title: Rewarding brain stimulation reverses the disruptive effect of amygdala damage on emotional learning.
abstract: Intracranial self-stimulation (SS) in the lateral hypothalamus, a rewarding deep-brain stimulation, is able to improve acquisition and retention of implicit and explicit memory tasks in rats. SS treatment is also able to reverse cognitive deficits associated with aging or with experimental brain injuries and evaluated in a two-way active avoidance (2wAA) task. The main objective of the present study was to explore the potential of the SS treatment to reverse the complete learning and memory impairment caused by bilateral lesion in the lateral amygdala (LA). The effects of post-training SS, administered after each acquisition session, were evaluated on distributed 2wAA acquisition and 10-day retention in rats with electrolytic bilateral LA lesions. SS effect in acetylcholinestaresase (AchE) activity was evaluated by immunohistochemistry in LA-preserved and Central nuclei (Ce) of the amygdala of LA-damaged rats. Results showed that LA lesion over 40% completely impeded 2wAA acquisition and retention. Post-training SS in the LA-lesioned rats improved conditioning and retention compared with both the lesioned but non-SS treated and the non-lesioned control rats. SS treatment also seemed to induce a decrease in AchE activity in the LA-preserved area of the lesioned rats, but no effects were observed in the Ce. This empirical evidence supports the idea that self-administered rewarding stimulation is able to completely counteract the 2wAA acquisition and retention deficits induced by LA lesion. Cholinergic mechanisms in preserved LA and the contribution of other brain memory-related areas activated by SS could mediate the compensatory effect observed.
authors.affiliation: Universitat de Girona, Departament de Biologia, 17071 Girona, Spain.
authors.forename: Elisabet
authors.initials: E
authors.lastname: Kádár
authors.affiliation: Universitat Autònoma de Barcelona, Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Institut de Neurociències, 08193 Bellaterra, Barcelona, Spain.
authors.forename: Marc
authors.initials: M
authors.lastname: Ramoneda
authors.affiliation: Universitat Autònoma de Barcelona, Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Institut de Neurociències, 08193 Bellaterra, Barcelona, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Aldavert-Vera
authors.affiliation: Universitat de Girona, Departament de Biologia, 17071 Girona, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Huguet
authors.affiliation: Universitat Autònoma de Barcelona, Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Institut de Neurociències, 08193 Bellaterra, Barcelona, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Morgado-Bernal
authors.affiliation: Universitat Autònoma de Barcelona, Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Institut de Neurociències, 08193 Bellaterra, Barcelona, Spain. Electronic address: pilar.segura@uab.cat.
authors.forename: Pilar
authors.initials: P
authors.lastname: Segura-Torres
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000679:Amygdala / Q000293:injuries*; D000704:Analysis of Variance; D000818:Animals; D001362:Avoidance Learning / Q000502:physiology; D001930:Brain Injuries / Q000150:complications* / Q000473:pathology; D046690:Deep Brain Stimulation / Q000379:methods*; D004195:Disease Models, Animal; D004572:Electrolysis / Q000009:adverse effects; D008297:Male; D008569:Memory Disorders / Q000209:etiology / Q000628:therapy*; D051381:Rats; D017208:Rats, Wistar; D012201:Reward; D012646:Self Administration
chemical_list: D000110:Acetylcholinesterase
keywords: Acetylcholine; Deep brain stimulation; Intracranial self-stimulation; Lateral amygdala lesion; Memory enhancement