Functional organization of the cortical 17/18 border region in the cat

Diao, Yun‐Cheng; Jia, Wenbin; Swindale, Nicholas V.; Cynader, Max S.

doi:10.1007/bf00608236

Cited by 42 publications

(42 citation statements)

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“…Moreover, the notion that the TZ receives convergent projection from contralateral regions outside the TZ is in accord with previous physiological data indicating that the magnification factor in the ipsilateral cortical representation is low (hamster: Tiao and Blakemore, 1976;sheep: Clarke and Whitteridge, 1976;cat: Whitteridge and Clarke, 1982) and that cells in this region tend to have large receptive fields (Whitteridge and Clarke, 1982;Pettigrew and Dreher, 1987;Diao et al, 1990;Payne, 1990;Payne and Siwek, 1991). It is likely that this convergentidivergent pattern of projections will be reflected in the morphology of individual callosal axons, with axons projecting from the TZ to contralateral regions outside the TZ having broader terminal arbors than axons projecting from regions outside the TZ into the contralateral TZ.…”

Section: Convergence/divergence Of Callosal Linkagessupporting

confidence: 74%

“…This difference is in accord with the difference in size between the representations of the contralateral and ipsilateral visual fields segments that are interconnected: the ipsilateral field representation is quite compressed (Whitteridge and Clarke, 1982;Pettigrew and Dreher, 1987;Diao et al, 1990;Payne, 1990;Payne and Siwek, 1991).…”

Section: Convergence/divergence Of Callosal Linkagessupporting

confidence: 58%

“…Thus, area 17 injections placed away from the border of the TZ-labeled cells within the TZ, whereas injections close to or overlapping the medial border straddling the medial border of the contralateral TZ, con. There is general agreement about the existence of an ipsilateral representation of the visual field in the 17/18 border region in the cat (i.e., segment 1-3 of the visual field is represented on the left TZ, and segment 3.5 of the visual field is represented on the right TZ), although its extent varies among different studies (Hubel and Wiesel, 1962;Tusa et al, 1978Tusa et al, , 1979Albus and Beckman, 1980;Harvey, 1980;Whitteridge and Clarke, 1982;Blakemore et al, 1983;Pettigrew and Dreher, 1987;Diao et al, 1990;Payne, 1990). Recently, Payne (1990) reported that the ipsilateral representation is contained in the TZ and that the maximum ipsilateral incursion of receptive field centers varies with elevation, being about 4" at the 0" horizontal meridian and 10" or more at superior or inferior elevations.…”

Section: Discussionmentioning

confidence: 93%

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Non-mirror-symmetric patterns of callosal linkages in areas 17 and 18 in cat visual cortex

Olavarría

1996

J. Comp. Neurol.

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In the cat, callosal connections in area 17 are largely confined to a 5-6-mm-wide strip at the 17/18 border. It is commonly thought that callosal fibers extending from between the 17/18 border regions interconnect loci that are mirror-symmetric with respect to the midline of the brain, but this idea has not been tested experimentally. The present study examined the organization of callosal linkages in the 17/18 border region of normal adult cats by analyzing the patterns of connections revealed in one hemisphere after small injections of different fluorescent tracers into the opposite 17/18 callosal region. The location of the injection sites within areas 17 and 18 was assessed by examining architectonic data and by inspecting the labeling pattern in the ipsilateral visual thalamus. Area 17 and 18 were separated by a 1-1.5-mm-wide zone of cytoarchitectonic transition rather than by a sharp border. The results show that, in general, callosal fibers interconnect loci that are not mirror-symmetric with respect to the midline. Thus, area 17 injections placed nearly 3 mm away from the 17/18 transition zone produced discrete labeled areas located preferentially within the contralateral 17/18 transition zone. However, when the injection site was within the 17/18 transition zone, labeled cells were found primarily medial and lateral to, but not within, the 17/18 transition zone in the contralateral hemisphere. Previous studies have indicated that the 17/18 transition zone contains a representation of a strip of the ipsilateral visual field. Comparison of the retinotopy of the 17/18 border region with the mirror-reversed pattern of callosal linkages found in the present study suggests that callosal fibers link points that are in retinotopic correspondence in both hemispheres.

