title: Cholinergic septo-hippocampal innervation is required for trace eyeblink classical conditioning.
abstract: We studied the effects of a selective lesion in rats, with 192-IgG-saporin, of the cholinergic neurons located in the medial septum/diagonal band (MSDB) complex on the acquisition of classical and instrumental conditioning paradigms. The MSDB lesion induced a marked deficit in the acquisition, but not in the retrieval, of eyeblink classical conditioning using a trace paradigm. Such a deficit was task-selective, as lesioned rats were able to acquire a fixed-interval operant conditioning as controls, and was not due to nonspecific motor alterations, because spontaneous locomotion and blink reflexes were not disturbed by the MSDB lesion. The deficit in the acquisition of a trace eyeblink classical conditioning was reverted by the systemic administration of carbachol, a nonselective cholinergic muscarinic agonist, but not by lobeline, a nicotinic agonist. These results suggest a key role of muscarinic denervation on the acquisition of new motor abilities using trace classical conditioning procedures. It might also be suggested that muscarinic agents would be useful for the amelioration of some associative learning deficits observed at early stages in patients with Alzheimer's disease.
authors.affiliation: División de Neurociencias, Universidad Pablo de Olavide de Sevilla, 41013-Sevilla, Spain.
authors.forename: Angela
authors.initials: A
authors.lastname: Fontán-Lozano
authors.forename: Julieta
authors.initials: J
authors.lastname: Troncoso
authors.forename: Alejandro
authors.initials: A
authors.lastname: Múnera
authors.forename: Angel Manuel
authors.initials: AM
authors.lastname: Carrión
authors.forename: José María
authors.initials: JM
authors.lastname: Delgado-García
mesh_terms: D000818:Animals; D001245:Association Learning / Q000502:physiology; D002799:Cholinergic Fibers / Q000502:physiology*; D003215:Conditioning, Eyelid / Q000502:physiology*; D005143:Eyelids / Q000294:innervation*; D006624:Hippocampus / Q000166:cytology / Q000502:physiology*; D008297:Male; D009434:Neural Pathways / Q000166:cytology / Q000502:physiology; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000502:physiology; D012686:Septal Nuclei / Q000166:cytology / Q000502:physiology*
chemical_list: D011976:Receptors, Muscarinic