Löwel, Siegrid

[["dc.bibliographiccitation.journal","Frontiers in Cellular Neuroscience"],["dc.bibliographiccitation.volume","14"],["dc.contributor.author","Xu, Weifeng"],["dc.contributor.author","Löwel, Siegrid"],["dc.contributor.author","Schlüter, Oliver M."],["dc.date.accessioned","2021-04-14T08:23:50Z"],["dc.date.available","2021-04-14T08:23:50Z"],["dc.date.issued","2020"],["dc.description.abstract","Critical periods are postnatal, restricted time windows of heightened plasticity in cortical neural networks, during which experience refines principal neuron wiring configurations. Here, we propose a model with two distinct types of synapses, innate synapses that establish rudimentary networks with innate function, and gestalt synapses that govern the experience-dependent refinement process. Nascent gestalt synapses are constantly formed as AMPA receptor-silent synapses which are the substrates for critical period plasticity. Experience drives the unsilencing and stabilization of gestalt synapses, as well as synapse pruning. This maturation process changes synapse patterning and consequently the functional architecture of cortical excitatory networks. Ocular dominance plasticity (ODP) in the primary visual cortex (V1) is an established experimental model for cortical plasticity. While converging evidence indicates that the start of the critical period for ODP is marked by the maturation of local inhibitory circuits, recent results support our model that critical periods end through the progressive maturation of gestalt synapses. The cooperative yet opposing function of two postsynaptic signaling scaffolds of excitatory synapses, PSD-93 and PSD-95, governs the maturation of gestalt synapses. Without those proteins, networks do not progress far beyond their innate functionality, resulting in rather impaired perception. While cortical networks remain malleable throughout life, the cellular mechanisms and the scope of critical period and adult plasticity differ. Critical period ODP is initiated with the depression of deprived eye responses in V1, whereas adult ODP is characterized by an initial increase in non-deprived eye responses. Our model proposes the gestalt synapse-based mechanism for critical period ODP, and also predicts a different mechanism for adult ODP based on the sparsity of nascent gestalt synapses at that age. Under our model, early life experience shapes the boundaries (the gestalt) for network function, both for its optimal performance as well as for its pathological state. Thus, reintroducing nascent gestalt synapses as plasticity substrates into adults may improve the network gestalt to facilitate functional recovery."],["dc.identifier.doi","10.3389/fncel.2020.00213"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/81065"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-399"],["dc.publisher","Frontiers Media S.A."],["dc.relation.eissn","1662-5102"],["dc.rights","http://creativecommons.org/licenses/by/4.0/"],["dc.title","Silent Synapse-Based Mechanisms of Critical Period Plasticity"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1335"],["dc.bibliographiccitation.journal","Neurocomputing"],["dc.bibliographiccitation.lastpage","1339"],["dc.bibliographiccitation.volume","38-40"],["dc.contributor.author","Kaschube, Matthias"],["dc.contributor.author","Wolf, Fred"],["dc.contributor.author","Geisel, Theo"],["dc.contributor.author","Löwel, Siegrid"],["dc.date.accessioned","2017-09-07T11:46:12Z"],["dc.date.available","2017-09-07T11:46:12Z"],["dc.date.issued","2001"],["dc.description.abstract","Our visual system preferentially groups contour segments that not only have the same orientation but are colinear as well. Long-range horizontal connections are thought to play an important role in context-dependent modifications of neuronal responses. Since the topology of these connections shows a close relation to the perceptual grouping criterion of colinearity, we tested whether the statistical properties of real world images are biased towards colinear contours. By wavelet analysis we detected contours in images of natural environments and calculated their spatial correlations. In urban as well as in natural environments, the correlations between colinear contour segments were larger than the correlations for parallel contour segments. These observations indicate that colinear contour segments dominate real world images and thus might bias the functional and structural development of our visual system."],["dc.identifier.doi","10.1016/s0925-2312(01)00493-3"],["dc.identifier.gro","3151855"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8684"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.issn","0925-2312"],["dc.subject","Image analysis; Natural scenes; Wavelets; Visual cortex"],["dc.title","The prevalence of colinear contours in the real world"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","28"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Neuroforum"],["dc.bibliographiccitation.lastpage","+"],["dc.bibliographiccitation.volume","19"],["dc.contributor.author","Moser, Tobias"],["dc.contributor.author","Löwel, Siegrid"],["dc.contributor.author","Goepfert, Martin C."],["dc.date.accessioned","2018-11-07T09:28:18Z"],["dc.date.available","2018-11-07T09:28:18Z"],["dc.date.issued","2013"],["dc.identifier.isi","000321725500008"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/30741"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Spektrum