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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.


Related in: MedlinePlus

Near-vertical passage of a recording electrode through S1, from (x, y, z) = (−2.8, −2, 2) to (−3.2, −2, −1.2), K = 0.4. Top: Interfaces demarcating synaptic skeins in two adjacent macrocolumns, viewed from obliquely above cortical surface. Each of the left and right pairs of disks represent the interfaces between an upper skein and a lower skein of local cells, receiving projections via patchy connections from surrounding cortex, with a mixed area between upper and lower disks. The projections wind clockwise in one skein, and anticlockwise in the other. Colors of the spectrum on the disks indicate the direction of winding, reversed in the pair of macrocolumns. The track of the recording electrode is marked with red and blue dots to distinguish neurons in clockwise and anticlockwise skeins. Middle: positions of recorded neurons in plan view. First and last neurons discovered by the advancing recording electrode numbered accordingly. Bottom: RFs centroids, strongly clustered into two groups, associated with clockwise and anticlockwise skeins respectively.
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Figure 3: Near-vertical passage of a recording electrode through S1, from (x, y, z) = (−2.8, −2, 2) to (−3.2, −2, −1.2), K = 0.4. Top: Interfaces demarcating synaptic skeins in two adjacent macrocolumns, viewed from obliquely above cortical surface. Each of the left and right pairs of disks represent the interfaces between an upper skein and a lower skein of local cells, receiving projections via patchy connections from surrounding cortex, with a mixed area between upper and lower disks. The projections wind clockwise in one skein, and anticlockwise in the other. Colors of the spectrum on the disks indicate the direction of winding, reversed in the pair of macrocolumns. The track of the recording electrode is marked with red and blue dots to distinguish neurons in clockwise and anticlockwise skeins. Middle: positions of recorded neurons in plan view. First and last neurons discovered by the advancing recording electrode numbered accordingly. Bottom: RFs centroids, strongly clustered into two groups, associated with clockwise and anticlockwise skeins respectively.

Mentions: Since complete skein separation could only be approached as ideal, at an intermediate level mixing and intertwining of the skeins is anticipated. The skeins are necessarily continuous at some angle directed from the central singularity, so mixing at the skeins would be lesser at the continuity. (See Figure 3, Top panels).


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

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

Near-vertical passage of a recording electrode through S1, from (x, y, z) = (−2.8, −2, 2) to (−3.2, −2, −1.2), K = 0.4. Top: Interfaces demarcating synaptic skeins in two adjacent macrocolumns, viewed from obliquely above cortical surface. Each of the left and right pairs of disks represent the interfaces between an upper skein and a lower skein of local cells, receiving projections via patchy connections from surrounding cortex, with a mixed area between upper and lower disks. The projections wind clockwise in one skein, and anticlockwise in the other. Colors of the spectrum on the disks indicate the direction of winding, reversed in the pair of macrocolumns. The track of the recording electrode is marked with red and blue dots to distinguish neurons in clockwise and anticlockwise skeins. Middle: positions of recorded neurons in plan view. First and last neurons discovered by the advancing recording electrode numbered accordingly. Bottom: RFs centroids, strongly clustered into two groups, associated with clockwise and anticlockwise skeins respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 3: Near-vertical passage of a recording electrode through S1, from (x, y, z) = (−2.8, −2, 2) to (−3.2, −2, −1.2), K = 0.4. Top: Interfaces demarcating synaptic skeins in two adjacent macrocolumns, viewed from obliquely above cortical surface. Each of the left and right pairs of disks represent the interfaces between an upper skein and a lower skein of local cells, receiving projections via patchy connections from surrounding cortex, with a mixed area between upper and lower disks. The projections wind clockwise in one skein, and anticlockwise in the other. Colors of the spectrum on the disks indicate the direction of winding, reversed in the pair of macrocolumns. The track of the recording electrode is marked with red and blue dots to distinguish neurons in clockwise and anticlockwise skeins. Middle: positions of recorded neurons in plan view. First and last neurons discovered by the advancing recording electrode numbered accordingly. Bottom: RFs centroids, strongly clustered into two groups, associated with clockwise and anticlockwise skeins respectively.
Mentions: Since complete skein separation could only be approached as ideal, at an intermediate level mixing and intertwining of the skeins is anticipated. The skeins are necessarily continuous at some angle directed from the central singularity, so mixing at the skeins would be lesser at the continuity. (See Figure 3, Top panels).

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.


Related in: MedlinePlus