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
References in periodicals archive ?
Therefore, we postulated that post- and pre-synaptic transneuronal damage between each cortical layer could be one of the reasons.
Vertebral cortical layer and trabecular bone material physical properties are given in the Table 1.
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].
Finally, it receives projections from cortical area, but not necessarily from the same cortical layer.
The number of neurons and GFAP-immunoreactive astrocytes in each cortical layer were counted per unit area.
The neurons were randomly arranged without laminar organisation from the superficial molecular layer to the deeper cortical layer (Figure 1D).
He theorized that by disrupting the continuity of this cortical layer of bone, he was actually creating and moving blocks of bone in which teeth were embedded.
8 In most reported studies, the jawbone is usually assumed to be a system composed of a trabecular bone core surrounded by a cortical layer with a constant thickness.
Statistical analysis of the gathered data revealed that for interpretation of hand radiograms following parameters are of highest usefulness: bone thickness of cortical layer (BT), relative density (CBDN2CT), corrected bone density normalized (NCBDN), bone proportion index (CT/BTx100), corrected optical density normalized (CBDN).