cortical column

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column, cortical 

In the visual cortex, neurons with similar properties are arranged in columns (about 2 mm high) perpendicular to the surface of the cortex. The columns traverse the six cortical layers until they reach the white matter. Neurons throughout a column respond either to stimuli oriented at the same angle (orientation column) or to the inputs from the same eye (ocular dominance column, ocular dominance slab). A neighbouring column will then have neurons responding to a slightly different orientation from the one next to it and perhaps the same eye or the other eye. Neurons in layer 4 represent an exception, as they may respond to any orientation or to one eye only. Strabismus in early childhood disrupts the development of ocular dominance columns, thus preventing the development of depth perception. See visual area; blobs; hypercolumn.
Table C5 Approximate colour temperature (in K) of some light sources
clear blue sky12000-26000
overcast sky6600
electronic flashabout 5600
tungsten-halogen lamp3000
tungsten filament lamp2600
candle flame2000

Table C6 Prevalence (%) and classification of colour vision defects
anomalous trichromats
colour responseslight green deficiencyred deficiencyblue deficiency
colour responsegreen deficiency insensitive to redblue deficiency
neutral point498 nm 493 nm570 nm
cone monochromatrod monochromat
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
References in periodicals archive ?
5) which is named as follows; ventricular zone (VZ), sub-ventricular zone (SZ), intermediate zone (IZ), cortical layer (CL), and marginal zone (MZ).
Interestingly, in oocytes of invertebrates, such as starfish, fruit fly, jelly fish, oligochaetes, and surf clam, during polar body formation, the actin cortical layer is very thin or almost absent at the animal pole (Shimizu 1997, Pielak et al.
The zygomatic bone has thick cortical layer that offers a solid and extended anchorage that can bear the vertical masticatory forces.
These novel topographical chips revealed that guidance of neurites of both immature DIV40+1 progeny, as well as neuronal cells with a lower cortical layer phenotype (DIV40+15), could be induced at different angles depending on the topography.
Vertebral cortical layer and trabecular bone material physical properties are given in the Table 1.
At first, a round bur was used to mark the implant site and penetrate the cortical layer. Subsequently, twist drills with diameters of 2.0, 2.4/2.8, 3.0, 3.2, and 3.4 mm were used to drill holes to a depth of 10 mm under generous saline cooling.
Cardiorespiratory fitness levels among all participants improved by eight percent over the course of the study, and those whose fitness levels increased the most also showed the most growth in the brains cortical layer, according to a report published in the Nov.
Cortical layer thickness of the model is chosen between 1 and 2 mm in many finite element studies [15].
The number of neurons and GFAP-immunoreactive astrocytes in each cortical layer were counted per unit area.
These include, but are not limited to, differentiation and maturation of pyramidal cells in cortical layer 3, axonal genesis and guidance to the subplate, synapse formation and establishment of connectivity with the developing cortical plate, and selection (or pruning) of connections [27].
The neurons were randomly arranged without laminar organisation from the superficial molecular layer to the deeper cortical layer (Figure 1D).