There is increasing evidence indicating that slow wave sleep (SWS) supports memory consolidation. This effect may in part originate from phasic noradrinergic (NE) activity occurring during SWS in the presence of tonically lowered NE levels. Here, we examined whether NE supports the consolidation of amygdala-dependent emotional memory during SWS.

In a double-blind cross-over study, 15 men learned emotional and neutral materials (stories, pictures) in the evening before a 3-h period of early SWS-rich retention sleep, during which either placebo or clonidine, an α2-adrenoceptor agonist which blocks locus coeruleus NE release, was intravenously infused. Memory retrieval as well as affective ratings and heart rate responses to the pictures were assessed 23 h after learning.

Clonidine reduced plasma NE levels but had no effect on SWS. While retention of story content words and pictures per se remained unaffected, clonidine distinctly blocked the superiority of emotional compared to neutral memory for temporal order, with this superiority of emotional over neutral memories observed only in the placebo condition. Heart rate responses to pictures were not affected, but whereas under placebo conditions familiar negative pictures were rated less arousing and with a more negative valence compared to pictures not seen before; these differences were abolished after clonidine.

Given that memory for the temporal order of events depends on the hippocampus to a greater extent than item memory, our findings suggest that NE activity during early SWS-rich sleep facilitates consolidation of memories that involve both, a strong amygdalar and hippocampal component.

Direct Link:

Journal: Psychoneuroendocrinology. 2011 Oct 1;36(9):1342-50

Keywords: amygdala, clonidine, emotional memory, Heart Rate, norepinephrine, slow wave sleep,

Applications: Heart Rate,

CamNtech Reference: AH11037

Back to Search Results

UK & International customers

CamNtech Ltd.
Manor Farm
PE28 9JD, UK

US customers

CamNtech Inc.
630 Boerne Stage Airfield,
Texas 78006,


© 2022 CamNtech Ltd and CamNtech Inc

Company information

Registered in England No. 2221302
VAT No: GB486 3019 34

Privacy Policy