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Diffusion MRI of structural brain plasticity induced by a learning and memory task.

Blumenfeld-Katzir T, Pasternak O, Dagan M, Assaf Y - PLoS ONE (2011)

Bottom Line: Here we used diffusion tensor imaging (DTI) to examine the microstructural manifestations of neuroplasticity in rats that performed a spatial navigation task.We found that DTI can be used to define the selective localization of neuroplasticity induced by different tasks and that this process is age-dependent in cingulate cortex and corpus callosum and age-independent in the dentate gyrus.We relate the observed DTI changes to the structural plasticity that occurs in astrocytes and discuss the potential of MRI for probing structural neuroplasticity and hence indirectly localizing LTP.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.

ABSTRACT

Background: Activity-induced structural remodeling of dendritic spines and glial cells was recently proposed as an important factor in neuroplasticity and suggested to accompany the induction of long-term potentiation (LTP). Although T1 and diffusion MRI have been used to study structural changes resulting from long-term training, the cellular basis of the findings obtained and their relationship to neuroplasticity are poorly understood.

Methodology/principal finding: Here we used diffusion tensor imaging (DTI) to examine the microstructural manifestations of neuroplasticity in rats that performed a spatial navigation task. We found that DTI can be used to define the selective localization of neuroplasticity induced by different tasks and that this process is age-dependent in cingulate cortex and corpus callosum and age-independent in the dentate gyrus.

Conclusion/significance: We relate the observed DTI changes to the structural plasticity that occurs in astrocytes and discuss the potential of MRI for probing structural neuroplasticity and hence indirectly localizing LTP.

Show MeSH
Statistical parametric maps of the interactions between scan time and study group [learning (L), swimming only (S) and nonlearning (NL)] for (a) the apparent diffusion coefficient (ADC) and (b) the fractional anisotropy (FA).The statistical maps (colored regions) are superimposed on an averaged FA map of all rats that were scanned, with borders of the different anatomical regions outlined in blue (see Methods). Voxels that exceed a statistical threshold of P<0.05 (non-corrected) are colored according to the threshold they exceeded (see color scale), while those that did not exceed the threshold are not colored. We report only on regional clusters that exceeded a statistical threshold of P<0.05 corrected for multiple comparisons; these regions are shown in the insets. These regions include the dentate gyrus (DG), piriform cortex (PC), and S1/S2 cortex (SC) in the ADC maps (a), and the corpus callosum (CC) and PC in the FA maps (b).
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pone-0020678-g001: Statistical parametric maps of the interactions between scan time and study group [learning (L), swimming only (S) and nonlearning (NL)] for (a) the apparent diffusion coefficient (ADC) and (b) the fractional anisotropy (FA).The statistical maps (colored regions) are superimposed on an averaged FA map of all rats that were scanned, with borders of the different anatomical regions outlined in blue (see Methods). Voxels that exceed a statistical threshold of P<0.05 (non-corrected) are colored according to the threshold they exceeded (see color scale), while those that did not exceed the threshold are not colored. We report only on regional clusters that exceeded a statistical threshold of P<0.05 corrected for multiple comparisons; these regions are shown in the insets. These regions include the dentate gyrus (DG), piriform cortex (PC), and S1/S2 cortex (SC) in the ADC maps (a), and the corpus callosum (CC) and PC in the FA maps (b).

Mentions: Voxel-based mixed-design analysis of variance (ANOVA) between the two factors, group (learning [L], swimming only [S], and nonlearning [NL]) and time (1st and 2nd MRI scans), revealed significant multiregional interaction, indicating that in certain brain regions changes in DTI indices differed between the three groups (Fig. 1) as a function of scanning time. This was observed for both the apparent diffusion coefficient (ADC) and the fractional anisotropy (FA) in several brain regions, including the: dentate gyrus (DG), cingulate cortex (CG, posterior part), piriform cortex (PC), S1/S2 cortex (SC) and corpus callosum (CC). These regions exceeded a statistical threshold of P<0.05 (corrected for multiple comparisons); nevertheless, for visualization purposes figure 1 also shows voxels that exceeded a non-corrected threshold (P<0.05). Similar analysis was performed on the radial and axial diffusivities (see supporting text S1 and Figure S2).


