running on a complex wheel | 1 week Mice were euthanized at various time points | Mice P85 | WM: Significant increase in newly differentiating OLs in subcortical white matter | 2.5 h | Xiao et al. (2016) |
| WM & GM: Significant increase in newly differentiating OLs in the motor cortex and subcortical white matter | 4 hours | |||||
| WM & GM: 50% increase in newly differentiating OLs in the motor cortex and subcortical white matter | 12 h | |||||
| WM & GM: Two fold increase in newly differentiating OLs in the motor cortex and subcortical white matter | 24 h | |||||
| WM & GM: Significant increase in newly formed OLs in the motor cortex and subcortical white matter | 2–4 days | |||||
| WM & GM: Increase of newly differentiating OLs compared to earlier persisted | 8 days | |||||
| Voluntary physical exercise | Running on a regular wheel | 2 weeks | Mice 8 weeks | GM: Increase MBP expression in the motor cortex | 2 weeks | **Zheng et al. (2019) |
| GM: Significantly more OL lineage cells, OLs, and OPCs in the motor cortex | ||||||
| GM: No change in density PDGFRα+/Olig 2+ OPCs in the motor cortex | ||||||
| Voluntary physical exercise | Running on a regular wheel | 12 days Mice were euthanized at various time points | Mice P65 (adult) | WM: Significant increase in OPCs in the corpus callosum | 4 days | McKenzie et al. (2014) |
| Voluntary physical exercise | Running on a regular wheel | 125 days | Mice P21–P23 | GM: No increase in myelin in the cerebellum | 125 days | **Alvarez-Saavedra et al. (2016) |
| GM: Slight increase in OPC proliferation in the cerebellum | ||||||
| Voluntary physical exercise | Running on a regular wheel | 6 weeks | Mice 8 weeks | GM: No significant difference in MBP or CNP expression in the striatum | 6 weeks | **Mandolesi et al. (2019) |
| Voluntary physical exercise | Running on a regular wheel | 3, 7 or 28 days | Rats 2 months | No difference in the major components of myelin -- the four isoforms of MBP, CNP, or PLP/DM20 in the spinal cord | 3 days | Ghiani et al. (2007) |
| 1 week | ||||||
| 4 weeks | ||||||
| Voluntary physical exercise | Running on a regular wheel | 7 weeks | Mice 9 weeks | No increase in protein expression of MBP. 1.4-fold increase in PLP1 expression. Elevated RNA expression for MBP and PLP. No effect on CNP RNA expression. 1.4-fold increase in Myrf expression. No significant increase in the number of OPCs or OLs. All observations were made in the spinal cord. | 7 weeks | Yoon et al. (2016) |
| Voluntary physical exercise | Running on a regular wheel | 2 weeks | Rats | GM: Significant increase in OPCs in the frontal cortex but not in the retrosplenial cortex or occipital cortex | 2 weeks | Hall et al. (2014) |
| Forced exercise | Treadmill running | 3 weeks | Mice 4 weeks | WM: Increase in proliferating OPCs and mature OLs. Higher MBP intensity in the corpus callosum | 3 weeks | Chen et al. (2019) |
| Voluntary physical exercise | Running on a regular wheel | 2 weeks | Mice 8–12 weeks | GM: 1.2 fold increase in number of OPCs WM: No OPC proliferation or differentiation observed in the corpus callosum GM: No OPC proliferation or differentiation observed in the piriform cortex | 2 weeks | Eugenin von Bernhardi and Dimou (2022) |
| 4 weeks | GM: significant increase differentiation of GPR17+ OPC cells GM: 1.45 fold increase proliferation of GPR17+ OPC glia GM: 1.4 fold increase in number of OPCs GM: 36.6% increase in OPC proliferation 130.2% increase in NG2 cell differentiation WM: No OPC proliferation or differentiation observed in the corpus callosum GM: No OPC proliferation or differentiation observed in the piriform cortex | 4 weeks | ||||
(**) indicates that although a voluntary exercise paradigm was used, the experiment also used motor learning assays to assess motor ability. It is indicated whether changes in OL lineage cells occurred in white matter (WM) or grey matter (GM). Acronyms: fractional anisotropy (FA), oligodendrocytes (OL), oligodendrocyte precursors cells (OPC).