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Psychology Commons

Open Access. Powered by Scholars. Published by Universities.®

Medicine and Health Sciences

Western University

2008

Magnetic Resonance Imaging

Articles 1 - 3 of 3

Full-Text Articles in Psychology

Illusory Vowels Resulting From Perceptual Continuity: A Functional Magnetic Resonance Imaging Study, Antje Heinrich, Robert P Carlyon, Matthew H Davis, Ingrid Johnsrude Oct 2008

Illusory Vowels Resulting From Perceptual Continuity: A Functional Magnetic Resonance Imaging Study, Antje Heinrich, Robert P Carlyon, Matthew H Davis, Ingrid Johnsrude

Brain and Mind Institute Researchers' Publications

We used functional magnetic resonance imaging to study the neural processing of vowels whose perception depends on the continuity illusion. Participants heard sequences of two-formant vowels under a number of listening conditions. In the "vowel conditions," both formants were always present simultaneously and the stimuli were perceived as speech-like. Contrasted with a range of nonspeech sounds, these vowels elicited activity in the posterior middle temporal gyrus (MTG) and superior temporal sulcus (STS). When the two formants alternated in time, the "speech-likeness" of the sounds was reduced. It could be partially restored by filling the silent gaps in each formant with …


Freesurfer-Initiated Fully-Automated Subcortical Brain Segmentation In Mri Using Large Deformation Diffeomorphic Metric Mapping., Ali R Khan, Lei Wang, Mirza Faisal Beg Jul 2008

Freesurfer-Initiated Fully-Automated Subcortical Brain Segmentation In Mri Using Large Deformation Diffeomorphic Metric Mapping., Ali R Khan, Lei Wang, Mirza Faisal Beg

Brain and Mind Institute Researchers' Publications

Fully-automated brain segmentation methods have not been widely adopted for clinical use because of issues related to reliability, accuracy, and limitations of delineation protocol. By combining the probabilistic-based FreeSurfer (FS) method with the Large Deformation Diffeomorphic Metric Mapping (LDDMM)-based label-propagation method, we are able to increase reliability and accuracy, and allow for flexibility in template choice. Our method uses the automated FreeSurfer subcortical labeling to provide a coarse-to-fine introduction of information in the LDDMM template-based segmentation resulting in a fully-automated subcortical brain segmentation method (FS+LDDMM). One major advantage of the FS+LDDMM-based approach is that the automatically generated segmentations generated are …


Functional Imaging Of The Auditory Processing Applied To Speech Sounds, Roy D Patterson, Ingrid Johnsrude Mar 2008

Functional Imaging Of The Auditory Processing Applied To Speech Sounds, Roy D Patterson, Ingrid Johnsrude

Brain and Mind Institute Researchers' Publications

In this paper, we describe domain-general auditory processes that we believe are prerequisite to the linguistic analysis of speech. We discuss biological evidence for these processes and how they might relate to processes that are specific to human speech and language. We begin with a brief review of (i) the anatomy of the auditory system and (ii) the essential properties of speech sounds. Section 4 describes the general auditory mechanisms that we believe are applied to all communication sounds, and how functional neuroimaging is being used to map the brain networks associated with domain-general auditory processing. Section 5 discusses recent …