Science posts

See science posts on page 71 below.

    • 2012
    • Thomas Naselaris
    • Cortical representation of animate and inanimate objects in complex natural scenes
    • The representations of animate and inanimate objects appear to be anatomically and functionally dissociated in the primate brain. How much of the variation in object-category tuning across cortical locations can be explained in terms of the animate/inanimate distinction? How is the distinction between animate and inanimate reflected in the arrangement of object representations along the cortical surface? To investigate these issues we recorded BOLD activity in visual cortex while subjects viewed streams of natural scenes. We then constructed an explicit model of object-category tuning for each voxel along the cortical surface. We verified that these models accurately predict responses to novel scenes for voxels located in anterior visual areas, and that they can be used to accurately decode multiple objects simultaneously from novel scenes. Finally, we used principal components analysis to characterize the variation in object-category tuning across voxels. Remarkably, we found that t..
    • Thomas Naselarisa, Dustin E. Stansburyb, Jack L. Gallant
    • fMRI, Visual cortex, Object representation, Encoding models, Decoding, Natural scenes
    • 2003
    • Alex Martina, Jill Weisberg
    • Neural foundations for understanding social and mechanical concepts
    • Motivated by neuropsychological investigations of category-specific impairments, many functional brain imaging studies have found distinct patterns of neural activity associated with different object categories. However, the extent to which these category-related activation patterns reflect differences in conceptual representation remains controversial. To investigate this issue, functional magnetic resonance imaging (fMRI) was used to record changes in neural activity while subjects interpreted animated vignettes composed of simple geometric shapes in motion. Vignettes interpreted as conveying social interactions elicited a distinct and distributed pattern of neural activity, relative to vignettes interpreted as mechanical actions. This neural system included regions in posterior temporal cortex associated with identifying human faces and other biological objects. In contrast, vignettes interpreted as conveying mechanical actions resulted in activity in posterior temporal lobe sites..
    • 2009
    • Alison J. Wiggett
    • Animate and inanimate objects in human visual cortex: Evidence for task-independent category effects
    • Evidence from neuropsychology suggests that the distinction between animate and inanimate kinds is fundamental to human cognition. Previous neuroimaging studies have reported that viewing animate objects activates ventrolateral visual brain regions, whereas inanimate objects activate ventromedial regions. However, these studies have typically compared only a small number of animate and inanimate kinds (e.g. animals and tools) and some evidence indicates that task demands determine whether these effects occur at all. In the current study we test whether a lateral–medial animacy bias is evident across a variety of stimuli, and across different tasks (matching two stimuli at a general, intermediate and exemplar level). Images of objects were presented sequentially in pairs, and match/mismatch judgements were made at different levels in different scans. The fMRI data showed ventrolateral activation for animate objects and ventromedial activation for inanimate objects. Additional analyses..
    • Alison J. Wiggett, Iwan C. Pritchard, Paul E. Downing
    • Animacy, Category-specificity, Task modulation, Ventral stream, fMRI


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