Akademischer Verlag-springer-verlag Gmbh"],["dc.relation.issn","0947-0875"],["dc.title","Cellular Mechanisms of Sensory Processing"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.subtype","letter_note"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2606"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Investigative Ophthalmology & Visual Science"],["dc.bibliographiccitation.lastpage","2618"],["dc.bibliographiccitation.volume","52"],["dc.contributor.author","Krempler, Katja"],["dc.contributor.author","Schmeer, Christian W."],["dc.contributor.author","Isenmann, Stefan"],["dc.contributor.author","Witte, Otto-Wilhelm"],["dc.contributor.author","Loewel, Siegrid"],["dc.date.accessioned","2018-11-07T08:57:15Z"],["dc.date.available","2018-11-07T08:57:15Z"],["dc.date.issued","2011"],["dc.description.abstract","PURPOSE. The major aims of this study were to evaluate the effect of retinal ischemia by behavioral testing and histologic analyses, to visualize ischemia-induced changes of cortical activity by optical imaging of intrinsic signals, and to test the therapeutic effectiveness of simvastatin. METHODS. Retinal ischemia was induced monocularly by elevating intraocular pressure. Visual function was tested behaviorally with a virtual reality optomotor system, physiologically with optical imaging of intrinsic signals, and histologically by counting the surviving retinal ganglion cells (RGCs) in the same animal. RESULTS. Visual acuity (-38%) and contrast sensitivity (-78%) were significantly reduced 6 days after ischemia compared with controls. The number of RGCs was reduced by 16%. In contrast, optical imaging revealed essentially unchanged cortical activity maps in spite of the lesion. Treatment of mice with simvastatin applied after the ischemic insult significantly improved both visual function as measured behaviorally (similar to 95% visual acuity, similar to 165% contrast sensitivity) and RGC survival (similar to 30%) compared with vehicle-treated animals (similar to 42% visual acuity, similar to 85% contrast sensitivity). CONCLUSIONS. This specific combination of behavioral measurements of visual function, cortical activity imaging, and histologic analyses is ideally suited to follow ischemia-induced changes and to monitor the effect of therapeutic approaches. Statin therapy may be a promising pharmacologic tool for the treatment of acute retinal ischemia in particular because, in our study, simvastatin was applied after ischemia, a treatment regimen with much greater clinical relevance than preventive administration, as in previous studies. (Invest Ophthalmol Vis Sci. 2011;52:2606-2618) DOI:10.1167/iovs.10-6005"],["dc.identifier.doi","10.1167/iovs.10-6005"],["dc.identifier.isi","000290111000014"],["dc.identifier.pmid","21245399"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/23349"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Assoc Research Vision Ophthalmology Inc"],["dc.relation.issn","0146-0404"],["dc.title","Simvastatin Improves Retinal Ganglion Cell Survival and Spatial Vision after Acute Retinal Ischemia/Reperfusion in Mice"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2801"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","European Journal of Neuroscience"],["dc.bibliographiccitation.lastpage","2811"],["dc.bibliographiccitation.volume","36"],["dc.contributor.author","Yeritsyan, Naira"],["dc.contributor.author","Lehmann, Konrad"],["dc.contributor.author","Puk, Oliver"],["dc.contributor.author","Graw, Jochen"],["dc.contributor.author","Loewel, Siegrid"],["dc.date.accessioned","2018-11-07T09:06:24Z"],["dc.date.available","2018-11-07T09:06:24Z"],["dc.date.issued","2012"],["dc.description.abstract","By combining behavioural analyses with intrinsic signal optical imaging, we analysed visual performance and visual cortical activity in the albino mouse strain BALB/c, which is increasingly being used as an animal model of neuropsychological disorders. Visual acuity, as measured by a virtual-reality optomotor system, was 0.12 cycles per degree (cyc/deg) in BALB/c mice and 0.39 cyc/deg in pigmented C57BL/6 mice. Surprisingly, BALB/c mice showed reflexive head movements against the direction of the rotating stimulus. Contrast sensitivity was significantly lower in BALB/c mice (45% contrast at 0.064 cyc/deg) than in C57BL/6 mice (6% contrast). In the visual water task, visual acuity was 0.3 cyc/deg in BALB/c mice and 0.59 cyc/deg in C57BL/6 mice. Thus, the visual performance of BALB/c mice was significantly impaired in both behavioural tests visual acuity was similar to 0.3 cyc/deg lower than in C57BL/6 mice, and contrast sensitivity was reduced by a factor of similar to 8. In BALB/c mice, visual cortical maps induced by stimulation of the contralateral eye were normal in both activation strength and retinotopic map quality. In contrast, maps induced by ipsilateral eye stimulation differed significantly between the strains activity in a region representing 15 degrees to 19 degrees elevation in the visual field was significantly weaker in BALB/c mice than in C57BL/6 mice. Taken together, our observations show that BALB/c mice, like the albino animals of other species, have a significantly lower visual performance than C57BL/6 mice and a modified cortical representation of the ipsilateral eye that may impair stereopsis. Thus, our results caution against disregarding vision as a confounding factor in behavioural tests of neuropsychological