Wörgötter, Florentin Andreas

[["dc.bibliographiccitation.firstpage","997"],["dc.bibliographiccitation.lastpage","1002"],["dc.contributor.author","Quill, Ulrich"],["dc.contributor.author","Woergoetter, Florentin"],["dc.contributor.author","Funke, Klaus"],["dc.contributor.author","Lansner, Anders"],["dc.contributor.editor","Niklasson, Lars"],["dc.contributor.editor","Bodén, Mikael"],["dc.contributor.editor","Ziemke, Tom"],["dc.date.accessioned","2017-09-07T11:45:31Z"],["dc.date.available","2017-09-07T11:45:31Z"],["dc.date.issued","2013"],["dc.description.abstract","Although the functional role synchronous oscillations may play has been investigated in depth, the underlying processes and spatio-temporal aspects that establish the synchrony are still not thoroughly understood. Experimental studies suggest the existence of two kinds of oscillations: stimulus-locked and stimulus-induced. While stimulus-locked oscillations are systematically dependent on the stimulus, stimulus-induced oscillations (occurring in the γ frequency range) show only little stimulus dependency. We propose a unifying approach which employs very generic connection structures. Different degrees of synchrony on different time scales are observed as an emergent feature of the network structure. Our model demonstrates that both, stimulus-locked and stimulus-induced oscillations are just two different states of the same system. A transition from one state to the other is observed, and the synchronous activity provides the basis for binding visual features."],["dc.identifier.doi","10.1007/978-1-4471-1599-1_156"],["dc.identifier.gro","3151787"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8614"],["dc.language.iso","en"],["dc.notes.status","public"],["dc.notes.submitter","chake"],["dc.publisher","Springer"],["dc.publisher.place","London"],["dc.relation.isbn","978-3-540-76263-8"],["dc.relation.ispartof","ICANN 98"],["dc.relation.issn","1431-6854"],["dc.title","The role of spatio-temporal neural response characteristics in the formation of synchrony"],["dc.type","book_chapter"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","430"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Experimental Brain Research"],["dc.bibliographiccitation.lastpage","444"],["dc.bibliographiccitation.volume","144"],["dc.contributor.author","Suder, Katrin"],["dc.contributor.author","Funke, Klaus"],["dc.contributor.author","Zhao, Yongqiang"],["dc.contributor.author","Kerscher, Nicolas"],["dc.contributor.author","Wennekers, Thomas"],["dc.contributor.author","Woergoetter, Florentin"],["dc.date.accessioned","2017-09-07T11:45:25Z"],["dc.date.available","2017-09-07T11:45:25Z"],["dc.date.issued","2002"],["dc.description.abstract","We investigated how changes in the temporal firing rate of thalamocortical activity affect the spatiotemporal structure of receptive field (RF) subunits in cat primary visual cortex. Spike activity of 67 neurons (48 simple, 19 complex cells) was extracellulary recorded from area 17/18 of anesthetized and paralyzed cats. A total of 107 subfields (on/off) were mapped by applying a reverse correlation technique to the activity elicited by bright and dark rectangles flashed for 300 ms in a 20×10 grid. We found that the width of the (suprathreshold) discharge fields shrank on average by 22% during this 300-ms-long stimulus presentation time. Fifty-eight subfields (54%) shrank by more than 20% of peak width and only ten (less than 10%) showed a slight increase over time. The main size reduction took place 40–60 ms after response onset, which corresponded to the transition from transient peak firing to tonic visual activity in thalamocortical relay cells (TC). The experimentally obtained RFs were then fitted with the aid of a neural field model of the primary visual pathway. Assuming a Gaussian-shaped spatial sensitivity profile across the RF subfield width, the model allowed us to estimate the subthreshold RF (depolarization field, D-field) from the minimal discharge field (MDF). The model allowed us to test to what degree the temporal dynamics of thalamocortical activity contributes to the spatiotemporal changes of cortical RFs. To this end, we performed the fitting procedure either with a pure feedforward model or with a field model that also included intracortical feedback. Spatial and temporal parameters obtained from fits of the experimental RFs matched closely to those achieved by simulating a pure feedforward system with the field model but were not compatible with additional intracortical feedback. Thus, our results show that dot stimulation, which optimally excites