A Center for Mind/Brain Sciences Lecture

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Oct 16, 2013 (3 years and 9 months ago)

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A Center for Mind/Brain Sciences Lecture


Who:

Prof. James Haxby
,
Princeton University, USA

When:

T
hurs
day
,
June
21
st
,

200
7

at 16:30

Where:

Mattarello



V
ia delle

Regole, 101
, for directions please
visit
http://www.cimec.unitn.it/contact_us.php




Title:

"

Pattern classifiers for analysis of fMRI: what can they tell us
about visual representations?
"


Abstr
act:

fMRl experiments produce large, numerically rich, but noisy data
sets that pose a challenge for extracting the signal variance and
establishing the correspondence between that signal and cognitive
variables. Conventional analysis has reduced the dim
ensionality of
fMRl data by searching for clusters of voxels that show similar
responses to experimental manipulations and averaging the signal
within those clusters. We have introduced a new approach to fMRl
data analysis, "multi
-
voxel pattern analysis"
of MVPA, that
examines higher spatial frequency patterns of activity
-

the voxel
-
by
-
voxel variation of response within a region
-

and have shown
that this method greatly increases the sensitivity of fMRI. These
methods use pattern classifiers from machine

learning such as
linear discriminant analysis, neural networks, and support vector
machines. In addition to increasing the sensitivity of fMRI analysis,
MVPA can measure the multi
-
dimensional similarity structure of
neural representations, which can be r
elated to the multi
-
dimensional similarity structure of cognitive representations. The
use of MVPA will be illustrated with studies of the representations of
faces and objects in visual extrastriate cortex.