TY  - JOUR
A1  - Borchers, Svenja
A1  - Müller, Laura
A1  - Synofzik, Matthis
A1  - Himmelbach, Marc
T1  - Guidelines and quality measures for the diagnosis of optic ataxia
JF  - Frontiers in Human Neuroscience
N2  - Since the first description of a systematic mis-reaching by Balint in 1909, a reasonable number of patients showing a similar phenomenology, later termed optic ataxia (OA), has been described. However, there is surprising inconsistency regarding the behavioral measures that are used to detect OA in experimental and clinical reports, if the respective measures are reported at all. A typical screening method that was presumably used by most researchers and clinicians, reaching for a target object in the peripheral visual space, has never been evaluated. We developed a set of instructions and evaluation criteria for the scoring of a semi-standardized version of this reaching task. We tested 36 healthy participants, a group of 52 acute and chronic stroke patients, and 24 patients suffering from cerebellar ataxia. We found a high interrater reliability and a moderate test-retest reliability comparable to other clinical instruments in the stroke sample. The calculation of cut-off thresholds based on healthy control and cerebellar patient data showed an unexpected high number of false positives in these samples due to individual outliers that made a considerable number of errors in peripheral reaching. This study provides first empirical data from large control and patient groups for a screening procedure that seems to be widely used but rarely explicitly reported and prepares the grounds for its use as a standard tool for the description of patients who are included in single case or group studies addressing optic ataxia similar to the use of neglect, extinction, or apraxia screening tools.
KW  - systems
KW  - deficit
KW  - target
KW  - damage
KW  - delay
KW  - posterior cortical atrophy
KW  - Balints-Syndrome
KW  - hand
KW  - impairments
KW  - reliability
KW  - cerebellar atrophy
KW  - cerebellar ataxia
KW  - cerebellum
KW  - parietal lobe
KW  - optic ataxia
KW  - beside test
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-122439
SN  - 1662-5161
VL  - 7
IS  - 324
ER  - 
TY  - JOUR
A1  - Pfeiffer, Verena
A1  - Götz, Rudolf
A1  - Xiang, Chaomei
A1  - Camarero, Guadelupe
A1  - Braun, Attila
A1  - Zhang, Yina
A1  - Blum, Robert
A1  - Heinsen, Helmut
A1  - Nieswandt, Bernhard
A1  - Rapp, Ulf R.
T1  - Ablation of BRaf Impairs Neuronal Differentiation in the Postnatal Hippocampus and Cerebellum
JF  - PLoS ONE
N2  - This study focuses on the role of the kinase BRaf in postnatal brain development. Mice expressing truncated, non-functional BRaf in neural stem cell-derived brain tissue demonstrate alterations in the cerebellum, with decreased sizes and fuzzy borders of the glomeruli in the granule cell layer. In addition we observed reduced numbers and misplaced ectopic Purkinje cells that showed an altered structure of their dendritic arborizations in the hippocampus, while the overall cornus ammonis architecture appeared to be unchanged. In male mice lacking BRaf in the hippocampus the size of the granule cell layer was normal at postnatal day 12 (P12) but diminished at P21, as compared to control littermates. This defect was caused by a reduced ability of dentate gyrus progenitor cells to differentiate into NeuN positive granule cell neurons. In vitro cell culture of P0/P1 hippocampal cells revealed that BRaf deficient cells were impaired in their ability to form microtubule-associated protein 2 positive neurons. Together with the alterations in behaviour, such as autoaggression and loss of balance fitness, these observations indicate that in the absence of BRaf all neuronal cellular structures develop, but neuronal circuits in the cerebellum and hippocampus are partially disturbed besides impaired neuronal generation in both structures.
KW  - granule cells
KW  - hippocampus
KW  - neurons
KW  - neuronal dendrites
KW  - embryos
KW  - dentate gyrus
KW  - neuronal differentiation
KW  - cerebellum
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-130304
VL  - 8
IS  - 3
ER  -