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Möbius-strip-like columnar functional connections are revealed in somato-sensory receptive field centroids.

Wright JJ, Bourke PD, Favorov OV - Front Neuroanat (2014)

Bottom Line: Locations of the field centroids indicated the presence of a functional system in which cortical homotypic representations of the limb surfaces are entwined in three-dimensional Möbius-strip-like patterns of synaptic connections.Boundaries of somatosensory receptive field in nested groups irregularly overlie the centroid order, and are interpreted as arising from the superposition of learned connections upon the embryonic order.Since the theory of embryonic synaptic self-organization used to model these results was devised and earlier used to explain findings in primary visual cortex, the present findings suggest the theory may be of general application throughout cortex and may reveal a modular functional synaptic system, which, only in some parts of the cortex, and in some species, is manifest as anatomical ordering into columns.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychological Medicine, Faculty of Medicine, The University of Auckland Auckland, New Zealand.

ABSTRACT
Receptive fields of neurons in the forelimb region of areas 3b and 1 of primary somatosensory cortex, in cats and monkeys, were mapped using extracellular recordings obtained sequentially from nearly radial penetrations. Locations of the field centroids indicated the presence of a functional system in which cortical homotypic representations of the limb surfaces are entwined in three-dimensional Möbius-strip-like patterns of synaptic connections. Boundaries of somatosensory receptive field in nested groups irregularly overlie the centroid order, and are interpreted as arising from the superposition of learned connections upon the embryonic order. Since the theory of embryonic synaptic self-organization used to model these results was devised and earlier used to explain findings in primary visual cortex, the present findings suggest the theory may be of general application throughout cortex and may reveal a modular functional synaptic system, which, only in some parts of the cortex, and in some species, is manifest as anatomical ordering into columns.

No MeSH data available.


Calculation of cortical anisotropy for an RF. Against an outline of the cat's standard forelimb with reference axes, the blue lines indicate the longest and broadest axes of the RF.
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Figure 6: Calculation of cortical anisotropy for an RF. Against an outline of the cat's standard forelimb with reference axes, the blue lines indicate the longest and broadest axes of the RF.

Mentions: Calculations were then made to allow for effects of cortical anisotropy. Figure 6 shows a typical RF against a cat's forepaw outline. The size and elliptical shape of the RF reflects the anisotropic representation of the skin surface in S1 (e.g., Kaas et al., 1979) in which cortical representation is of roughly inverse size to skin extension. Length of the longest axis of each RF and its angle to a reference frame on the animal's limb, and length on the broadest axis orthogonal to the long axis, were measured and averaged over the RFs in a dataset. Subsequently the average anisotropy for the dataset was applied to the spatial distribution of theoretical points at each trial of fit.


Möbius-strip-like columnar functional connections are revealed in somato-sensory receptive field centroids.

Wright JJ, Bourke PD, Favorov OV - Front Neuroanat (2014)

Calculation of cortical anisotropy for an RF. Against an outline of the cat's standard forelimb with reference axes, the blue lines indicate the longest and broadest axes of the RF.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4215792&req=5

Figure 6: Calculation of cortical anisotropy for an RF. Against an outline of the cat's standard forelimb with reference axes, the blue lines indicate the longest and broadest axes of the RF.
Mentions: Calculations were then made to allow for effects of cortical anisotropy. Figure 6 shows a typical RF against a cat's forepaw outline. The size and elliptical shape of the RF reflects the anisotropic representation of the skin surface in S1 (e.g., Kaas et al., 1979) in which cortical representation is of roughly inverse size to skin extension. Length of the longest axis of each RF and its angle to a reference frame on the animal's limb, and length on the broadest axis orthogonal to the long axis, were measured and averaged over the RFs in a dataset. Subsequently the average anisotropy for the dataset was applied to the spatial distribution of theoretical points at each trial of fit.

Bottom Line: Locations of the field centroids indicated the presence of a functional system in which cortical homotypic representations of the limb surfaces are entwined in three-dimensional Möbius-strip-like patterns of synaptic connections.Boundaries of somatosensory receptive field in nested groups irregularly overlie the centroid order, and are interpreted as arising from the superposition of learned connections upon the embryonic order.Since the theory of embryonic synaptic self-organization used to model these results was devised and earlier used to explain findings in primary visual cortex, the present findings suggest the theory may be of general application throughout cortex and may reveal a modular functional synaptic system, which, only in some parts of the cortex, and in some species, is manifest as anatomical ordering into columns.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychological Medicine, Faculty of Medicine, The University of Auckland Auckland, New Zealand.

ABSTRACT
Receptive fields of neurons in the forelimb region of areas 3b and 1 of primary somatosensory cortex, in cats and monkeys, were mapped using extracellular recordings obtained sequentially from nearly radial penetrations. Locations of the field centroids indicated the presence of a functional system in which cortical homotypic representations of the limb surfaces are entwined in three-dimensional Möbius-strip-like patterns of synaptic connections. Boundaries of somatosensory receptive field in nested groups irregularly overlie the centroid order, and are interpreted as arising from the superposition of learned connections upon the embryonic order. Since the theory of embryonic synaptic self-organization used to model these results was devised and earlier used to explain findings in primary visual cortex, the present findings suggest the theory may be of general application throughout cortex and may reveal a modular functional synaptic system, which, only in some parts of the cortex, and in some species, is manifest as anatomical ordering into columns.

No MeSH data available.