scholarly journals Influence of ocular dominance columns and patchy callosal connections on binocularity in lateral striate cortex: Long Evans versus albino rats

2019 ◽  
Vol 528 (4) ◽  
pp. 650-663
Author(s):  
Adrian K. Andelin ◽  
Zane Doyle ◽  
Robyn J. Laing ◽  
Josef Turecek ◽  
Baihan Lin ◽  
...  
Keyword(s):  
Striate Cortex ◽  
Ocular Dominance ◽  
Albino Rats ◽  
Ocular Dominance Columns ◽  
Callosal Connections ◽  
Long Evans

scholarly journals Monocular Cells Without Ocular Dominance Columns

2006 ◽  
Vol 96 (5) ◽  
pp. 2253-2264 ◽  
Author(s):  
Daniel L. Adams ◽  
Jonathan C. Horton
Keyword(s):  
Squirrel Monkey ◽  
Visual Processing ◽  
Striate Cortex ◽  
Single Cells ◽  
Ocular Dominance ◽  
Squirrel Monkeys ◽  
Ocular Dominance Columns ◽  
Receptive Field Property ◽  
Field Property ◽  
Made In

In many regions of the mammalian cerebral cortex, cells that share a common receptive field property are grouped into columns. Despite intensive study, the function of the cortical column remains unknown. In the squirrel monkey, the expression of ocular dominance columns is variable, with columns present in some animals and not in others. By searching for differences between animals with and without columns, it should be possible to infer how columns contribute to visual processing. Single-cell recordings outside layer 4C were made in nine squirrel monkeys, followed by labeling of ocular dominance columns in layer 4C. In the squirrel monkey, compared with the macaque, cells outside layer 4C were more likely to respond to stimulation of either eye whether ocular dominance columns were present or not. In three animals lacking ocular dominance columns, single cells were recorded from layer 4C. Remarkably, 20% of cells in layer 4C were monocular despite the absence of columns. This observation means that ocular dominance columns are not necessary for monocular cells to occur in striate cortex. In macaques each row of cytochrome oxidase (CO) patches is aligned with an ocular dominance column and receives koniocellular input serving one eye only. In squirrel monkeys this was not true: CO patches and ocular dominance columns had no spatial correlation and the koniocellular input to CO patches was binocular. Thus even when ocular dominance columns occur in the squirrel monkey, they do not transform the functional architecture to resemble that of the macaque.

scholarly journals The cortical column: a structure without a function

2005 ◽  
Vol 360 (1456) ◽  
pp. 837-862 ◽  
Author(s):  
Jonathan C Horton ◽  
Daniel L Adams
Keyword(s):  
Receptive Field ◽  
Striate Cortex ◽  
Ocular Dominance ◽  
50Th Anniversary ◽  
Cortical Column ◽  
Cortical Function ◽  
Ocular Dominance Columns ◽  
Cortical Areas ◽  
Architectural Feature ◽  
Joint Receptors

This year, the field of neuroscience celebrates the 50th anniversary of Mountcastle's discovery of the cortical column. In this review, we summarize half a century of research and come to the disappointing realization that the column may have no function. Originally, it was described as a discrete structure, spanning the layers of the somatosensory cortex, which contains cells responsive to only a single modality, such as deep joint receptors or cutaneous receptors. Subsequently, examples of columns have been uncovered in numerous cortical areas, expanding the original concept to embrace a variety of different structures and principles. A ‘column’ now refers to cells in any vertical cluster that share the same tuning for any given receptive field attribute. In striate cortex, for example, cells with the same eye preference are grouped into ocular dominance columns. Unaccountably, ocular dominance columns are present in some species, but not others. In principle, it should be possible to determine their function by searching for species differences in visual performance that correlate with their presence or absence. Unfortunately, this approach has been to no avail; no visual faculty has emerged that appears to require ocular dominance columns. Moreover, recent evidence has shown that the expression of ocular dominance columns can be highly variable among members of the same species, or even in different portions of the visual cortex in the same individual. These observations deal a fatal blow to the idea that ocular dominance columns serve a purpose. More broadly, the term ‘column’ also denotes the periodic termination of anatomical projections within or between cortical areas. In many instances, periodic projections have a consistent relationship with some architectural feature, such as the cytochrome oxidase patches in V1 or the stripes in V2. These tissue compartments appear to divide cells with different receptive field properties into distinct processing streams. However, it is unclear what advantage, if any, is conveyed by this form of columnar segregation. Although the column is an attractive concept, it has failed as a unifying principle for understanding cortical function. Unravelling the organization of the cerebral cortex will require a painstaking description of the circuits, projections and response properties peculiar to cells in each of its various areas.