thalamocortical cells, leads to a shrinkage with respect to the size of the RF subfield at the first transient response of visual cortical RFs which seems mainly due to a change in the thalamic firing pattern. In these experiments little or no influence from intracortical sources was observed, which, however, may play a role when using more complex visual stimuli."],["dc.identifier.doi","10.1007/s00221-002-1061-5"],["dc.identifier.gro","3151757"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8581"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","0014-4819"],["dc.title","Spatial dynamics of receptive fields in cat primary visual cortex related to the temporal structure of thalamocortical feedforward activity"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2130"],["dc.bibliographiccitation.issue","13"],["dc.bibliographiccitation.journal","NeuroReport"],["dc.bibliographiccitation.lastpage","2134"],["dc.bibliographiccitation.volume","7"],["dc.contributor.author","Funke, Klaus"],["dc.contributor.author","Nelle, Eckart"],["dc.contributor.author","Li, Bing"],["dc.contributor.author","Woergoetter, Florentin"],["dc.date.accessioned","2017-09-07T11:45:24Z"],["dc.date.available","2017-09-07T11:45:24Z"],["dc.date.issued","2006"],["dc.identifier.doi","10.1097/00001756-199609020-00013"],["dc.identifier.gro","3151755"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8579"],["dc.language.iso","en"],["dc.notes.status","public"],["dc.notes.submitter","chake"],["dc.relation.issn","0959-4965"],["dc.title","Corticofugal feedback improves the timing of retino-geniculate signal transmission"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1823"],["dc.bibliographiccitation.issue","1428"],["dc.bibliographiccitation.journal","Philosophical Transactions of the Royal Society of London. B, Biological Sciences"],["dc.bibliographiccitation.lastpage","1834"],["dc.bibliographiccitation.volume","357"],["dc.contributor.author","Wörgötter, Florentin"],["dc.contributor.author","Eyding, Dirk"],["dc.contributor.author","Macklis, Jeffrey D."],["dc.contributor.author","Funke, Klaus"],["dc.date.accessioned","2017-09-07T11:45:34Z"],["dc.date.available","2017-09-07T11:45:34Z"],["dc.date.issued","2002"],["dc.description.abstract","We review results on the in vivo properties of neurons in the dorsal lateral geniculate nucleus (dLGN) that receives its afferent input from the retina and projects to the visual cortex. In addition, the dLGN receives input from the brain stem and from a rather strong corticothalamic back–projection, which originates in layer 6 of the visual cortex. We compare the behaviour of dLGN cells during spontaneous changes of the frequency contents of the electroencephalograph (EEG) (which are mainly related to a changing brain stem influence), with those that are obtained when experimentally silencing the corticothalamic feedback. The spatial and temporal response properties of dLGN cells are compared during these two conditions, and we report that the neurons behave similarly during a synchronized EEG state and during inactive corticothalamic feedback. In both situations, dLGN cells are rather phasic and their remaining tonic activity is temporally dispersed, indicating a hyperpolarizing effect. By means of a novel method, we were able to chronically eliminate a large proportion of the corticothalamic projection neurons from the otherwise intact cortex. In this condition, we found that cortical cells also lose their EEG specific response differences but, in this instance, probably due to a facilitatory (depolarizing) plasticity reaction of the remaining network."],["dc.identifier.doi","10.1098/rstb.2002.1159"],["dc.identifier.gro","3151814"],["dc.identifier.pmid","12626015"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8644"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","0962-8436"],["dc.title","The influence of the corticothalamic projection on responses in thalamus and cortex"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","171"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Experimental Brain Research"],["dc.bibliographiccitation.lastpage","176"],["dc.bibliographiccitation.volume","104"],["dc.contributor.author","Funke, Klaus"],["dc.contributor.author","Woergoetter, Florentin"],["dc.date.accessioned","2017-09-07T11:45:37Z"],["dc.date.available","2017-09-07T11:45:37Z"],["dc.date.issued","2004"],["dc.description.abstract","The temporal structure of spike trains recorded from optic fibers and single units of the lateral geniculate nucleus (LGN) and primary visual cortex of the cat was studied with a novel method of inter-spike