Probing Human Orofacial-Related Brain Pathways in Vivo
Objectives: Invasive techniques using animals demonstrated multiple white matter (WM) projections related to orofacial somatosensation that projects directly from primary somatosensory cortex (SI) to the trigeminal sensory nuclear complex (TSNC) within the brainstem. Diffusion magnetic resonance imaging (dMRI) allows, with limitations, similar investigations in vivo in humans (tractography). This research analyzed dMRI data to determine in vivo WM SI-TSNC projections in humans. Methods: The Human Connectome Project (HCP) aims to “elucidate the neural pathways that underlie brain function and behavior” by providing MRI data from normal adults to the scientific community. dMRI data from 50 randomly selected non-twin HCP subjects (22 females; mean age(years±SD)=28.6±3.9) were processed using FSL tools to perform diffusion tractography. These tools estimated WM fiber bundles orientation in order to compute streamlines between a “seed” to a “target” going through pre-determined brain regions, from which connectivity strength can be inferred. Four tracts were probed that originated from SI orofacial regions (“seed”) and terminated at the TSNC (“target”). The tracts included streamlines that went through: Ipsilateral thalamus but avoided ipsilateral corticospinal tract (CST) terminating in (1) Contralateral or (2) Ipsilateral TSNC; and Ipsilateral CST but avoided ipsilateral thalamus terminating in (3) Contralateral and (4) Ipsilateral TSNC. Total number of streamlines was normalized by dividing it by the number of voxels within the seed mask (after transformation to each subject’s diffusion space). Results: Normalized mean number of streamlines (±95% confidence interval) for all tracts probed is reported in Table 1. Tracts 3 and 4 suggest direct SI-TSNC projections. Significant connectivity strength asymmetries were found for tracts 2, 3 and 4. Conclusions: HCP data indicate multiple pathways connecting cortico-trigeminal structures in normal human subjects, and suggests asymmetries that need to be assessed in larger sample sizes. Such approach allows quantification of orofacial-related brain anatomical connectivity that could serve as normative templates for comparison purposes.
Division: IADR/APR General Session
Meeting:2016 IADR/APR General Session (Seoul, Korea) Location: Seoul, Korea
Year: 2016 Final Presentation ID:1994 Abstract Category|Abstract Category(s):Neuroscience
Authors
Moana-filho, Estephan
( University of Minnesota School of Dentistry
, Minneapolis
, Minnesota
, United States
)
Nixdorf, Donald
( University of Minnesota
, Minneapolis
, Minnesota
, United States
)
Bereiter, David
( University of Minnesota
, Minneapolis
, Minnesota
, United States
)
Lenglet, Christophe
( University of Minnesota
, Minneapolis
, Minnesota
, United States
)
Support Funding Agency/Grant Number: Data were provided by the Human Connectome Project, WUMinn Consortium (Principal Investigators: David Van Essen and Kamil Ugurbil; 1U54MH091657) funded by the 16 NIH Institutes and Centers that support the NIH Blueprint for Neuroscience Research; and by t
Financial Interest Disclosure: NONE