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.

Ferrier lecture - Functional architecture of macaque monkey visual cortex

1977 ◽  
Vol 198 (1130) ◽  
pp. 1-59 ◽  
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Receptive Field ◽  
Striate Cortex ◽  
Single Cells ◽  
Ocular Dominance ◽  
Receptive Fields ◽  
Macaque Monkey ◽  
Area 17 ◽  
Orientation Specificity

Of the many possible functions of the macaque monkey primary visual cortex (striate cortex, area 17) two are now fairly well understood. First, the incoming information from the lateral geniculate bodies is rearranged so that most cells in the striate cortex respond to specifically oriented line segments, and, second, information originating from the two eyes converges upon single cells. The rearrangement and convergence do not take place immediately, however: in layer IVc, where the bulk of the afferents terminate, virtually all cells have fields with circular symmetry and are strictly monocular, driven from the left eye or from the right, but not both; at subsequent stages, in layers above and below IVc, most cells show orientation specificity, and about half are binocular. In a binocular cell the receptive fields in the two eyes are on corresponding regions in the two retinas and are identical in structure, but one eye is usually more effective than the other in influencing the cell; all shades of ocular dominance are seen. These two functions are strongly reflected in the architecture of the cortex, in that cells with common physiological properties are grouped together in vertically organized systems of columns. In an ocular dominance column all cells respond preferentially to the same eye. By four independent anatomical methods it has been shown that these columns have the form of vertically disposed alternating left-eye and right-eye slabs, which in horizontal section form alternating stripes about 400 μm thick, with occasional bifurcations and blind endings. Cells of like orientation specificity are known from physiological recordings to be similarly grouped in much narrower vertical sheeet-like aggregations, stacked in orderly sequences so that on traversing the cortex tangentially one normally encounters a succession of small shifts in orientation, clockwise or counterclockwise; a 1 mm traverse is usually accompanied by one or several full rotations through 180°, broken at times by reversals in direction of rotation and occasionally by large abrupt shifts. A full complement of columns, of either type, left-plus-right eye or a complete 180° sequence, is termed a hypercolumn. Columns (and hence hypercolumns) have roughly the same width throughout the binocular part of the cortex. The two independent systems of hypercolumns are engrafted upon the well known topographic representation of the visual field. The receptive fields mapped in a vertical penetration through cortex show a scatter in position roughly equal to the average size of the fields themselves, and the area thus covered, the aggregate receptive field, increases with distance from the fovea. A parallel increase is seen in reciprocal magnification (the number of degrees of visual field corresponding to 1 mm of cortex). Over most or all of the striate cortex a movement of 1-2 mm, traversing several hypercolumns, is accompanied by a movement through the visual field about equal in size to the local aggregate receptive field. Thus any 1-2 mm block of cortex contains roughly the machinery needed to subserve an aggregate receptive field. In the cortex the fall-off in detail with which the visual field is analysed, as one moves out from the foveal area, is accompanied not by a reduction in thickness of layers, as is found in the retina, but by a reduction in the area of cortex (and hence the number of columnar units) devoted to a given amount of visual field: unlike the retina, the striate cortex is virtually uniform morphologically but varies in magnification. In most respects the above description fits the newborn monkey just as well as the adult, suggesting that area 17 is largely genetically programmed. The ocular dominance columns, however, are not fully developed at birth, since the geniculate terminals belonging to one eye occupy layer IVc throughout its length, segregating out into separate columns only after about the first 6 weeks, whether or not the animal has visual experience. If one eye is sutured closed during this early period the columns belonging to that eye become shrunken and their companions correspondingly expanded. This would seem to be at least in part the result of interference with normal maturation, though sprouting and retraction of axon terminals are not excluded.

Receptive-field characteristics of neurons in cat striate cortex: Changes with visual field eccentricity

1976 ◽  
Vol 39 (3) ◽  
pp. 512-533 ◽  
Author(s):  
J. R. Wilson ◽  
S. M. Sherman
Keyword(s):  
Visual Field ◽  
Receptive Field ◽  
Striate Cortex ◽  
Ocular Dominance ◽  
Receptive Fields ◽  
Direction Selectivity ◽  
Orientation Selectivity ◽  
Simple Cells ◽  
Complex Cells ◽  
Cat Striate Cortex

