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
  • 1
    Electronic Resource
    Electronic Resource
    The role of the corpus callosum in the development of interocular eye alignment and the organization of the visual field in the cat (1979)
    Springer
    Experimental brain research 36 (1979), S. 71-85 
    Details
    ISSN: 1432-1106
    Keywords: Corpus callosum ; Visual field ; Interocular eye alignment ; Visual development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In young cats, the posterior portion of the corpus callosum was sectioned 13–29 days after birth. The animal's eyes were photographed at weekly intervals for six months using the pupil-reflex method. From the corneal reflection evident in the photographs the degree of alignment for the optical axes of each cat was estimated (Sherman, 1972). The 17 experimental cats all showed a significant tendency toward permanent divergent strabismus, as compared to six normal cats. The limits of the visual field were determined for both groups of cats using a perimetry technique similar to that of Sprague and Meikle (1965) and Sherman (1973). With one eye open normal cats responded from 90 ° ipsilateral to 45 ° past the vertical midline into the contralateral visual field. With either eye the experimental cats responded from 90 ° ipsilateral to approximately the vertical midline. The loss of visual responsiveness is within the contralateral region of the normally binocular zone. Three cats received the same operation at 9, 13, or 20 months old. Eye alignment and visual field perimetry were unaffected by the surgery. It is not known whether the observed abnormalities result from arrested development, or disruption of intrinsically determined ocular alignment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238468
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Spatial frequency thresholds of single striate cortical cells in neonatal corpus callosum sectioned cats (1990)
    Springer
    Experimental brain research 82 (1990), S. 617-627 
    Details
    ISSN: 1432-1106
    Keywords: Corpus callosum ; Visual acuity ; Spatial frequency threshold ; Striate cortex ; Development ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Following section of the corpus callosum at 1–6 postnatal weeks in cats, behavioral visual acuity was measured binocularly and monocularly from 6–29 postnatal weeks; physiological determination of spatial frequency thresholds of single striate cortical cells was performed when the cats were at least 8 months old. Results were compared between cats with callosum section at each postnatal week, as well as with normal cats. Cats with callosotomy at 1–3 postnatal weeks had deficits in behavioral visual acuity, and the deficits were greatest in the youngest operated cats. Cats with callosotomy at 1–2 postnatal weeks failed to resolve as high spatial frequencies as did normal cats, and the resolution of the 1 week operated cats was lower than the resolution of the 2 week operated cats. Cats with callosotomy at 3–6 postnatal weeks had spatial frequency thresholds that were equivalent to those of normal cats. To determine what kinds of striate cells had reduced spatial resolution following neonatal corpus callosum section, cells were categorized according to class (Simple, Complex), receptive field location (Central, Peripheral), and monocular behavioral acuity eye performance (Better Eye, Worse Eye). Cats with corpus callosum section during postnatal week 1 had the lowest spatial resolution for all cell categories compared to all groups tested. However, cats with callosum section during postnatal week 2 had normal spatial frequency thresholds for Simple, Central and Better Eye categories. The cats with callosum section in postnatal weeks 3–6 had normal spatial frequency thresholds for all cell categories. For corpus callosum sectioned cats with and without visual deficits, and for normal cats, visual acuity measured behaviorally is significantly related to visual acuity measured physiologically. The results show that neonatal corpus callosum section in cats can affect behavioral visual acuity, as well as the spatial frequency thresholds of many categories of striate cortical cells. However, callosum section at different ages affects different populations of cortical cells. Furthermore, the results suggest that neonatal corpus callosum section may directly affect a single fundamental property of cells in primary visual cortex with a resulting disruption of many visual functions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228803
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The critical period for corpus callosum section to affect cortical binocularity (1985)
    Springer
    Experimental brain research 57 (1985), S. 213-223 
    Details
    ISSN: 1432-1106
