TY - JOUR
T1 - An explanation of contextual modulation by short-range isotropic connections and orientation map geometry in the primary visual cortex
AU - Okamoto, Tsuyoshi
AU - Watanabe, Masataka
AU - Aihara, Kazuyuki
AU - Kondo, Shunsuke
PY - 2004/12/1
Y1 - 2004/12/1
N2 - Recent experimental studies on the primary visual cortex have revealed complicated nonclassical neuronal activities. Contextual modulation on orientation-contrast is one typical example of nonclassical neuronal behavior. This modulation by surrounding stimuli in a nonclassical receptive field is mainly thought to be mediated by short- and long-range horizontal connections within the primary visual cortex. Short-range connections are circularly symmetrical and relatively independent of orientation preferences, while long-range connections are patchy, asymmetrical, and orientation specific. Although this modulation can be explained by long-range specific connections qualitatively, recent studies suggest that long-range connections alone may be insufficient with respect to the balance between two types of connections. Here, in order to clarify the role of short-range connections in the process of contextual modulation, we propose a model of the primary visual cortex with isotropic short-range connections and a geometric orientation map. Computational simulations using the model have demonstrated that contextual modulation can be explained by short-range connections alone. This is due to the interaction between the spatial periodicity of orientation domains and the excitatory-inhibitory regions arising from the propagation of activities.
AB - Recent experimental studies on the primary visual cortex have revealed complicated nonclassical neuronal activities. Contextual modulation on orientation-contrast is one typical example of nonclassical neuronal behavior. This modulation by surrounding stimuli in a nonclassical receptive field is mainly thought to be mediated by short- and long-range horizontal connections within the primary visual cortex. Short-range connections are circularly symmetrical and relatively independent of orientation preferences, while long-range connections are patchy, asymmetrical, and orientation specific. Although this modulation can be explained by long-range specific connections qualitatively, recent studies suggest that long-range connections alone may be insufficient with respect to the balance between two types of connections. Here, in order to clarify the role of short-range connections in the process of contextual modulation, we propose a model of the primary visual cortex with isotropic short-range connections and a geometric orientation map. Computational simulations using the model have demonstrated that contextual modulation can be explained by short-range connections alone. This is due to the interaction between the spatial periodicity of orientation domains and the excitatory-inhibitory regions arising from the propagation of activities.
UR - http://www.scopus.com/inward/record.url?scp=10844248438&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=10844248438&partnerID=8YFLogxK
U2 - 10.1007/s00422-004-0528-9
DO - 10.1007/s00422-004-0528-9
M3 - Article
C2 - 15597178
AN - SCOPUS:10844248438
VL - 91
SP - 396
EP - 407
JO - Biological Cybernetics
JF - Biological Cybernetics
SN - 0340-1200
IS - 6
ER -