Bibliothek

X
Sie haben 0 gespeicherte Treffer.
Markieren Sie die Treffer und klicken Sie auf "Zur Merkliste hinzufügen", um sie in dieser Liste zu speichern.
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    Digitale Medien
    Digitale Medien
    Convergence of parvocellular and magnocellular information channels in the primary visual cortex of the macaque (2002)
    Oxford, UK : Blackwell Science, Ltd
    European journal of neuroscience 16 (2002), S. 0 
    Details
    ISSN: 1460-9568
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: We investigated whether responses of single cells in the striate cortex of anaesthetized macaque monkeys exhibit signatures of both parvocellular (P) and magnocellular (M) inputs from the dorsal lateral geniculate nucleus (dLGN). We used a palette of 128 isoluminant hues at four different saturation levels to test responses to chromatic stimuli against a white background. Spectral selectivity with these isoluminant stimuli was taken as an indication of P inputs. The presence of magnocellular inputs to a given cortical cell was deduced from its responses to a battery of tests, including assessment of achromatic contrast sensitivity, relative strengths of chromatic and luminance borders in driving the cell at different velocities and conduction velocity of their retino-geniculo-cortical afferents. At least a quarter of the cells in our cortical sample appear to receive convergent P and M inputs. We cannot however, exclude the possibility that some of these cells could be receiving a convergent input from the third parallel channel from the dLGN, namely the koniocellular (K) rather than the P channel. The neurons with convergent P and M inputs were recorded not only from supragranular and infragranular layers but also from the principal geniculate input recipient layer 4. Thus, our results challenge classical ideas of strict parallelism between different information streams at the level of the primate striate cortex.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1460-9568.2002.02137.x
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    Limit of single vision in stereopsis depends on contour sharpness (1978)
    [s.l.] : Nature Publishing Group
    Nature 275 (1978), S. 126-127 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Figure la shows three gratings of sinusoidal luminance profile; the adjacent gratings are in antiphase, that is, each light bar in one grating corresponds to a dark bar in the other. Each grating is surrounded by a contour and provided with short vertical lines at the top and bottom to facilitate ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/275126a0
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    Primate cortical area V4 important for colour constancy but not wavelength discrimination (1985)
    [s.l.] : Nature Publishing Group
    Nature 313 (1985), S. 133-135 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Fig. 1 a, Intended extent of V4 ablations in the two macaque monkeys used. LS, lunate sulcus; IOS, inferior occipital sulcus; STS, superior temporal sulcus; PMTS, posterior middle temporal sulcus. b, Performance of animals with lesions (·) and controls (O) on the constancy task. Scores are ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/313133a0
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 4
    Digitale Medien
    Digitale Medien
    Fourier analysis and spatial representation in the visual cortex (1981)
    Springer
    Cellular and molecular life sciences 37 (1981), S. 160-163 
    Details
    ISSN: 1420-9071
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Simple cells in the cat visual cortex are shown to be general purpose analyzers of visual information achieving, at the same time, minimum uncertainty in spatial localization and spatial frequency. Their responses to moving bars, edges and gratings are linearly interrelated and predictable from each other.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01963207
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 5
    Digitale Medien
    Digitale Medien
    Theory of spatial position and spatial frequency relations in the receptive fields of simple cells in the visual cortex (1982)
    Springer
    Biological cybernetics 43 (1982), S. 187-198 
    Details
    ISSN: 1432-0770
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Informatik , Physik
    Notizen: Abstract Striate cells showing linear spatial summation obey very general mathematical inequalities relating the size of their receptive fields to the corresponding spatial frequency and orientation tuning characteristics. The experimental data show that, in the preferred direction of stimulus motion, the spatial response profiles of cells in the simple family are well described by the mathematical form of Gabor elementary signals. The product of the uncertainties in signalling spatial position (δx) and spatial frequency (δf) has, therefore, a theoretical minimum value of δxδf=1/2. We examine the implications that these conclusions have for the relationship between the spatial response profiles of simple cells and the characteristics of their spatial frequency tuning curves. Examples of the spatial frequency tuning curves and their associated spatial response profiles are discussed and illustrated. The advantages for the operation of the visual system of different relationships between the spatial response profiles and the characteristics of the spatial frequency tuning curves are examined. Two examples are discussed in detail, one system having a constant receptive field size and the other a constant bandwidth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319978
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 6
    Digitale Medien
    Digitale Medien
    Spatial arrangements of responses by cells in the cat visual cortex to light and dark bars and edges (1981)