interval analysis. ON type relay cells of the LGN exhibited a multimodal interval distribution preferring a distinct interval (fundamental interval) and its multiples during the sustained light response, whereas most OFF cells showed a broad, unimodal distribution. The general pattern of the interval distribution was relatively independent of stimulus size and contrast and the degree of light adaptation. Simultaneously recorded S-potentials originating from the retinal input generally produced only a single peak at the fundamental interval length. Therefore, the multimodal interval distribution of LGN cells seems to be a result of intra-geniculate inhibition. Cortical cells also showed a weak tendency to fire with spike intervals similar to LGN cells. Therefore, the regular firing pattern observed at peripheral stages of the visual pathway can persist at higher levels and might promote the occurrence of oscillatory activity."],["dc.identifier.doi","10.1007/bf00229868"],["dc.identifier.gro","3151825"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8655"],["dc.language.iso","en"],["dc.notes.status","public"],["dc.notes.submitter","chake"],["dc.relation.issn","0014-4819"],["dc.title","Differences in the temporal dynamics of the visual ON and OFF pathways"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","165"],["dc.bibliographiccitation.lastpage","188"],["dc.contributor.author","Wörgötter, Florentin"],["dc.contributor.author","Suder, Katrin"],["dc.contributor.author","Pugeault, Nicolas"],["dc.contributor.author","Funke, Klaus"],["dc.contributor.editor","Buracas, G. T."],["dc.contributor.editor","Ruksenas, O."],["dc.contributor.editor","Boyton, G. M."],["dc.contributor.editor","Albright, T. D."],["dc.date.accessioned","2017-11-22T13:04:43Z"],["dc.date.available","2017-11-22T13:04:43Z"],["dc.date.issued","2003"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/10195"],["dc.language.iso","en"],["dc.notes.status","new -primates"],["dc.publisher","Springer"],["dc.publisher.place","Heidelberg"],["dc.relation.ispartof","Life and Behavioral Sciences"],["dc.title","Response characteristics in the lateral geniculate nucleus and their primary afferent influences on the visual cortex of cat. Modulation of Neuronal Responses: Implications for Active Vision"],["dc.type","book_chapter"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","469"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Visual Neuroscience"],["dc.bibliographiccitation.lastpage","484"],["dc.bibliographiccitation.volume","12"],["dc.contributor.author","Woergoetter, Florentin"],["dc.contributor.author","Funke, Klaus"],["dc.date.accessioned","2017-09-07T11:45:25Z"],["dc.date.available","2017-09-07T11:45:25Z"],["dc.date.issued","1995"],["dc.description.abstract","This study focuses on the analysis of temporal patterns in the spike train of cells in the lateral geniculate nucleus (LGN) of cat. Two-hundred eighty-three units have been recorded extracellularly in anesthetized animals during visual stimulation with flashing spot stimuli of different size. We used a novel method of temporally local computed interval distributions (intervalogram; Funke & Wörgötter, 1995) to visualize the statistical distribution of interspike intervals during different phases of the visual response. Multimodal interval distributions were observed mainly in X- and Y-ON cells, reflecting the tendency of these cells to fire with preferred intervals during the sustained light response. The shortest preferred interval is called the fundamental interval and the longer ones (higher-order intervals) are, in general, multiples thereof. During increasing surround inhibition a redistribution of the intervals towards the higher orders was observed. We regarded the different peaks in the interval distributions as different components of possible temporal spike sequences and performed a pattern search up to the level of five subsequent intervals. While it is obvious, that the dominant peak is most strongly represented in any interval sequence, we also show that a significant overrepresentation of short sequences of similar intervals exists. The repetition rate is rather small (4–5 intervals) and, therefore, no long-lasting oscillatory pattern was observed in the autocorrelograms. Power spectral analysis of the peristimulus-time histograms, however, revealed that the sequential firing pattern is strongly stimulus locked at least for the majority of sweeps in the records.The mean firing rate of an LGN cell decreases with increasing stimulus size as well as with decreasing contrast. Therefore, the mean rate cannot