Self-Reported Dental Public Health Competencies of Senior Dental Students: A Cross-Sectional Study

Objective: To reach the World Health Organization's goal of improving community oral health, Iranian oral health policy-makers expanded the scope of oral health by including dental public health (DPH) courses in the latest dental curriculum to improve students' competencies. The aim of the current study was to evaluate DPH competencies in senior dental students at Shahid Beheshti University of Medical Sciences, according to specified educational objectives. Methods: In the present cross-sectional study, 195 senior dental students (enrolled in 2014-2015) filled up an online standardized questionnaire. The instrument included demographic information as well as 31 statements about ten domains of DPH. Participants used self-assessment method to report the level of their competencies on a Likert scale of 0-10; Zero indicating "not competent at all", and 10 indicating "fully competent" for each statement. Then the mean score was calculated for each domain. Data analysis was conducted using Independent samples, T-test, One-way ANOVA, Mann-Whitney U-test, and Kruskal-Wallis via SPSS version 21. ResultsThe sum of scores for each participant was within the range of 63 to 310, and the mean (SD) was 216.68 (±43.69). Students were most competent in "Providing preventive dental care" (8.22±1.59), "Adherence to professional ethics" (7.56±1.68), and" Understanding determinants of oral health" (7.50±1.52). They were least competent in "Understanding components and functions of healthcare system" (5.96±2.06), "Planning" (6.06±2.45), and "Oral health research" (6.24±2.44). The mean score for females' (223.30±38.21) was significantly higher than males' score (207.15±49.25), (P=0.011). Conclusion: Although higher competencies were achieved in "Providing preventive dental care", "Adherence to professional ethics", and" Understanding determinants of oral health"; there are more areas to be accomplished, such as "Understanding components and functions of healthcare system", "Planning", and "Oral health research". These findings could be helpful either in revising the content materials, teaching methods, or both

Distinct roles of dorsal and ventral subthalamic neurons in action selection and cancellation

The subthalamic nucleus (STN) supports action selection by inhibiting all motor programs except the desired one. Recent evidence suggests that STN can also cancel an already selected action when goals change, a key aspect of cognitive control. However, there is little neurophysiological evidence for dissociation between selecting and cancelling actions in the human STN. We recorded single neurons in the STN of humans performing a stop-signal task. Movement-related neurons suppressed their activity during successful stopping, whereas stop-signal neurons activated at low-latencies near the stop-signal reaction time. In contrast, STN and motor-cortical beta-bursting occurred only later in the stopping process. Task-related neuronal properties varied by recording location from dorsolateral movement to ventromedial stop-signal tuning. Therefore, action selection and cancellation coexist in STN but are anatomically segregated. These results show that human ventromedial STN neurons carry fast stop-related signals suitable for implementing cognitive control

Movement-Modulation of Local Power and Phase Amplitude Coupling in Bilateral Globus Pallidus Interna in Parkinson Disease

There is converging evidence that bilateral basal ganglia motor networks jointly support normal movement behaviors including unilateral movements. The extent and manner in which these networks interact during lateralized movement remains unclear. In this study, simultaneously recorded bilateral Globus Pallidus interna (GPi) local field potentials (LFP) were examined from 19 subjects with idiopathic Parkinson disease (PD), while undergoing awake deep brain stimulation (DBS) implantation. Recordings were carried out during two behavioral states; rest and cued left hand movement (finger tapping). The state-dependent effects on α- β oscillatory power and β phase-encoded phase amplitude coupling (PAC), including symmetrical and assymetrical changes between hemispheres, were identified. Unilateral hand movement resulted in symmetrical oscillatory power suppression within bilateral GPi at α (8–12 Hz) and high β (21–35 Hz) and increase in power of high frequency oscillations (HFO, 200–300 Hz) frequency bands. Asymmetrical attenuation was also observed at both low β (13–20 Hz) and low γ (40–80 Hz) bands within the contralateral GPi (P = 0.009). In addition, unilateral movement effects on PAC were confined to the contralateral GPi with attenuation of both low β-low γ and β-HFO PAC (P < 0.05). Further analysis showed that the lateralized attenuation of low β and low γ power did not correlate with low β-low γ PAC changes. The overall coherence between bilateral GPi was not significantly altered with unilateral movement, however the preferred phase difference in the high β range increased from 0.23 (±1.31) radians during rest to 1.99 (±0.78) radians during movement execution. Together, the present results suggest that unilateral motor control involves bilateral basal ganglia networks with movement features differentially encoded by distinct frequency bands. The lateralization of low β and low γ attenuation with movement suggests that these frequency bands are specific to the motor act whereas symmetrical expression of α, high β, and HFO oscillations best correspond to motor state. The restriction of movement-related PAC modulation to the contralateral GPi indicates that cross-frequency interactions appear to be associated with lateralized movements. Despite no significant movement-related changes in the interhemispheric coherence, the increase in phase difference suggests that the communication between bilateral GPi is altered with unilateral movement

