[Paper available] COMBINATORIAL CODES in Obj Recognition

[Matsuka, Toshihiko]

Dear Connectionists:

We would like to announce the paper:
COMBINATORIAL CODES IN VENTRAL TEMPORAL LOBE FOR OBJECT RECOGNITION: HAXBY
(2001) REVISITED: IS THERE A "FACE" AREA?
by Stephen Jose Hanson, Toshihiko Matsuka, and James V. Haxby.
to appear in NeuroImage

---abstract---
Haxby et al (2001) recently argued that category-related responses in the
ventral temporal (VT) lobe during visual object identification were
overlapping and distributed in topography.  This observation contrasts with
prevailing views that object codes are focal and localized to specific areas
such as the fusiform and parahippocampal gyri.   We provide a critical test
of Haxby's hypothesis using a Neural Network classifier which can detect
more general topographic representations and achieves 83% correct
generalization performance on patterns of voxel responses in out-of-sample
tests. Using voxel-wise sensitivity analysis we show that substantially the
same VT lobe voxels contribute to the classification of all object
categories, suggesting the code is combinatorial.    Moreover, we found no
evidence for local single category representations.  The neural network
representations of the voxel codes were sensitive to both category and to
superordinate level features which were only available implicitly in the
object categories.

A preprint is available at:
http://www.rumba.rutgers.edu/pubs/objrecog_shj_tm_jvh.PDF

Best regards,

Toshihiko Matsuka

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toshihiko matsuka
rutgers university
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