    Springer
    Experimental brain research 44 (1981), S. 371-385 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Striate and prestriate cortex ; Cell classification ; Receptive field subregions ; Simple cells ; Fast simple cells ; A-cells ; Silent periodic cells ; Complex cells
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Detailed examination is made of the responses of visual cortical cells (area 17, border 17–18 and adjacent area 18) in the anaesthetized cat to stationary flashing bars and to bars (lines) and edges moving at their optimal velocities. Particular attention is given to the receptive field organization of cells in the simple family. While there is good general agreement between the main receptive field subregions revealed by stationary and moving stimuli, the responses to moving light and dark bars, supplemented by the responses to moving light and dark edges, provide a much more rapid, accurate and complete guide to the spatial organization of the receptive fields than do the response profiles to a stationary flashing bar. Moving light and dark bars between them generally reveal more subregions in the receptive fields of simple cells than is evident from the response profiles to a stationary flashing bar, particularly when the receptive fields have many subregions. In addition the responses to moving edges provide a rapid guide to spatial summation across the width of a subregion and the possible antagonistic effects of the next subregion in sequence. Two subclasses of cells in the simple family have been recognized: ordinary simple and fast simple cells. Two cell classes (A-cells and silent periodic cells) having properties intermediate between simple and complex types are discriminated and their properties described.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238830
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 7
    Digitale Medien
    Digitale Medien
    Linear analysis of the responses of simple cells in the cat visual cortex (1981)
    Springer
    Experimental brain research 44 (1981), S. 386-400 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Striate cortex ; Simple cells ; Linear analysis ; Spatial response profiles ; Spatial frequency tuning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Spatial response profiles to stationary and moving stimuli and spatial frequency tuning curves to drifting sinusoidal gratings were recorded from a series of cells in the simple family. The spatial response profiles were recorded both to stationary flashing bars and sinusoidal gratings as well as to light and dark bars and edges and gratings moving at the optimal velocity. On the assumption that cells in the simple family operate linearly, spatial response profiles recorded experimentally were compared with those predicted by inverse Fourier transformation of the spatial frequency tuning curves. Conversely, the spatial frequency tuning curves recorded experimentally were compared with those predicted from the response profiles to moving and stationary stimuli. As a result of these comparisons, it is clear that moving stimuli provide a more accurate estimate of the spatial organization of the receptive field than do stationary stimuli. Cells with the higher optimal spatial frequencies tended to have narrower bandwidths. The simple cell with the narrowest bandwidth (0.94 octave) had five, and possibly six, subregions in the spatial response profile to moving light and dark bars, the largest number of subregions we encountered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238831
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 8
    Digitale Medien
    Digitale Medien
    Space and spatial frequency: analysis and representation in the macaque striate cortex (1986)
    Springer
    Experimental brain research 64 (1986), S. 5-18 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Striate cortex ; Fourier analysis ; Receptive fields
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Simple cells in the macaque striate cortex were tested with bars, edges and gratings. Spatial frequency tuning curves could be predicted from the spatial profiles plotted with bars and edges and the bandwidth could be evaluated more accurately by computing the mean from measured and predicted tuning curves. The results suggest that the mean relative spatial frequency bandwidth (Δf/fo) is nearly constant and of a moderate value. But at each optimal spatial frequency, cells with different bandwidths (about a factor of two) were recorded. The shapes of spatial response profiles resemble the corresponding spatial and spatial frequency characteristics of line and edge detectors evaluated psychophysically. Among the remaining cell types, concentric cells tend to be tuned to lower spatial frequencies and have broader bandwidths, whereas periodic cells prefer higher spatial frequencies and have narrower bandwidths. Thus the mean relative bandwidth tends to decrease significantly with spatial frequency (as required by a system of patch-by-patch Fourier analysis) only when cells with poor orientation selectivity and the non-linear silent periodic cells are included along with the simple cells. Simple cells, on their own, seem to form a quasi-linear contrast processing system which is more biased towards spatial accuracy than spatial frequency selectivity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238196
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 9
    Digitale Medien
    Digitale Medien
    A simple magnetic device for testing theories of synaptic function (1966)
    Springer
    Medical & biological engineering & computing 4 (1966), S. 491-494 
    Details
    ISSN: 1741-0444
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02476172
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...