The Longevity of Hippocampus-Dependent Memory Is Orchestrated by the Locus Coeruleus-Noradrenergic System

Table 1

Modulation of hippocampus-dependent memory via locus coeruleus activation.

Memory stages	Method of LC activation/suppression	Effect on memory	Reference
Encoding	Bilateral LC lesions	Impaired spatial memory in T-maze	[21]
	Electrical LC stimulation with 100 Hz	Improved acquisition of food-reinforced task	[57]
	Bilateral/unilateral LC lesions	Unilateral mildly, bilateral severely impaired memory assessed by Greek cross version of water maze	[23]
	LC clonidine injection	Deficits in attention, radial maze: no effect on working memory	[83]
	Electrical LC stimulation with 100 Hz	Promoted encoding of spatial memory via ß-adrenoreceptor activation	[27]
	LC lidocaine injection	Impaired acquisition of reference and working memory	[84]
	DSP 4 treatment in APP/PS1 mice	Exacerbation of short-term olfactory memory deficits	[85]
	Immunotoxic ablation of LC neurons	Water maze task: working memory deficits	[86]
	Photostimulation of LC axons	Spatial object recognition memory enhancement, D1/5 receptor dependent	[41]
Consolidation	Electrolytic LC lesions	Memory consolidation is achieved	[22]
	LC lidocaine injection	Affected memory retention in an inhibitory avoidance task after training impaired memory consolidation	[87]
	LC muscimol microinfusion	Impaired object recognition memory consolidation	[88]
	Electrical LC stimulation with 100 Hz	Caused reference memory deficit	[89]
	Electrical LC stimulation with 20 Hz	No effect on spatial learning	[89]
	Photostimulation of LC TH+ neurons	Novelty associated memory enhancement, D1/5 receptor dependent	[40]
Retrieval	Electrical LC stimulation	Facilitated memory retrieval	[50]
	Idazoxan treatment	α2 receptor antagonism enhance memory retrieval	[51]
	Electrical LC stimulation	Reduced forgetting via activation of ß-adrenoreceptors	[52]
	LC agmatine infusion	Facilitated memory retrieval, yohimbine facilitated, whereas clonidine attenuated the effects of agmatine within the LC	[90]
Extinction	Electrical LC stimulation with 100 Hz	Improved extinction of food-reinforced task	[57]

APP/PS1: amyloid precursor protein/presenilin 1; D1/5: dopamine D1/5 receptors: Hz: hertz; LC: locus coeruleus; min: minutes; SP4: N-(2-chloroethyl)-N-ethyl-bromo-benzylamine; LC: locus coeruleus; TH+: thyrosine hydroxylase positive.