Category: Sleep

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Memory Papers Publications Sleep

New Paper in PNAS by Ngo et al. enti­tled “Shap­ing overnight con­sol­i­da­tion via slow-oscil­la­tion closed-loop tar­get­ed mem­o­ry reactivation”

Sleep is cen­tral for our abil­i­ty to trans­form new­ly acquired infor­ma­tion into sta­ble mem­o­ry traces. A process hypoth­e­sized to be medi­at­ed by unique brain oscil­la­tions found sole­ly dur­ing sleep, first in fore­most the <1 Hz slow oscil­la­tion, which ini­ti­ate a reac­ti­va­tion of the infor­ma­tion to be con­sol­i­dat­ed. But what is the tem­po­ral rela­tion between sleep slow oscil­la­tions and mem­o­ry reactivation?

Togeth­er with Bern­hard Staresina from the Uni­ver­si­ty of Oxford, Hong-Viet V. Ngo recent­ly pub­lished a study uti­liz­ing tar­get­ed mem­o­ry reac­ti­va­tion (TMR): a tech­nique to exter­nal­ly dri­ve reac­ti­va­tion by expos­ing sleep­ing sub­jects to audi­to­ry reminder cues. Using this approach, they com­pared the impact of slow oscil­la­tion phase on the TMR out­come, i.e. they con­trast­ed a cue­ing phase-locked to slow oscil­la­tion peaks (up-states) vs. cues pre­sent­ing dur­ing slow oscil­la­tion troughs (or down-states). Their results show that up-state cue­ing led to a sig­nif­i­cant­ly low­er for­get­ting than down-state cue­ing. More­over, elec­tro­phys­i­o­log­i­cal brain pat­terns reflect­ing reac­ti­vat­ed infor­ma­tion were more pro­nounced after up-state cue­ing. Alto­geth­er these results pro­vide impor­tant insight for the endeav­or to exper­i­men­tal­ly mod­u­late mem­o­ries dur­ing sleep.

You can find the full arti­cle here.

 

 

Categories
Brain stimulation Memory Papers Psychiatry Publications Sleep

New Paper in Jour­nal of Sleep Research by Wein­hold et al.

In a col­lab­o­ra­tion with Sara Lena Wein­hold and Robert Göder at the Chris­t­ian-Albrechts-Uni­ver­si­ty Kiel, Hong-Viet V. Ngo recent­ly pub­lished a study inves­ti­gat­ing the influ­ence of audi­to­ry stim­u­la­tion dur­ing sleep on mem­o­ry con­sol­i­da­tion in peo­ple with schizophrenia.

The study shows that audi­to­ry stim­u­la­tion tar­get­ing slow oscil­la­tions – a key rhythm medi­at­ing mem­o­ry pro­cess­ing – in real-time in peo­ple with schiz­o­phre­nia results in an elec­tro­phys­i­o­log­i­cal response that is sim­i­lar to that in healthy par­tic­i­pants. Albeit an absent effect of stim­u­la­tion on mem­o­ry con­sol­i­da­tion, the authors found the stronger the slow oscil­la­tion enhance­ment the less par­tic­i­pants for­got, i.e., the bet­ter mem­o­ry per­for­mance was, the fol­low­ing morning.

Thus, this paper not only con­firms the over­all fea­si­bil­i­ty of this approach and pro­vides essen­tial elec­tro­phys­i­o­log­i­cal insights. It fur­ther­more high­lights the poten­tial of audi­to­ry stim­u­la­tion to pro­vide alter­na­tive treat­ments for sleep-relat­ed dys­func­tions in patients with schiz­o­phre­nia. The arti­cle is avail­able here.