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).

Effects of neocortical ectopias upon the acquisition and retention of a non-spatial reference memory task in BXSB mice

1998 ◽  
Vol 111 (2) ◽  
pp. 291-293 ◽  
Author(s):  
S.A Balogh ◽  
G.F Sherman ◽  
L.A Hyde ◽  
V.H Denenberg
Keyword(s):  
Memory Task ◽  
Reference Memory ◽  
Spatial Reference ◽  
Spatial Reference Memory ◽  
Reference Memory Task ◽  
Bxsb Mice

GluR-A-deficient mice display normal acquisition of a hippocampus-dependent spatial reference memory task but are impaired during spatial reversal.

2003 ◽  
Vol 117 (4) ◽  
pp. 866-870 ◽  
Author(s):  
D. M. Bannerman ◽  
R. M. J. Deacon ◽  
P. H. Seeburg ◽  
J. N. P. Rawlins
Keyword(s):  
Memory Task ◽  
Reference Memory ◽  
Spatial Reversal ◽  
Spatial Reference ◽  
Spatial Reference Memory ◽  
Deficient Mice ◽  
Reference Memory Task

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

Bilateral peripheral vestibular lesions produce long-term changes in spatial learning in the rat

2003 ◽  
Vol 13 (1) ◽  
pp. 9-16
Author(s):  
Noah A. Russell ◽  
Arata Horii ◽  
Paul F. Smith ◽  
Cynthia L. Darlington ◽  
David K. Bilkey
Keyword(s):  
Spatial Learning ◽  
Memory Task ◽  
Reference Memory ◽  
Learning Task ◽  
Maze Learning ◽  
Vestibular Information ◽  
Spatial Reference Memory ◽  
Long Term Changes ◽  
Control Lesion

In order to investigate whether bilateral peripheral vestibular lesions cause long-term impairment of spatial learning, rats were tested in a reference memory radial arm maze learning task at least 5 weeks following a bilateral labyrinthectomy (BL) or sham control lesion. All control rats reached criterion (i.e., 1 error or less, averaged across 7 trials for 3 consecutive days of training) but only 4 of the 8 BL rats had reached criterion by day 21 of the training sessions. The control rats reached criterion more quickly than the lesioned rats (Control, 7.0 ± 0.63 days, Lesioned, 15.8 ± 1.4 days, t 10 = 5.84, p < 0.0001). This difference resulted from the greater number of errors made by the BL animals. However, the latency to respond was comparable as a result of the increased locomotor activity of the BL group (i.e., ’hyperkinesis), and the overall rate of acquisition of the task, as indicated by analysis of the exponential decrease in errors over the entire training period, was not significantly different between the 2 groups. The results of this study demonstrate that BL in rats produces long-term changes in performance in a spatial reference memory task, which are not simply due to the inability to move but may relate to the way that the brain uses vestibular information to create spatial representations and determines behavioural strategies on the basis of these representations.

scholarly journals Effects of Early Training and Nicotine Treatment on the Performance of Male NMRI Mice in the Water Maze

2003 ◽  
Vol 10 (4) ◽  
pp. 303-317 ◽  
Author(s):  
Paloma Vicens ◽  
M. Carmen Carrasco ◽  
Rosa Redolat
Keyword(s):  
Spatial Learning ◽  
Water Maze ◽  
Memory Task ◽  
Reference Memory ◽  
Learning Task ◽  
Nicotine Treatment ◽  
Age Related ◽  
Spatial Reference Memory ◽  
First Time ◽  
Early Training

This research aimed to evaluate the effect of nicotine treatment and prior training on a spatial learning task in differently aged NMRI male mice. In a longitudinal study, mice were randomly assigned to one of 14 experimental groups receiving different combinations of chronically injected nicotine (0.35 mg/kg) administered for 10 days (5 days before and during 5 days acquisition of task) or control treatments and training in the water maze at different ages. The mice displayed shorter escape latencies when evaluated at 6 and 10 months than when tested in this task at 2 months for the first time, demonstrating that early training preserves performance in the water maze up to 8 months after the initial experience. Nicotine treatment did not significantly change performance in the water maze at any age tested. Early practice in a spatial reference memory task appears to have lasting consequences and can potentially contribute to preventing some age-related spatial learning deficits.

Spatial reference memory in GluR-A-deficient mice using a novel hippocampal-dependent paddling pool escape task

Hippocampus ◽  
2004 ◽  
Vol 14 (2) ◽  
pp. 216-223 ◽  
Author(s):  
W.B. Schmitt ◽  
R.M.J. Deacon ◽  
D. Reisel ◽  
R. Sprengel ◽  
P.H. Seeburg ◽  
...  
Keyword(s):  
Reference Memory ◽  
Spatial Reference ◽  
Spatial Reference Memory ◽  
Deficient Mice

Unimpaired acquisition of spatial reference memory, but impaired homing performance in hippocampal-ablated pigeons

1988 ◽  
Vol 27 (2) ◽  
pp. 179-187 ◽  
Author(s):  
Verner P. Bingman ◽  
Paolo Ioalé ◽  
Giovanni Casini ◽  
Paola Bagnoli
Keyword(s):  
Reference Memory ◽  
Spatial Reference ◽  
Spatial Reference Memory ◽  
Homing Performance
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