Parkinson's disease (PD) is a progressive neurologic disorder primarily characterized by an altered motor function. Lower extremity forced exercise (FE) has been shown to reduce motor symptoms in patients with PD. Recent functional magnetic resonance imaging (fMRI) studies have shown that FE and medication produce similar changes in brain activation patterns. Functional connectivity MRI (fcMRI) affords the ability to look at how strongly nodes of the motor circuit communicate with each other and can provide insight into the complementary effects of various therapies. Past work has demonstrated an abnormal motor connectivity in patients with PD compared to controls and subsequent normalization after treatment. Here we compare the effects of FE and medication using both resting and continuous visuomotor task fcMRI. Ten patients with mild to moderate PD completed three fMRI and fcMRI scanning sessions randomized under the following conditions: on PD medication, off PD medication, and FE+off medication. Blinded clinical ratings of motor function (a Unified Parkinson's Disease Rating Motor Scale-III exam) indicated that FE and medication resulted in 51% and 33% improvement in clinical ratings, respectively. In most nodes of the motor circuit, the observed changes in the functional connectivity produced by FE and medication were strongly positively correlated. These findings suggest that medication and FE likely use the same pathways to produce symptomatic relief in patients with PD. However, the connectivity changes, while consistent across therapy, were inconsistent in polarity for each patient. This finding may explain some past inconsistencies in connectivity changes after medication therapy.

Forced-rate lower-extremity exercise has recently emerged as a potential safe and low-cost therapy for Parkinson's disease (PD). The efficacy is believed to be dependent on pedaling rate, with rates above the subjects' voluntary exercise rates being most beneficial. In this study, we use functional connectivity magnetic resonance imaging (MRI) to further elucidate the mechanism underlying this effect. Twenty-seven PD patients were randomized to complete 8 weeks of forced-rate exercise (FE) or voluntary-rate exercise (VE). Exercise was delivered using a specialized stationary bicycle, which can augment patients' voluntary exercise rates. The FE group received assistance from the cycle. Imaging was conducted at baseline, end of therapy, and after 4 weeks of follow-up. Functional connectivity (FC) was determined via seed-based correlation analysis, using activationbased seeds in the primary motor cortex (M1). The change in FC after exercise was compared using linear correlation with pedaling rate. Results of the correlation analysis showed a strong positive correlation between pedaling rate and change in FC from the most affected M1 to the ipsilateral thalamus. This effect persisted after 4 weeks of follow-up. These results indicate that a plausible mechanism for the therapeutic efficacy of high-rate exercise in PD is that it improves thalamo-cortical connectivity.

Background: Cholesteatoma is potentially dangerous condition as it can extend and erode into adjacent structures and can cause various serious complications. HRCT temporal bone very clearly depicts the anatomy of various small important structures in middle and inner ear cavity. Hence it is an excellent modality and investigation of choice in diagnosing and defining the extent of cholesteatoma. It has become essential investigation in preoperative planning for surgeon. Present study shows good correlation of various preoperative HRCT findings with intraoperative findings. Aims & Objective: To study the role of HRCT temporal bone in pre-operative evaluation of cholesteatoma. Material and Methods: Total 35 cases with clinically suspected cholesteatoma were selected for this study. All the patients were from Sir Sayajirao General Hospital, Vadodara and were scanned at the CT scan, Radiology Department of the hospital. The important intraoperative surgical findings were correlated with pre-operative HRCT findings. The results were analyzed, studied and compared with similar studies of the past. Results: Present study shows good correlation between the preoperative findings of cholesteatoma by HRCT temporal bone and intraoperative surgical findings. Conclusion: In present study HRCT enabled the pre-operative delineation of the cholesteatoma and the recognition of its manifestations and complications. HRCT is confirmed to be valuable in the diagnosis and in guiding the surgical management of cholesteatoma.

Locating the source of an epidemic, or patient zero (P0), can provide critical insights into the infection's transmission course and allow efficient resource allocation. Existing methods use graph-theoretic centrality measures and expensive message-passing algorithms, requiring knowledge of the underlying dynamics and its parameters. In this paper, we revisit this problem using graph neural networks (GNNs) to learn P0. We establish a theoretical limit for the identification of P0 in a class of epidemic models. We evaluate our method against different epidemic models on both synthetic and a real-world contact network considering a disease with history and characteristics of COVID-19. We observe that GNNs can identify P0 close to the theoretical bound on accuracy, without explicit input of dynamics or its parameters. In addition, GNN is over 100 times faster than classic methods for inference on arbitrary graph topologies. Our theoretical bound also shows that the epidemic is like a ticking clock, emphasizing the importance of early contact-tracing. We find a maximum time after which accurate recovery of the source becomes impossible, regardless of the algorithm used.

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