scholarly journals The Expression Patterns of Cytochrome Oxidase and Immediate-Early Genes Show Absence of Ocular Dominance Columns in the Striate Cortex of Squirrel Monkeys Following Monocular Inactivation

2021 ◽  
Vol 15 ◽  
Author(s):  
Shuiyu Li ◽  
Songping Yao ◽  
Qiuying Zhou ◽  
Toru Takahata
Keyword(s):  
Cytochrome Oxidase ◽  
Striate Cortex ◽  
Ocular Dominance ◽  
Expression Patterns ◽  
Immediate Early Genes ◽  
Squirrel Monkeys ◽  
Immediate Early ◽  
Ocular Dominance Columns ◽  
Early Genes ◽  
Layer 4

Because at least some squirrel monkeys lack ocular dominance columns (ODCs) in the striate cortex (V1) that are detectable by cytochrome oxidase (CO) histochemistry, the functional importance of ODCs on stereoscopic 3-D vision has been questioned. However, conventional CO histochemistry or trans-synaptic tracer study has limited capacity to reveal cortical functional architecture, whereas the expression of immediate-early genes (IEGs), c-FOS and ZIF268, is more directly responsive to neuronal activity of cortical neurons to demonstrate ocular dominance (OD)-related domains in V1 following monocular inactivation. Thus, we wondered whether IEG expression would reveal ODCs in the squirrel monkey V1. In this study, we first examined CO histochemistry in V1 of five squirrel monkeys that were subjected to monocular enucleation or tetrodotoxin (TTX) treatment to address whether there is substantial cross-individual variation as reported previously. Then, we examined the IEG expression of the same V1 tissue to address whether OD-related domains are revealed. As a result, staining patterns of CO histochemistry were relatively homogeneous throughout layer 4 of V1. IEG expression was also moderate and homogeneous throughout layer 4 of V1 in all cases. On the other hand, the IEG expression was patchy in accordance with CO blobs outside layer 4, particularly in infragranular layers, although they may not directly represent OD clusters. Squirrel monkeys remain an exceptional species among anthropoid primates with regard to OD organization, and thus are potentially good subjects to study the development and function of ODCs.

scholarly journals Blockade of retinal or cortical activity does not prevent the development of callosal patches normally associated with ocular dominance columns in primary visual cortex

2021 ◽  
Vol 38 ◽  
Author(s):  
Hsueh Chung Lu ◽  
Robyn J. Laing ◽  
Jaime F. Olavarria
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Neural Activity ◽  
Single Injection ◽  
Ocular Dominance ◽  
Cell Activity ◽  
Ocular Dominance Columns ◽  
Callosal Connections ◽  
Monocular Enucleation ◽  
Physiological Evaluation

Abstract Callosal patches in primary visual cortex of Long Evans rats, normally associated with ocular dominance columns, emerge by postnatal day 10 (P10), but they do not form in rats monocularly enucleated a few days before P10. We investigated whether we could replicate the results of monocular enucleation by using tetrodotoxin (TTX) to block neural activity in one eye, or in primary visual cortex. Animals received daily intravitreal (P6–P9) or intracortical (P7–P9) injections of TTX, and our physiological evaluation of the efficacy of these injections indicated that the blockade induced by a single injection lasted at least 24 h. Four weeks later, the patterns of callosal connections in one hemisphere were revealed after multiple injections of horseradish peroxidase in the other hemisphere. We found that in rats receiving either intravitreal or cortical injections of TTX, the patterns of callosal patches analyzed in tangential sections from the flattened cortex were not significantly different from the pattern in normal rats. Our findings, therefore, suggest that the effects of monocular enucleation on the distribution of callosal connections are not due to the resulting imbalance of afferent ganglion cell activity, and that factors other than neural activity are likely involved.