Proceedings of the Eighth Annual Deep Brain Stimulation Think Tank: Advances in Optogenetics, Ethical Issues Affecting DBS Research, Neuromodulatory Approaches for Depression, Adaptive Neurostimulation, and Emerging DBS Technologies

We estimate that 208,000 deep brain stimulation (DBS) devices have been implanted to address neurological and neuropsychiatric disorders worldwide. DBS Think Tank presenters pooled data and determined that DBS expanded in its scope and has been applied to multiple brain disorders in an effort to modulate neural circuitry. The DBS Think Tank was founded in 2012 providing a space where clinicians, engineers, researchers from industry and academia discuss current and emerging DBS technologies and logistical and ethical issues facing the field. The emphasis is on cutting edge research and collaboration aimed to advance the DBS field. The Eighth Annual DBS Think Tank was held virtually on September 1 and 2, 2020 (Zoom Video Communications) due to restrictions related to the COVID-19 pandemic. The meeting focused on advances in: (1) optogenetics as a tool for comprehending neurobiology of diseases and on optogenetically-inspired DBS, (2) cutting edge of emerging DBS technologies, (3) ethical issues affecting DBS research and access to care, (4) neuromodulatory approaches for depression, (5) advancing novel hardware, software and imaging methodologies, (6) use of neurophysiological signals in adaptive neurostimulation, and (7) use of more advanced technologies to improve DBS clinical outcomes. There were 178 attendees who participated in a DBS Think Tank survey, which revealed the expansion of DBS into several indications such as obesity, post-traumatic stress disorder, addiction and Alzheimer’s disease. This proceedings summarizes the advances discussed at the Eighth Annual DBS Think Tank

Subcortical-Cortical Network Dynamics in the Human Brain

The cerebral cortex is connected to various subcortical structures such as the thalamus and the basal ganglia (BG). The diffuse yet specific patterns of structural connectivity of the thalamus with the cortex suggest thalamocortical connectivity could play an important role in addressing the binding problem. Previous research has established the presence of BG oscillations and their link to functional and pathological connectivity states to the cortical structures. Considering the topographically organized connections between thalamus, BG and the cortex it has been proposed that disruptions to normal oscillatory activity within the cortico-BG-thalamocortical circuits may partly account for the pathophysiology of Parkinson's disease (PD) . Using simultaneous invasive recordings of cortical and thalamic electrophysiological activity in two awake and spontaneously behaving human subjects, we provide direct evidence of thalamic regulation of cortical activity through a mechanism of phase-amplitude coupling (PAC). Specifically, we show that cortical PAC between the θ phase and β amplitude is spatially dependent on and time variant with the magnitude of thalamocortical θ coherence. Moreover, using causality analysis and MR diffusion tractrography, we provide evidence that thalamic θ activity drives cortical θ oscillations and PAC across structures via structurally constrained pathways..In PD, pathologic oscillatory activity, particularly in the β band, is present in BG and motor cortex. The role of these β oscillations in modulating activity at a network level have not been thoroughly characterized. Using simultaneously recorded cortical and pallidal local field potentials in 20 patients with PD undergoing deep brain stimulation surgery, we confirm increased β activity and β-γ PAC in motor cortical areas. The cortical β band is highly coherent with β activity in the motor region of the GPi where local β-γ and β-(200-300Hz) PAC and cross-site pallido-cortical PAC were observed. Contralateral movement significantly decreased pallido-cortical coherence and PAC as well as local cortical PAC, but did not completely eliminate this coupling, possibly manifesting a deficiency in the diseased BG to disentrain the motor network during action. These results shed light on the dynamic nature of pallidocortical coupling, suggesting β oscillations reverberate through the motor network and modulate activity at a network level