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In preterm infants, the risk to develop attention-deficit/hyperactivity disorder is 3 to 4-fold higher than in term infants. Moreover, preterm infants exhibit deficits in motor coordination and balance. Based on clinical data, higher oxygen levels in preterm infants lead to worse neurological outcome, and experimental hyperoxia causes wide-ranging cerebral changes in neonatal rodents. We hypothesize that hyperoxia in the immature brain may affect motor activity in preterm infants. We subjected newborn mice from P6 to P8 to 48 h of hyperoxia (80% O(2)) and tested motor activity in running wheels starting at adolescent age P30. Subsequently, from P44 to P53, regular wheels were replaced by complex wheels with variable crossbar positions to assess motor coordination deficits. MRI with diffusion tensor imaging was performed in the corpus callosum to determine white matter diffusivity in mice after hyperoxia at ages P30 and P53 in comparison to control animals. Adolescent mice after neonatal hyperoxia revealed significantly higher values for maximum velocity and mean velocity in regular wheels than controls (P<0.05). In the complex running wheels, however, maximum velocity was decreased in animals after hyperoxia, as compared to controls (P<0.05). Decreased fractional anisotropy and increased radial diffusion coefficient were observed in the corpus callosum of P30 and P53 mice after neonatal hyperoxia compared to control mice. Hyperoxia in the immature brain causes hyperactivity, motor coordination deficits, and impaired white matter diffusivity in adolescent and young adult mice., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Objective: Transcranial direct current stimulation (tDCS) induces changes in cortical excitability and improves hand-motor function in chronic stroke. These effects depend on polarity, duration of stimulation and current intensity applied. Towards evaluating the therapeutic potential of tDCS in acute stroke, we investigated tDCS-effects on cerebral blood flow (CBF) in a tDCS rat model adapted for this purpose., Methods: In a randomised crossover design eight Sprague-Dawley rats received three single cathodal and anodal tDCS for 15 min every other day. At each polarity, current intensities of 25, 50 and 100 μA were applied. CBF was measured prior and after tDCS for at least 30 min with laser Doppler flowmetry (LDF)., Results: At higher intensities (50 and 100 μA) anodal tDCS increased CBF up to 30 min. At 100 μA CBF was increased by about 25%, at 50 μA by about 18%. In contrast, cathodal tDCS led to a decrease of CBF, likewise depending on the current intensity applied. At 100 μA the effects were about 25% of baseline levels and persisted for at least 30 min. At 25 and 50 μA, baseline-levels were mostly re-established within 30 min., Conclusions: tDCS modulates CBF in a polarity specific way, the extent of modulation depending on the stimulation parameters applied. Because of its polarity-specificity, we assume that CBF-alterations are causally related to tDCS-induced alterations in cortical excitability via neuro-vascular coupling. tDCS may constitute a therapeutic option in acute stroke patients or in patients at risk for vasospasm-induced ischemia after subarachnoid hemorrhage., (Copyright © 2010 Elsevier Inc. All rights reserved.)

We have recently shown that two techniques of brain stimulation - repetitive electrical stimulation (ES) (that mimics transcranial magnetic stimulation) and transcranial direct current stimulation (tDCS) - modify the velocity of cortical spreading depression (CSD) significantly. Herein we aimed to study the effects of these two techniques combined on CSD. Thirty-two Wistar rats were divided into four groups according to the treatment: sham tDCS/sham ES, sham tDCS/1 Hz ES, anodal tDCS/1 Hz ES, cathodal tDCS/1 Hz ES. Our findings show that 1 Hz ES reduced CSD velocity, and this effect was modified by either anodal or cathodal tDCS. Anodal tDCS induced larger effects than cathodal tDCS. Hereby CSD velocity was actually increased significantly after anodal tDCS/1 Hz ES. Our results show that combining two techniques of brain stimulation can modify significantly the effects of ES alone on cortical excitability as measured by the neurophysiological parameter of cortical spreading depression and therefore provide important insights into the effects of this new approach of brain stimulation on cortical activity.