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Sleep EEG dynamics in rat barrel cortex associated with sensory deprivation.
SLEEP
Neuroreport. 15(17):2681-2684, December 3, 2004.Iwasaki, Naoko CA; Karashima, Akihiro; Tamakawa, Yuichi; Katayama, Norihiro; Nakao, Mitsuyuki
Abstract:
Sleep is involved in the development and maintenance of neural networks. We investigated how somatosensory deprivation affects EEG dynamics of adult rats during sleep, which might be a result of changes in neural organization. Rats' whiskers were clipped unilaterally daily and the resulting changes in the balance of EEG spectral powers between the intact and sensory deprived barrel cortices were recorded for a month. Both delta and theta band spectral powers in the deprived cortex initially decreased in terms of their ratio to the intact cortex. Subsequently, the ratio was restored to control levels. This non-monotonic change in EEG activity might reflect the re-organization process of the cortical circuit.
EEG spectral analysis of relaxation techniques; Jacobs, Gregg; Friedman, Richard; Applied Psychophysiology and Biofeedback, 2004 vol. 29
Abstract:
The acute central nervous system effects of relaxation techniques (RT) have not been systematically studied. We conducted a controlled, randomized study of the central nervous system effects of RT using spectral analysis of EEG activity. Thirty-six subjects were randomized to either RT or a music comparison condition. After listening to an RTaudiotape or music audiotapes daily for 6 weeks, the acute central nervous system effects of RT and music were measured using power spectral analysis of alpha and theta EEG activity in all cortical regions. RT produced significantly greater increases in theta activity in multiple cortical regions compared to the music condition. These endings are consistent with widespread reductions in cortical arousal during RT. They extend previous findings and suggest that theta, and not alpha, EEG may be the most reliable marker of the central nervous system effects ofRT. These findings demonstrate that RT produce greater reductions in central nervous system activity than a credible comparison condition. The findings suggest that RT represent a hypoactive central nervous system state that may be similar to Stage I sleep and that RT may exert their therapeutic effects, in part, through cerebral energy conservation/restoration.=======================
| Title | More accurate sound localization induced by short-term light deprivation | |||||||||||||||
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| Author | Lewald, Jörg1 | |||||||||||||||
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| Affiliation | (1)Department of Cognitive and Environmental Psychology, Ruhr University, Bochum, Germany | |||||||||||||||
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| Source | Neuropsychologia. Vol 45(6), 2007, pp. 1215-1222 | |||||||||||||||
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| ISSN | 0028-3932 | |||||||||||||||
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| Abstract | Crossmodal reorganization processes in the brain are mainly associated with early blindness, on the assumption that recruitment of genuine visual areas, such as primary visual cortex, for non-visual functions results in superior auditory and tactile performance of blind, compared to sighted, humans. This study shows that in sighted subjects the accuracy of sound localization, measured by a task of head pointing to acoustic targets, is reversibly increased after short-term light deprivation of 90 min. However, only the systematic deviations from target positions (constant error) were reduced after light deprivation, while the general precision of head pointing remained unchanged. Return to pre-deprivation values was observed after 180 min of re-exposure to light. The post-deprivation change was similar, though less in magnitude, to the effect of blindness that was demonstrated previously. Generally, these findings indicate that auditory-visual crossmodal plasticity can be quite rapidly initiated by deprivation of the visual cortex from visual input. It seems possible that visual deprivation has an influence on neuronal circuits, that are involved in processing of auditory information in visual brain areas of normal sighted humans. Since exclusively the constant error in sound localization, not general performance, was changed, the present effect of visual deprivation may, however, not be attributable to reorganization processes in the sense of a compensation for the absence of vision. It is more likely that the observed change in accuracy was specifically induced by the absence of visual calibration of the neural representation of auditory space during light deprivation. (PsycINFO Database Record (c) 2007 APA, all rights reserved) (journal abstract) | |||||||||||||||
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| Email Address | joerg.lewald@rub.de | |||||||||||||||