This research will be done in collaboration with Dr. Laszlo Negyessy at Budapest, Hungary at Semmelweis University as an extension of parent grant NIH R01 NS044375 (PI: Anna W. Roe). The goal of the proposed studies is to investigate the neuroanatomical basis of tactile information processing in SI of the squirrel monkey. The goals of the parent grant are to 1) study the functional organization of vibrotactile modality- specific (pressure, flutter, and vibration) representation in Area 3b and 1, and 2) compare the simple vs. complex response preferences in Area 3b and 1. The studies proposed in this Firca will be guided by and integrated with the optical imaging and neurophysiological studies conducted under the parent grant. Neuroanatomical tracer injections (both anterograde and retrograde) will be made into functionally identified domains in Areas 3b and 1. In Aim 1, we will examine modality-specificity of vibrotactile networks within Areas 3b and Area 1. In Aim 2, we will examine topographic specificity of connections within Areas 3b and 1. In Aim 3, in ultrastructural studies, we will examine synaptic relationships of GABAergic targets of synapses formed by the intrinsic-, and interareal connections to help interpret whether functional effects of specific connections are excitatory or inhibitory. These data will provide an anatomical underpinning to imaged vibrotactile networks, to spatial topographies, to functional comparisons between Areas 3b and 1, and to maps of perceptual phenomena such as the funneling illusion. There are very few studies examining local anatomical circuitries within somatosensory cortex and to our knowledge none have been conducted in an integrated fashion with functional studies of local functional organization and perceptual processes. These anatomical data will be highly valuable in their own right, but will be even more so when interpreted in parallel with functional studies in the parent grant. [unreadable] [unreadable] [unreadable]