Limits...
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

Exploration procedures and catFISH.(A) The animals explored the first environment for 5 min, and 25 min later they explored the second environment for 5 min in either the AA (same box same room), AA’ (different box same room), or AB (different box different room) condition. Animals were sacrificed immediately after the second 5 min exploration and their brains extracted, frozen and later process for FISH to detect Arc mRNA. Examples of CA1 (B) and CA3 (C) confocal images (1 filtered plane from the stack) stained for Arc mRNA detection and used to perform the catFISH analysis; in green is the nuclear counterstaining “Sytox” and in red is the Arc signal. Note that neuronal nuclei have texture, and their Sytox signal is dim, while glial cells look solid and bright. The Arc signal can be observed as 2 transcription foci inside the nuclei (solid arrows), or as cytoplasmic Arc staining surrounding the neuronal nuclei (open arrows), or as double Arc staining (arrowhead). The bar represents 50 μm.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4526663&req=5

pone.0132676.g002: Exploration procedures and catFISH.(A) The animals explored the first environment for 5 min, and 25 min later they explored the second environment for 5 min in either the AA (same box same room), AA’ (different box same room), or AB (different box different room) condition. Animals were sacrificed immediately after the second 5 min exploration and their brains extracted, frozen and later process for FISH to detect Arc mRNA. Examples of CA1 (B) and CA3 (C) confocal images (1 filtered plane from the stack) stained for Arc mRNA detection and used to perform the catFISH analysis; in green is the nuclear counterstaining “Sytox” and in red is the Arc signal. Note that neuronal nuclei have texture, and their Sytox signal is dim, while glial cells look solid and bright. The Arc signal can be observed as 2 transcription foci inside the nuclei (solid arrows), or as cytoplasmic Arc staining surrounding the neuronal nuclei (open arrows), or as double Arc staining (arrowhead). The bar represents 50 μm.

Mentions: The “catFISH” imaging method was done by detecting the immediate early gene Arc (or Arg3.1), and used as a neurophysiological measure of spatial pattern separation [22, 23]. Arc expression is used as a tag of neuronal activity [24], and we can distinguish its presence in the nuclei vs the cytoplasm, indicating recent or earlier neural activation, respectively. With this, we can distinguish the neural units activated by each of two spatial exploration experiences separated by a ~30-min interval, which we term epochs (Fig 2). With the similarity score from catFISH results we can determine, with one measurement, the extent of overlap between the ensembles recruited by each of the two independent behavioral epochs [23]. This provided a neurophysiological measure of spatial pattern separation [22, 23, 25 and 26] and support for the idea that a previous “spatial experience” improve it, as observed particularly in animals that underwent the WM, but also, the SC treatment.


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)

Exploration procedures and catFISH.(A) The animals explored the first environment for 5 min, and 25 min later they explored the second environment for 5 min in either the AA (same box same room), AA’ (different box same room), or AB (different box different room) condition. Animals were sacrificed immediately after the second 5 min exploration and their brains extracted, frozen and later process for FISH to detect Arc mRNA. Examples of CA1 (B) and CA3 (C) confocal images (1 filtered plane from the stack) stained for Arc mRNA detection and used to perform the catFISH analysis; in green is the nuclear counterstaining “Sytox” and in red is the Arc signal. Note that neuronal nuclei have texture, and their Sytox signal is dim, while glial cells look solid and bright. The Arc signal can be observed as 2 transcription foci inside the nuclei (solid arrows), or as cytoplasmic Arc staining surrounding the neuronal nuclei (open arrows), or as double Arc staining (arrowhead). The bar represents 50 μm.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0132676.g002: Exploration procedures and catFISH.(A) The animals explored the first environment for 5 min, and 25 min later they explored the second environment for 5 min in either the AA (same box same room), AA’ (different box same room), or AB (different box different room) condition. Animals were sacrificed immediately after the second 5 min exploration and their brains extracted, frozen and later process for FISH to detect Arc mRNA. Examples of CA1 (B) and CA3 (C) confocal images (1 filtered plane from the stack) stained for Arc mRNA detection and used to perform the catFISH analysis; in green is the nuclear counterstaining “Sytox” and in red is the Arc signal. Note that neuronal nuclei have texture, and their Sytox signal is dim, while glial cells look solid and bright. The Arc signal can be observed as 2 transcription foci inside the nuclei (solid arrows), or as cytoplasmic Arc staining surrounding the neuronal nuclei (open arrows), or as double Arc staining (arrowhead). The bar represents 50 μm.
Mentions: The “catFISH” imaging method was done by detecting the immediate early gene Arc (or Arg3.1), and used as a neurophysiological measure of spatial pattern separation [22, 23]. Arc expression is used as a tag of neuronal activity [24], and we can distinguish its presence in the nuclei vs the cytoplasm, indicating recent or earlier neural activation, respectively. With this, we can distinguish the neural units activated by each of two spatial exploration experiences separated by a ~30-min interval, which we term epochs (Fig 2). With the similarity score from catFISH results we can determine, with one measurement, the extent of overlap between the ensembles recruited by each of the two independent behavioral epochs [23]. This provided a neurophysiological measure of spatial pattern separation [22, 23, 25 and 26] and support for the idea that a previous “spatial experience” improve it, as observed particularly in animals that underwent the WM, but also, the SC treatment.

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