Poster board 14 - Tue 11/07, 16:00 - Hall X
Session 179 - Vision II
Abstract A179.14, published in FENS Forum Abstracts, vol. 3, 2006.
Ref.: FENS Abstr., vol.3, A179.14, 2006
|Author(s)||Karube F. & Kisvárday Z. F.|
|Fac. of Med., Univ. of Debrecen, Debrecen, Hungary|
|Title||Bouton distribution of deep-layer spiny neurons on the functional maps in cat visual cortex.|
|Text||In cat visual cortex, neurons with similar receptive field preferences form columnar clusters. Here we studied relationship between presynaptic structure bouton distribution and cortical architectures.
In vivo optical imaging was carried out in the cat visual cortex during the presentation of moving gratings as visual stimuli. Then, extra- and intra-cellular recordings were made from single units to define their physiological properties followed by extracellular tracer injection for retrograde staining. Labelled spiny neurons were reconstructed by Neurolucida. Bouton distributions and other morphological features were determined and compared to optical imaging functional maps.
We obtained orientation, direction and ocular dominance maps by optical imaging and a retinotopic map by electrophysiological recordings. Here we focused on layer 4-6 spiny neurons, containing star pyramid and pyramidal cells. Both groups had long horizontal collaterals providing distal clusters of terminals beyond several millimetres range. Star pyramids showed more dense local axonal innervations than pyramidal cells, though in most cases, over 60 % of their boutons were beyond the dendritic fields of the same cell. Single branches issuing from a main thick axon could contribute to both local and distal clusters and not restricted in the layer of origin. Orientation preferences of distal boutons often showed two broad peaks, at similar and orthogonal angles to the parent soma, while local boutons were always confined to similar angles to the parent soma. Among neighbouring cells, those with similar orientation preferences tended to share their terminal area, while cells with distinct preferences avoided each other. These results suggest selective connections can occur depending on receptive field preference.
The work is supported by the Hungarian Government Scholarship Board and the FACETS project (FP6-015879) of the European Commission.
Vision / Striate visual cortex: Functional organization and circuitry