Activation of the phasic pontine-wave generator enhances improvement of learning performance: a mechanism for sleep-dependent plasticity.
The aim of this study was to test the hypothesis that supplementary activation of the phasic pontine wave (P-wave) generator during rapid eye movement (REM) sleep enhances consolidation and integration of memories, resulting in improved learning. To test this hypothesis, two groups of rats were trained on a two-way active avoidance learning task in the morning. Immediately after training, one group of rats received a carbachol microinjection into the P-wave generator and the other group was microinjected with control saline into the same target area. After training trials and microinjections, rats were allowed a 6-h period of undisturbed sleep in the polygraphic recording chamber. At the end of 6 h of undisturbed sleep-wake recordings, rats were retested in a session of avoidance learning trials. After learning trials, the total percentage of time spent in REM sleep was significantly increased in both saline (15.36%)- and carbachol (17.70%)-microinjected rats. After learning trials, REM sleep P-wave density was significantly greater throughout the 6-h period of recordings in carbachol treated rats than in the saline treated rats. In the retrial session, the improvement in learning task performance was 22.75% higher in the carbachol-microinjected rats than in the saline-microinjected rats. These findings show that the consolidation and integration of memories create a homeostatic demand for P-waves. In addition, these findings provide experimental evidence, for the first time, that activation of the P-wave generator may enhance consolidation and integration of memories, resulting in improved performance on a recently learned task.
Mavanji
Vijayakumar
V
Sleep Research Laboratory, Department of Psychiatry and Program in Behavioural Neuroscience, Boston University School of Medicine, Building M-913, 715 Albany Street, Boston, Massachusetts 02118, USA.
Datta
Subimal
S
D000818:Animals; D002217:Carbachol / Q000008:administration & dosage / Q000494:pharmacology; D018679:Cholinergic Agonists / Q000008:administration & dosage / Q000494:pharmacology; D004569:Electroencephalography; D007276:Injections, Intraventricular; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D011149:Pons / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012895:Sleep, REM / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors
D018679:Cholinergic Agonists; D002217:Carbachol