Using a linear dynamic system to measure functional connectivity from M/EEG.

Objective.Measures of functional connectivity (FC) can elucidate which cortical regions work together in order to complete a variety of behavioral tasks. This study's primary objective was to expand a previously published model of measuring FC to include multiple subjects and several regions of interest. While FC has been more extensively investigated in vision and other sensorimotor tasks, it is not as well understood in audition. The secondary objective of this study was to investigate how auditory regions are functionally connected to other cortical regions when attention is directed to different distinct auditory stimuli.Approach.This study implements a linear dynamic system (LDS) to measure the structured time-lagged dependence across several cortical regions in order to estimate their FC during a dual-stream auditory attention task.Results.The model's output shows consistent functionally connected regions across different listening conditions, indicative of an auditory attention network that engages regardless of endogenous switching of attention or different auditory cues being attended.Significance.The LDS implemented in this study implements a multivariate autoregression to infer FC across cortical regions during an auditory attention task. This study shows how a first-order autoregressive function can reliably measure functional connectivity from M/EEG data. Additionally, the study shows how auditory regions engage with the supramodal attention network outlined in the visual attention literature.

Comparison of various risk indicators among patients with chronic and aggressive periodontitis in davangere population.

BACKGROUND: The aim of the present study was to compare various risk indicators of chronic periodontitis (CP) and aggressive periodontitis (AP) among patients of Davangere population. MATERIALS AND METHODS: Totally, 89 CP and 90 AP patients were selected from outpatient Department of Periodontics, College of Dental Sciences, Davangere. Various clinical parameters proven to be risk indicators were determined for each patient such as age, gender, occupation, oral hygiene habits, personal habits, income, level of education, place of residence, frequency of dental visits, various oral hygiene indices, gingival status, wasting diseases, malocclusion, laboratory investigations, and the results were subjected to statistical analysis. RESULTS: This study demonstrated that AP is manifested early in life in susceptible individuals. Proven risk indicators for AP and CP in the present study population included young age, place of residence, income and education levels, frequency of dental visits. Patients with AP had better oral hygiene habits and oral hygiene index results than patients with CP. Paan chewing and smoking could be considered as risk factors, both in CP and AP cases. The similar association of plaque scores but higher bleeding tendency in AP patients supported the fact of higher susceptibility of AP patients to periodontal breakdown. Malocclusion being present in the majority of cases could also be put forth as a risk factor for AP and CP. CONCLUSION: This study identifies the different risk indicators for CP and AP and demonstrates the need for constructing nationwide oral health promotion programs to improve the level of oral health awareness and standards in Indian population.