be used to distinguish between these situations. While in the whole network this tradeoff can be resolved by the combined activity of multiple cells, our findings additionally suggest that contrast and size can be distinguished already at the single-cell level using different temporal patterns."],["dc.identifier.doi","10.1017/s0952523800008373"],["dc.identifier.gro","3151774"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8600"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","0952-5238"],["dc.title","Fine structure analysis of temporal patterns in the light response of cells in the lateral geniculate nucleus of cat"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","857"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","The Journal of Physiology"],["dc.bibliographiccitation.lastpage","874"],["dc.bibliographiccitation.volume","514"],["dc.contributor.author","Li, Bing"],["dc.contributor.author","Funke, Klaus"],["dc.contributor.author","Wörgötter, Florentin"],["dc.contributor.author","Eysel, Ulf T."],["dc.date.accessioned","2017-09-07T11:45:23Z"],["dc.date.available","2017-09-07T11:45:23Z"],["dc.date.issued","1999"],["dc.description.abstract","1 Simultaneous recordings of the EEG and the visual activity of cat dorsal lateral geniculate nucleus (dLGN) relay cells were analysed for covariance. Sliding time-window analyses were performed in parallel for the EEG power spectrum and single unit visual activity. The EEG power ratio (EEG-PR) of low (1-8 Hz) to high (20-40 Hz) frequencies was chosen to achieve a quantitative measure of the EEG which could be compared with the spike rate of a dLGN unit at any time. A high EEG-PR value indicates a synchronized EEG dominated by low frequencies (δ waves and sleep spindles), a low value indicates a less synchronized EEG. 2In the anaesthetized animal, two different underlying patterns of activity in the EEG-PR were found: slow gradual changes (slow gradations) and oscillatory changes. In many cases both were accompanied by correlated variations in dLGN spike rate, either for overall activity or for burst firing. 3The slow gradations appear for long time periods of up to 200 s and, in most cases (76·3 %), show a negative correlation between EEG-PR and overall spike rate, but predominantly a positive correlation for burst firing (85·1 %). 4The oscillatory changes, which have not previously been reported, appear as temporally well-coupled variations in EEG-PR and spike rate with a stable cycle length within the range 4-10 s. In about 77 % of correlated changes the temporal delay between the change in EEG-PR and that of the spike rate was less than ± 1·0 s. 5During simultaneous recordings from two dLGN cells the variations in spike rate tend to show the same sign of correlation with respect to the EEG pattern. This relationship is more pronounced with the slow gradations than with the oscillatory changes. 6Slow gradations in the spectral composition of the EEG may indicate global transitions between different stages within the sleep-wake cycle, reflecting the well-known influences of the brainstem arousal system. The oscillations in the spectral composition of the EEG are accompanied by gradual variations in thalamic transmission mode and are more likely to be due to involvement of a local feedback system via the thalamo-cortico-thalamic loop. The difference between the effects on overall and burst firing activity supports the notion that phasic (burst firing) and tonic visual responses may play distinctive roles in information processing, which are functionally related to the animal's behavioural state."],["dc.identifier.doi","10.1111/j.1469-7793.1999.857ad.x"],["dc.identifier.gro","3151761"],["dc.identifier.pmid","9882756"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8586"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","0022-3751"],["dc.title","Correlated variations in EEG pattern and visual responsiveness of cat lateral geniculate relay cells"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","331"],["dc.bibliographiccitation.journal","Proceedings of the ... British Neural Network Society Meeting"],["dc.bibliographiccitation.lastpage","336"],["dc.contributor.author","Suder, Katrin"],["dc.contributor.author","Funke, Klaus"],["dc.contributor.author","Woergoetter, Florentin"],["dc.contributor.editor","Niklasson, Lars"],["dc.contributor.editor","Bodén, Mikael"],["dc.contributor.editor","Ziemke, Tom"],["dc.date.accessioned","2017-09-07T11:45:26Z"],["dc.date.available","2017-09-07T11:45:26Z"],["dc.date.issued","1998"],["dc.description.abstract","Changing patterns in the EEG