Novel self-organizing rules for retinotopic remapping
-
1
Ruhr-University Bochum, Germany
-
2
VU Amsterdam, Netherlands
Retinotopic maps in the primary visual cortex are plastic even in the mature brain. Particularly after permanent changes in external input, i.e. after focal retinal lesions, maps in the cortex adapt so that neurons deprived of input (lesion projection zone, LPZ) become responsive to adjacent input representations. This 'filling-in' process is currently explained by STDP. However, STDP is a fast process while the time course of reorganization continues over weeks up to one year [1]. Recent data indicate that structural plasticity (forming new synapses, breaking old ones) is involved in this reorganization [2,3] and acts very much on the same timescale. Therefore, we propose the first model investigating structural plasticity in application to cortical remapping. The model implements local activity-dependent rules for changes in the morphology of the neuron. In accordance with experimental findings, model neurons aim to maintain their electrical activity on average at a certain pre-defined set-point [4] by adapting the number of contact sites (axonal and dendritic elements). New (vacant) synaptic elements are offered to the network and connect to form synapses. The probability for synapse formation between two neurons depends on the amounts of vacant synaptic elements offered, and on the Euclidean distance between the two neurons. Network rewiring is therefore a reciprocal process between activity and network structure: Activity levels inside the LPZ (low) and outside the LPZ (high) locally induce the formation of axonal and dendritic elements, respectively, that in turn form synapses in a cooperative and compensatory manner leading to increasing activities in the LPZ again. The consequence of transporting activities via new synapses from the outside of the LPZ into the LPZ is an enlargement of input representation from intact areas and a sequential filling-in of the LPZ (Fig.1)—by contrast not obtained in self-organizing maps. The novelty of the model is to generate predictions how local cellular responses lead to rewiring and remapping on an anatomical network level. Literature: [1] Giannikopoulos, D.V., Eysel, U.T. (2006) Proc Natl Acad Sci U S A, 103(28):10805-10. [2] Keck, T. et al. (2008) Nat. Neurosci. 11: 1162-1167. [3] Yamahachi, H. et al. (2009) Neuron 64:719-729. [4] Butz M et al. (2009) Front Comput Neurosci. 2009;3:10.
Keywords:
computational neuroscience,
Retinotopic mapping,
Visual Cortex,
neuron morphology,
synapse formation
Conference:
5th INCF Congress of Neuroinformatics, Munich, Germany, 10 Sep - 12 Sep, 2012.
Presentation Type:
Poster
Topic:
Neuroinformatics
Citation:
Butz
M and
Van Ooyen
A
(2014). Novel self-organizing rules for retinotopic remapping.
Front. Neuroinform.
Conference Abstract:
5th INCF Congress of Neuroinformatics.
doi: 10.3389/conf.fninf.2014.08.00018
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
21 Mar 2013;
Published Online:
27 Feb 2014.
*
Correspondence:
Dr. Markus Butz, Ruhr-University Bochum, Bochum, Germany, mbutz@ini.rub.de