disorders."],["dc.identifier.doi","10.1111/j.1460-9568.2012.08195.x"],["dc.identifier.isi","000308941000009"],["dc.identifier.pmid","22738127"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/25548"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.relation.issn","0953-816X"],["dc.title","Visual capabilities and cortical maps in BALB/c mice"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","7206"],["dc.bibliographiccitation.issue","16"],["dc.bibliographiccitation.journal","Journal of Neuroscience"],["dc.bibliographiccitation.lastpage","7217"],["dc.bibliographiccitation.volume","22"],["dc.contributor.author","Kaschube, M."],["dc.contributor.author","Geisel, Theo"],["dc.contributor.author","Lowel, S."],["dc.contributor.author","Wolf, Fred"],["dc.date.accessioned","2018-11-07T10:10:41Z"],["dc.date.available","2018-11-07T10:10:41Z"],["dc.date.issued","2002"],["dc.description.abstract","The layout of functional cortical maps exhibits a high degree of interindividual variability that may account for individual differences in sensory and cognitive abilities. By quantitatively assessing the interindividual variability of orientation preference columns in the primary visual cortex, we demonstrate that column sizes and shapes as well as a measure of the homogeneity of column sizes across the visual cortex are significantly clustered in genetically related animals and in the two hemispheres of individual brains. Taking the developmental timetable of column formation into account, our data indicate a substantial genetic influence on the developmental specification of visual cortical architecture and suggest ways in which genetic information may influence an individual's visual abilities."],["dc.identifier.isi","000177421000036"],["dc.identifier.pmid","12177215"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/39905"],["dc.language.iso","en"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Soc Neuroscience"],["dc.relation.eissn","1529-2401"],["dc.relation.issn","0270-6474"],["dc.subject","visual cortex; development; orientation columns; cortical maps; area 17; genetic determination"],["dc.title","Genetic influence on quantitative features of neocortical architecture"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3251"],["dc.bibliographiccitation.issue","12"],["dc.bibliographiccitation.journal","European Journal of Neuroscience"],["dc.bibliographiccitation.lastpage","3266"],["dc.bibliographiccitation.volume","18"],["dc.contributor.author","Kaschube, Matthias"],["dc.contributor.author","Wolf, Fred"],["dc.contributor.author","Puhlmann, Mathias"],["dc.contributor.author","Rathjen, Stefan"],["dc.contributor.author","Schmidt, Karl-Friedrich"],["dc.contributor.author","Geisel, Theo"],["dc.contributor.author","Löwel, Siegrid"],["dc.date.accessioned","2017-09-07T11:45:37Z"],["dc.date.available","2017-09-07T11:45:37Z"],["dc.date.issued","2003"],["dc.description.abstract","We present a comprehensive analysis of the intrinsic variability of the periodicity of ocular dominance columns in cat primary visual cortex (area 17) and its relationship to genetic background and visual experience. We characterized the intra-areal and interindividual variability of column spacing in a large set (n = 49) of ocular dominance patterns adapting a recently developed technique for the two-dimensional analysis of orientation column patterns. Patterns were obtained from three different cat colonies (termed F, M and D), the cats having either normal visual experience or experimentally induced strabismus. Two-dimensional maps of local column spacing were calculated for every pattern. In individual cortices, local column spacings varied by > 50% with the majority of column spacings ranging between 0.6 and 1.5 mm in different animals. In animals from colonies F and M (n = 29), the mean column spacing ranged between 1.03 and 1.27 mm and exhibited no significant differences, either between the two breeds or between strabismic and normal animals. The mean spacing was moderately clustered in the left and right brain hemisphere of individual animals but not in littermates. In animals from colony D (n = 2), average column spacing ranged between 0.73 and 0.95 mm, and was thus significantly different from the distribution of spacings in animals from breeds F and M, suggesting an influence of genetic factors on the layout of ocular dominance columns. Local column spacing exhibited a considerable systematic intra-areal variation, with largest spacings along the representation of the horizontal meridian and smallest spacings along the peripheral representation of the vertical meridian. The total variability of ocular dominance column spacing comprised 24% systematic intra-areal variation, 18% interindividual differences of mean column spacing and 58% nonsystematic intra-areal variability."],["dc.identifier.doi","10.1111/j.1460-9568.2003.02979.x"],["dc.identifier.gro","3151826"],["dc.identifier.pmid","14686899"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8656"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","0953-816X"],["dc.title","The pattern of ocular dominance columns in cat primary visual cortex: intra- and interindividual variability of column spacing and its dependence on genetic