reflect changing states of attentiveness and are correlated to changes in the firing behavior of single cells. Prom experiments it is known that LGN cells of the Thalamus exhibit a tonic firing pattern during desynchronized EEG reflecting faithfully properties of a stimulus; whereas they are in a burst mode during synchronized EEG, which leads to a stereotype stimulus response. We introduce a model in which these changes in the neural temporal behavior lead to changes in the spatial characteristics of cortical receptive fields through variations in the effective connectivity between thalamic and cortical cells. This spatio-temporal receptive field restructuring reflects different modes of information processing and might be controlled by selective attention."],["dc.identifier.doi","10.1007/978-1-4471-1599-1_48"],["dc.identifier.gro","3151768"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8593"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.publisher","Springer"],["dc.publisher.place","London"],["dc.relation.conference","98 International Conference on Artificial Neural Networks"],["dc.relation.doi","10.1007/978-1-4471-1599-1"],["dc.relation.eventend","1998-09-04"],["dc.relation.eventlocation","Schweden"],["dc.relation.eventstart","1998-09-02"],["dc.relation.isbn","978-3-540-76263-8"],["dc.relation.ispartof","ICANN 98"],["dc.relation.issn","1431-6854"],["dc.title","State-dependent Spatio-temporal Restructuring of Receptive Fields in the Primary Visual Pathway"],["dc.type","conference_paper"],["dc.type.internalPublication","no"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","7021"],["dc.bibliographiccitation.issue","18"],["dc.bibliographiccitation.journal","The Journal of neuroscience : the official journal of the Society for Neuroscience"],["dc.bibliographiccitation.lastpage","7033"],["dc.bibliographiccitation.volume","23"],["dc.contributor.author","Eyding, Dirk"],["dc.contributor.author","Macklis, Jeffrey D."],["dc.contributor.author","Neubacher, Ute"],["dc.contributor.author","Funke, Klaus"],["dc.contributor.author","Wörgötter, Florentin"],["dc.date.accessioned","2017-11-22T13:39:54Z"],["dc.date.available","2017-11-22T13:39:54Z"],["dc.date.issued","2003"],["dc.description.abstract","The role of corticogeniculate feedback in the organization, function, and state dependence of visual responses and receptive fields (RFs) is not well understood. We investigated the contribution of the corticogeniculate loop to state-dependent changes of characteristics of the primary visual cortex response by using a novel approach of eliminating corticogeniculate projection neurons with targeted neuronal apoptosis. Experiments were performed in anesthetized cats (N2O plus halothane) with parallel recordings of single units from experimental (right) and control (left) hemispheres approximately 2 weeks after induction of apoptosis. Within the experimental hemispheres, neurons of area 17 and of the dorsal lateral geniculate nucleus (dLGN) showed an unusually enhanced and prolonged tonic visual response during episodes of synchronized (syn) EEG activity, whereas response levels during less synchronized states were almost normal. In addition, dLGN cells showed a reduced tendency for burst firing and a less regular spike interval distribution compared with those of controls. These changes are likely attributable to a tonic depolarization of dLGN relay neurons or, more likely, to a decreased responsiveness of thalamic inhibitory processes to cortical feedback. Cortical neurons also displayed an activity-dependent increase in RF size, in contrast to an almost activity-invariant RF size of controls, a phenomenon likely related to the elimination of collateral, intracortical projections of layer 6 neurons. Together, these results demonstrate that selective chronic elimination of corticogeniculate feedback results in the loss of EEG-correlated differences of visual processing in the remaining thalamocortical network, accompanied by a significant increase in excitability during syn EEG, at the expense of noticeably reduced spatial receptive-field specificity in the remaining cortical neurons."],["dc.identifier.doi","10.1523/JNEUROSCI.23-18-07021.2003"],["dc.identifier.pmid","12904463"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/10200"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.eissn","1529-2401"],["dc.title","Selective Elimination of Corticogeniculate Feedback Abolishes the Electroencephalogram Dependence of Primary Visual Cortical Receptive Fields and Reduces Their Spatial Specificity"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]