Diffusion MRI of structural brain plasticity induced by a learning and memory task.

Blumenfeld-Katzir T, Pasternak O, Dagan M, Assaf Y - PLoS ONE (2011)

Statistical parametric maps of the interactions between scan time and study group [learning (L), swimming only (S) and nonlearning (NL)] for (a) the apparent diffusion coefficient (ADC) and (b) the fractional anisotropy (FA).The statistical maps (colored regions) are superimposed on an averaged FA map of all rats that were scanned, with borders of the different anatomical regions outlined in blue (see Methods). Voxels that exceed a statistical threshold of P<0.05 (non-corrected) are colored according to the threshold they exceeded (see color scale), while those that did not exceed the threshold are not colored. We report only on regional clusters that exceeded a statistical threshold of P<0.05 corrected for multiple comparisons; these regions are shown in the insets. These regions include the dentate gyrus (DG), piriform cortex (PC), and S1/S2 cortex (SC) in the ADC maps (a), and the corpus callosum (CC) and PC in the FA maps (b).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3119075&req=5

pone-0020678-g001: Statistical parametric maps of the interactions between scan time and study group [learning (L), swimming only (S) and nonlearning (NL)] for (a) the apparent diffusion coefficient (ADC) and (b) the fractional anisotropy (FA).The statistical maps (colored regions) are superimposed on an averaged FA map of all rats that were scanned, with borders of the different anatomical regions outlined in blue (see Methods). Voxels that exceed a statistical threshold of P<0.05 (non-corrected) are colored according to the threshold they exceeded (see color scale), while those that did not exceed the threshold are not colored. We report only on regional clusters that exceeded a statistical threshold of P<0.05 corrected for multiple comparisons; these regions are shown in the insets. These regions include the dentate gyrus (DG), piriform cortex (PC), and S1/S2 cortex (SC) in the ADC maps (a), and the corpus callosum (CC) and PC in the FA maps (b).
Mentions: Voxel-based mixed-design analysis of variance (ANOVA) between the two factors, group (learning [L], swimming only [S], and nonlearning [NL]) and time (1st and 2nd MRI scans), revealed significant multiregional interaction, indicating that in certain brain regions changes in DTI indices differed between the three groups (Fig. 1) as a function of scanning time. This was observed for both the apparent diffusion coefficient (ADC) and the fractional anisotropy (FA) in several brain regions, including the: dentate gyrus (DG), cingulate cortex (CG, posterior part), piriform cortex (PC), S1/S2 cortex (SC) and corpus callosum (CC). These regions exceeded a statistical threshold of P<0.05 (corrected for multiple comparisons); nevertheless, for visualization purposes figure 1 also shows voxels that exceeded a non-corrected threshold (P<0.05). Similar analysis was performed on the radial and axial diffusivities (see supporting text S1 and Figure S2).

Bottom Line: Here we used diffusion tensor imaging (DTI) to examine the microstructural manifestations of neuroplasticity in rats that performed a spatial navigation task.We found that DTI can be used to define the selective localization of neuroplasticity induced by different tasks and that this process is age-dependent in cingulate cortex and corpus callosum and age-independent in the dentate gyrus.We relate the observed DTI changes to the structural plasticity that occurs in astrocytes and discuss the potential of MRI for probing structural neuroplasticity and hence indirectly localizing LTP.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.

ABSTRACT

Background: Activity-induced structural remodeling of dendritic spines and glial cells was recently proposed as an important factor in neuroplasticity and suggested to accompany the induction of long-term potentiation (LTP). Although T1 and diffusion MRI have been used to study structural changes resulting from long-term training, the cellular basis of the findings obtained and their relationship to neuroplasticity are poorly understood.

Methodology/principal finding: Here we used diffusion tensor imaging (DTI) to examine the microstructural manifestations of neuroplasticity in rats that performed a spatial navigation task. We found that DTI can be used to define the selective localization of neuroplasticity induced by different tasks and that this process is age-dependent in cingulate cortex and corpus callosum and age-independent in the dentate gyrus.

Conclusion/significance: We relate the observed DTI changes to the structural plasticity that occurs in astrocytes and discuss the potential of MRI for probing structural neuroplasticity and hence indirectly localizing LTP.

Show MeSH