A Canonical Microcircuit for Neocortex

Douglas, Rodney J.; Martin, Kevan A; Whitteridge, D.

doi:10.1162/neco.1989.1.4.480

Cited by 454 publications

(347 citation statements)

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“…These have been most extensively studied in area V1. One set of connections comprises the connections that form the intracolumnar canonical microcircuit (see Douglas, Martin, & Whitteridge, 1989;Douglas & Martin, 1990;, connecting cells in layer IV, which receive inputs from lower layers in the hierarchy, with cells in other layers (these are sometimes called vertical connections). The other set is intercolumnar, connecting cells in layers II/III (see Gilbert, 1993;Levitt, Lund, & Yoshioka, 1996;Fitzpatrick, 1996).…”

Section: Introductionmentioning

confidence: 99%

Recurrent Sampling Models for the Helmholtz Machine

Dylan

1999

Neural Computation

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Many recent analysis-by-synthesis density estimation models of cortical learning and processing have made the crucial simplifying assumption that units within a single layer are mutually independent given the states of units in the layer below or the layer above. In this article, we suggest using either a Markov random field or an alternative stochastic sampling architecture to capture explicitly particular forms of dependence within each layer. We develop the architectures in the context of real and binary Helmholtz machines. Recurrent sampling can be used to capture correlations within layers in the generative or the recognition models, and we also show how these can be combined.

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Section: Introductionmentioning

confidence: 99%

Recurrent Sampling Models for the Helmholtz Machine

Dylan

1999

Neural Computation

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“…The model we use to simulate the dynamics of a column is motivated by anatomical and physiological properties of the cortex on the scale of a few hundred microns. In particular, it reflects the columnar organization of the cortex (see, e.g., Mountcastle 1997) and the concept of canonical cortical microcircuits as suggested, e.g., by Douglas et al (1989). Columns are physiologically defined groups of neurons that extend through all cortical layers and have a diameter of roughly one mm.…”

Section: Neurobiological Backgroundmentioning

confidence: 96%

Information Routing, Correspondence Finding, and Object Recognition in the Brain

Wolfrum¹

2010

Studies in Computational Intelligence

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This work would not have been possible without the people I have had the honor of working with over the past years. First of all I want to thank Christoph von der Malsburg, whose scientific concepts have inspired large parts of this thesis, and who granted me enough freedom to follow my own research directions while at the same time providing motivation whenever this was necessary. I also thank Rudolf Mester for good discussions that helped me retain my engineering viewpoint on the interdisciplinary problems that I worked on. Discussions with Geoff Goodhill, Bruno Olshausen, Jochen Triesch, and Alan Yuille, among others, have shaped my thinking and had an important impact on this thesis.I thank Urs Bergmann, Jenia Jitsev, and Junmei Zhu for proof-reading parts of the thesis, and Jörg Lücke for good collaboration. The neurogroups at FIAS have provided a rich and stimulating environment, it has been fun working and thinking with you! I also thank all colleagues at FIAS for good company and the truly interdisciplinary interaction we had (e.g. at Hirschegg). Last but not least I owe this thesis to my parents, who planted curiosity and a desire for understanding in me that were stronger than the difficulties I met during this dissertation. iv

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“…However, local cortical circuits include dense recurrent connections among spiny stellate cells (Douglas et al 1989Stratford et al 1996). Such connections provide a signi®cant source of recurrent excitation and have been suggested to be very eective in generating cortical direction selectivity .…”

Section: Eects Of Additional Recurrent Excitationmentioning

confidence: 99%

“…Orientation speci®city and direction selectivity of simple cells have been revealed as emergent properties of massive excitatory and inhibitory interactions [cf. canonical cortical microcircuit (Douglas et al 1989)]. Due to the computational complexity (high-dimension) of the system of coupled nonlinear partial dierential equations at stake, analytical predictions of the network's behavior have only rarely been attempted, under heavy simplifying assumptions, and always restricted to basic functioning mechanisms of cortical microcircuits Orban 1992, 1996;Suarez et al 1995).…”

Section: Comparison To Other Modelsmentioning

confidence: 99%

An architectural hypothesis for direction selectivity in the visual cortex: the role of spatially asymmetric intracortical inhibition

Sabatini

Solari

1999

Biological Cybernetics

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Abstract. Within a linear ®eld approach, an architectural model for simple cell direction selectivity in the visual cortex is proposed. The origin of direction selectivity is related to recurrent intracortical interactions with a spatially asymmetric character along the axis of stimulus motion. No explicit asymmetric temporal mechanisms are introduced or adopted. The analytical investigation of network behavior, carried out under the assumption of a linear superposition of geniculate and intracortical contributions, shows that motion sensitivity of the resulting receptive ®elds emerges as a dynamic property of the cortical network without any feed-forward direction selectivity bias. A detailed analysis of the eects of the architectural characteristics of the cortical network on directionality and velocityresponse curves was conducted by systematically varying the model's parameters. IntroductionRecent theoretical and neurophysiological studies (DeAngelis et al. 1993a,b;Hamilton et al. 1989;McLean et al. 1994; Reid et al. 1991;Tolhurst and Dean 1991) pointed out that the origin of direction selectivity can be related to the linear space-time receptive ®eld structure of simple cells. A large class of simple cells shows a very speci®c space-time behavior in which the spatial phase of the receptive ®eld changes gradually as a function of time. This results in receptive ®eld pro®les that tilt along an oblique axis in the space-time domain (i.e., they are space-time inseparable). Accurate estimates of the velocity components to which the cell is selective (the preferred speed of motion) can be derived by measuring the slope of oriented receptive ®eld subregions in the space-time domain. Since lateral geniculate nucleus (LGN) cells do not exhibit tilted subregions, the origin of space-time inseparability must take place within the striate cortex. In general, the construction of inseparable simple-cell receptive ®elds implies a position-dependent alteration of the temporal response characteristics of the aerent inputs, presumably associated with cortical circuits characterized by asymmetric architectural schemes in space and/or time (for a review, see Koch and Hildreth 1987). Several models have been proposed. Some postulate the combination of spatially oset geniculate receptive ®elds with dierent temporal dynamics (Mastronarde 1987;Saul and Humphrey 1990;Wimbauer et al. 1994Wimbauer et al. , 1997. Others assume intracortical interactions among separable simple-cell receptive ®elds, possibly mediated by cortical interneurons (Ganz 1984;Ru et al. 1987;Sillito 1977;Somers et al. 1995). Most models, however, do not consider explicit recurrent asymmetric intracortical processes, and furthermore, a clear distinction between the roles of purely spatial and purely temporal mechanisms has not yet been made.In this paper, we point out that a purely spatial asymmetry is sucient to generate directional selectivity when spatially asymmetric contributions arise through recurrent intracortical inhibitory circuits. Therefore, the spac...

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A Canonical Microcircuit for Neocortex

Cited by 454 publications

References 10 publications

Recurrent Sampling Models for the Helmholtz Machine

Recurrent Sampling Models for the Helmholtz Machine

Information Routing, Correspondence Finding, and Object Recognition in the Brain

An architectural hypothesis for direction selectivity in the visual cortex: the role of spatially asymmetric intracortical inhibition

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