The aim of the proposal is to study the functional role of a number of connections of area 17 of the cat visual cortex. Local circuit interactions will be studied by inactivating small regions of cortex with iontophoretic injections of GABA and studying orientation and direction selectivities in neighbouring cells. The synaptic and morphological bases of these interactions will be examined using in vivo and vitro preparations for intracellular recording and anatomical methods. Interactions between areas 17 and 18 in the cat will also be studied using similar methods. Cross-correlation between neuronal activities in these two areas and electrical stimulation will be used to identify inteconnected neurons. Comparisons of their receptive field properties will reveal whether efficient coric-cortical connections link neurons with similar functional characteristics. A second project will consist in inactivating area 18 while recording from neurons in area 17 in order to determine the functional contribution of this set of afferents to the receptive field properties of are 17 neurons. Finally, an in vitro preparation will be developped in order to study the synaptic effects of the interconnections between areas 17 and 18 on the intracellularly recorded membrane potentials of neurons in area 17. Another set of projects are aimed at understanding the functional role of the cortico-geniculate feedback. Extracellular electrophysiological experiments will be performed in order to characterize the receptive field properties of cortical cells involved in the corticogeniculate feedback. Reversible inactivation of area 17 will be used to reveal the functional contribution of this pathway on the response properties of LGN cells. Finally the synaptic and neurotransmitter mechanisms involved in this pathway will be studied by intracellular recordings and pharmacological techniques.
Funding SchemeCSC - Cost-sharing contracts
WC1E 7HU London