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  • 1
    Electronic Resource
    Electronic Resource
    M-cells: A logic circuit model to account for some features of CNS inhibition (1978)
    Springer
    Biological cybernetics 29 (1978), S. 1-9 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract A truth table definition for neural inhibition is used to develop a model for stimulus specificity in a sensory system. An example from the mammalian visual system, that of orientation selectivity in visual cortex, is worked out in detail. Using the assumption that logical processing of signals may take place in a nerve cell's dendritic tree, a digital circuit is transformed into a neural model. An important feature of the model is an inhibitory neuron, termed an M-cell, which by its actions confers response specificity on neighboring principal cells. The M-cell is shown to have several properties in common with basket cells seen in cerebellar, hippocampal and cerebral cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00365230
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of luminance and flicker on ocular dominance shift in kitten visual cortex (1984)
    Springer
    Experimental brain research 54 (1984), S. 186-190 
    Details
    ISSN: 1432-1106
    Keywords: Monocular deprivation ; Kitten visual cortex ; Scotopic vision ; Visual flicker ; Ocular dominance shift
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We raised monocularly deprived kittens in visual environments with low level illumination that was either steady or flickering. With steady scotopic luminance ocular dominance shifted as it does in normal photopic lighting. In flickering light with an average frequency of 2 Hz there was virtually no ocular dominance shift, while in flickering light averaging 0.1 Hz there was a significant shift. Recordings from the 2 Hz flicker-reared were similar to the dark-reared recordings. The flickering illumination was produced in one case by a high contrast-low brightness TV near the cage, and in another case, by a low voltage incandescent bulb driven by a pseudo-random sequence generator. This circuit delivered either a maximum ON time of 1.7 s or a maximum of 40 s, for the 2 Hz and 0.1 Hz respectively. Both the TV and flickering bulb produced average illumination comparable to the dim (0.01 cd/ m2) steady scotopic illumination. We conclude that dim flickering light is not a sufficient stimulus for promoting ocular dominance shift in kittens in the critical period unless the flicker rate approaches 0.1 Hz. Furthermore results from the TV rearing suggest that flicker may be capable of preventing an ocular dominance shift expected from a concurrent steady low light level background.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235830
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of intracortical infusion of 6-hydroxydopamine on the response of kitten visual cortex to monocular deprivation (1983)
    Springer
    Experimental brain research 51 (1983), S. 413-422 
    Details
    ISSN: 1432-1106
    Keywords: Visual cortex ; Plasticity ; Catecholamines ; 6-Hydroxydopamine ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Between 4 and 10 weeks of age 10 normally reared kittens were bilaterally implanted with osmotic minipumps. The visual cortex of one hemisphere was infused with 4 mM 6-hydroxydopamine while the other hemisphere received only a vehicle solution. The pumps delivered the solutions at 1 μl/h for one week concurrent with monocular deprivation. Subsequent electrophysiological recording was performed blind and revealed a marked effect of the 6-OHDA treatment: while most cells in the control hemisphere were primarily activated by stimulation of the non-deprived eye, cells in the 6-OHDA-treated hemisphere were significantly more binocular. High pressure liquid chromatography revealed that the loss of normal ocular dominance plasticity in 6-OHDA-infused hemispheres was always accompanied by at least a 50% decrease in cortical norepinephrine levels and a smaller decrease in dopamine levels. Furthermore, there appeared to be a positive correlation of the degree of ocular dominance shift and the relative amount of norepinephrine present. These results are consistent with the hypothesis that catecholamines, especially norepinephrine, are normally required for ocular dominance plasticity during the critical period in kittens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237878
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  • 4
    Electronic Resource
    Electronic Resource
    Biases for oriented moving bars in lateral geniculate nucleus neurons of normal and stripe-reared cats (1977)
    Springer
    Experimental brain research 29 (1977), S. 155-172 
    Details
    ISSN: 1432-1106
    Keywords: Lateral geniculate nucleus ; Orientation specificity ; Stripe-rearing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Visual receptive fields of 42 LGN cells from normal cats and 110 cells from striped cylinder-reared kittens were studied with the aid of a computer controlled optical system. In the normal cats, ten of the 42 cells were weakly biased for orientation of the visual stimulus when tested with bars swept through the receptive field. Of those ten, eight were classified as transient. The orientation preferences of the ten biased units appeared randomly distributed around the clock. Of the LGN cells from the cylinder-reared group, about half of the transient cells had weak biases for orientation; only 7% of the sustained cells had biases. The orientation preferences of the biased LGN cells in the stripe-reared animals were either parallel to or orthogonal to the stripes each animal saw during its time in the conditioning cylinder. In 16 out of 18 of the biased LGN cells it was found that increasing the velocity of the test target reduced or eliminated the bias apparent at the lower velocity. For some LGN cells special techniques, such as inhibition of activated discharge, were needed to reveal orientation biases. The results described here, considered with data from others, suggest a role for the corticofugal projection in modulating the responses of some LGN cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237039
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  • 5
    Electronic Resource
    Electronic Resource
    Two methods of catecholamine depletion in kitten visual cortex yield different effects on plasticity (1983)
    [s.l.] : Nature Publishing Group
    Nature 302 (1983), S. 245-247 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] In the first group of kittens (N = W) we followed the 6-OHDA delivery procedures of Kasamatsu et al.5'6. Animals normally reared to 4-8 weeks of age were fitted with two osmotic minipumps (Alza) connected to cannulae inserted in each hemisphere, 0.5-2.5 mm below the cortical surface, near the areae ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/302245a0
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Pyrotechnic illusion (1989)
    [s.l.] : Nature Publishing Group
    Nature 341 (1989), S. 492-492 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIRá€"While watching a recent display of fireworks, I observed a robust illusion of motion. Clearly, when a flare shot into the sky bursts, and its payload of self-luminescent fragments scatters, there must be a uniform distribution of horizontal directions of fragment ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/341492b0
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    Paper (German National Licenses)
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