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Hippocampal Synaptic Expansion Induced by Spatial Experience in Rats Correlates with Improved Information Processing in the Hippocampus.

Carasatorre M, Ochoa-Alvarez A, Velázquez-Campos G, Lozano-Flores C, Ramírez-Amaya V, Díaz-Cintra SY - PLoS ONE (2015)

Bottom Line: The "catFISH" imaging method provided neurophysiological evidence that hippocampal pattern separation improved in animals treated as SC, and this improvement was even clearer in animals that experienced the WM training.By measuring the area occupied by synaptophysin staining in both the stratum oriens and the stratun lucidum of the distal CA3, we found evidence of structural synaptic plasticity that likely includes MF expansion.Finally, the measures of hippocampal network coding obtained with catFISH correlate significantly with the increased density of synaptophysin staining, strongly suggesting that structural synaptic plasticity in the hippocampus induced by the WM and SC experience is related to the improvement of spatial information processing in the hippocampus.

View Article: PubMed Central - PubMed

Affiliation: Department of "Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología", Universidad Nacional Autónoma de México, Querétaro, México.

ABSTRACT
Spatial water maze (WM) overtraining induces hippocampal mossy fiber (MF) expansion, and it has been suggested that spatial pattern separation depends on the MF pathway. We hypothesized that WM experience inducing MF expansion in rats would improve spatial pattern separation in the hippocampal network. We first tested this by using the the delayed non-matching to place task (DNMP), in animals that had been previously trained on the water maze (WM) and found that these animals, as well as animals treated as swim controls (SC), performed better than home cage control animals the DNMP task. The "catFISH" imaging method provided neurophysiological evidence that hippocampal pattern separation improved in animals treated as SC, and this improvement was even clearer in animals that experienced the WM training. Moreover, these behavioral treatments also enhance network reliability and improve partial pattern separation in CA1 and pattern completion in CA3. By measuring the area occupied by synaptophysin staining in both the stratum oriens and the stratun lucidum of the distal CA3, we found evidence of structural synaptic plasticity that likely includes MF expansion. Finally, the measures of hippocampal network coding obtained with catFISH correlate significantly with the increased density of synaptophysin staining, strongly suggesting that structural synaptic plasticity in the hippocampus induced by the WM and SC experience is related to the improvement of spatial information processing in the hippocampus.

No MeSH data available.


Related in: MedlinePlus

Synaptophysin-staining analysis in the hippocampus.Representative MosaiX montage images that covers all the CA3 and part (after trimming) of the CA1 hippocampal regions: in green is the Map-2 immunostaining and in red the synaptophysin staining in animals from the IC (A), SC (B), and WM (C) groups; the white bar represents 500 μm. (D) The bars represent the average synaptophysin/Map2 staining (±SEM) in each group (IC, SC, and WM) for each ROI (see Methods). Note that only in the CA3 SOd (stratum oriens distal), the CA3 SLd (stratum lucidum distal), and the CA1 SO (stratum oriens) were significant differences found between groups. Fisher post hoc analysis of the WM vs. the IC ***p<0.001, **p<0.01, *p<0.05; WM vs. the SC ##p<0.01.
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pone.0132676.g008: Synaptophysin-staining analysis in the hippocampus.Representative MosaiX montage images that covers all the CA3 and part (after trimming) of the CA1 hippocampal regions: in green is the Map-2 immunostaining and in red the synaptophysin staining in animals from the IC (A), SC (B), and WM (C) groups; the white bar represents 500 μm. (D) The bars represent the average synaptophysin/Map2 staining (±SEM) in each group (IC, SC, and WM) for each ROI (see Methods). Note that only in the CA3 SOd (stratum oriens distal), the CA3 SLd (stratum lucidum distal), and the CA1 SO (stratum oriens) were significant differences found between groups. Fisher post hoc analysis of the WM vs. the IC ***p<0.001, **p<0.01, *p<0.05; WM vs. the SC ##p<0.01.

Mentions: Immonostained tissue for synaptophysin and Map2 imaged with the Zeiss ApoTome™ system, equipped with a motorized stage which allows the acquisition of montage or mosaic images with the MosaiX software. Images were taken with the 25X/0.8 NA objective. One Zeiss LSM file containing the MosaiX montage was open using imageJ software and the color channels were separated (split channels). Then each channel went through the median filter and assigned its representative color. The nuclear counterstaining DAPI is shown in blue (A for CA1 and E for CA3). Map 2 is shown in Green (B for CA1 and F for CA3) and synaptophysin is shown in RED (C for CA1 and G for CA3). The merge colors image is shown in D for CA1 and H for CA3. The magnification shown here was done by only trimming the montage image and by applying a regular zoom-in using adobe photoshop. This is a proper example of the image resolution the experimenter had available for analysis (He can perform the same simple zoom-in magnification with the same results), and was obtained from a similar montage image as those shown in Figs 6 and 8. Calibration bar (lower right) represents 200 μm.


