SYNAPTIC ORGANIZATION OF THE PRIMATE PULVINAR NUCLEUS

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The pulvinar nucleus appears to play a key role in directing visual attention, in the process of selecting salient visual targets, and directing eye movements toward these targets. However, theories of pulvinar function remain quite speculative. The goal of this grant proposal is to understand how cortical and subcortical inputs structurally interact within the synaptic circuitry of the primate pulvinar nucleus. This proposal focuses on the dorsal/medial regions of the monkey pulvinar nucleus because in this region physiological studies have demonstrated a clear relation to visual attention, but nothing is known regarding its synaptic circuitry. We propose to examine the ultrastructure and synaptic targets of terminals that originate from the pretectum, the penduculopontine tegmentum, and cortical areas 7a and 23. These four areas display activity related to eye movements, attentional state, visual spatial location, and memory. All of these areas are themselves extensively interconnected and have been predicted to contribute to networks underlying visual attention. We have made injections in areas 7a and 23 of macaque prefrontal cortex and analyzed the location of the injection sites. We are analyzing the injectin sites and providing blocks of the pulvinar to Dr. Bickford who is using double label tract tracing techniques, the proposed studies will determine how the pulvinar nucleus links diverse signals. The results of these studies will provide the first comprehensive ultrastructural description of the primate pulvinar nucleus, providing an anatomical basis for further investigation of this region?s role in visual attention. The funding for this project ended in February of 2005 and it is currently in a no cost extension year.