Network connectivity predicts language processing in healthy adults

Brain imaging has been used to predict language skills during development and neuropathology but its accuracy in predicting language performance in healthy adults has been poorly investigated. To address this shortcoming, we studied the ability to predict reading accuracy and single‐word comprehension scores from rest‐ and task‐based functional magnetic resonance imaging (fMRI) datasets of 424 healthy adults. Using connectome‐based predictive modeling, we identified functional brain networks with >400 edges that predicted language scores and were reproducible in independent data sets. To simplify these complex models we identified the overlapping edges derived from the three task‐fMRI sessions (language, working memory, and motor tasks), and found 12 edges for reading recognition and 11 edges for vocabulary comprehension that accounted for 20% of the variance of these scores, both in the training sample and in the independent sample. The overlapping edges predominantly emanated from language areas within the frontoparietal and default‐mode networks, with a strong precuneus prominence. These findings identify a small subset of edges that accounted for a significant fraction of the variance in language performance that might serve as neuromarkers for neuromodulation interventions to improve language performance or for presurgical planning to minimize language impairments.     

Immediate loading of implants placed with the osteotome technique: one-year prospective case series

Background: There is limited information regarding marginal bone‐level changes around immediately loaded implants placed with the osteotome technique. The aim of this case series is to prospectively evaluate the clinical and radiographic outcome of immediately loaded implants placed with the osteotome technique over a 12‐month period. Methods: Eighteen patients in need of oral prosthetic rehabilitation that included single implant placement in positions #4 to #13 and/or #20 to #29 participated in this prospective trial. A modified implant installation procedure with an under preparation of the implant bed using the osteotome technique and immediate loading of the implant was performed. Clinical examinations were performed at 2 weeks, 6 months, and 12 months of follow‐up. Radiographic examinations were performed at implant installation and at the 6‐ and 12‐month follow‐up visits. Results: One implant failed to integrate and was removed at 3 months after implant installation. Four of 20 implants had insertion torque value >35 Ncm. The mean marginal bone loss was ‐0.09 mm at the 6‐month and ‐0.19 mm at the 12‐month follow‐up visits. Conclusion: The present case series indicates that implants placed with the osteotome technique and immediately loaded did not demonstrate a high insertion torque and exhibited minimal marginal bone loss.     

Full-mouth ultrasonic debridement and risk of disease recurrence: a 1-year follow-up

AIM: To evaluate the incidence of disease recurrence following a full-mouth pocket/root debridement approach with ultrasonic instrumentation versus that following a traditional approach of quadrant-wise scaling and root planing (Q-SRP) performed with hand instrumentation. METHODS: Thirty-seven patients were re-examined 1 year after the completion of a 6-month clinical trial comparing two different treatment protocols: a 1-h session of full-mouth ultrasonic debridement (UD--19 patients) or four sessions of Q-SRP with hand instruments (Q-SRP--18 patients). At 3 months, re-instrumentation was performed of pockets showing a remaining probing pocket depth (PPD) of > or =5 mm using the same type of instruments as used during the initial treatment phase. The clinical examinations comprised assessments of plaque, bleeding on probing (BoP) and PPD. The primary outcome variable was the incidence of recurrent diseased sites (i.e., sites showing PPD > or =5 mm and BoP+) between the post-treatment and 1-year follow-up examinations. All sites that were healed (PPD < or =4 mm and BoP(-)) at the post-treatment examination were included in the study sample, with a mean number of sites per patient of 23.5. RESULTS: In the UD group, 29 (7%) out of 430 initially healed sites showed disease recurrence at the 1-year follow-up examination compared with 47 (11%) of 440 sites in the Q-SRP group (p>0.05). Twelve patients (63%) in the UD group presented recurrent diseased pockets, compared with 14 patients (78%) in the Q-SRP group. Two or more recurrent, diseased pockets were observed in nine patients in the UD group versus 11 in the Q-SRP group. All but one of the smokers belonged to the group of patients presenting recurrences. A tendency towards a higher mean plaque score was observed for the patients with recurrent sites. CONCLUSION: The study revealed no significant difference in the incidence of recurrence of diseased periodontal pockets between the full-mouth UD approach and the traditional approach of Q-SRP.     

Balanced modulation of striatal activation from D2/D3 receptors in caudate and ventral striatum: Disruption in cannabis abusers

Proper communication between dorsal caudate (CD) and ventral striatum (VS) is likely to be crucial for on‐time responses and its disruption might result in impulsivity. Here, we used functional magnetic resonance imaging (fMRI) with a sensorimotor reaction time task and positron emission tomography (PET) with [¹¹C]raclopride in 14 healthy controls and 18 cannabis abusers to contrast the modulation of striatal fMRI responses by dopamine receptors (D₂/D₃R) in CD and VS. In controls, we show that the fMRI signals in VS that occurs concomitantly with on‐time responses showed opposite modulation from D₂/D₃R in CD (inhibitory) and D₂/D₃R in VS (stimulatory). In contrast, this modulation was not significant in cannabis abusers. Findings suggest that action speed requires balanced VS‐inhibition from D₂/D₃R in CD and VS‐facilitation from D₂/D₃R in VS. Hum Brain Mapp 36:3154–3166, 2015. © 2015 Wiley Periodicals, Inc.     

Methylphenidate enhances brain activation and deactivation responses to visual attention and working memory tasks in healthy controls

Methylphenidate (MPH) is a stimulant drug that amplifies dopamineric and noradrenergic signaling in the brain, which is believed to underlie its cognition enhancing effects. However, the neurobiological effects by which MPH improves cognition are still poorly understood. Here, functional magnetic resonance imaging (fMRI) was used together with working memory (WM) and visual attention (VA) tasks to test the hypothesis that 20mg oral MPH would increase activation in the dorsal attention network (DAN) and deactivation in the default mode network (DMN) as well as improve performance during cognitive tasks in healthy men. The group of subjects that received MPH (MPH group; N=16) had higher activation than the group of subjects who received no medication (control group: N=16) in DAN regions (parietal and prefrontal cortex, regions increasingly activated with increased cognitive load) and had increased deactivation in the insula and posterior cingulate cortex (regions increasingly deactivated with increased cognitive load) and these effects did not differ for the VA and the WM tasks. These findings provide the first evidence that MPH enhances activation of the DAN whereas it alters DMN deactivation. This suggests that MPH (presumably by amplifying dopamine and noradrenergic signaling) modulates cognition in part through its effects on DAN and DMN.