Faculty Bibliography

Deformable image registration in the presence of considerable contrast differences and large-scale size and shape changes represents a significant challenge for image registration. A representative driving application is the study of early brain development in neuroimaging, which requires co-registration of images of the same subject across time or building 4-D population atlases. Growth during the first few years of development involves significant changes in size and shape of anatomical structures but also rapid changes in tissue properties due to myelination and structuring that are reflected in the multi-modal Magnetic Resonance (MR) contrast measurements. We propose a new registration method that generates a mapping between brain anatomies represented as a multi-compartment model of tissue class posterior images and geometries. We transform intensity patterns into combined probabilistic and geometric descriptors that drive the matching in a diffeomorphic framework, where distances between geometries are represented using currents which does not require geometric correspondence. We show preliminary results on the registrations of neonatal brain MRIs to two-year old infant MRIs using class posteriors and surface boundaries of structures undergoing major changes. Quantitative validation demonstrates that our proposed method generates registrations that better preserve the consistency of anatomical structures over time.

The trajectory of early brain development is marked by rapid growth presented by volume but also by tissue property changes. Capturing regional characteristics of axonal structuring and myelination via neuroimaging requires analysis of longitudinal image data with multiple modalities. Complementary to earlier studies of volume and cortical folding analysis, this paper focuses on white matter tissue changes as seen in multimodal MRI and DTI. We propose a new framework for analyzing early maturation in white matter that generates a normative spatiotemporal model and provides 3D maps of absolute and relative indices of maturation. The method, using a continuous model of intensity changes using modified Legendre polynomials, has been applied to a multimodal dataset (T1W, T2W, PD, DTI) with 8 subjects that have been scanned at approximately 2 weeks, 1 year, and 2 years. We demonstrate that spatial maturation maps generated from different modalities capture different properties of white matter growth which might lead to a better understanding of the underlying neurobiology.

The olfactory code is influenced by numerous factors, including behavioral state, odor-sampling patterns and cross-modal sensory convergence. Growing evidence supports the view that primary olfactory cortical regions are not unimodal, but instead represent information from several sensory modalities - providing a substrate for sensory convergence early in olfactory processing. Adding to previous reports of both gustatory and visual influences on the cortical processing of odors, here we report novel findings revealing that the olfactory code is subject to auditory cross-modal influences. In vivo extracellular recordings from the olfactory tubercle, a trilaminar structure within the basal forebrain, of anesthetized mice revealed that olfactory tubercle single-units selectively respond to odors - with 65% of units showing significant odor-evoked activity. Remarkably, 19% of olfactory tubercle single-units also showed robust responses to an auditory tone. Furthermore, 29% of single-units tested displayed supra-additive or suppressive responses to the simultaneous presentation of odor and tone, suggesting cross-modal modulation. In contrast, olfactory bulb units did not show significant responses to tone presentation, nor modulation of odor-evoked activity by tone - suggesting a lack of olfactory- auditory convergence upstream from the olfactory tubercle. Thus, the tubercle presents itself as a source for direct multimodal convergence within an early stage of odor processing, and may serve as a seat for psychophysical interactions between smells and sounds

The Building Bridges Initiative (BBI) provides a framework for achieving positive outcomes for youth and families served in residential and community programs. Founded on core principles, an emerging evidence base, and acknowledged best practices, the BBI emphasizes collaboration and coordination between providers, families, youth, advocates, and policymakers to achieve its aims. Examples are presented of successful state, community, and provider practice changes, and available tools and resources to support all constituencies in achieving positive outcomes.