Postnatal development of corticocortical efferents from area 17 in the cat's visual cortex
We are interested in the postnatal development of corticocortical connections in the cat's visual cortex. In this study, we injected the anterograde tracer 3H-proline into visual cortical area 17 of kittens, aged 4-70 d, and adult cats to visualize the distribution of terminals of the association projections to areas 18, 19, 21a, and the lateral suprasylvian visual cortex. The density of anterograde label was quantified using computerized image analysis. There was dense labeling at topographically appropriate locations in area 18 in animals of all ages. In 4- and 8-d-old kittens, other extrastriate areas (19, 21a and the lateral suprasylvian cortex) contained only sparse label, localized in a few solitary axons; these areas were densely labeled in animals aged 12 d or more. In kittens aged 4-20 d there was considerable, widespread label within fibers located in the white matter, and many of these axons lay underneath regions of extrastriate, and also striate, cortex that were almost certainly not destined to be persistently innervated by cells at the injection site. This pattern of extensive white matter label was not seen in animals older than 20 d. In each extrastriate region, from the earliest age at which we identified dense cortical innervation from area 17, the terminals were distributed in clusters. At first these patches were mainly in infragranular layers, but later, during the second and third postnatal weeks, they began to appear in more superficial laminae. By 70 d, an adult-like distribution of terminals was found in each extrastriate area: most fibers appeared to end in layers II and III in areas 18, 19, and 21a and centered on layer IV in the medial bank of the middle suprasylvian sulcus in adult cats. We suggest that the development of ipsilateral association projections from area 17 to extrastriate cortex is a 2-stage process.
- Research Organization:
- Univ. Laboratory of Physiology, Oxford (England)
- OSTI ID:
- 6325233
- Journal Information:
- J. Neurosci.; (United States), Journal Name: J. Neurosci.; (United States) Vol. 9:2; ISSN JNRSD
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
AGE DEPENDENCE
AMINES
AMINO ACIDS
ANIMALS
AZOLES
BODY
BRAIN
CARBOXYLIC ACIDS
CATS
CENTRAL NERVOUS SYSTEM
CEREBRAL CORTEX
CEREBRUM
COMPUTERIZED TOMOGRAPHY
DIAGNOSTIC TECHNIQUES
DISTRIBUTION
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MEDICINE
NERVES
NERVOUS SYSTEM
NEUROLOGY
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PROLINE
PYRROLES
PYRROLIDINES
TISSUE DISTRIBUTION
TOMOGRAPHY
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES