| 21. |
- Bergstedt, Kerstin, et al.
(författare)
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Postischaemic changes in protein synthesis in the rat brain : effects of hypothermia
- 1993
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Ingår i: Experimental Brain Research. - 0014-4819. ; 95:1, s. 91-99
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Tidskriftsartikel (refereegranskat)abstract
- Protein synthesis, measured as [14C]-leucine incorporation into proteins, was studied in the normothermic rat brain following 15 min of transient cerebral ischaemia and 1 h, 24 h and 48 h of recirculation, and in the hypothermic (33°C) brain following 1 h and 48 h of recirculation. Ischaemia was induced by bilateral common carotid occlusion combined with hypotension. Following normothermic ischaemia, incorporation of [14C]-leucine was depressed by 40-80% at 1 h of recirculation in all brain regions studied. At 48 h postischaemia, incorporation returned to normal or above normal levels in the inner layers of neocortex, the CA3 region, the striatum and the dentate gyrus, while in the outer layers of neocortex and in the hippocampal CA1 region the incorporation was persistently decreased by 26% and 40% respectively. At 24 and 48 h postischaemia, protein synthesis in the CA1 region and the striatum could be attributed to proliferating microglia. Intra-ischaemic hypothermia ameliorated the persistent depression of protein synthesis in the CA1 region at 48 h postischaemia, and a two-fold increase compared to the normothermic group was observed both in the CA1 region and the striatum. In the cortex, eucaryotic initiation factor 2 activity transiently decreased at 30 min postischaemia. In animals subjected to intra-ischaemic hypothermia, the eucaryotic initiation factor 2 activity was reduced by 50% of control at 30 min of recirculation compared with 77% in normothermic animals. We conclude that the postischaemic depression of protein synthesis is in part caused by a decrease in eucaryotic initiation factor 2 activity. The early postischaemic depression may reflect a reaction of the tissue to stress, while the late persistent depression, which is normalised by intra-ischaemic hypothermia, may be related to the mechanism of cell death.
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| 22. |
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| 23. |
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| 24. |
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| 25. |
- Bjursten, Lars Magnus, et al.
(författare)
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Behavioural repertory of cats without cerebral cortex from infancy
- 1976
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Ingår i: Experimental Brain Research. - 0014-4819. ; 25:2, s. 115-130
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Tidskriftsartikel (refereegranskat)abstract
- Bilateral removal of the cerebral cortex was made in cats neonatally. Spontaneous and imposed behaviour was studied while they were growing up and after they had become adult. Special emphasis was put on the utilization of visual cues and on learning. The cats ate, drank and groomed themselves adequately. Adequate maternal and female sexual behaviour was observed. They utilized the visual and haptic senses with respect to external space. Two cats were trained to perform visual discrimination if a T-maze. The adequacy of the behaviour of these cats is compared to that of animals with similar lesions made at maturity.
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| 26. |
- Björnsdotter, Malin, et al.
(författare)
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Feeling good : on the role of C fiber mediated touch in interoception.
- 2010
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Ingår i: Experimental Brain Research. - : Springer. - 0014-4819 .- 1432-1106. ; 207:3, s. 149-155
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Tidskriftsartikel (refereegranskat)abstract
- The human skin is innervated by a network of thin, slow-conducting afferent (C and Aδ) fibers, transmitting a diverse range of information. Classically, these fibers are described as thermo-, noci- or chemoreceptive, whereas mechanoreception is attributed exclusively to thick, fast-conducting (Aβ) afferents. A growing body of evidence, however, supports the notion that C tactile afferents comprise a second anatomically and functionally distinct system signaling touch in humans. This review discusses established as well as recent findings which highlight fundamental differences in peripheral and central information coding and processing between Aβ and C mechanoreception. We conclude that from the skin through the brain, C touch shares more characteristics with interoceptive modalities (e.g. pain, temperature, and itch) than exteroceptive Aβ touch, vision or hearing. In this light, we discuss the motivational-affective role of C touch as an integral part of a thin-fiber afferent homeostatic network for the maintenance of physical and social well-being.
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| 27. |
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| 28. |
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| 29. |
- Bojsen-Møller, Emil, et al.
(författare)
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The effect of breaking up prolonged sitting on paired associative stimulation-induced plasticity.
- 2020
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Ingår i: Experimental Brain Research. - : Springer. - 0014-4819 .- 1432-1106. ; 238, s. 2497-2506
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Tidskriftsartikel (refereegranskat)abstract
- Paired associative stimulation (PAS) can induce plasticity in the motor cortex, as measured by changes in corticospinal excitability (CSE). This effect is attenuated in older and less active individuals. Although a single bout of exercise enhances PAS-induced plasticity in young, physically inactive adults, it is not yet known if physical activity interventions affect PAS-induced neuroplasticity in middle-aged inactive individuals. Sixteen inactive middle-aged office workers participated in a randomized cross-over design investigating how CSE and short-interval intracortical inhibition (SICI) were affected by PAS preceded by 3 h of sitting (SIT), 3 h of sitting interrupted every 30 min by 3 min of frequent short bouts of physical activity (FPA) and 2.5 h of sitting followed by 25 min of moderate-intensity exercise (EXE). Transcranial magnetic stimulation was applied over the primary motor cortex (M1) of the dominant abductor pollicis brevis to induce recruitment curves before and 5 min and 30 min post-PAS. Linear mixed models were used to compare changes in CSE using time and condition as fixed effects and subjects as random effects. There was a main effect of time on CSE and planned within-condition comparisons showed that CSE was significantly increased from baseline to 5 min and 30 min post-PAS, in the FPA condition, with no significant changes in the SIT or EXE conditions. SICI decreased from baseline to 5 min post-PAS, but this was not related to changes in CSE. Our findings suggest that in middle-aged inactive adults, FPAs may promote corticospinal neuroplasticity. Possible mechanisms are discussed.
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| 30. |
- Boris-Möller, Fredrik, et al.
(författare)
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Changes in the extracellular levels of glutamate and aspartate during ischemia and hypoglycemia. Effects of hypothermia
- 1998
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Ingår i: Experimental Brain Research. - : Springer Science and Business Media LLC. - 0014-4819 .- 1432-1106. ; 121:3, s. 277-284
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Tidskriftsartikel (refereegranskat)abstract
- Hypothermia (33°C) dramatically diminishes ischemic but not hypoglycemic brain damage. The beneficial effects of hypothermia in ischemia have been partly attributed to a reduction in the ischemia-induced increase in synaptic levels of glutamate or aspartate. With the microdialysis technique, we studied the effects of hypothermia (33°C) on the brain extracellular levels of glutamate and aspartate during hypoglycemia, ischemia, and their combination. In isoelectric hypoglycemia, striatal levels of glutamate and aspartate frequently show large transients of transmitter release occurring during both normothermia and hypothermia, whereas in the cortex levels of glutamate and aspartate are slightly lower during hypothermia compared with normothermia. In both regions studied, complete ischemia induced by i.v. KCl results in a progressive increase in glutamate and aspartate levels over time. In normoglycemic animals, hypothermia markedly attenuates the increase in glutamate and aspartate levels in the striatum but not in the cortex. Also in hypoglycemic animals, complete ischemia causes a progressive increase in the glutamate and aspartate levels. However, hypothermia affects only striatal glutamate levels. Since hypothermia protects both cortex and striatum against ischemic brain injury and not against hypoglycemic injury, presumably the protective effect of hypothermia is due to factors other than prevention of glutamate or aspartate overflow.
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