Evolution of Delta Activity Within the NonREM Sleep Episode: A Biphasic Hypothesis
| Autor: | Jean-Michel Gaillard, H. Merica, Ronald D. Fortune, R. Blois |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Adult
Male Delta Polysomnography media_common.quotation_subject Models Neurological Rapid eye movement sleep Sleep REM Experimental and Cognitive Psychology Electroencephalography Non-rapid eye movement sleep Developmental psychology Behavioral Neuroscience Thalamus Reference Values Neural Pathways medicine Homeostasis Humans media_common Cerebral Cortex Fourier Analysis medicine.diagnostic_test Signal Processing Computer-Assisted Delta wave Delta Rhythm Female Sleep Stages Psychology Neuroscience Vigilance (psychology) |
| Zdroj: | Physiology & Behavior. 62:213-219 |
| ISSN: | 0031-9384 |
| DOI: | 10.1016/s0031-9384(96)00111-4 |
| Popis: | The time course of delta activity within nonREM (NREM) episodes is measured for 24 healthy subjects with normal REM latencies. The first two NREM episodes in particular, show two very clearly separated peaks for about 35% of the subjects. Another 25% show two less well separated peaks. These double peak patterns are also prevalent in the literature, but there has been a tendency to dismiss them as a skipped REM effect. They are, however, still evident even when the data are averaged over the 24 subjects, indicating a systematic phenomenon. These averaged data are well fitted by an analytic function given by the sum of two consecutive overlapping Gaussian curves. The well-behaved residuals also, are an indication that a biphasic model of this kind is statistically appropriate. The model proposed is simple, with parameters related to physiological phenomena, and it suggests that there may be an underlying process with delta waves emanating from two separate signal sources. Recent neurophysiological findings suggest that delta oscillations are generated both in the thalamus and in the cortex and show that excessive synchronization of slow oscillations may lead to seizures. Hence the speculation that the biphasic process may emanate from cortical and thalamic sources and be protective in the sense that it permits smaller delta amplitudes at each source while retaining the integral delta energy necessary to satisfy sleep pressure. It is significant that the two peaks are most evident in the first two NREM episodes where delta power is high. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect