Cholinergic afferents to the locus coeruleus and noradrenergic afferents to the medial septum mediate LTP-reinforcement in the dentate gyrus by stimulation of the amygdala

Jorge A. Bergado, Sabine Martina Frey, Jeffrey López, William Almaguer-Melian, Julietta Uta Frey

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Transient long-term potentiation (E-LTP) can be transformed into a long-lasting LTP (L-LTP) in the dentate gyrus (DG) by behavioral stimuli with high motivational content. Previous research from our group has identified several brain structures, such as the basolateral amygdala (BLA), the locus coeruleus (LC), the medial septum (MS) and transmitters as noradrenaline (NA) and acetylcholine (ACh) that are involved in these processes. Here we have investigated the functional interplay among brain structures and systems which result in the conversion of a E-LTP into a L-LTP (reinforcement) by stimulation of the BLA (BLA-R). We used topical application of specific drugs into DG, and other targets, while following the time course of LTP induced by stimulation of the perforant pathway (PP) to study their specific contribution to BLA-R. One injection cannula, a recording electrode in the DG and stimulating electrodes in the PP and the BLA were stereotactically implanted one week before electrophysiological experiments. Topical application of atropine or propranolol into the DG blocked BLA-R in both cases, but the effect of propranolol occurred earlier, suggesting a role of NA within the DG during an intermediate stage of LTP maintenance. The injection of lidocaine into the LC abolished BLA-R indicating that the LC is part of the functional neural reinforcing system. The effect on the LC is mediated by cholinergic afferents because application of atropine into the LC produced the same effect. Injection of lidocaine inactivating the MS also abolished BLA-R. This effect was mediated by noradrenergic afferents (probably from the LC) because the application of propranolol into the MS prevented BLA-R. These findings suggest a functional loop for BLA-R involving cholinergic afferents to the LC, a noradrenergic projection from the LC to the DG and the MS, and finally, the cholinergic projection from the MS to the DG.

Original languageEnglish (US)
Pages (from-to)331-341
Number of pages11
JournalNeurobiology of Learning and Memory
Volume88
Issue number3
DOIs
StatePublished - Oct 1 2007

Fingerprint

Locus Coeruleus
Dentate Gyrus
Amygdala
Cholinergic Agents
Propranolol
Perforant Pathway
Lidocaine
Atropine
Injections
Norepinephrine
Electrodes
Basolateral Nuclear Complex
Long-Term Potentiation
Brain
Acetylcholine
Maintenance

Keywords

  • Early-LTP
  • Hippocampus
  • Late-LTP
  • Learning
  • Memory formation
  • Memory system
  • Reinforcement

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Cognitive Neuroscience
  • Behavioral Neuroscience

Cite this

Cholinergic afferents to the locus coeruleus and noradrenergic afferents to the medial septum mediate LTP-reinforcement in the dentate gyrus by stimulation of the amygdala. / Bergado, Jorge A.; Frey, Sabine Martina; López, Jeffrey; Almaguer-Melian, William; Frey, Julietta Uta.

In: Neurobiology of Learning and Memory, Vol. 88, No. 3, 01.10.2007, p. 331-341.

Research output: Contribution to journalArticle

Bergado, Jorge A. ; Frey, Sabine Martina ; López, Jeffrey ; Almaguer-Melian, William ; Frey, Julietta Uta. / Cholinergic afferents to the locus coeruleus and noradrenergic afferents to the medial septum mediate LTP-reinforcement in the dentate gyrus by stimulation of the amygdala. In: Neurobiology of Learning and Memory. 2007 ; Vol. 88, No. 3. pp. 331-341.
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AU - Almaguer-Melian, William

AU - Frey, Julietta Uta

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