background"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1113"],["dc.bibliographiccitation.issue","6007"],["dc.bibliographiccitation.journal","Science"],["dc.bibliographiccitation.lastpage","1116"],["dc.bibliographiccitation.volume","330"],["dc.contributor.author","Kaschube, Matthias"],["dc.contributor.author","Schnabel, Michael"],["dc.contributor.author","Löwel, Siegrid"],["dc.contributor.author","Coppola, David M."],["dc.contributor.author","White, Leonard E."],["dc.contributor.author","Wolf, Fred"],["dc.date.accessioned","2017-09-07T11:46:14Z"],["dc.date.available","2017-09-07T11:46:14Z"],["dc.date.issued","2010"],["dc.description.abstract","The brain’s visual cortex processes information concerning form, pattern, and motion within functional maps that reflect the layout of neuronal circuits. We analyzed functional maps of orientation preference in the ferret, tree shrew, and galago—three species separated since the basal radiation of placental mammals more than 65 million years ago—and found a common organizing principle. A symmetry-based class of models for the self-organization of cortical networks predicts all essential features of the layout of these neuronal circuits, but only if suppressive long-range interactions dominate development. We show mathematically that orientation-selective long-range connectivity can mediate the required interactions. Our results suggest that self-organization has canalized the evolution of the neuronal circuitry underlying orientation preference maps into a single common design."],["dc.identifier.doi","10.1126/science.1194869"],["dc.identifier.gro","3151861"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8691"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","0036-8075"],["dc.title","Universality in the Evolution of Orientation Columns in the Visual Cortex"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","e0124917"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","PLoS ONE"],["dc.bibliographiccitation.volume","10"],["dc.contributor.author","Michael, Neethu"],["dc.contributor.author","Loewel, Siegrid"],["dc.contributor.author","Bischof, Hans-Joachim"],["dc.date.accessioned","2018-11-07T09:58:36Z"],["dc.date.available","2018-11-07T09:58:36Z"],["dc.date.issued","2015"],["dc.description.abstract","The visual wulst of the zebra finch comprises at least two retinotopic maps of the contralateral eye. As yet, it is not known how much of the visual field is represented in the wulst neuronal maps, how the organization of the maps is related to the retinal architecture, and how information from the ipsilateral eye is involved in the activation of the wulst. Here, we have used auto-fluorescent flavoprotein imaging and classical anatomical methods to investigate such characteristics of the most posterior map of the multiple retinotopic representations. We found that the visual wulst can be activated by visual stimuli from a large part of the visual field of the contralateral eye. Horizontally, the visual field representation extended from -5 degrees beyond the beak tip up to +125 degrees laterally. Vertically, a small strip from -10 degrees below to about +25 degrees above the horizon activated the visual wulst. Although retinal ganglion cells had a much higher density around the fovea and along a strip extending from the fovea towards the beak tip, these areas were not overrepresented in the wulst map. The wulst area activated from the foveal region of the ipsilateral eye, overlapped substantially with the middle of the three contralaterally activated regions in the visual wulst, and partially with the other two. Visual wulst activity evoked by stimulation of the frontal visual field was stronger with contralateral than with binocular stimulation. This confirms earlier electrophysiological studies indicating an inhibitory influence of the activation of the ipsilateral eye on wulst activity elicited by stimulating the contralateral eye. The lack of a foveal overrepresentation suggests that identification of objects may not be the primary task of the zebra finch visual wulst. Instead, this brain area may be involved in the processing of visual information necessary for spatial orientation."],["dc.description.sponsorship","Open-Access-Publikationsfonds 2015"],["dc.identifier.doi","10.1371/journal.pone.0124917"],["dc.identifier.isi","000352478400148"],["dc.identifier.pmid","25853253"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/11761"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/37397"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Public Library Science"],["dc.relation.issn","1932-6203"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.title","Features of the Retinotopic Representation in the Visual Wulst of a Laterally Eyed Bird, the Zebra Finch (Taeniopygia guttata)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.contributor.author","Hoffsümmer, Frank"],["dc.contributor.author","Wolf, F."],["dc.contributor.author","Geisel, Theo"],["dc.contributor.author","Löwel, Siegrid"],["dc.contributor.author","Schmidt, K."],["dc.contributor.editor","Bower, James M."],["dc.date.accessioned","2017-11-22T09:37:46Z"],["dc.date.available","2017-11-22T09:37:46Z"],["dc.date.issued","1996"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/10180"],["dc.language.iso","en"],["dc.notes.status","new -primates"],["dc.publisher","Springer"],["dc.publisher.place","New York"],["dc.relation.ispartof","Computation and Neural Systems"],["dc.title","Sequential bifurcation and dynamic rearrangement of columnar patterns during cortical development"],["dc.type","book_chapter"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]