TY  - JOUR
AU  - Tatsuno, Masami
AU  - Malek, Soroush
AU  - Kalvi, LeAnna
AU  - Ponce-Alvarez, Adrian
AU  - Ali, Karim
AU  - Euston, David R.
AU  - Grün, Sonja
AU  - McNaughton, Bruce L.
TI  - Memory reactivation in rat medial prefrontal cortex occurs in a subtype of cortical UP state during slow-wave sleep
JO  - Philosophical transactions / B
VL  - 375
IS  - 1799
SN  - 1471-2970
CY  - London
PB  - Royal Society
M1  - FZJ-2020-04069
SP  - 20190227 -
PY  - 2020
AB  - Interaction between hippocampal sharp-wave ripples (SWRs) and UP states, possibly by coordinated reactivation of memory traces, is conjectured to play an important role in memory consolidation. Recently, it was reported that SWRs were differentiated into multiple subtypes. However, whether cortical UP states can also be classified into subtypes is not known. Here, we analysed neural ensemble activity from the medial prefrontal cortex from rats trained to run a spatial sequence-memory task. Application of the hidden Markov model (HMM) with three states to epochs of UP–DOWN oscillations identified DOWN states and two subtypes of UP state (UP-1 and UP-2). The two UP subtypes were distinguished by differences in duration, with UP-1 having a longer duration than UP-2, as well as differences in the speed of population vector (PV) decorrelation, with UP-1 decorrelating more slowly than UP-2. Reactivation of recent memory sequences predominantly occurred in UP-2. Short-duration reactivating UP states were dominated by UP-2 whereas long-duration ones exhibit transitions from UP-1 to UP-2. Thus, recent memory reactivation, if it occurred within long-duration UP states, typically was preceded by a period of slow PV evolution not related to recent experience, and which we speculate may be related to previously encoded information. If that is the case, then the transition from UP-1 to UP-2 subtypes may help gradual integration of recent experience with pre-existing cortical memories by interleaving the two in the same UP state.
LB  - PUB:(DE-HGF)16
C6  - pmid:32248781
UR  - <Go to ISI:>//WOS:000523698100007
DO  - DOI:10.1098/rstb.2019.0227
UR  - https://juser.fz-juelich.de/record/885757
ER  -