Book contents
- Frontmatter
- Contents
- Preface
- Acknowledgments
- 1 Pioneering steps in studies on sleep and epilepsy
- 2 Neuronal types and circuits in sleep and epilepsy
- 3 Neuronal properties, network operations and behavioral signs during sleep states and wakefulness
- 4 Plastic changes in thalamocortical systems developing from low-frequency sleep oscillations
- 5 Neuronal mechanisms of seizures
- References
- Index
- Plate section
4 - Plastic changes in thalamocortical systems developing from low-frequency sleep oscillations
Published online by Cambridge University Press: 23 September 2009
- Frontmatter
- Contents
- Preface
- Acknowledgments
- 1 Pioneering steps in studies on sleep and epilepsy
- 2 Neuronal types and circuits in sleep and epilepsy
- 3 Neuronal properties, network operations and behavioral signs during sleep states and wakefulness
- 4 Plastic changes in thalamocortical systems developing from low-frequency sleep oscillations
- 5 Neuronal mechanisms of seizures
- References
- Index
- Plate section
Summary
This chapter is a continuation of the preceding one. I shall attempt to demonstrate that, far from being epiphenomena with little or no functional significance, spontaneously occurring brain rhythms exert strong influences on neighboring neurons by changing their probability of firing and forcing them into synchrony and produce plastic changes in neuronal responsiveness. That spontaneous brain oscillations may be related to imagination and attention was shown by the blockade of alpha waves even in the absence of a visual stimulus when attempting to “see” in a totally darkened room or when expecting a light stimulus that was omitted. The hypothesized and somewhat controversial role of fast (beta/gamma) oscillations in the binding of different facets of an object into a global percept was discussed in the previous chapter (section 3.3.2).
Although earlier hypotheses postulated that slow-wave sleep (SWS) is associated with a global cortical inhibition that prevents any mental activity (see note [224] and related main text in Chapter 3), neocortical neurons display unexpectedly rich spontaneous activity during this sleep stage that is also associated with prolonged and cyclic hyperpolarizations, all of which indicates that neocortex is quite active and suggests a reorganization/specification of neuronal circuits in cortex and target structures. This view is supported by studies using indicators of neuronal activities during SWS in humans, revealing more marked changes in those neocortical areas that are implicated in memory tasks and decision-making during wakefulness.
- Type
- Chapter
- Information
- Neuronal Substrates of Sleep and Epilepsy , pp. 209 - 284Publisher: Cambridge University PressPrint publication year: 2003