[Abstract Title]. - Society for Neuroscience

Authors: *C. S. KONEN 1,2 , M. A. PINSK 1,2 , M. ARCARO 1,2 , X. LI 1,2 , S. J. INATI 3 , S.
KASTNER 1,2,4 ;
1 CSBMB, 2 Dept. Psychology, Princeton Univ., Princeton, NJ; 3 Ctr. for Brain Imaging, New
York Univ., New York City, NY; 4 Princeton Neurosci. Inst., Princeton Uni., Princeton, NJ
Abstract: The visual system is broadly divided into two separate pathways (Ungerleider &
Mishkin 1982), a dorsal stream to posterior parietal cortex (PPC) that is associated with visuallyguided
action, and a ventral stream to temporal cortex that is involved with object recognition.
Despite this classical view, we have recently reported object-selectivity, and size and viewpoint
invariance in areas along the dorsal pathway (Konen & Kastner 2008). Here, we investigated
object-selective responses in monkey PPC using fMRI adaptation and compared them with those
in human PPC.
Two monkeys viewed geometric 2D-objects that alternated with scrambled pictures while
maintaining fixation (Siemens Allegra 3T). In the adapted condition, one object was presented
15 times. In the non-adapted condition, 15 different objects were presented once. In the sizeinvariance
experiment, the adapted condition consisted of 15 presentations of one object in
different sizes. Regions of interest were defined on the basis of anatomical locations (Saleem &
Logothetis 2007).
The comparison between adapted and non-adapted conditions revealed object-selective
responses in monkey V4, TE, and TEO in the ventral pathway and LIP and VIP in the dorsal
pathway. Similarly, ventral V4 and LOC as well as dorsal IPS1 and IPS2 in humans exhibited
object-selectivity. In contrast to humans, intermediate areas of the dorsal pathway did not
respond object-selective in monkeys. Further, invariant responses evoked by 2D-objects
presented in different sizes were found in monkey LIP and VIP as well as in human IPS1 and
IPS2 (in addition to ventral stream areas). Taken together, the organization of the ventral
pathway in humans and non-human primates appears to be similar, while the organization of
dorsal pathway may be fundamentally different in the two species.
Disclosures: C.S. Konen, None; M.A. Pinsk, None; M. Arcaro, None; X. Li, None; S.J. Inati,
None; S. Kastner, None.
Poster
261. Object and Faces: Neuronal Representation I
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 261.3/BB34
Topic: D.04.j. Processing of objects and faces
Support: NIH Grant EY011797