Interlaminar and lateral excitatory amino acid connections in the striate cortex of monkey

Journal Article · Wed Feb 01 04:00:00 EST 1989 · J. Neurosci.; (United States)

OSTI ID:6075937

Kisvarday, Z F; Cowey, A; Smith, A D; Somogyi, P

The intrinsic excitatory amino acid pathways within the striate cortex of monkeys were studied by autoradiographic detection of retrogradely labeled somata following microinjections of D-3H-aspartate (D-3H-Asp) into different layers. The labeled amino acid was selectively accumulated by subpopulations of neurons and, to a small extent, by glial cells, the latter mainly in the supragranular layers. Immunocytochemical detection of neurons containing GABA showed that, apart from a few cells exclusively in layer I, GABAergic neurons do not accumulate D-3H-Asp. Several lines of evidence suggest that D-3H-Asp uptake occurred only at nerve terminals; thus, the pattern of perikaryal labeling allowed the delineation of interlaminar and lateral projections. Neurons in layer I probably project laterally, and layer I receives wide-ranging projections from layer IVB and layer V from cells up to 1300 microns laterally. Some neurons in layer II send a focused projection to lower layer VI. Some neurons in layers II/III project up to 1 mm laterally within their own layer, but relatively few neurons can be labeled in these projections. Similarly, in layers II/III few neurons can be retrogradely labeled from layers V and upper VI, and this projection is organized such that cells closer to the pia project deeper in layer V/VI. The connections of layer IVA could not be revealed separately because of the difficulty of confining injections to this thin sublamina. Neurons in layer IVB project up to 1300 microns within IVB itself. A small number of cells from IVB also project to layers III, IVC-alpha, V, and VI with much more restricted lateral spread. Neurons in upper IVC-alpha send axons to layer IVB with at least 600-800 microns lateral spread. Neurons in lower IVC-alpha/upper IVC-beta project to layer III with at least 300-500 microns lateral spread.

• Research Organization: Semmelweis Univ. Medical School, Budapest (Hungary)
• OSTI ID: 6075937
• Journal Information: J. Neurosci.; (United States), Journal Name: J. Neurosci.; (United States) Vol. 9:2; ISSN JNRSD
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMAL CELLS
ANIMALS
ASPARTIC ACID
AUTORADIOGRAPHY
BIOLOGICAL PATHWAYS
BODY
BRAIN
CARBOXYLIC ACIDS
CENTRAL NERVOUS SYSTEM
CEREBRAL CORTEX
CEREBRUM
CHEMICAL COMPOSITION
LABELLED COMPOUNDS
MAMMALS
MEDICINE
MONKEYS
NERVE CELLS
NERVOUS SYSTEM
NEUROLOGY
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PRIMATES
SOMATIC CELLS
TRITIUM COMPOUNDS
VERTEBRATES