The swimming control group in spatial reference memory task: analysis of its motor cortex activity

2020 ◽  
pp. 45-55
Author(s):  
S. Cid-Duarte ◽  
A. Gutiérrez-Menéndez ◽  
C. Zorzo ◽  
J.L. Arias ◽  
M. Méndez
Keyword(s):  
Motor Cortex ◽  
Task Analysis ◽  
Memory Task ◽  
Reference Memory ◽  
Control Group ◽  
Spatial Reference ◽  
Spatial Reference Memory ◽  
Reference Memory Task

scholarly journals Dentate spikes and learning: disrupting hippocampal function during memory consolidation can improve pattern separation

2019 ◽  
Vol 121 (1) ◽  
pp. 131-139 ◽  
Author(s):  
Sanna Lensu ◽  
Tomi Waselius ◽  
Markku Penttonen ◽  
Miriam S. Nokia
Keyword(s):  
Associative Learning ◽  
Memory Consolidation ◽  
Memory Task ◽  
Reference Memory ◽  
Learning Task ◽  
Pattern Separation ◽  
Spatial Reference ◽  
Neural Representations ◽  
Spatial Reference Memory ◽  
Reference Memory Task

Hippocampal dentate spikes (DSs) are short-duration, large-amplitude fluctuations in hilar local field potentials and take place while resting and sleeping. During DSs, dentate gyrus granule cells increase firing while CA1 pyramidal cells decrease firing. Recent findings suggest DSs play a significant role in memory consolidation after training on a hippocampus-dependent, nonspatial associative learning task. Here, we aimed to find out whether DSs are important in other types of hippocampus-dependent learning tasks as well. To this end, we trained adult male Sprague-Dawley rats in a spatial reference memory task, a fixed interval task, and a pattern separation task. During a rest period immediately after each training session, we either let neural activity to take place as usual, timed electrical stimulation of the ventral hippocampal commissure (vHC) to immediately follow DSs, or applied the vHC stimulation during a random neural state. We found no effect of vHC stimulation on performance in the spatial reference memory task or in the fixed interval task. Surprisingly, vHC stimulation, especially contingent on DSs, improved performance in the pattern separation task. In conclusion, the behavioral relevance of hippocampal processing and DSs seems to depend on the task at hand. It could be that in an intact brain, offline memory consolidation by default involves associating neural representations of temporally separate but related events. In some cases this might be beneficial for adaptive behavior in the future (associative learning), while in other cases it might not (pattern separation). NEW & NOTEWORTHY The behavioral relevance of dentate spikes seems to depend on the learning task at hand. We suggest that dentate spikes are related to associating neural representations of temporally separate but related events within the dentate gyrus. In some cases this might be beneficial for adaptive behavior in the future (associative learning), while in other cases it might not (pattern separation).

scholarly journals Ketamine affects the integration of developmentally generated granule neurons in the adult stage

2019 ◽  
Author(s):  
Zhanqiang Zhao ◽  
Bing Li ◽  
Yuqing Wu ◽  
Xujun Chen ◽  
Yan Guo ◽  
...  
Keyword(s):  
Functional Integration ◽  
Reference Memory ◽  
Control Group ◽  
Granule Neurons ◽  
Sprague Dawley ◽  
General Anesthetic ◽  
Spatial Reference ◽  
Spatial Reference Memory ◽  
Dividing Cells ◽  
Hippocampus Dependent Memory

Abstract Background Ketamine has been reported to cause neonatal neurotoxicity in a variety of developing animal models. Various studies have been conducted to study the mechanism of neurotoxicity for general anesthetic use during the neonatal period. Previous experiments have suggested that developmentally generated granule neurons in the hippocampus dentate gyrus (DG) supported hippocampus-dependent memory. Therefore, this study aimed to investigate whether ketamine affects the functional integration of developmentally generated granule neurons in the DG. For this purpose ， the postnatal day 7 (PND-7) Sprague-Dawley (SD) rats were divided into the control group and the ketamine group (rats who received 4 injections of 40 mg/kg ketamine at 1 h intervals). To label dividing cells, BrdU was administered for three consecutive days after the ketamine explore; NeuN+/BrdU+ cells were observed by using immunofluorescence. To evaluate the developmentally generated granule neurons that support hippocampus-dependent memory, spatial reference memory was tested by using Morris Water Maze at 3 months old, after which the immunofluorescence was used to detect c-Fos expression in the NeuN + /BrdU + cells. The expression of caspase-3 was measured by western blot to detect the apoptosis in the hippocampal DG. Results The present results showed that the neonatal ketamine exposure did not influence the survival rate of developmentally generated granule neurons at 2 and 3 months old, but ketamine interfered with the integration of these neurons into the hippocampal DG neural circuits and caused a deficit in hippocampal-dependent spatial reference memory tasks. Conclusions In summary, these findings may promote more studies to investigate the neurotoxicity of ketamine in the developing brain.

scholarly journals Ketamine affects the integration of developmentally generated granule neurons in the adult stage

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Zhanqiang Zhao ◽  
Bing Li ◽  
Yuqing Wu ◽  
Xujun Chen ◽  
Yan Guo ◽  
...  
Keyword(s):  
Functional Integration ◽  
Reference Memory ◽  
Control Group ◽  
Granule Neurons ◽  
Sprague Dawley ◽  
General Anesthetic ◽  
Spatial Reference ◽  
Spatial Reference Memory ◽  
Dividing Cells ◽  
Hippocampus Dependent Memory

Abstract Background Ketamine has been reported to cause neonatal neurotoxicity in a variety of developing animal models. Various studies have been conducted to study the mechanism of neurotoxicity for general anesthetic use during the neonatal period. Previous experiments have suggested that developmentally generated granule neurons in the hippocampus dentate gyrus (DG) supported hippocampus-dependent memory. Therefore, this study aimed to investigate whether ketamine affects the functional integration of developmentally generated granule neurons in the DG. For this purpose,the postnatal day 7 (PND-7) Sprague-Dawley (SD) rats were divided into the control group and the ketamine group (rats who received 4 injections of 40 mg/kg ketamine at 1 h intervals). To label dividing cells, BrdU was administered for three consecutive days after the ketamine exposure; NeuN+/BrdU+cells were observed by using immunofluorescence. To evaluate the developmentally generated granule neurons that support hippocampus-dependent memory, spatial reference memory was tested by using Morris Water Maze at 3 months old, after which the immunofluorescence was used to detect c-Fos expression in the NeuN+/BrdU+ cells. The expression of caspase-3 was measured by western blot to detect the apoptosis in the hippocampal DG. Results The present results showed that the neonatal ketamine exposure did not influence the survival rate of developmentally generated granule neurons at 2 and 3 months old, but ketamine interfered with the integration of these neurons into the hippocampal DG neural circuits and caused a deficit in hippocampal-dependent spatial reference memory tasks. Conclusions In summary, these findings may promote more studies to investigate the neurotoxicity of ketamine in the developing brain.

scholarly journals Ketamine affects the integration of developmentally generated granule neurons in the adult stage

2019 ◽  
Author(s):  
Zhanqiang Zhao ◽  
Bing Li ◽  
Yuqing Wu ◽  
Xujun Chen ◽  
Yan Guo ◽  
...  
Keyword(s):  
Functional Integration ◽  
Reference Memory ◽  
Control Group ◽  
Granule Neurons ◽  
Sprague Dawley ◽  
General Anesthetic ◽  
Spatial Reference ◽  
Spatial Reference Memory ◽  
Dividing Cells ◽  
Hippocampus Dependent Memory

Abstract Background Ketamine has been reported to cause neonatal neurotoxicity in a variety of developing animal models. Various studies have been conducted to study the mechanism of neurotoxicity for general anesthetic use during the neonatal period. Previous experiments have suggested that developmentally generated granule neurons in the hippocampus dentate gyrus (DG) supported hippocampus-dependent memory. Therefore, this study aimed to investigate whether ketamine affects the functional integration of developmentally generated granule neurons in the DG. For this purpose，the postnatal day 7 (PND-7) Sprague-Dawley (SD) rats were divided into the control group and the ketamine group (rats who received 4 injections of 40 mg/kg ketamine at 1 h intervals). To label dividing cells, BrdU was administered for three consecutive days after the ketamine exposure; NeuN+/BrdU+ cells were observed by using immunofluorescence. To evaluate the developmentally generated granule neurons that support hippocampus-dependent memory, spatial reference memory was tested by using Morris Water Maze at 3 months old, after which the immunofluorescence was used to detect c-Fos expression in the NeuN+/BrdU+ cells. The expression of caspase-3 was measured by Western blot to detect the apoptosis in the hippocampal DG.ResultsThe present results showed that the neonatal ketamine exposure did not influence the survival rate of developmentally generated granule neurons at 2 and 3 months old, but ketamine interfered with the integration of these neurons into the hippocampal DG neural circuits and caused a deficit in hippocampal-dependent spatial reference memory tasks.ConclusionsIn summary, these findings may promote more studies to investigate the neurotoxicity of ketamine in the developing brain.

scholarly journals Selective H3 Antagonist (ABT-239) Differentially Modifies Cognitive Function Under the Impact of Restraint Stress

2021 ◽  
Vol 14 ◽  
Author(s):  
Emil Trofimiuk ◽  
Przemysław Wielgat ◽  
Halina Car
Keyword(s):  
Spatial Memory ◽  
Restraint Stress ◽  
Reference Memory ◽  
Control Group ◽  
Memory Impairments ◽  
Spatial Reference ◽  
Spatial Reference Memory ◽  
Pre Treatment ◽  
New Compounds ◽  
The Impact

Background: A considerable number of competitive antagonists/inverse agonists of histamine H3 receptor (H3R) have progressed to clinical assessment, with pitolisant approved for the treatment of narcolepsy. H3R, highly expressed in the CNS, is regarded as a relevant target in CNS disorders. At the same time, new compounds including ABT-239 H3R antagonist (ABT; benzonitrile, 4-[2-[2-[(2R)-2-methyl-1-pyrrolidinyl]ethyl]-5-benzofuranyl]-) are continually being tested. The study aimed to test ABT-239 as a prophylactic agent in stress-induced memory impairments.Methods: Stressed and non-stressed rats were pre-treated with ABT-239 and subsequently subjected to several behavioral tests aimed at assessing the animals’ working and spatial reference memory [Morris water maze (MWM), Barnes maze (BM)], assessing the locomotor function and anxiety-like behavior [Open field (OF), elevated “plus” maze—EPM].Results: Chronically stressed rats displayed a significant decline in spatial (working and reference) memory. In the MWM test, we observed an improvement in spatial reference memory in stressed animals and a positive after ABT-239 pre-treatment. In the BM test, the effect of ABT-239 administration on spatial memory changed in successive attempts, from negative initially to favorable in subsequent attempts, and negative in the last trial of the test in the control group of rats. However, a beneficial effect is noted in the group of stressed animals, which remained throughout the entire testing period.Conclusions: Presented findings demonstrate that ABT-239 shows the potential to abolish or prevent restraint stress-induced spatial memory impairments and cognitive deficits. However, in conditions of appetitive modulation, it could increase damage to memory (unstressed animals).

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