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The zona incerta (ZI) is a small gray matter region of the deep brain first identified in the 19th century, yet direct in vivo visualization and characterization has remained elusive. Noninvasive detection of the ZI and surrounding region could be critical to further our understanding of this widely connected but poorly understood deep brain region and could contribute to the development and optimization of neuromodulatory therapies. We demonstrate that high resolution (submillimetric) longitudinal (T1) relaxometry measurements at high magnetic field strength (7 T) can be used to delineate the ZI from surrounding white matter structures, specifically the fasciculus cerebellothalamicus, fields of Forel (fasciculus lenticularis, fasciculus thalamicus, and field H), and medial lemniscus. Using this approach, we successfully derived in vivo estimates of the size, shape, location, and tissue characteristics of substructures in the ZI region, confirming observations only previously possible through histological evaluation that this region is not just a space between structures but contains distinct morphological entities that should be considered separately. Our findings pave the way for increasingly detailed in vivo study and provide a structural foundation for precise functional and neuromodulatory investigation.

A variety of clinical scales are available to assess dyskinesia severity in Parkinson's disease patients; however, such assessments are subjective, do not provide long term monitoring, and their use is subject to inter- and intra-rater variability. In this paper, an objective dyskinesia score was developed using an IMU -based motion capture system. Deep brain stimulation (DBS) surgery is currently the only acute intervention that results in the rapidly progressive reduction of dyskinesia's severity; hence, this form of therapy was selected as a model to validate the proposed method. Thirteen Parkinson's disease participants undergoing DBS surgery and 12 age-matched healthy control participants were assessed using the motion capture system. Concurrent Unified Dyskinesia Rating Scale (UDysRS) ratings were also performed. Parkinson's disease participants were assessed pre-operatively and for five visits post-operatively while seated at rest, during arms outstretched and while performing an action task. The kinematic data were used to develop an objective measure defined as the dyskinesia severity score. Generally, a strong correlation was observed between the UDysRS ratings and the full-body dyskinesia severity scores. The results suggest that it is feasible and clinically meaningful to utilize an objective full-body dyskinesia score for the assessment of dyskinesia. The portable motion capture system along with the developed software can be used remotely to monitor the full-body severity of dyskinesia, necessary for therapeutic optimization, especially in the patients home environment.

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