Plasticity of ocular dominance columns in monkey striate cortex

1977 ◽  
Vol 278 (961) ◽  
pp. 377-409 ◽  
Keyword(s):  
Striate Cortex ◽  
Ocular Dominance ◽  
Lateral Geniculate Body ◽  
Silver Stain ◽  
Repeat Distance ◽  
Direction Parallel ◽  
Ocular Dominance Columns ◽  
Mild Degree ◽  
Lateral Geniculate ◽  
Normal Monkey

Ocular dominance columns were examined by a variety of techniques in juvenile macaque monkeys in which one eye had been removed or sutured closed soon after birth. In two monkeys the removal was done at 2 weeks and the cortex studied at 1 1/2 years. Physiological recordings showed continuous responses as an electrode advanced along layer IV C in a direction parallel to the surface. Examination of the cortex with the Fink-Heimer modification of the Nauta method after lesions confined to single lateral-geniculate layers showed a marked increase, in layer IV G, in the widths of columns belonging to the surviving eye, and a corresponding shrinkage of those belonging to the removed eye. Monocular lid closures were made in one monkey at 2 weeks of age, for a period of 18 months, in another at 3 weeks for 7 months, and in a third at 2 days for 7 weeks. Recordings from the lateral geniculate body showed brisk activity from the deprived layers and the usual abrupt eye transitions at the boundaries between layers. Cell shrinkage in the deprived layers was moderate - far less severe than that following eye removal, more marked ipsilaterally than contralaterally, and more marked the earlier the onset of the deprivation. In autoradiographs following eye injection with a mixture of tritiated proline and tritiated fucose the labelling of terminals was confined to geniculate layers corresponding to the injected eye. Animals in which the open eye was injected showed no hint of invasion of terminals into the deprived layers. Similarly in the tectum there was no indication of any change in the distribution of terminals from the two eyes. The autoradiographs of the lateral geniculates provide evidence for several previously undescribed zones of optic nerve terminals, in addition to the six classical subdivisions. In the cortex four independent methods, physiological recording, transneuronal autoradiography, Nauta degeneration, and a reduced-silver stain for normal fibres, all agreed in showing a marked shrinkage of deprived-eye columns and expansion of those of the normal eye, with preservation of the normal repeat distance (left-eye column plus right-eye column). There was a suggestion that changes in the columns were more severe when closure was done at 2 weeks as opposed to 3, and more severe on the side ipsilateral to the closure. The temporal crescent representation in layer IV C of the hemisphere opposite the closure showed no obvious adverse effects. Cell size and packing density in the shrunken IVth layer columns seemed normal. In one normal monkey in which an eye was injected the day after birth, autoradiographs of the cortex at 1 week indicated only a very mild degree of segregation of input from the two eyes; this had the form of parallel bands. Tangential recordings in layer IV C at 8 days likewise showed considerable overlap of inputs, though some segregation was clearly present; at 30 days the segregation was much more advanced. These preliminary experiments thus suggest that the layer IV C columns are not fully developed until some weeks after birth. Two alternate possibilities are considered to account for the changes in the ocular dominance columns in layer IVG following deprivation. If one ignores the above evidence in the newborn and assumes that the columns are fully formed at birth, then after eye closure the afferents from the normal eye must extend their territory, invading the deprived-eye columns perhaps by a process of sprouting of terminals. On the other hand, if at birth the fibres from each eye indeed occupy all of layer IV C, retracting to form the columns only during the first 6 weeks or so, perhaps by a process of competition, then closure of one eye may result in a competitive disadvantage of the terminals from that eye, so that they retract more than they would normally. This second possibility has the advantage that it explains the critical period for deprivation effects in the layer IV columns, this being the time after birth during which retraction is completed. It would also explain the greater severity of the changes in the earlier closures, and would provide an interpretation of both cortical and geniculate effects in terms of competition of terminals in layer IV C for territory on postsynaptic cells.

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