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Frequency of network synchronization in the hippocampus marks learning
Author(s) -
Ponomarenko Alexey A.,
Li JayShake,
Korotkova Tatiana M.,
Huston Joseph P.,
Haas Helmut L.
Publication year - 2008
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2008.06232.x
Subject(s) - neuroscience , rhythm , ripple , hippocampal formation , synchronization (alternating current) , psychology , reinforcement , interval (graph theory) , hippocampus , computer science , physics , mathematics , acoustics , channel (broadcasting) , social psychology , quantum mechanics , voltage , combinatorics , computer network
The synchronization of neuronal networks may be instrumental in plasticity and learning. Hippocampal high‐frequency oscillations (140–200 Hz, ‘ripples’) characteristic of consummatory behaviours are thought to promote memory formation. We recorded ripple oscillations from the CA1 area in temporal learning tasks. Rats learned to adjust their operant response to the timing of food reward delivery [fixed interval schedule (FI)]. The intrinsic frequency of ripples was elevated following the switch in reinforcement timing. Learning, as assessed from the response pattern, correlated with fluctuations of intraripple frequency and amplitude. Changes in motor activity did not account for the variability of ripple oscillations. At the same time, features of ripples were unaltered when the fixed interval of reward delivery was changed but did not depend on the lever press response. Thus, in addition to the known replay of neuronal firing patterns during ripple oscillations, the rhythm itself appears to be modulated in an experience‐specific way and represents a direct correlate of learning.