Thomas Berkefeld

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Getting older is associated with a decline of cognitive and sensorimotor abilities, but it remains elusive whether age-related changes are due to accumulating degenerational processes, rendering them largely irreversible, or whether they reflect plastic, adaptational and presumably compensatory changes. Using aged rats as a model we studied how aging(More)
We measured reflectance changes by means of optical imaging of intrinsic signals to study the topography of the paw representations in rat somatosensory cortex. Following circumscribed tactile stimulation of single digits or pads, we found large and partially overlapping areas of reflectance changes (delta R). The diameters of their focal zones defined at(More)
Aged rats show a characteristic decline of the sensorimotor state, most strikingly expressed in an impairment of the hindlimbs leading to significantly reduced sensory stimulation on the hindpaw. We review recent studies using optical imaging and electrophysiological recordings to investigate the effects of aging on somatosensory cortex and to identify(More)
In order to increase the corrected field of view of an adaptive optics (AO) system, several deformable mirrors (DM) have to be placed in the conjugate planes of the dominant turbulent layers (multi-conjugate adaptive optics, MCAO (Beckers, 1988)). The performance of MCAO systems depends on the quality of the wavefront sensing of the individual layers and on(More)
In this paper we present the setup including optics and components, the reconstruction scheme and performance measurements of the adaptive optics (AO) system implemented at the 26 cm transportable optical ground station (TAOGS) which is presently located at the Observatorio del Teide, Tenerife. The system is used to improve the signal-to-noise ratio of(More)
The mid-infrared interferometric instrument is one of three instruments that will equip the focus of the Very Large Telescope Interferometer. During the design phase of the instrument we made use of a program of simulations to define the constraints imposed by atmospheric turbulence. We present our results for the estimated fringe motion, during a typical(More)
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