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Section CELLULAR NEUROSCIENCE
2006). We checked EEG state before and after blocks of random single (110% MT) and paired (90% - 110% MT, 2 or 10 ms IPI (intracortical facilitation (ICF) and short-interval intracortical inhibition (SICI)); 4 - 8 sec between single or paired pulses) pulse stimulation (about 300 total stimuli) by calculation of Long-Range Temporal Correlations (LRTC, Linken-kaer-Hansen et al., 2001; Nikulin et al., 2012) in EEG . LRTC in the alpha frequency range were calculated with Detrend-ed Fluctuation Analysis applied to multichannel EEG recordings.
LRTC in the alpha frequency range showed moderate intra-class correlation between the two rest sessions thus indicating a relative stability of the temporal dynamics between the sessions. Topographically, intra-class correlation was least pronounced over the stimulated areas thus demonstrating a potential long-lasting offline effect of TMS on neuronal activity. This was further confirmed by showing that there was a positive correlation between the magnitude of ICF and the magnitude of LRTC in 8-13 Hz range. Importantly, such correlation was regionally specific demonstrating strongest values over sensorimotor areas where TMS was applied. Our data suggests single and paired pulses TMS can have a previously unobserved long lasting effect on the temporal dynamics of neuronal oscillations and can be considered as offline.
References
1. Terao Y, Ugawa Y(2006),' Studying higher cerebral functions by transcranial magnetic stimulation.' Suppl Clin Neuro-physiol., vol. 59, pp.9-17.
2. Linkenkaer-Hansen, K. (2001), 'Long-range temporal correlations and scaling behavior in human brain oscillations.' Journal of Neuroscience, vol. 21, no. 4, pp. 1370-1377
3. Nikulin, V. (2012), 'Attenuation of long-range temporal correlations in the amplitude dynamics of alpha and beta neuronal oscillations in patients with schizophrenia.' NeuroImage, vol. 61 no. 1, pp. 162-169
OM&P
Role of the Oligodendrocyte Lineage in Acute CNS Trauma
Frank Kirchhoff *
Molecular Physiology, Center for Integrative Physiology and Molecular Medicine, Homburg, Germany. * Presenting e-mail: [email protected]
Acute brain injuries activate signaling cascades essential for scar formation. Here, we report that acute lesions associated with a disruption of the blood-brain barrier (BBB) trigger re-programming of the oligodendrocyte lineage. Differentiated oligodendrocytes and their precursor cells can generate another neuroglial cell type: astrocytes. By in vivo 2P-LSM analysis we followed oligodendrocytes after injury in PLP-DsRed/GFAP-EGFP transgenic mice. Adjacent to the lesion site, oligodendrocytes first turned into an intermediate cell stage with astro- and oligodendroglial gene expression properties (AO cells). Subsequently, portions of AO cells differentiated into astrocytes, while others stayed in the oligodendrocyte lineage. In split-Cre mice, AO cells showed a clear glia-restricted differentiation potential that also depended on local cues. At the lesion higher expression levels of glial differentiation factors were detected. And indeed, local injection of IL-6 promoted the formation of AO cells. In summary, our findings highlight the plastic potential of oligodendrocytes in acute brain trauma.
Molecular Changes in Penumbra After Focal Photothrombotic Stroke in the Rat Cerebral Cortex
A.B. Uzdensky* and S.V. Demyanenko
Southern Federal University, Rostov-on-Don, Russia. * Presenting e-mail: [email protected]
Aims
Ischemic stroke is a leading cause of human disability and mortality. Vascular occlusion and energy deficit rapidly, for a few minutes induce cerebral infarct. The cell damage propagates from the infarct core to surrounding tissues (penumbra). Acute cell necrosis inside the infarct core cannot be prevented, but tissue damage in penumbra develops slower,
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