Name: Semantic information is represented in hundreds of distinct areas and gradients distributed across much of the human cerebral cortex
Uploaded: 2014-04-11
Duration: 1 h 11 min 5 s

Semantic information is represented in hundreds of distinct areas and gradients distributed across much of the human cerebral cortex

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Air date:	Friday, April 11, 2014, 2:00:00 PM Time displayed is Eastern Time, Washington DC Local
Views:	Total views: 110 (2 Live, 108 On-demand)
Category:	Special
Runtime:	01:11:05
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Description:	In the mammalian brain, semantic knowledge about the world is represented in a constellation of many distinct functional areas and maps that tile the cerebral cortex. In work published in 2012, my laboratory used a sensitive new voxel-wise modeling (VM) approach to analyze in detail the brain activity signals evoked by natural movies (Huth et al., Neuron, 76, 1210-1224, 2012). We found that information about thousands of distinct object and action categories is represented in complex gradients and areas distributed densely across visual cortex. We have now extended this approach to discover how semantic information in narrative stories is represented across the cortical sheet. We used fMRI to record brain activity while subjects listened to natural stories, and then used VM to discover what specific semantic information is represented in each voxel. Analysis of these data shows that all subjects share a common, low-dimensional semantic space that is mapped systematically across temporal, parietal, and frontal lobes. To identify the constituent functional areas within these maps, we developed a new modeling approach called PrAGMATiC (Probabilistic and Generative Modeling of Areas Tiling Cortex). Using PrAGMATiC to approximate the functional maps reveals that the meaning of narrative language is represented in more than 100 distinct functional areas in each hemisphere, tiling much of the prefrontal, parietal, and temporal cortices. Thus, our results provide a complete overview of how the meaning of narrative language is represented in the human brain. In a broader sense, VM and PrAGMATiC provide a powerful new method for mapping the representation of many different perceptual and cognitive processes across the human brain, and for investigating how these representations are modulated by attention, memory and learning.

NLM Title:	Semantic information is represented in hundreds of distinct areas and gradients distributed across much of the human cerebral cortex / Jack Gallant.
Author:	Gallant, Jack. National Institute of Mental Health (U.S.). Laboratory of Brain and Cognition,
Publisher:
Abstract:	(CIT): In the mammalian brain, semantic knowledge about the world is represented in a constellation of many distinct functional areas and maps that tile the cerebral cortex. In work published in 2012, my laboratory used a sensitive new voxel-wise modeling (VM) approach to analyze in detail the brain activity signals evoked by natural movies (Huth et al., Neuron, 76, 1210-1224, 2012). We found that information about thousands of distinct object and action categories is represented in complex gradients and areas distributed densely across visual cortex. We have now extended this approach to discover how semantic information in narrative stories is represented across the cortical sheet. We used fMRI to record brain activity while subjects listened to natural stories, and then used VM to discover what specific semantic information is represented in each voxel. Analysis of these data shows that all subjects share a common, low-dimensional semantic space that is mapped systematically across temporal, parietal, and frontal lobes. To identify the constituent functional areas within these maps, we developed a new modeling approach called PrAGMATiC (Probabilistic and Generative Modeling of Areas Tiling Cortex). Using PrAGMATiC to approximate the functional maps reveals that the meaning of narrative language is represented in more than 100 distinct functional areas in each hemisphere, tiling much of the prefrontal, parietal, and temporal cortices. Thus, our results provide a complete overview of how the meaning of narrative language is represented in the human brain. In a broader sense, VM and PrAGMATiC provide a powerful new method for mapping the representation of many different perceptual and cognitive processes across the human brain, and for investigating how these representations are modulated by attention, memory and learning.
Subjects:	Cerebral Cortex--physiology Cognition--physiology Models, Neurological Semantics
Publication Types:	Lecture Webcast

NLM Classification:	WL 337
NLM ID:	101631798
CIT Live ID:	14082
Permanent link:	https://videocast.nih.gov/watch=14082

NIH VideoCasting

Semantic information is represented in hundreds of distinct areas and gradients distributed across much of the human cerebral cortex