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  • 1975-1979  (2)
  • Cat  (1)
  • Inorganic Chemistry  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 34 (1979), S. 273-286 
    ISSN: 1432-1106
    Keywords: Stimulus velocity ; Single cell responses ; LGN ; Area 17 ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neuronal responses to moving visual stimuli were recorded in the lateral geniculate nucleus (LGN) and area 17 of cats. Response duration (DE), number of spikes (NT), and mean frequency (FM) were estimated from the response histograms and analysed for their dependence on stimulus velocity. In the LGN, for about 2/3 of cells these response parameters changed monotonically with velocity up to about 100 °/s. In 1/3 of the cells, the response frequency was tuned to velocity. The speed at which individual cells reached a peak or plateau firing rate was correlated with their receptive field size. In area 17, most neurones were tuned to velocity. Nine out of 59 cells were insensitive to stimulus speed in that they responded equally well at stimulus velocities up to about 10 °/s. The results suggest that at higher levels in the nervous system information about velocity is represented in discrete groups of neurones. It is pointed out that different response parameters may be relevant for different perceptual phenomena associated with movement. The significance of integrational properties and lateral inhibition of nerve cells for the development of complex response properties is discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 421 (1976), S. 61-70 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structure of a Hydroxostannate: Copperdiammine-hexahydroxostannate Cu(NH3)2Sn (OH)6Single crystals of Cu(NH3)2, Sn(OH)6, have been prepared by the reaction of K2Sn(OH)6, with Cu(NO3)2· 3 H2O in aqueous solution of NH3. The complex crystallizes in the triclinic space group P1 with a = 5.643(2) Å, b = 6.621(2) Å, c = 4.885(2) Å, α = 91.83(3)°, β = 93.58(3)°, γ = 107.69(3)° and Z = 1. The crystal structure has been solved by Pattersonsyntheses. The hydrogen atoms could be localized by difference Fourier syntheses. The structure contains infinite chains of alternating Sn(OH)6- and Cu(OH)4(NH3)2-octahedra linked parallel to the b-axis by common edges. The chains are connected by hydrogen-bonding to their neighbouring chains. An almost regular octahedra is found for the coordination of the Sn-atoms, whereas the Cu(OH)4(NH3)2-octahedra show a pronounced (4+2)-distortion with two OH—-groups in the axial positions in a distance of 2.627(2) Å. The structure can also be described in terms of slightly distorted hexagonal close packed layers of oxygen and nitrogen. The metal atoms occupy 1/4 of the octahedral sites in an ordered arrangement. Thus the structure bears a close relationship to thc layer structure of α-NbI4.
    Notes: Einkristalle von Cu(NH3)2Sn(OH)3 wurden durch Umsetzung von K2Sn(OH)6 mit Cu(NO3)2 · 3 H2O in wäßriger ammoniakalischer Lösung gewonnen. Die Verbindung kristallisiert in der triklinen Raumgruppe P1 mit a = 5,643(2) Å, b = 6,621(2) Å, c = 4,885(2) Å, α = 91,83(3)°, β = 93,58(3)°, γ = 107,69(3)° und Z = 1. Die Kristallstruktur wurde aus Pattersonsynthesen aufgeklärt, und aus Differenzfouriersynthesen konnten auch die Positionen der Wasserstoffatome ermittelt werden. Die Struktur enthält unendliche Ketten von alternierenden Sn(OH)6-und Cu(OH)4(NH3)2-Oktaedern, welche parallel zur b-Achse über gemeinsame Kanten verknüpft sind. Die Ketten sind durch Wasserstoffbrückenbindungen mit ihren Nachbarketten verknüpft. Während das Sn(OH)6-Oktaeder nahezu regulär gebaut ist, zeigt das Cu(OH)4(NH3)2-Oktaeder eine ausgeprägte (4+2)-Verzerrung mit zwei OH--Gruppen in den axialen Positionen in einem Abstand von 2,627(2) Å. Die Struktur kann auch als Folge von leicht verzerrten hexagonal dichtest gepackten Schichten von Sauerstoff und Stickstoff beschrieben werden, wobei die Metallatome 1/4 der Oktaederlücken geordnet besetzen. Sie zeigt eine enge Verwandtschaft mit der Schichtstruktur des α-NbJ4.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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