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Category: Memory

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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
Attention Memory Papers

New Paper in Sci­en­tif­ic Reports by Lui&Wöstmann

A tick­ing clock in the liv­ing room; an ambi­ent music in the café; the foot­steps of a passers­by on the street – We are sur­round­ed by a pletho­ra of dis­tract­ing events with reg­u­lar tem­po­ral struc­tures in dai­ly life. Can we ignore these dis­trac­tors better?

Tro­by Ka-Yan Lui and Malte Wöst­mann recent­ly pub­lished a study on the effect of tem­po­ral­ly reg­u­lar ver­sus irreg­u­lar dis­trac­tors on the abil­i­ty to main­tain items in mem­o­ry. Sur­pris­ing­ly, they found that the tem­po­ral reg­u­lar­i­ty of dis­trac­tors did not have an effect on participant’s mem­o­ry per­for­mance. Instead, they found an effect of the tem­po­ral reg­u­lar­i­ty of dis­trac­tors on response behav­iour – par­tic­i­pants were faster and more biased in respond­ing whether the cur­rent num­ber matched with the num­ber in memory.

These results have the­o­ret­i­cal impli­ca­tions: exter­nal dis­trac­tion may have a more per­va­sive influ­ence on dif­fer­ent aspects of cog­ni­tive process­es than mem­o­ry main­te­nance. The arti­cle will soon be avail­able in Sci­en­tif­ic Reports.

Categories
Attention fMRI Memory Papers

New paper in Neu­roIm­age, Lim et al.

Atten­tion lets us focus our lim­it­ed cog­ni­tive resources on behav­ioral­ly impor­tant infor­ma­tion. Less obvi­ous is that atten­tion also helps us to hold infor­ma­tion in mem­o­ry with high pre­ci­sion. But how does the brain imple­ment this direct­ed atten­tion to mem­o­ry, and what behav­iour­al ben­e­fits does it yield for us humans?

For­mer post­doc Sung-Joo Lim (now at Bing­ham­ton Uni­ver­si­ty), Jonas Obleser, and a team of col­lab­o­ra­tors from Old­en­burg (Chris­tiane Thiel) and Leipzig (Bern­hard Sehm, Lorenz Deser­no, and Jöran Lep­sien) have now a new arti­cle on this old prob­lem, to appear in NeuroImage.

Using the changes in brain blood oxy­gena­tion as mea­sured with fMRI, this study demon­strates that atten­tion enables mem­o­ry main­te­nance of speech sound infor­ma­tion across mul­ti­ple brain regions. A speech-sen­si­tive brain region in the tem­po­ral lobe (the left supe­ri­or tem­po­ral sul­cus) con­tributes the most in pre­dict­ing the indi­vid­ual gain in recall pre­ci­sion of audi­to­ry objects from mem­o­ry. This study high­lights that func­tion­al­ly dis­crete brain regions work togeth­er in main­tain­ing and atten­tion­al­ly enhanc­ing work­ing mem­o­ry infor­ma­tion, but they exert dif­ferental influ­ences depend­ing on their func­tion­al specializations.

The full arti­cle is now avail­able 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.