Emotional episodes

Emotional memories, sleep and depression

Recent investigations have demonstrated that negative episodic memories are selectively strengthened overnight [1,2], and specifically during rapid eye movement (REM) sleep [3]. Depressed patients show drastic increases in REM [4] and have a bias towards negative memories [5]. Antidepressants, which are associated with a gradual recovery of mood, typically correct the REM imbalance [6,7]. Based on these data, we have proposed that the strengthening of negative memories during excessive REM may be a factor in deepening and maintaining depression.

Work in our lab has demonstrated that overnight enhancement of negative memory is associated with enhanced connectivity between amygdala and hippocampus [8], a change believed to occur during REM [9]. A portion of our current work builds on this finding by examiningthe interaction between such strengthening and the altered sleep physiology (enhanced REM) and pharmacology of depressed patients.

Reference list

  1. Hu P, Stylos-Allan M, Walker MP (2006) sleep facilitates consolidation of emotionally arousing declarative memory. Psychological Sciences
  2. Wagner U, Hallschmid M, Rasch B, Born J (2006) Brief sleep after learning keeps emotional memories alive for years. Biol Psychiatry 60: 788-790
  3. Wagner U, Gais S, Born J (2001) Emotional memory formation is enhanced across sleep intervals with high amounts of rapid eye movement sleep. Learn Mem 8: 112-119
  4. Hornung OP, Regen F, nker-Hopfe H, Heuser I, Anghelescu I (2007) Sleep-related memory consolidation in depression: an emerging field of research. Depress Anxiety
  5. Hertel PT, Gerstle M (2003) Depressive deficits in forgetting. Psychol Sci 14: 573-578
  6. Holland P, Lewis PA (2007) Emotional memory: selective enhancement by sleep. Curr Biol 17: R179-R181
  7. Argyropoulos SV, Wilson SJ (2005) Sleep disturbances in depression and the effects of antidepressants. Int Rev Psychiatry 17: 237-245
  8. Lewis PA, Manning L, Walker MP, Critchley H (2008) sleep dependent emotional plasticity in emotional source memory. ESRS Glasgow
  9. Vazquez J, Baghdoyan HA (2001) Basal forebrain acetylcholine release during REM Sleep is significantly greater than during waking. Am J Physiol Regul Integr Comp Physiol 280: R598-R601