Synchronization between hippocampal theta waves and PGO waves during REM sleep.
We investigated the temporal relationship between hippocampal theta waves (referred to as 'theta waves') and ponto-geniculo-occipital (PGO) waves in cats. We measured the time intervals between an occurrence of a PGO wave and the prior and posterior adjacent positive peaks of the theta wave. The unimodal distributions of these intervals suggested a close temporal relationship between PGO and theta waves (i.e. synchronization). In addition, the period of a theta wave during which a PGO wave occurred was not statistically different from that without a PGO wave. This result suggests that the synchronization found here is characterized by phase-locking rather than phase-resetting. Common mechanisms are suggested to underlie the generation of PGO and theta waves.
Karashima
A
A
Laboratory of Neurophysiology and Bioinformatics, Graduate School of Information Sciences, Tohoku University, Sendai 980-8579, Japan. karasima@yamamoto.ecei.tohoku.ac.jp
Nakamura
K
K
Watanabe
M
M
Sato
N
N
Nakao
M
M
Katayama
N
N
Yamamoto
M
M
D000818:Animals; D002415:Cats; D005829:Geniculate Bodies / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D009622:Noise; D009778:Occipital Lobe / Q000502:physiology*; D010775:Photic Stimulation; D011149:Pons / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology*; D013826:Theta Rhythm; D013997:Time Factors