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Stretch induced hyperexcitability of mice callosal pathway.

Fan A, Stebbings KA, Llano DA, Saif T - Front Cell Neurosci (2015)

Bottom Line: Memory and learning are thought to result from changes in synaptic strength.FA amplitude and activation rate decrease as excitability increases in stretch cases but not in electrically enhanced cases.These results collectively demonstrate that a small stretch in physiological range can modulate neural activities significantly, suggesting that mechanical events can be employed as a novel tool for the modulation of neural plasticity.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Science and Engineering, University of Illinois Urbana, IL, USA.

ABSTRACT
Memory and learning are thought to result from changes in synaptic strength. Previous studies on synaptic physiology in brain slices have traditionally been focused on biochemical processes. Here, we demonstrate with experiments on mouse brain slices that central nervous system plasticity is also sensitive to mechanical stretch. This is important, given the host of clinical conditions involving changes in mechanical tension on the brain, and the normal role that mechanical tension plays in brain development. A novel platform is developed to investigate neural responses to mechanical stretching. Flavoprotein autofluoresence (FA) imaging was employed for measuring neural activity. We observed that synaptic excitability substantially increases after a small (2.5%) stretch was held for 10 min and released. The increase is accumulative, i.e., multiple stretch cycles further increase the excitability. We also developed analytical tools to quantify the spatial spread and response strength. Results show that the spatial spread is less stable in slices undergoing the stretch-unstretch cycle. FA amplitude and activation rate decrease as excitability increases in stretch cases but not in electrically enhanced cases. These results collectively demonstrate that a small stretch in physiological range can modulate neural activities significantly, suggesting that mechanical events can be employed as a novel tool for the modulation of neural plasticity.

No MeSH data available.


Related in: MedlinePlus

Fluorescence intensities are averaged over the calculated activation areas. (A) Spatial activities in subsequent baseline measurements. Normalized activation area of the stretched and control groups are plotted. Two examples of activation areas: stretched on top, and control at the bottom. (B) An example of the  signal in one stretch experiment. Each line denotes the first FA response (out of 50 stimulations) in baseline 1–5 as labeled. All measurements are made when stretch is zero. After each baseline measurement, slice is held stretched for 10 min and then brought back to the original position before the next baseline measurement commences. Activation rate is defined as . (C) Normalized average amplitudes are plotted for the stretched and control groups. Slope of (D,F) amplitude and (E,G) rate vs. baseline measurement number and excitability from each experiment is averaged and compared. All error bars in SD. P-values obtained from 2-tail t-test with unequal variance.
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Figure 3: Fluorescence intensities are averaged over the calculated activation areas. (A) Spatial activities in subsequent baseline measurements. Normalized activation area of the stretched and control groups are plotted. Two examples of activation areas: stretched on top, and control at the bottom. (B) An example of the signal in one stretch experiment. Each line denotes the first FA response (out of 50 stimulations) in baseline 1–5 as labeled. All measurements are made when stretch is zero. After each baseline measurement, slice is held stretched for 10 min and then brought back to the original position before the next baseline measurement commences. Activation rate is defined as . (C) Normalized average amplitudes are plotted for the stretched and control groups. Slope of (D,F) amplitude and (E,G) rate vs. baseline measurement number and excitability from each experiment is averaged and compared. All error bars in SD. P-values obtained from 2-tail t-test with unequal variance.

Mentions: We note that the area of activation of the slice fluctuates in the stretched group (Figure 3A). Further looking into the spatial distribution and the strength of variation in the activation area, we observed a shift in the location of maximum activity in the stretched group. An example is shown in Figure 3A, with the stretched group at the top row and the control group at the bottom. It is thus possible that the stretch applied and released in between the 2 baseline measurements can lead to a spatial reconfiguration of excitability.


Stretch induced hyperexcitability of mice callosal pathway.

Fan A, Stebbings KA, Llano DA, Saif T - Front Cell Neurosci (2015)

Fluorescence intensities are averaged over the calculated activation areas. (A) Spatial activities in subsequent baseline measurements. Normalized activation area of the stretched and control groups are plotted. Two examples of activation areas: stretched on top, and control at the bottom. (B) An example of the  signal in one stretch experiment. Each line denotes the first FA response (out of 50 stimulations) in baseline 1–5 as labeled. All measurements are made when stretch is zero. After each baseline measurement, slice is held stretched for 10 min and then brought back to the original position before the next baseline measurement commences. Activation rate is defined as . (C) Normalized average amplitudes are plotted for the stretched and control groups. Slope of (D,F) amplitude and (E,G) rate vs. baseline measurement number and excitability from each experiment is averaged and compared. All error bars in SD. P-values obtained from 2-tail t-test with unequal variance.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525056&req=5

Figure 3: Fluorescence intensities are averaged over the calculated activation areas. (A) Spatial activities in subsequent baseline measurements. Normalized activation area of the stretched and control groups are plotted. Two examples of activation areas: stretched on top, and control at the bottom. (B) An example of the signal in one stretch experiment. Each line denotes the first FA response (out of 50 stimulations) in baseline 1–5 as labeled. All measurements are made when stretch is zero. After each baseline measurement, slice is held stretched for 10 min and then brought back to the original position before the next baseline measurement commences. Activation rate is defined as . (C) Normalized average amplitudes are plotted for the stretched and control groups. Slope of (D,F) amplitude and (E,G) rate vs. baseline measurement number and excitability from each experiment is averaged and compared. All error bars in SD. P-values obtained from 2-tail t-test with unequal variance.
Mentions: We note that the area of activation of the slice fluctuates in the stretched group (Figure 3A). Further looking into the spatial distribution and the strength of variation in the activation area, we observed a shift in the location of maximum activity in the stretched group. An example is shown in Figure 3A, with the stretched group at the top row and the control group at the bottom. It is thus possible that the stretch applied and released in between the 2 baseline measurements can lead to a spatial reconfiguration of excitability.

Bottom Line: Memory and learning are thought to result from changes in synaptic strength.FA amplitude and activation rate decrease as excitability increases in stretch cases but not in electrically enhanced cases.These results collectively demonstrate that a small stretch in physiological range can modulate neural activities significantly, suggesting that mechanical events can be employed as a novel tool for the modulation of neural plasticity.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Science and Engineering, University of Illinois Urbana, IL, USA.

ABSTRACT
Memory and learning are thought to result from changes in synaptic strength. Previous studies on synaptic physiology in brain slices have traditionally been focused on biochemical processes. Here, we demonstrate with experiments on mouse brain slices that central nervous system plasticity is also sensitive to mechanical stretch. This is important, given the host of clinical conditions involving changes in mechanical tension on the brain, and the normal role that mechanical tension plays in brain development. A novel platform is developed to investigate neural responses to mechanical stretching. Flavoprotein autofluoresence (FA) imaging was employed for measuring neural activity. We observed that synaptic excitability substantially increases after a small (2.5%) stretch was held for 10 min and released. The increase is accumulative, i.e., multiple stretch cycles further increase the excitability. We also developed analytical tools to quantify the spatial spread and response strength. Results show that the spatial spread is less stable in slices undergoing the stretch-unstretch cycle. FA amplitude and activation rate decrease as excitability increases in stretch cases but not in electrically enhanced cases. These results collectively demonstrate that a small stretch in physiological range can modulate neural activities significantly, suggesting that mechanical events can be employed as a novel tool for the modulation of neural plasticity.

No MeSH data available.


Related in: MedlinePlus