Age-variant and age-invariant rhythmicities in the cortical and hippocampal electrical activities of neonatal rats.
The neocortical and hippocampal electrical activities were studied in 8, 15, 22, and 29-day-old rats. Segments of EEG recorded for 4 hours were analyzed by means of fast Fourier transformation. The sleep-wake activity stages were determined. The developments in the neocortical and hippocampal EEG activities were characterized by the gradual appearance of adult-like EEG waves and a shift towards higher frequencies in the theta wave range of the hippocampal electrical activity. The power value in the theta range, however, exhibited age-invariant rhythmicities with cycle lengths of about 9.5-11 and 16-22 min. The manifestation of such an age-invariant rhythm can be interpreted as an electrical manifestation of the rest-activity cycle originally described by KLEITMAN25.
Dux
M
M
Department of Physiology, Albert Szent-Györgyi Medical University, Szeged, Hungary.
Rubicsek
G
G
Wolff
J
J
Joó
F
F
Benedek
G
G
D000204:Activity Cycles / Q000502:physiology; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001143:Arousal / Q000502:physiology; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography; D004594:Electrophysiology; D006624:Hippocampus / Q000502:physiology*; D010507:Periodicity; D051381:Rats; D017208:Rats, Wistar; D012894:Sleep Stages / Q000502:physiology