1. Receptive-field properties of 214 neurons from cat striate cortex were studied with particular emphasis on: a) classification, b) field size, c) orientation selectivity, d) direction selectivity, e) speed selectivity, and f) ocular dominance. We studied receptive fields located throughtout the visual field, including the monocular segment, to determine how receptivefield properties changed with eccentricity in the visual field.2. We classified 98 cells as "simple," 80 as "complex," 21 as "hypercomplex," and 15 in other categories. The proportion of complex cells relative to simple cells increased monotonically with receptive-field eccenticity.3. Direction selectivity and preferred orientation did not measurably change with eccentricity. Through most of the binocular segment, this was also true for ocular dominance; however, at the edge of the binocular segment, there were more fields dominated by the contralateral eye.4. Cells had larger receptive fields, less orientation selectivity, and higher preferred speeds with increasing eccentricity. However, these changes were considerably more pronounced for complex than for simple cells.5. These data suggest that simple and complex cells analyze different aspects of a visual stimulus, and we provide a hypothesis which suggests that simple cells analyze input typically from one (or a few) geniculate neurons, while complex cells receive input from a larger region of geniculate neurons. On average, this region is invariant with eccentricity and, due to a changing magnification factor, complex fields increase in size with eccentricity much more than do simple cells. For complex cells, computations of this geniculate region transformed to cortical space provide a cortical extent equal to the spread of pyramidal cell basal dendrites.

scholarly journals Sequence memory for prediction, inference and behaviour

2009 ◽  
Vol 364 (1521) ◽  
pp. 1203-1209 ◽  
Author(s):  
Jeff Hawkins ◽  
Dileep George ◽  
Jamie Niemasik
Keyword(s):  
Receptive Field ◽  
Cortical Column ◽  
Bottom Up ◽  
Cortical Areas ◽  
Receptive Field Properties ◽  
Recall Time ◽  
Receptive Field Property ◽  
Sequence Memory ◽  
Biological Constraints ◽  
Field Property

In this paper, we propose a mechanism which the neocortex may use to store sequences of patterns. Storing and recalling sequences are necessary for making predictions, recognizing time-based patterns and generating behaviour. Since these tasks are major functions of the neocortex, the ability to store and recall time-based sequences is probably a key attribute of many, if not all, cortical areas. Previously, we have proposed that the neocortex can be modelled as a hierarchy of memory regions, each of which learns and recalls sequences. This paper proposes how each region of neocortex might learn the sequences necessary for this theory. The basis of the proposal is that all the cells in a cortical column share bottom-up receptive field properties, but individual cells in a column learn to represent unique incidences of the bottom-up receptive field property within different sequences. We discuss the proposal, the biological constraints that led to it and some results modelling it.

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 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.

Chronic recordings from single sites of kitten striate cortex during experience-dependent modifications of receptive-field properties

1989 ◽  
Vol 62 (1) ◽  
pp. 185-197 ◽  
Author(s):  
L. Mioche ◽  
W. Singer
Keyword(s):  
Receptive Field ◽  
Time Course ◽  
Striate Cortex ◽  
Ocular Dominance ◽  
Repeated Measurements ◽  
Monocular Deprivation ◽  
Binocular Summation ◽  
Moderate Increase ◽  
Receptive Field Properties ◽  
Excitatory Responses

1. With the use of chronically implanted floating microelectrodes, we obtained simultaneous single-unit recordings from multiple sites in the kitten striate cortex and followed experience-dependent modifications of receptive-field properties. For induction of experimental modifications, we used the paradigm of monocular deprivation and reverse occlusion. Kittens were implanted when 4-5 wk old. During the following 2 days, receptive-field properties of the recorded units were determined once under light ketamine anesthesia and repeatedly while the kittens were awake and only lightly restrained. Subsequently, one eye was patched, and the resulting changes in neuronal eye preference were followed by repeated measurements of response properties. For investigation of the effects of reverse occlusion, the deprived eye was opened and the previously open eye closed when the neurons had become unresponsive to the initially deprived eye. Alternatively, kittens were monocularly deprived for 1 wk by lid suture before implantation. The closed eye was then opened, the other eye patched, and the effects of reverse occlusion were studied for up to 1 wk by repeated measurements of receptive-field properties. 2. The earliest effect of monocular deprivation was the disappearance of binocular summation, i.e., binocular responses ceased to be superior over monocular responses. Overt changes of ocular dominance were observed as early as 6 h after the beginning of monocular deprivation. These consisted of a gradual decrease of the excitatory response to deprived eye stimulation and, on occasions, of an additional moderate increase of responses to the normal eye. A complete loss of excitatory responses to deprived-eye stimulation was seen as early as 12 h after occlusion. In numerous cells, however, stimulation of the deprived eye continued to evoke inhibitory responses even after excitatory responses had vanished completely. During this shift in ocularity, neurons preserved their orientation and direction selectively. 3. The minimal time required for the manifestation of ocular dominance changes was similar regardless of whether the animals were stimulated continuously or were asleep part of the time, suggesting the existence of an experience-independent consolidation period for ocular dominance changes. 4. The first change after reverse occlusion was a reduction of the response to the newly deprived eye. The time course of this inactivation was similar to that observed after initial deprivation, whereas the recovery of responses to the previously deprived eye had a considerably slower time course.(ABSTRACT TRUNCATED AT 400 WORDS)

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