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Section: Convergence/divergence Of Callosal Linkagessupporting

confidence: 74%

Section: Convergence/divergence Of Callosal Linkagessupporting

confidence: 58%

Section: Discussionmentioning

confidence: 93%

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Non-mirror-symmetric patterns of callosal linkages in areas 17 and 18 in cat visual cortex

Olavarría

1996

J. Comp. Neurol.

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“…1). In most of the cases, however, these bands are organized around orientation singularities (22,29). Linear zones along the 17͞18 border are more common in area 17 of the tree shrew, where elongated iso-orientation domains intersect the border at right angles (23,30,31) (linear zones are also common at the caudal edge of the dorsal portion of area 17 of the tree shrew).…”

Section: Discussionmentioning

confidence: 99%

Coexistence of linear zones and pinwheels within orientation maps in cat visual cortex

Shmuel

Grinvald

2000

Proc. Natl. Acad. Sci. U.S.A.

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Revealing the layout of cortical maps is important both for understanding the processes involved in their development and for uncovering the mechanisms underlying neural computation. The typical organization of orientation maps in the cat visual cortex is radial; complete orientation cycles are mapped around orientation singularities. In contrast, long linear zones of orientation representation have been detected in the primary visual cortex of the tree shrew. In this study, we searched for the existence of long linear sequences and wide linear zones within orientation preference maps of the cat visual cortex. Optical imaging based on intrinsic signals was used. Long linear sequences and wide linear zones of preferred orientation were occasionally detected along the border between areas 17 and 18, as well as within area 18. Adjacent zones of distinct radial and linear organizations were observed across area 18 of a single hemisphere. However, radial and linear organizations were not necessarily segregated; long (7.5 mm) linear sequences of preferred orientation were found embedded within a typical pinwheel-like organization of orientation. We conclude that, although the radial organization is dominant, perfectly linear organization may develop and perform the processing related to orientation in the cat visual cortex.

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“…T herefore, this spectrum is no t show n here; instead we refer the reader to the work of Diao et al (1990). In Fig.…”

Section: Real Spectramentioning

confidence: 97%

Cortical column design: a link between the maps of preferred orientation and orientation tuning strength?

Wörgötter

Niebur

1993

Biol. Cybern.

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Abstract. We demonstrate that the map of the preferred orientations and the corresponding map of the orientation tuning strengths as measured with optical imaging are not independent, but that band-pass filtering of the preferred orientation map at each location yields a good approximation of the orientation tuning strength. Bandpass filtering is performed by convolving the map of orientation preference with its own autocorrelation function. We suggest an interpretation of the autocorrelation function of the preferred orientations as synaptic coupling function, i.e., synaptic strength as a function of intracortical distance between cortical cells. In developmental models it has been shown previously that a "Mexican hat"-shaped synaptic coupling function (with a shape similar to that of the autocorrelation function) can produce a realistical-looking pattern of preferred orientations. Since optical imaging performs surface averaging, we discuss the possibility that the connection between the two maps is a measurement artifact of optical imaging. Whether this is the case can only be decided by combining electrode penetrations with optical imaging techniques for which we suggest experiments. We present a model for the generation of both maps from a single computational concept. The model is based on inverse Fourier transform of rather simple twodimensional annulus-shaped spectra which will produce a column structure very similar to real data. Thus, our approach shows that the complex appearance of cortical orientation columns has a rather simple description in the Fourier domain. Our theoretical analysis explains why singularities in the cortex do not have vorticities other than ± 1/2, a result which corresponds to recent experimental findings. This study combines the results from several modeling approaches with recently available optical imaging data to construct a model of both aspects (angle and strength) of the cortical orientation column system. This could alter ideas about cortical development if the link between the two maps can be established as a physiological result.

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Functional organization of the cortical 17/18 border region in the cat

Cited by 42 publications

References 50 publications

Non-mirror-symmetric patterns of callosal linkages in areas 17 and 18 in cat visual cortex

Non-mirror-symmetric patterns of callosal linkages in areas 17 and 18 in cat visual cortex

Coexistence of linear zones and pinwheels within orientation maps in cat visual cortex

Cortical column design: a link between the maps of preferred orientation and orientation tuning strength?

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