Fading memory in the visual cortex of awake monkeys
Zusammenfassung der Projektergebnisse
In the present study, we investigated the impact of repetitive visual exposure on the distributed dynamics of populations of neurons, recorded simultaneously from cat area 17. We expanded on previous studies on exposure-triggered learning, by considering stimuli that were less redundant than oriented bars and gratings from an information perspective and thus better suited to capture aspects of distributed coding. In particular, we asked how brief, repetitive exposure to a large set of abstract visual shapes (alphabet letters and digits), affected the capacity of hypothetical downstream decoders to discriminate between different stimuli based on the reverberatory responses of primary visual cortex populations. We employed brief stimulus presentations at high contrast, which have previously been shown to induce strong recurrent activity. We showed that the performance of a Bayesian classifier, trained to predict stimulus identity based on short segments of data, was improved by stimulus exposure over the course of a recording session: early trials had lower performance scores than late trials. To identify the mechanisms underlying these changes, we sought neuronal correlates of the improvement in classification performance by characterizing the population firing rates, the firing rate variabilities, the correlation structures between pairs of neurons and the selectivity of low-dimensional stimulus representations extracted via principal component analyses. Finally, we investigated the impacts of sensory experiences on stimulus encoding during the sequential presentations of multiple visual shapes.
Projektbezogene Publikationen (Auswahl)
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(2013) Encoding through patterns: regression tree based neuronal population models. Neural Computation
Haslinger, R., G. Pipa, L. Lewis, D. Nikolić, Z. Williams, and E. Brown
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(2013) Gamma oscillations: precise temporal coordination without a metronome. Trends in Cognitive Sciences, 17: 54-55
Nikolić D., P. Fries, and W. Singer
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(2013) Psychophysiological evidence for the genuineness of swimming-style colour synaesthesia. Consciousness and Cognition, 22(1):35-46
Rothen N., D. Nikolić, U.M. Jürgens, A. Mroczko-Wąsowicz, J. Cock, and B. Meier
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(2013) Synchronisation hubs in the visual cortex may arise from strong rhythmic inhibition during gamma oscillations. European Journal of Neuroscience, 38(6): 2864–2883
Folias, S.E., S. Yu, A. Snyder, D. Nikolić, and J.E. Rubin
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Orienting Towards Ensembles: From Single Cells to Neural Populations. (2013) The Journal of Neuroscience 33(1), 2-3
Lewis C. M., Lazar A. E.
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(2014) Semantic mechanisms may be responsible for developing synesthesia. Frontiers in Human Neuroscience 8:509
Mroczko-Wąsowicz, A., D. Nikolić
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(2014) Spike avalanches in vivo suggest a driven, slightly subcritical brain state. Frontiers in Systems Neuroscience 8:108
Priesemann V., M. Wibral, M. Valderrama, R. Pröpper, M. Le Van Quyen, T. Geisel, J. Triesch, D. Nikolić, M.H.J. Munk
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(2014) Where’s the noise? Key features of spontaneous activity and neural variability arise through learning in a deterministic network. PLoS Computational Biology 11 (12), e1004640
Hartmann, C., Lazar, A., Nessler, B., Triesch, J.
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Untangling Perceptual Memory: Hysteresis and Adaptation Map into Separate Cortical Networks. (2014) Cerebral Cortex 24 (5), 1152-1164
Schwiedrzik, C. M., Ruff, C. C., Lazar, A., Leitner, F. C., Singer, W., Melloni, L.
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(2015) Practopoiesis: Or how life fosters a mind. Journal of Theoretical Biology. Volume 373, 21 May 2015, Pages 40–61
Nikolić, D.
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(2015) The merit of synesthesia for consciousness research. Front. Psychol. 6:1850
Van Leeuwen T.M., Singer W. and Nikolić D.