    Keywords: Corpus callosum ; Binocularity ; Critical period ; Striate cortex ; Ocular dominance ; Cats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The period of time during which surgical section of the corpus callosum (CC) is effective in altering the physiological properties of cells in cat striate cortex was investigated. Cats which had the CC transected between 13 days and 24 weeks of age were studied using extracellular, single-unit recording procedures. Analysis of the results from 1,747 cortical units indicate that when the CC was sectioned prior to 19 days of age there was a reduction in the encounter rate of binocularly activated neurons and an increase in the proportion of neurons dominated by the contralateral eye. The decrease in cortical binocularity was observed in both simple and complex cell populations, and at all receptive field eccentricities studied (0–39°). However, when the CC was sectioned after 19 postnatal days, no physiological changes were detected. Thus, in contrast with previous studies (Payne et al. 1980a, b) no changes were found following CC section in adult cats. The results therefore define a critical period which ends before 3 weeks of age during which corpus callosum section reduces striate cortex binocularity. Although the corpus callosum critical period is much shorter than the critical period for experiential alterations in cortical binocularity, the physiologically determined limits of the callosal critical period agree with the behaviorally determined limits previously found for the callosal critical period (Elberger 1984).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236526
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Binocularity and single cell acuity are related in striate cortex of corpus callosum sectioned and normal cats (1989)
    Springer
    Experimental brain research 77 (1989), S. 213-216 
    Details
    ISSN: 1432-1106
    Keywords: Corpus callosum ; Striate cortex ; Binocular interaction ; Spatial frequency threshold ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cats with corpus callosum section at 4–37 postnatal days underwent electrophysiological recording in striate cortex after they reached adulthood. Single cells were examined to determine both their ocular dominance and spatial frequency threshold (acuity). Data were analyzed for each cat according to the extent of binocular interaction (binocularity) and the mean striate acuity. Both visual functions were found to be significantly related to the age at which the corpus callosum section occurred, with the greatest deficits in visual function resulting from callosum section at the younger ages. There was a significant relationship between striate binocularity and acuity in the callosum sectioned, as well as in normal, cats. This suggests that visual resolution is at least partially determined by the ability to integrate information from both eyes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00250583
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Ocular dominance in striate cortex is altered by neonatal section of the posterior corpus callosum in the cat (1981)
    Springer
    Experimental brain research 41 (1981), S. 280-291 
    Details
    ISSN: 1432-1106
    Keywords: Corpus callosum ; Ocular dominance ; Visual development ; Striate cortex ; Visual field
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In adult cats that had previously undergone surgical section of the posterior corpus callosum at 13–18 days after birth, the striate cortex was examined using extracellular single unit recordings. The receptive fields of the cells examined were located from the vertical meridian to 39 ° peripherally, and ranged from above to below the horizontal meridian. Cells were classified according to type (simple, complex), ocular dominance, receptive field size and location. Callosum sectioned cats had 53% of striate cells activated monocularly as compared to 25% for control cats. This increase in monocularly activated units primarily occurred for receptive fields in the paracentral region of the visual field, from 4–39 °. The age at which the neonatal surgery had occurred was correlated with the individual cat's proportion of monocularly activated cells. Therefore, the increase in monocular activation of striate units occurred within a large portion of the normal binocular visual field. This physiological change was partially predicted by a previous behavioral study showing a substantial loss in the extent of the binocular visual field following neonatal corpus callosum section (Elberger 1979).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238885
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Binocular depth perception in the cat following early corpus callosum section (1985)
    Springer
    Experimental brain research 60 (1985), S. 19-26 
    Details
    ISSN: 1432-1106
    Keywords: Corpus callosum ; Binocular depth perception ; Stereoacuity ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The role of the corpus callosum in the mediation of binocular depth perception was examined by measuring monocular and binocular depth discrimination thresholds in cats which had undergone section of the corpus callosum shortly after birth. Three kittens had the posterior callosum sectioned at the age of eleven days. A fourth kitten underwent a sham operation and one additional animal served intitially as an unoperated control. Monocular and binocular depth thresholds were measured for all kittens when they were between three and five months old. Although there was some individual variability, none of the callosum-sectioned kittens showed any deficits of binocular depth perception relative to normal animals. The initially unoperated kitten had its callosum sectioned at five months and was retested following surgery. Its performance did not change from preoperated levels. Finally, the three neonatal callosum-sectioned kittens underwent section of the optic chiasm when they were six months old, causing a complete breakdown in binocular depth discrimination. The results are interpreted to indicate that although the corpus callosum may be a sufficient pathway for the maintenance of stereopsis in cat, it is not necessary.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237014
    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...