The long term goal of the proposed research is to understand the functional organization of inferotemporal cortical areas and to determine their role in visual perception and memory. Several lines of evidence indicate that inferotemporal cortex (IT) is functionally and antomically heterogeneous, yet there is little agreement concerning the exact number, location, organization and connections of well defined areas within IT. The current proposal will focus on the initial stages of temporal lobe visual processing by examining the organization, and connections of posterior inferotemporal cortex (PIT). The first goal is to determine the location and topographic organization of posterior IT. Electrophysiological mapping of visual topography in PIT and adjacent cortical areas will be used to determine whether posterior IT consists of one visual area, PIT (or TEO), two areas, (PITd and PlTv), or some other configuration. These studies will also determine the borders of PIT with adjacent prestriate and inferotemporal cortical areas. The second goal is to determine the patterns of connections linking PIT with other subdivisions of visual cortex. Multiple retrogade and anterograde tracers will be injected into physiologically characterized loci in PITd and/or PITv and the intracortical labeling will be correlated with the pattern of interhemispheric connections and cortical architecture. These data will identify the specific visual areas and perhaps modules within areas which provide ascending and/or lateral inputs to PITd and/or PITv. In addition, these data will identify the forward connections of areas PITd and PITv to non-topographically organized portions of IT and adjacent cortical areas. The third goal is to determine whether there is a form of modular organization within PIT that reflects segregated inputs from distinct processing streams in prestriate cortex. Multiple anterograde and distinguishable retrograde tracers will be injected into corresponding loci in areas V4, V4t, and FST to determine whether inputs from different compartments in area V4, or inputs from areas V4t and FST, are segegated from one another in PITd and/or PITv. These studies should provide new ideas concerning the flow of visual information into the temporal lobe and will provide new insights into the anatomical substrates of high level pattern discrimination and visual memory.
| Felleman, Daniel J; Lim, Heejin; Xiao, Youping et al. (2015) The Representation of Orientation in Macaque V2: Four Stripes Not Three. Cereb Cortex 25:2354-69 |
| Lim, Heejin; Wang, Yi; Xiao, Youping et al. (2009) Organization of hue selectivity in macaque V2 thin stripes. J Neurophysiol 102:2603-15 |
| Wang, Yi; Xiao, Youping; Felleman, Daniel J (2007) V2 thin stripes contain spatially organized representations of achromatic luminance change. Cereb Cortex 17:116-29 |
