Center for Biomedical Imaging at Stanford  

CBIS Report
March 25, 2011

In This Issue:

2011 3rd Annual Symposium

CBIS Seed Grants 2011

Faculty Profile: Kalanit Grill-Spector


 

CBIS logo

2011 3rd Annual Symposium
Pushing the Limits of Imaging: Faster, Higher, Stronger

It's not too late to register to attend the 3rd Annual CBIS Symposium on March 29, 2011!

Register for this event at cbis.stanford.edu.

Details on the day's agenda and events has been available and is online here.

The Symposium will be held at the magnificent new Li Ka Shing Center for Learning and Knowledge, the brand new educational facilty in the School of Medicine. We are proud to announce our keynote speaker is Dr. Rod Pettigrew, Director of the NIBIB.

Our faculty speakers will be:

Roger Kornberg, PhD
Structural Biology, Stanford UniversityLi Ka Shing Center for Learning

David Ehrhardt, PhD
Plant Biology, Carnegie Institute for Science

Stephen Smith, PhD
Molecular and Cellular Biology, Stanford University

Sarah Nelson, PhD
Radiology, UC San Francisco

There are many opportunities built into the day's schedule for networking, viewing posters, chatting over coffee and relaxing. If you have any questions about the event, or questions about CBIS in general, please don't hesitate to contact us.


Seed Funds Image

CBIS Seed Grants 2011

CBIS is pleased to announce that we are now accepting applications for our available Seed Grant funds. The Center for Biomedical Imaging at Stanford (CBIS) makes available $150,000 to fund imaging research or educational projects up to $25,000 each for one year. The goals of this program are to fund strategic research directions in biomedical imaging campus-wide, to promote cooperation between different research programs and different schools on campus, and to promote educational opportunities in biomedical imaging.

For more information about application eligibility and submission guidelines, please visit the Research Management Group (RMG) website, here:

med.stanford.edu/rmg/funding/cbis.html

The deadline for submission is May 16, 2011.


Using high-resolution fMRI to Uncover the Neural Coding of the Human Ventral Cortex (VTC)

By Julie Ruiz-Wibbelsmann, PhD
Grill-Spector photo Kevin Weiner photo
Kalanit Grill-Spector, Ph.D. Kevin Weiner

Functional magnetic resonance imaging (fMRI) can reveal the neural basis of visual perception and link brain activations to human perception. Recent findings from fMRI studies indicate that the human ventral temporal cortex (VTC) contains regions responding more strongly to faces or body parts, relative to other objects, as well as discriminable distributed activation patterns for object categories across the VTC. However, there is an ongoing debate regarding the spatial organization, function, and neural coding of object categories in these VTC regions. CBIS Member Kalanit Grill-Spector, PhD, associate professor of psychology and the Neuroscience Institute, along with researchers from her Vision & Perception Neuroscience Lab (vpnl.stanford.edu/), is investigating the structure and function of the VTC. Their research promises to deepen our understanding of disorders such as autism, prosopagnosia (the inability to recognize faces), as well as Williams syndrome, which leads to a fascination and fixation on faces.

One view of the functional organization of the VTC suggests a highly overlapping and distributed organization for faces, limbs, and objects, which each generate different distributed imaging response patterns (referred to as multivoxel patterns, MVP) across the VTC. Using high-resolution fMRI (1.5 mm voxels), Dr. Grill-Spector and graduate student Kevin Weiner measured subjects' brain activations in the VTC while they viewed objects from 6 categories. They found that face- and limb-selective activations are located near each other on the brain, alternating in a series of largely nonoverlapping clusters in the lateral VTC along the inferior occipital gyrus (IOG), fusiform gyrus (FG), and occipito-temporal sulcus (OTS). Specifically, their research illustrates that there is not just one distinct region selective for each category in the VTC, but rather a series of face- and limb-selective clusters that minimally overlap, with a consistent organization relative to one another on a posterior to anterior axis along the occipito-temporal sulcus (OTS) and fusiform gyrus (FG).

Their discovery of face- and limb-selective clusters supports a sparsely-distributed organization of face- and limb-selective activations in the VTC. “Sparsely” refers to the presence of a series of minimally overlapping highly-selective clusters that are arranged in a consistent topography relative to one another as well as to retinotopic visual areas. “Distributed” refers to the fact that despite the minimal overlap across clusters, there is substantial (but different) amounts of information in the responses across voxels coding either category (i.e., face or limb). The consistent spatial organization and multiplicity of activations suggest that brain organization in high-level visual areas is highly structured and that information about faces and limbs in the human brain is both clustered spatially and distributed across a series of activations that may code for different aspects of faces and limbs.

Dr. Grill-Spector and her Lab (vpnl.stanford.edu/) use functional imaging, computational techniques, and behavioral methods to investigate visual object recognition and other high-level visual processes. Their goal is to discover the underlying representations and cortical mechanisms that subserve recognition (and the relation between these neural processes) as well as our visual perception of the world by exploring the following questions:

• What are the processing stages that underlie object and face perception?
• How are shapes, objects, and faces represented in the human brain?
• How does the brain process the large variability in the appearance of objects, while retaining the ability to discriminate between objects that are similar?
• To what extent are cortical representations dynamic, and how are they modified by learning?
• What are the mechanisms underlying the development of cortical circuits for face and object perception?
• How does the maturation of cortical circuits affect perception?
• How do different tasks modulate cortical circuits?

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