Structural plasticity in hippocampal cells related to the facilitative effect of intracranial self-stimulation on a spatial memory task.
Posttraining intracranial self-stimulation (SS) in the lateral hypothalamus facilitates the acquisition and retention of several implicit and explicit memory tasks. Here, intracellular injections of Lucifer yellow were used to assess morphological changes in hippocampal neurons that might be specifically related to the facilitative posttraining SS effect upon the acquisition and retention of a distributed spatial task in the Morris water maze. We examined the structure, size and branching complexity of cornus ammonis 1 (CA1) cells, and the spine density of CA1 pyramidal neurons and granular cells of the dentate gyrus (DG). Animals that received SS after each acquisition session performed faster and better than Sham ones--an improvement that was also evident in a probe trial 3 days after the last training session. The neuromorphological analysis revealed an increment in the size and branching complexity in apical CA1 dendritic arborization in SS-treated subjects as compared with Sham animals. Furthermore, increased spine density was observed in the CA1 field in SS animals, whereas no effects were observed in DG cells. Our results support the hypothesis that the facilitating effect of SS on the acquisition and retention of a spatial memory task could be related to structural plasticity in CA1 hippocampal cells.
Instituto de Neurociencia, Universidad Autonoma de Barcelona.
Jacobo
J
Chamorro-López
Departamento de Psicologia Basica I, Facultad de Psicologia, Universidad Nacional de Educacion a Distancia.
Miguel
M
Miguéns
Instituto de Neurociencia, Universidad Autonoma de Barcelona.
Ignacio
I
Morgado-Bernal
Laboratorio Cajal de Circuitos Corticales, Universidad Politecnica de Madrid.
Asta
A
Kastanauskaite
Departamento de Psicobiologia, Facultad de Psicologia, Universidad Nacional de Educacion a Distancia.
Abraham
A
Selvas
Instituto de Neurociencia, Universidad Autonoma de Barcelona.
Alberto
A
Cabané-Cucurella
Instituto de Neurociencia, Universidad Autonoma de Barcelona.
Laura
L
Aldavert-Vera
Instituto Cajal (CSIC), Centro de Investigacion Biomedica en Red, Enfermedades Neurodegenerativas (CIBERNED).
Javier
J
DeFelipe
Instituto de Neurociencia, Universidad Autonoma de Barcelona.
Pilar
P
Segura-Torres
D000818:Animals; D056547:CA1 Region, Hippocampal / Q000166:cytology / Q000502:physiology*; D049229:Dendritic Spines / Q000502:physiology; D018891:Dentate Gyrus / Q000166:cytology / Q000502:physiology*; D058542:Implantable Neurostimulators; D008297:Male; D018782:Maze Learning / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D011897:Random Allocation; D017208:Rats, Wistar; D012653:Self Stimulation / Q000502:physiology*; D065852:Spatial Memory / Q000502:physiology*