Post-training intracranial self-stimulation facilitates a hippocampus-dependent task.
Previous research has shown that post-training intracranial self-stimulation facilitates implicit or procedural memory. To know whether it can also facilitate explicit memory, post-training intracranial self-stimulation was given to Wistar rats immediately after every daily session of a delayed spatial alternation task that seems to depend on the integrity of the hippocampal memory system. We tested the effects of intracranial self-stimulation in three consecutive learning phases which tried to make the task progressively more difficult: 10 s delay (D10 phase), 30 s delay (D30 phase), and inverting the starting position of the animals to make their response more dependent on allocentric cues (INV phase). Every phase finished when each rat achieved a fixed learning criterion. Intracranial self-stimulation facilitated the flexible expression of the learned response (INV phase). That is, when the starting position was randomly inverted, only the rats that received intracranial self-stimulation maintained the performance level acquired in the previous training phases. Changing the starting position reduced the correct performance of the non-treated subjects, which need more training sessions to achieve the learning criterion and made less correct responses than treated rats. These findings show that post-training intracranial self-stimulation can facilitate hippocampus-dependent memories.
Soriano-Mas
Carles
C
Unitat de Psicobiologia, Institut de Neurociències, Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Facultat de Psicologia, Edifici B., Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
Redolar-Ripoll
Diego
D
Aldavert-Vera
Laura
L
Morgado-Bernal
Ignacio
I
Segura-Torres
Pilar
P
D000818:Animals; D001362:Avoidance Learning / Q000502:physiology / Q000528:radiation effects*; D001522:Behavior, Animal / Q000528:radiation effects; D004558:Electric Stimulation / Q000379:methods; D006624:Hippocampus / Q000502:physiology* / Q000528:radiation effects; D008297:Male; D018782:Maze Learning / Q000502:physiology / Q000528:radiation effects; D008568:Memory / Q000502:physiology*; D009043:Motor Activity / Q000502:physiology; D011214:Practice, Psychological; D051381:Rats; D017208:Rats, Wistar; D012153:Retention, Psychology / Q000502:physiology / Q000528:radiation effects; D012653:Self Stimulation; D013028:Space Perception / Q000502:physiology / Q000528:radiation effects; D013238:Stereotaxic Techniques; D013997:Time Factors