Name
Title | ||
|---|---|---|
fMRI activity patterns in human LOC carry information about object exemplars within category. |
Abstract | ||
|---|---|---|
Abstract The lateral occipital complex (LOC) is a set of areas in the human occipito-temporal cortex responding to objects as opposed to low-level control stimuli. Conventional functional magnetic resonance imaging (fMRI) analysis methods based on regional averages could not detect signals discriminative of different types of objects in this region. Here, we examined fMRI signals using multivariate pattern recognition (support vector classification) to systematically explore the nature of object-related information available in fine-grained activity patterns in the LOC. Distributed fMRI signals from the LOC allowed for above-chance discrimination not only of the category but also of within-category exemplars of everyday man-made objects, and such exemplar-specific information generalized across changes in stimulus size and viewpoint, particularly in posterior subregions. Object identity could also be predicted from responses of the early visual cortex, even significantly across the changes in size and viewpoint used here. However, a dissociation was observed between these two regions of interest in the degree of discrimination for objects relative to size: In the early visual cortex, two different sizes of the same object were even better discriminated than two different objects (in accordance with measures of pixelwise stimulus similarity), whereas the opposite was true in the LOC. These findings provide the first evidence that direct evoked fMRI activity patterns in the LOC can be different for individual object exemplars (within a single category). We propose that pattern recognition methods as used here may provide an alternative approach to study mechanisms of neuronal representation based on aspects of the fMRI response independent of those assessed in adaptation paradigms. |
Year | DOI | Venue |
|---|---|---|
2008 | 10.1162/jocn.2008.20019 | J. Cognitive Neuroscience |
Keywords | Field | DocType |
everyday man-made object,human loc,early visual cortex,fmri activity pattern,different type,different size,fmri response,different object,human occipito-temporal cortex,direct evoked fmri activity,fmri signal,individual object exemplar,shape,pattern recognition,region of interest,attention,representation | Brain mapping,Neuroscience,Visual cortex,Functional magnetic resonance imaging,Support vector machine,Cognitive psychology,Psychology,Stimulus (physiology),Occipital lobe,Discriminative model,Form perception | Journal |
Volume | Issue | ISSN |
20 | 2 | 0898-929X |
Citations | PageRank | References |
39 | 2.97 | 7 |
Authors | ||
5 | ||
Name | Order | Citations | PageRank |
|---|---|---|---|
| Evelyn Eger | 1 | 164 | 24.65 |
| John Ashburner | 2 | 3589 | 382.57 |
| John-Dylan Haynes | 3 | 445 | 34.11 |
| Raymond J Dolan | 4 | 419 | 49.74 |
| Geraint Rees | 5 | 315 | 37.03 |