Hippocampal Synaptic Expansion Induced by Spatial Experience in Rats Correlates with Improved Information Processing in the Hippocampus.

Carasatorre M, Ochoa-Alvarez A, Velázquez-Campos G, Lozano-Flores C, Ramírez-Amaya V, Díaz-Cintra SY - PLoS ONE (2015)

Synaptophysin-staining analysis in the hippocampus.Representative MosaiX montage images that covers all the CA3 and part (after trimming) of the CA1 hippocampal regions: in green is the Map-2 immunostaining and in red the synaptophysin staining in animals from the IC (A), SC (B), and WM (C) groups; the white bar represents 500 μm. (D) The bars represent the average synaptophysin/Map2 staining (±SEM) in each group (IC, SC, and WM) for each ROI (see Methods). Note that only in the CA3 SOd (stratum oriens distal), the CA3 SLd (stratum lucidum distal), and the CA1 SO (stratum oriens) were significant differences found between groups. Fisher post hoc analysis of the WM vs. the IC ***p<0.001, **p<0.01, *p<0.05; WM vs. the SC ##p<0.01.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526663&req=5

pone.0132676.g008: Synaptophysin-staining analysis in the hippocampus.Representative MosaiX montage images that covers all the CA3 and part (after trimming) of the CA1 hippocampal regions: in green is the Map-2 immunostaining and in red the synaptophysin staining in animals from the IC (A), SC (B), and WM (C) groups; the white bar represents 500 μm. (D) The bars represent the average synaptophysin/Map2 staining (±SEM) in each group (IC, SC, and WM) for each ROI (see Methods). Note that only in the CA3 SOd (stratum oriens distal), the CA3 SLd (stratum lucidum distal), and the CA1 SO (stratum oriens) were significant differences found between groups. Fisher post hoc analysis of the WM vs. the IC ***p<0.001, **p<0.01, *p<0.05; WM vs. the SC ##p<0.01.
Mentions: Immonostained tissue for synaptophysin and Map2 imaged with the Zeiss ApoTome™ system, equipped with a motorized stage which allows the acquisition of montage or mosaic images with the MosaiX software. Images were taken with the 25X/0.8 NA objective. One Zeiss LSM file containing the MosaiX montage was open using imageJ software and the color channels were separated (split channels). Then each channel went through the median filter and assigned its representative color. The nuclear counterstaining DAPI is shown in blue (A for CA1 and E for CA3). Map 2 is shown in Green (B for CA1 and F for CA3) and synaptophysin is shown in RED (C for CA1 and G for CA3). The merge colors image is shown in D for CA1 and H for CA3. The magnification shown here was done by only trimming the montage image and by applying a regular zoom-in using adobe photoshop. This is a proper example of the image resolution the experimenter had available for analysis (He can perform the same simple zoom-in magnification with the same results), and was obtained from a similar montage image as those shown in Figs 6 and 8. Calibration bar (lower right) represents 200 μm.

Bottom Line: The "catFISH" imaging method provided neurophysiological evidence that hippocampal pattern separation improved in animals treated as SC, and this improvement was even clearer in animals that experienced the WM training.By measuring the area occupied by synaptophysin staining in both the stratum oriens and the stratun lucidum of the distal CA3, we found evidence of structural synaptic plasticity that likely includes MF expansion.Finally, the measures of hippocampal network coding obtained with catFISH correlate significantly with the increased density of synaptophysin staining, strongly suggesting that structural synaptic plasticity in the hippocampus induced by the WM and SC experience is related to the improvement of spatial information processing in the hippocampus.

View Article: PubMed Central - PubMed

Affiliation: Department of "Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología", Universidad Nacional Autónoma de México, Querétaro, México.

ABSTRACT
Spatial water maze (WM) overtraining induces hippocampal mossy fiber (MF) expansion, and it has been suggested that spatial pattern separation depends on the MF pathway. We hypothesized that WM experience inducing MF expansion in rats would improve spatial pattern separation in the hippocampal network. We first tested this by using the the delayed non-matching to place task (DNMP), in animals that had been previously trained on the water maze (WM) and found that these animals, as well as animals treated as swim controls (SC), performed better than home cage control animals the DNMP task. The "catFISH" imaging method provided neurophysiological evidence that hippocampal pattern separation improved in animals treated as SC, and this improvement was even clearer in animals that experienced the WM training. Moreover, these behavioral treatments also enhance network reliability and improve partial pattern separation in CA1 and pattern completion in CA3. By measuring the area occupied by synaptophysin staining in both the stratum oriens and the stratun lucidum of the distal CA3, we found evidence of structural synaptic plasticity that likely includes MF expansion. Finally, the measures of hippocampal network coding obtained with catFISH correlate significantly with the increased density of synaptophysin staining, strongly suggesting that structural synaptic plasticity in the hippocampus induced by the WM and SC experience is related to the improvement of spatial information processing in the hippocampus.

No MeSH data available.


Related in: MedlinePlus