Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 61.50  (1)
  • Classification tectum cells  (1)
  • Depth perception  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Binocular depth perception mechanisms in tongue-projecting salamanders (1995)
    Springer
    Journal of comparative physiology 176 (1995), S. 365-377 
    Details
    ISSN: 1432-1351
    Keywords: Salamander ; Depth perception ; Stereopsis Optic tectum ; Visual maps
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Tongue-projecting salamanders (Bolitoglossini) combine extreme speed and high precision in prey capture. They possess all requirements for stereoscopic depth perception: frontally oriented eyes, a substantial amount of direct ipsilateral projection in addition to the contralateral one, and binocularly driven neurons. Extracellular recordings were made from retinal afferents in the tectum as well as from the somata of tectal neurons. RF-sizes of afferents and tectal neurons were determined, and the response properties of tectal neurons were tested under monocular and binocular conditions with stimuli of different size and velocity. While RF-sizes and response properties of binocular neurons during binocular and contralateral stimulation were similar, ipsilaterally stimulated neurons exhibited much smaller RFs, lower spike rates and different size preferences. Furthermore, the contralateral retinotectal projection from one eye and the ipsilateral from the other are in register. While retinal afferents are distributed linearly over the tectal surface, most tectal neurons are activated by a retinal area corresponding to the frontal visual field; this results in a magnification of this region. The two monocular receptive fields of binocular neurons exhibit zero disparities (horopter) at distances that coincide with the maximum reach of the tongue. We hypothesize that bolitoglossine salamanders (as well as amphibians in general) make use of two kinds of disparities: (1) between the maps in the left and right tectal hemisphere, coding for the lateral eccentricity of an object, and (2) between the ipsilateral and contralateral retinotectal map, coding for the distance. The presence of substantial direct ipsilateral afferents in bolitoglossine salamanders appears to be the basis for a fast computation of object distance, which is characteristic of these animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219062
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Responses in the optic tectum of the salamanderHydromantes italicus to moving prey stimuli (1982)
    Springer
    Experimental brain research 45 (1982), S. 386-392 
    Details
    ISSN: 1432-1106
    Keywords: Salamander optic tectum ; Stimulus velocity ; Classification tectum cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the tectum opticum ofHydromantes italicus neurons were recorded extracellularly which responded selectively to moving visual stimuli. Part of the recorded cells were marked iontophoretically by means of alcian-blue dye for anatomical localization. Out of a total of 110 neurons six groups could be distinguished which preferred the square stimulus but differred strongly in their responses to rectangles oriented either vertically or horizontally. Two of these groups showed stimulus preference inversion if the stimulus velocity was changed. These response patterns displayed characteristic differences with those known in other amphibia, well corresponding to differences in the prey catching behaviours.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01208598
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Preparation and crystal structure of C60S16 (1993)
    Springer
    Applied physics 56 (1993), S. 169-174 
    Details
    ISSN: 1432-0630
    Keywords: 61.50 ; 61.10
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A new fullerene-containing van der Waals-compound, C60S16, has been synthesized and its crystal structure determined from single-crystal X-ray diffraction data collected at room temperature. The compound is monoclinic, space group C 2/c with a=20.867(4) Å, b=21.062(4) Å, c=10.508(2) Å, β=111.25(7)° and four formula units per cell. The C60 molecules form a three-dimensional framework with one-dimensional channels along c which contain crown-shaped S8 rings. The structure has been determined by direct methods and has been refined to atomic resolution on the C60 molecule. The two independent C-C bond distances, averaged under the idealized point symmetry of the “free” C60 molecule, amount to 1.340(8) Å and 1.448(8) Å, corresponding to a “bond alternation” as large as 0.108(8) Å. The bond lengths are compared with the results of theoretical calculations of the molecular structure of C60 as well as with bond lengths from various experimental sources.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00539470
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...